2021/12/25 更新

写真a

カドタ イサオ
門田 功
KADOTA Isao
所属
自然科学学域 教授
職名
教授
外部リンク

学位

  • 博士(理学) ( 1993年3月   東北大学 )

研究キーワード

  • Synthetic Organic Chemistry

  • 有機金属化合物

  • 天然有機化合物

  • 有機合成化学

  • Organometalics

  • Natural Product

研究分野

  • ナノテク・材料 / 有機合成化学

学歴

  • 東北大学   Graduate School of Science  

    1990年4月 - 1993年3月

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  • 高知大学   大学院理学研究科   化学専攻

    1988年4月 - 1990年3月

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  • 高知大学   理学部   化学科

    1984年4月 - 1988年3月

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経歴

  • 岡山大学   大学院自然科学研究科   教授

    2006年8月 - 現在

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  • 東北大学   Graduate School of Science

    2004年4月 - 2006年7月

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  • 東北大学   Institute of Multidisciplinary Research for Advanced Materials

    2001年 - 2004年

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  • カリフォルニア大学アーバイン校 客員研究員

    1999年 - 2000年

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  • 東北大学反応化学研究所 講師

    1996年 - 2001年

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  • 東北大学   Faculty of Science

    1993年 - 1996年

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  • 日本学術振興会特別研究員(東北大学)

    1992年 - 1993年

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▼全件表示

所属学協会

委員歴

  • 岡山大学   自然系大学院改組・学位プログラム化検討委員  

    2021年4月 - 現在   

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  • 岡山大学   理学部広報委員  

    2021年4月 - 2023年3月   

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  • 岡山大学   教養教育科目自然部会委員  

    2020年4月 - 現在   

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  • 岡山大学   グローバル人材育成院ASEAN拠点事業統括マネージャー  

    2020年4月 - 現在   

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  • 岡山大学   理学部教務委員  

    2020年4月 - 2022年3月   

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  • 岡山大学   個別試験問題作成委員  

    2020年4月 - 2021年3月   

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  • 日本化学会中国四国支部   化学教育協議会委員長  

    2020年3月 - 2022年2月   

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  • 岡山大学   研究推進委員会委員  

    2018年4月 - 現在   

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  • 岡山大学   グローバル人材育成院副院長(派遣・受け入れ担当)  

    2018年4月 - 2020年3月   

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  • 日本化学会中国四国支部   化学教育協議会副委員長  

    2018年3月 - 2020年2月   

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  • 日本化学会中国四国支部   地区幹事  

    2016年3月 - 2018年2月   

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  • 文部科学省   学術調査官  

    2009年4月 - 2011年3月   

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▼全件表示

 

論文

  • Chemical Synthesis and Biological Effect on Xylem Formation of Xylemin and Its Analogues 査読

    Hiroyoshi Takamura, Hiroyasu Motose, Taichi Otsu, Shiori Shinohara, Ryugo Kouno, Isao Kadota, Taku Takahashi

    European Journal of Organic Chemistry   2020 ( 18 )   2745 - 2753   2020年5月

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    掲載種別:研究論文(学術雑誌)   出版者・発行元:Wiley  

    DOI: 10.1002/ejoc.202000322

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    その他リンク: http://onlinelibrary.wiley.com/wol1/doi/10.1002/ejoc.202000322/fullpdf

  • Stereocontrolled synthesis of the macrolactone core of neopeltolide 査読

    Andreas Meissner, Nobuhiro Tanaka, Hiroyoshi Takamura, Isao Kadota

    Tetrahedron Letters   60 ( 5 )   432 - 434   2019年1月

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    掲載種別:研究論文(学術雑誌)   出版者・発行元:Elsevier BV  

    DOI: 10.1016/j.tetlet.2018.12.066

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  • Unified Total Synthesis, Stereostructural Elucidation, and Biological Evaluation of Sarcophytonolides 査読

    Takamura, Hiroyoshi, Kikuchi, Takahiro, Iwamoto, Kohei, Nakao, Eiji, Harada, Naoki, Otsu, Taichi, Endo, Noriyuki, Fukuda, Yuji, Ohno, Osamu, Suenaga, Kiyotake, Guo, Yue-Wei, Kadota, Isao

    Journal of Organic Chemistry   83 ( 18 )   11028 - 11056   2018年9月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1021/acs.joc.8b01634

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  • Improved Synthesis of the A–E Ring Segment of Ciguatoxin CTX3C by Using Intramolecular Allylations 査読

    Tokihiro Tanaka, Hiroki Asakura, Rie Fujiwara, Kentaro Kumamoto, Hiroaki Izuka, Kengo Shiroma, Hiroyoshi Takamura, Isao Kadota

    Bulletin of the Chemical Society of Japan   91 ( 4 )   507 - 514   2018年4月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:The Chemical Society of Japan  

    An improved synthesis of the AE ring segment of ciguatoxin CTX3C is described. The E ring segment was synthesized by the intramolecular reaction of allylic stannane and aldehyde with high stereoselectivity. Construction of the AE ring framework was performed by using the intramolecular allylation of α-acetoxy ether followed by ring-closing metathesis.

    DOI: 10.1246/bcsj.20170390

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  • Convergent total synthesis of (−)-dactylolide 査読

    Tokihiro Tanaka, Yuto Murai, Takayuki Kishi, Hiroyoshi Takamura, Isao Kadota

    Tetrahedron Letters   59 ( 8 )   763 - 766   2018年2月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Elsevier BV  

    A convergent total synthesis of (−)-dactylolide is described. Constructing the 2,6-disubstituted exo-methylene THP moiety was achieved by the intramolecular allylation of α-acetoxy ether. The cyclization precursor was prepared from two segments, an alcohol and carboxylic acid derivatives, by esterification followed by reductive acetylation.

    DOI: 10.1016/j.tetlet.2018.01.034

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  • Total Synthesis of Two Possible Diastereomers of Natural 6-Chlorotetrahydrofuran Acetogenin and Its Stereostructural Elucidation 査読

    Hiroyoshi Takamura, Tomoya Katsube, Kazuki Okamoto, Isao Kadota

    Chemistry - A European Journal   23 ( 68 )   17191 - 17194   2017年12月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Wiley-VCH Verlag  

    The first total synthesis of two possible diastereomers of natural 6-chlorotetrahydrofuran acetogenin 1 has been achieved. The synthetic route features 5-exo-tet cyclization, Z selective Wittig reaction and Julia olefination for the construction of conjugated diene and enyne moieties, and stereoselective chlorination. Comparison of their 1H and 13C NMR data and specific rotation with those of the natural product elucidated the absolute configuration of natural (−)-6-chlorotetrahydrofuran acetogenin 1.

    DOI: 10.1002/chem.201703234

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  • Late-stage divergent synthesis and antifouling activity of geraniol-butenolide hybrid molecules 査読

    Hiroyoshi Takamura, Takumi Ohashi, Takahiro Kikuchi, Noriyuki Endo, Yuji Fukuda, Isao Kadota

    Organic and Biomolecular Chemistry   15 ( 26 )   5549 - 5555   2017年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Royal Society of Chemistry  

    Hybrid molecules consisting of geraniol and butenolide were designed and synthesized by the late-stage divergent strategy. In the synthetic route, ring-closing metathesis was utilized for the construction of a butenolide moiety. A biological evaluation of the eight synthetic hybrid compounds revealed that these molecules exhibit antifouling activity against the cypris larvae of the barnacle Balanus (Amphibalanus) amphitrite with EC50 values of 0.30-1.31 μg mL-1. These results show that hybridization of the geraniol and butenolide structural motifs resulted in the enhancement of the antifouling activity.

    DOI: 10.1039/c7ob01160a

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  • Convergent synthesis of the EFGH ring system of ciguatoxin CTX3C 査読

    Isao Kadota, Yuki Sato, Naoya Fujita, Hiroyoshi Takamura, Yoshinori Yamamoto

    TETRAHEDRON   71 ( 37 )   6547 - 6558   2015年9月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    Convergent synthesis of the EFGH ring segment of ciguatoxin CTX3C was investigated by using the intramolecular allylation of an alpha-chloroacetoxy ether and/or O,S-acetal, and subsequent ring-closing metathesis. A new method for the preparation of gamma-alkoxyallylstannane is also described. (C) 2015 Elsevier Ltd. All rights reserved.

    DOI: 10.1016/j.tet.2015.04.106

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  • STEREOCONTROLLED SYNTHESIS OF THE C1-C7 FRAGMENT OF ENIGMAZOLE A 査読

    Takayuki Kishi, Yuka Fujisawa, Hiroyoshi Takamura, Isao Kadota

    HETEROCYCLES   89 ( 2 )   515 - 522   2014年2月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    An enantio- and stereoselective synthesis of the C1-C7 fragment of enigmazole A is described. The three asymmetric centers of the molecule were constructed efficiently by using Evans chiral auxiliary protocol.

    DOI: 10.3987/COM-13-12905

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  • IMPROVDED SYNTHESIS OF THE A-E RING SEGMENT OF CIGUATOXIN CTX3C 査読

    Kengo Shiroma, Hiroki Asakura, Tokihiro Tanaka, Hiroyoshi Takamura, Isao Kadota

    HETEROCYCLES   88 ( 2 )   969 - 973   2014年1月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    The improved synthesis of the A-E ring segment of ciguatoxin CTX3C was performed via a highly convergent approach based on intramolecular allylation-RCM methodology.

    DOI: 10.3987/COM-13-S(S)106

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  • Total synthesis, structural elucidation, and structure-cytotoxic activity relationship of (-)-gummiferol 査読

    Takamura Hiroyoshi, Wada Hiroko, Lu Nan, Ohno Osamu, Suenaga Kiyotake, Kadota Isao

    Journal of Organic Chemistry   78 ( 6 )   2443 - 2454   2013年3月

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    記述言語:英語  

    <p>A highly stereoselective and stereodivergent synthesis of two possible diastereomers of (-)-gummiferol was achieved, wherein the stepwise epoxidation and Cadiot-Chodkiewicz reaction were utilized for the construction of the diepoxide moiety and triacetylene part, respectively. Detailed comparison of their <sup>1</sup>H and <sup>13</sup>C NMR data and specific rotation with those of the natural product unambiguously elucidated the absolute stereostructure of gummiferol. In addition, the cytotoxic activity of the synthesized gummiferol, its stereoisomers, and its truncated analogues was evaluated, which clearly indicates that (1) the absolute configuration of the diepoxide moiety has little influence on the cytotoxic activity against human cancer cells and (2) the triacetylene unit is the crucial structural element required for exerting the cytotoxic activity.</p>

    DOI: 10.1021/jo302665c

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  • SYNTHESIS OF THE E RING SEGMENT OF CIGUATOXIN CTX3C VIA THE NEGISHI COUPLING OF CYCLIC KETENE ACETAL TRIFLATES 査読

    Kengo Shiroma, Hiroyoshi Takamura, Isao Kadota

    HETEROCYCLES   86 ( 2 )   997 - 1001   2012年12月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    Stereocontrolled synthesis of the E ring segment of ciguatoxin CTX3C was performed via the Negishi coupling of cyclic ketene acetal triflates. Transformation of 8-membered lactones to the corresponding ketene acetal triflates was found to be affected by the protective groups of the substrates.

    DOI: 10.3987/COM-12-S(N)117

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  • Stereoselective synthesis of the C94-C104 fragment of symbiodinolide 査読

    Hiroyoshi Takamura, Kosuke Tsuda, Yohei Kawakubo, Isao Kadota, Daisuke Uemura

    Tetrahedron Letters   53 ( 33 )   4317 - 4319   2012年8月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Stereoselective synthesis of the C94-C104 fragment of symbiodinolide which is a polyol marine natural product with a molecular weight of 2860 has been accomplished. The synthetic route features Achmatowicz rearrangement and RuO 4-catalyzed dihydroxylation for the construction of the tetrahydropyran moiety and the dithiane addition to the aldehyde for the introduction of the side chain. © 2012 Elsevier Ltd. All rights reserved.

    DOI: 10.1016/j.tetlet.2012.06.005

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  • A convergent synthesis of the right-hand fragment of ciguatoxin CTX3C 査読

    Hiroyoshi Takamura, Takashi Abe, Naoki Nishiuma, Rie Fujiwara, Takahiko Tsukeshiba, Isao Kadota

    TETRAHEDRON   68 ( 10 )   2245 - 2260   2012年3月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    A convergent synthesis of the right-hand fragment of ciguatoxin CTX3C was investigated. The first and second generation stereocontrolled syntheses of the LM ring fragment were achieved via spiroacetalization as a key step, respectively. The polyether framework of the HIJKLM ring fragment was constructed in a convergent manner by using intramolecular allylation, ring-closing metathesis, and stereoselective hydrogenation to form the 36-methyl substituent as the key transformations. (C) 2012 Elsevier Ltd. All rights reserved.

    DOI: 10.1016/j.tet.2012.01.071

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  • Convergent Synthesis of the HIJKLM Ring System of Ciguatoxin CTX3C 査読

    Hiroyoshi Takamura, Naoki Nishiuma, Takashi Abe, Isao Kadota

    ORGANIC LETTERS   13 ( 17 )   4704 - 4707   2011年9月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:AMER CHEMICAL SOC  

    The HIJKLM ring system of ciguatozin CTX3C was synthesized in a convergent manner. The key steps were a conjugate addition/alkylation sequence, spiroacetalization, intramolecular allylation, ring-closing metathesis, and hydrogenation to form the 36-alpha-methyl substituent.

    DOI: 10.1021/ol2019136

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  • Total synthesis and absolute configuration of (-)-gummiferol 査読

    Hiroyoshi Takamura, Hiroko Wada, Nan Lu, Isao Kadota

    Organic Letters   13 ( 14 )   3644 - 3647   2011年7月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Stereoselective synthesis of two possible diastereomers of (-)-gummiferol was accomplished by the stepwise epoxidation and Cadiot-Chodkiewicz reaction as the key transformations. Detailed comparison of their 1H and 13C NMR data and specific rotation with those of the natural product led to the absolute structural elucidation of (-)-gummiferol. © 2011 American Chemical Society.

    DOI: 10.1021/ol201301b

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  • Stereocontrolled synthesis and structural confirmation of the C14 - C24 degraded fragment of symbiodinolide 査読

    Hiroyoshi Takamura, Yuichiro Kadonaga, Isao Kadota, Daisuke Uemura

    Tetrahedron   66 ( 38 )   7569 - 7576   2010年9月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    The C14-C24 fragment of symbiodinolide possessing the 17R/18R/21R absolute configuration, which was obtained as one of the degraded products of symbiodinolide, and its diastereomer possessing the 17R/18S/21R absolute stereochemistry were synthesized stereoselectively from cis-2-butene-1,4-diol, respectively. The detailed comparison of the synthetic products with the degraded product in the spectroscopic data confirmed unambiguously that the stereostructure of the C14 - C24 fragment was 17R, 18R, and 21R. © 2010 Elsevier Ltd. All rights reserved.

    DOI: 10.1016/j.tet.2010.07.045

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  • A new method for the stereoselective construction of angular methyl group of fuzed cyclic ethers 査読

    Isao Kadota, Takayuki Kishi, Yuka Fujisawa, Yuji Yamagami, Hiroyoshi Takamura

    TETRAHEDRON LETTERS   51 ( 30 )   3960 - 3961   2010年7月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    A convenient method for the stereoselective construction of angular methyl group of fuzed cyclic ethers is described. Reactions of mixed thioacetals with Me(2)Zn/Zn(OTO)(2) afforded the corresponding methylated products in good yields. Various protective groups such as MOM ether, benzylidene acetal, TBS ether, and pivaloyl group were stable under the reaction conditions. (C) 2010 Elsevier Ltd. All rights reserved.

    DOI: 10.1016/j.tetlet.2010.05.109

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  • Total synthesis of brevenal 査読

    Hiroyoshi Takamura, Yuji Yamagami, Takayuki Kishi, Shigetoshi Kikuchi, Yuichi Nakamura, Isao Kadota, Yoshinori Yamamoto

    TETRAHEDRON   66 ( 29 )   5329 - 5344   2010年7月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    The convergent total synthesis of brevenal, a non-toxic brevetoxin antagonist, has been achieved. The ABC ring segment and the E ring precursor were connected by the intramolecular allylation followed by ring-closing metathesis to furnish the pentacyclic ether compound. An alternative route to the key synthetic intermediate, a pentacyclic ether core, was also examined. The right- and left-hand side chains were introduced by Wittig and Horner-Wadsworth-Emmons reactions, respectively, to furnish brevenal (1). (C) 2010 Elsevier Ltd. All rights reserved.

    DOI: 10.1016/j.tet.2010.05.069

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  • Stereoselective synthesis of the C14-C24 degraded fragment of symbiodinolide 査読

    Hiroyoshi Takamura, Yuichiro Kadonaga, Isao Kadota, Daisuke Uemura

    TETRAHEDRON LETTERS   51 ( 19 )   2603 - 2605   2010年5月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    Symbiodinolide is a polyol macrolide isolated from the marine dinoflagellate Symbiodinium sp. in 2007. The C14-C24 fragment of symbiodinolide possessing the 17R/18R/21R absolute configuration, which was obtained as one of the degraded products of symbiodinolide, was synthesized stereoselectively from cis-2-butene-1,4-diol. The detailed comparison of the synthetic product with the degraded product in the spectroscopic data confirmed that the stereostructure of the C14-C24 fragment was 17R, 18R, and 21R. (C) 2010 Elsevier Ltd. All rights reserved.

    DOI: 10.1016/j.tetlet.2010.03.014

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  • 38 ブレベナールの全合成(口頭発表の部)

    山神 雄司, 菊池 重俊, 中村 祐一, 岸 敬之, 高村 浩由, 門田 功, 山本 嘉則

    天然有機化合物討論会講演要旨集   ( 51 )   223 - 228   2009年9月

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    記述言語:日本語   出版者・発行元:天然有機化合物討論会  

    Brevenal (1), a new family of marine polycyclic ether, was isolated from the Florida red tide dinoflagellate Karenia brevis by Baden and co-workers in 2004. This compound inhibits the binding of tritiated dihydrobrebetoxin-B to the voltage-sensitive sodium channels in a concentration dependent manner and acts as a nontoxic brevetoxin antagonist. Moreover, a significiant improvement of tracheal mucus velocity was observed in an animal model asthma. As well as the novel biological activities, the unique structural features have attracted attention of synthetic chemists. In 2006, the first total synthesis and structure revision of 1 were reported by Sasaki and co-workers. In this paper, we wish to report eht recent results and our efforts on the total synthesis of brevenal (1). The ABC ring segment 3 was prepared from the known compound 7 the B-alkyl Suzuki-Miyahara coupling of the phosphate 11 and the alkylborate from the iodine 5. Direct methylation of the O,S-acetal 16 was performed by using Me_2Zn/Zn(OTf)_2 in highly stereoselective manner. The ABC ring fragment obtained and the known alchol 4 were connected by our own synthetic strategy including the intramolecular allylation of α-acetoxy ether followed by ring-closing metathesis to furnish the pentacyclic ether 2. The right hand diene was introduced by the Nicolaoua's protocol. Construction of the left hand side chain, highly substituted dienyl moiety, was archieved by the modified Horner-Wadsworth-Emmons reaction with the phosphonate 33, newly developed, to afford the dienyl ether 34 as the sole product. A seris of functional transformation and deprotections of 34 furnished brevenal (1). The synthetic 1 exhiibited physical and spectroscopic data identical to those reported previously.

    DOI: 10.24496/tennenyuki.51.0_223

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  • Stereoselective synthesis and absolute configuration of the C33-C42 fragment of symbiodinolide 査読

    Hiroyoshi Takamura, Yuichiro Kadonaga, Yoshi Yamano, Chunguang Han, Isao Kadota, Daisuke Uemura

    TETRAHEDRON   65 ( 36 )   7449 - 7456   2009年9月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    Cross-metathesis of methyl ester which was prepared from symbiodinolide with ethylene was performed to give the C33-C42 degraded fragment. This fragment was estimated to be (36S,40S)-diol by the modified Mosher method. Stereoselective synthesis of the (36S,40S)-diol and its diastereomer (36R,40S)-diol was achieved from L-aspartic acid. Synthetic bis-(S)- and (R)-MTPA esters which were derivatized from the (36S,40S)-diol exhibited spectroscopic data identical with those of bis-(S)- and (R)-MTPA esters derived from the degraded product. Thus, the absolute stereochemistry of the C33-C42 fragment was elucidated to be (36S,40S). (C) 2009 Elsevier Ltd. All rights reserved.

    DOI: 10.1016/j.tet.2009.07.019

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  • Stereoselective Synthesis and Absolute Configuration of the C1 '-C25 ' Fragment of Symbiodinolide 査読

    Hiroyoshi Takamura, Takeshi Murata, Takahiro Asai, Isao Kadota, Daisuke Uemura

    JOURNAL OF ORGANIC CHEMISTRY   74 ( 17 )   6658 - 6666   2009年9月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:AMER CHEMICAL SOC  

    Stereoselective synthesis of the C1'-C25' fragment of symbiodinolide, which was obtained as a degraded product from symbiodinolide by alkaline hydrolysis, has been accomplished. The synthetic route features Kotsuki coupling and Julia-Kocienski olefination in the introduction of the side chains. This enantio-and stereoselective synthesis has established the absolute configuration of the C1'-C25' fragment.

    DOI: 10.1021/jo901162v

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  • Convergent synthesis of the A-E ring segment of ciguatoxin CTX3C 査読

    Isao Kadota, Takashi Abe, Miyuki Uni, Hiroyoshi Takamura, Yoshinori Yamamoto

    TETRAHEDRON   65 ( 37 )   7784 - 7789   2009年9月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    A convergent synthesis of the A-E ring segment of ciguatoxin CTX3C was achieved via the intramolecular allylation of an alpha-chloroacetoxy ether and subsequent ring-closing metathesis. (C) 2009 Elsevier Ltd. All rights reserved.

    DOI: 10.1016/j.tet.2009.07.037

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  • Selective cleavage of primary MPM ethers with TMSI/Et3N 査読

    Isao Kadota, Yuji Yamagami, Naoya Fujita, Hiroyoshi Takamura

    TETRAHEDRON LETTERS   50 ( 31 )   4552 - 4553   2009年8月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    A useful method for the selective cleavage of primary MPM ethers by using TMSI/Et3N is described. Other protective groups such as secondary MPM ethers, silyl ethers, and benzylidene acetal were stable under the reaction conditions. (C) 2009 Elsevier Ltd. Ail rights reserved.

    DOI: 10.1016/j.tetlet.2009.05.084

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  • Synthesis and structural revision of symbiodinolide C23-C34 fragment 査読

    Takeshi Murata, Masayuki Sano, Hiroyoshi Takamura, Isao Kadota, Daisuke Uemura

    Journal of Organic Chemistry   74 ( 13 )   4797 - 4803   2009年7月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    (Chemical Equation Presented) Stereoselective synthesis of the C23-C34 fragment of symbiodinolide, which possesses the originally proposed stereochemistry, and its diastereomers was achieved in 19 steps from L-aspartic acid, respectively. Comparison of spectroscopic data of the synthetic products with those of the degraded product of symbiodinolide led to a structural revision of the C23-C34 fragment. © 2009 American Chemical Society.

    DOI: 10.1021/jo900546k

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  • Total Synthesis of Brevenal 査読

    Hiroyoshi Takamura, Shigetoshi Kikuchi, Yuichi Nakamura, Yuji Yamagami, Takayuki Kishi, Isao Kadota, Yoshinori Yamamoto

    ORGANIC LETTERS   11 ( 12 )   2531 - 2534   2009年6月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:AMER CHEMICAL SOC  

    A total synthesis of brevenal is described. The pentacyclic ether core was constructed by the intramolecular allylation of alpha-acetoxy ether and subsequent ring-closing metathesis. Both of the diene side chains were introduced by Wittig olefination and a Horner-Wadsworth-Emmons reaction, respectively, in a highly stereoselective manner.

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  • Synthesis and structural determination of the C33-C42 fragment of symbiodinolide 査読

    Hiroyoshi Takamura, Yuichiro Kadonaga, Yoshi Yamano, Chunguang Han, Yoko Aoyama, Isao Kadota, Daisuke Uemura

    Tetrahedron Letters   50 ( 8 )   863 - 866   2009年2月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Symbiodinolide (1) is a polyol macrolide with a molecular weight of 2859 mu. As one of the degradation reactions, cross-metathesis of 2, which is a methyl ester of 1, with ethylene was performed to give the C33-C42 degraded fragment 4. The absolute configuration of 4 was estimated to be (36S,40S) by Mosher method. Stereoselective synthesis of 4 was achieved in 14 steps from l-aspartic acid. Synthetic bis-(S)- and (R)-MTPA esters exhibited the spectroscopic data identical with those of bis-(S)- and (R)-MTPA esters derived from the degraded fragment 4. Thus, the absolute stereochemistry of 4 was elucidated to be (36S,40S). © 2009.

    DOI: 10.1016/j.tetlet.2008.11.056

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  • A TRANSANNULAR DIELS-ALDER STRATEGY TO THE CONSTRUCTION OF THE CDE RING SYSTEM OF NAKITERPIOSIN 査読

    Hiroyoshi Takamura, Yuji Yamagami, Tomonori Ito, Masahiro Ito, Hirokazu Arimoto, Isao Kadota, Daisuke Uemura

    HETEROCYCLES   77 ( 1 )   351 - 364   2009年1月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    The transannular Diels-Alder (TADA) reaction was applied to the synthesis of the CDE ring system of nakiterpiosin (1). TADA product 28 is a key intermediate toward the total synthesis of 1.

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  • Stereocontrolled synthesis of the C79-C96 fragment of symbiodinolide 査読

    Hiroyoshi Takamura, Junki Ando, Takashi Abe, Takeshi Murata, Isao Kadota, Daisuke Uemura

    TETRAHEDRON LETTERS   49 ( 31 )   4626 - 4629   2008年7月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    The stereoselective synthesis of the C79-C96 fragment of symbiodinolide is described in which the spiroacetalization and Kotsuki coupling are the key steps. (c) 2008 Elsevier Ltd. All rights reserved.

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  • A cross-metathesis approach to the stereocontrolled synthesis of the AB ring segment of ciguatoxin 査読

    Isao Kadota, Takashi Abe, Miyuki Uni, Hiroyoshi Takamura, Yoshinori Yamamoto

    TETRAHEDRON LETTERS   49 ( 22 )   3643 - 3647   2008年5月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    Synthesis of the AB ring segments of ciguatoxin is described. The present synthesis includes a Lewis acid mediated cyclization of allylstannane with aldehyde, cross-metathesis reaction introducing the side chain, and Grieco-Nishizawa dehydration on the A ring. (C) 2008 Elsevier Ltd. All rights reserved.

    DOI: 10.1016/j.tetlet.2008.03.145

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  • Solvent-controlled stereoselective formation of a cyclic ether in the lewis acid-mediated allylation of an alpha-Chloroacetoxy acyclic ether. Very high stereoselectivity in CH3CN vs low stereoselectivity in CH2Cl2 査読

    Ilya D. Gridnev, Shigetoshi Kikuchi, Abeda S. Touchy, Isao Kadota, Yoshinori Yamamoto

    JOURNAL OF ORGANIC CHEMISTRY   72 ( 22 )   8371 - 8375   2007年10月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:AMER CHEMICAL SOC  

    The MgBr2-OEt2-mediated intramolecular allylation of a 4:1 diastereoisomeric mixture of the alpha-chloroacetoxyl ether la bearing the A-G/JK ring system of brevetoxin B in CH2Cl2 gave a 1: 1 diastereoisomeric mixture of the trans- and cis-cyclization products 4a and 5a having the A-G/I-K ring system, while that in CH3CN afforded the trans-isomer 4a nearly as the single product. To help clarify a reason for this marked solvent effect in the cyclization of the brevetoxin B precursor, DFT computations for the starting materials, intermediates, transition states, and products were carried out. The cyclization would proceed through a carbocation intermediate 3a having sp(2) flat structure (S(N)1 type mechanism) in CH2Cl2, in which the activation energies leading to both diastereoisomers are approximately identical, while in CH3CN alkylnitrilium salts 6a would be formed through the coordination of CH3CN to the carbocation leading to an sp(3)-type intermediate in which sever steric hindrance takes place in the transition state leading to the undesired diastereoisomer. The scope of this novel solvent-controlled stereo selectivity was tested for simple compounds. In small model compounds the marked solvent dependence was absent, but the model bearing two consecutive cyclic ether rings 1b exhibited a remarkable solvent effect similar to that observed in the brevetoxin B system.

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  • A convergent approach to the formal total synthesis of hemibrevetoxin B 査読

    Isao Kadota, Takashi Abe, Yukako Ishitsuka, Abeda S. Touchy, Ryoko Nagata, Yoshinori Yamamoto

    TETRAHEDRON LETTERS   48 ( 2 )   219 - 221   2007年1月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    A convergent synthesis of the key synthetic intermediate of hemibrevetoxin B was achieved via the intramolecular allylation of an alpha-chloroacetoxy ether and subsequent ring-closing metathesis. (c) 2006 Elsevier Ltd. All rights reserved.

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  • Formal total synthesis of hemibrevetoxin B via the intramolecular allylation followed by ring-closing metathesis 査読

    Isao Kadota, Takashi Abe, Yukako Ishitsuka, Abeda S. Touch, Ryoko Nagata, Yoshinori Yamamoto

    HETEROCYCLES   74   617 - 627   2007年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    A formal total synthesis of hemibrevetoxin B (1) is described. Intramolecular allylation of alpha-chloroacetoxy ether 10, prepared from carboxylic acid 11 and alcohol 12, was carried out with MgBr2 center dot OEt2 to give 27. Ring-closing metathesis of 27 furnished tetracycle 29, which was converted to a known synthetic intermediate 9, to complete a formal total synthesis of 1.

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  • Stereocontrolled synthesis of the IJK ring segment of yessotoxin 査読

    Isao Kadota, Takashi Abe, Yuki Sato, Chizuko Kabuto, Yoshinori Yamamoto

    TETRAHEDRON LETTERS   47 ( 37 )   6545 - 6548   2006年9月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    A stereocontrolled synthesis of the IJK ring segment of yessotoxin is described. Cyclization of 11 mediated by SmI2 gave the IJ ring system 12 as the sole product. Construction of the K ring moiety was performed by the acid catalyzed cyclization of epoxy alcohol 20 to afford the IJK ring segment in a highly stereocontrolled manner. (c) 2006 Elsevier Ltd. All rights reserved.

    DOI: 10.1016/j.tetlet.2006.07.027

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  • Improved synthesis of the A-G ring segment of brevetoxin B 査読

    Isao Kadota, Hiroki Nishii, Hiroki Ishioka, Hiroyoshi Takamura, Yoshinori Yamamoto

    JOURNAL OF ORGANIC CHEMISTRY   71 ( 11 )   4183 - 4187   2006年5月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:AMER CHEMICAL SOC  

    An efficient synthesis of the A-G ring segment 2, a key intermediate for the total synthesis of brevetoxin B (1), was achieved in 37 steps and 5.0% overall yield. The intramolecular allylation of the O,S-acetal 22, prepared from the ABC ring segment 15 and the FG ring segment 17, was carried out using AgOTf as a Lewis acid to give the desired compound 23, predominantly. Ring-closing metathesis of 23 with the Grubbs catalyst 12 afforded the heptacyclic ether 25. Selective hydrogenation of the E ring olefin of 25 was performed by diimide reduction to afford 2.

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  • Convergent synthesis of the FGHI ring segment of yessotoxin 査読

    Isao Kadota, Hirokazu Ueno, Yuki Sato, Yoshinori Yamamoto

    Tetrahedron Letters   47 ( 1 )   89 - 92   2006年1月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    A convergent synthesis of the FGHI ring segment of yessotoxin was achieved via the intramolecular allylation of an α-chloroacetoxy ether and subsequent ring-closing metathesis. © 2005 Elsevier Ltd. All rights reserved.

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  • Total synthesis of brevetoxin B 査読

    Kadota, I, H Takamura, H Nishii, Y Yamamoto

    JOURNAL OF THE AMERICAN CHEMICAL SOCIETY   127 ( 25 )   9246 - 9250   2005年6月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:AMER CHEMICAL SOC  

    The convergent total synthesis of brevetoxin B (1) has been achieved. The intramolecular allylation of the 0,S-acetal 20, prepared from the alpha-chlorosulfide 17 and the alcohol 5, was carried out using AgOTf as a Lewis acid to give the diene 21, predominantly. Ring-closing metathesis of 21 with the Grubbs catalyst 23 afforded the hexacyclic ether 25 which was converted to the A-G ring segment 2 through several steps. The intramolecular allylation of the alpha-acetoxy ether 42, prepared from 2 and the J-K ring segment 3, followed by ring-closing metathesis provided the polycyclic ether framework 44. A series of reactions of 44, including oxidation of the A ring, deprotection of the silyl ethers, and selective oxidation of the resulting allylic alcohol, furnished 1.

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  • A convenient and efficient route for the allylation of aromatic amines and alpha-aryl aldehydes with alkynes in the presence of a Pd(O)/PhCOOH combined catalyst system 査読

    NT Patil, HY Wu, Kadota, I, Y Yamamoto

    JOURNAL OF ORGANIC CHEMISTRY   69 ( 25 )   8745 - 8750   2004年12月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:AMER CHEMICAL SOC  

    The allylation of aromatic amines with alkynes proceeded smoothly in the presence of catalytic amounts of Pd(PPh3)(4) and benzoic acid. The allylation products were obtained in high yields in a regio- and stereoselective manner. The effect of various groups on the nitrogen atom of anilines was studied. Regardless of the substituent (electron withdrawing or electron donating) on the aromatic ring, the reaction proceeded well. Various functionalities, including -CH3, -OMe, -Cl, -CN, -COOMe, -NO2 and -COCH3 were tolerated under the reaction conditions. Similarly, the allylation of alpha-aryl aldehydes proceeded well with the same level of regio- and stereoselectivity as the allylation of aromatic amines. This reaction provides the second example of the transition metal catalyzed direct alpha-allylation of aldehydes.

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▼全件表示

MISC

  • 構造解明を指向したポリオール天然物シンビオジノライドの合成研究

    髙村 浩由, 門田 功, 上村 大輔

    有機合成化学協会誌   72 ( 1 )   6 - 17   2014年1月

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    記述言語:日本語   出版者・発行元:有機合成化学協会  

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  • 強力な生理活性を有する大型海洋産天然物の精密合成

    門田 功

    旭硝子財団助成研究成果報告   1 - 4   2013年

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    記述言語:日本語   出版者・発行元:旭硝子財団  

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  • Total synthesis of brevetoxin B

    Isao Kadota, Hiroyoshi Takamura

    JOURNAL OF SYNTHETIC ORGANIC CHEMISTRY JAPAN   65 ( 5 )   430 - 438   2007年5月

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    記述言語:日本語   掲載種別:書評論文,書評,文献紹介等   出版者・発行元:SOC SYNTHETIC ORGANIC CHEM JPN  

    Brevetoxin B was isolated from the red tide organism Karenia brevis in 1981 as the first example of marine polycyclic ethers. This compound shows potent neurotoxicity, by binding to sodium channels, causing massive fish kills and human health problems. Since further biological studies are hampered by the limited availability from nature, chemical synthesis has been the sole realistic way to obtain sufficient amounts of brevetoxin B. Moreover, the huge molecular architecture is a particularly attractive target for synthetic chemists. In this account, we describe the highly convergent total synthesis of brevetoxin B based on our methodology, including intramolecular allylation and subsequent ring-closing metathesis.

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  • Synthetic strategies of marine polycyclic ethers via intramolecular allylations: Linear and convergent approaches

    Kadota, I, Y Yamamoto

    ACCOUNTS OF CHEMICAL RESEARCH   38 ( 5 )   423 - 432   2005年5月

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    記述言語:英語   掲載種別:書評論文,書評,文献紹介等   出版者・発行元:AMER CHEMICAL SOC  

    Strategies for the synthesis of polycyclic ethers based on intramolecular allylations are overviewed. The intramolecular condensation of allylic stannanes and aldehydes is a powerful tool for the synthesis of oxepane derivatives. The reaction is successfully applied to the iterative total synthesis of hernibrevetoxin B (2). Further, the intramolecular allylation of alpha-acetoxy ethers provides an efficient method for the convergent synthesis of polycyclic ethers. The usefulness of the latter strategy is demonstrated in the convergent total synthesis of gambierol (4).

    DOI: 10.1021/ar040118a

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  • A unified approach to polyene macrolides: Synthesis of candidin and nystatin polyols

    Kadota, I, YQ Hu, GK Packard, SD Rychnovsky

    PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA   101 ( 33 )   11992 - 11995   2004年8月

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    記述言語:英語   出版者・発行元:NATL ACAD SCIENCES  

    Polyene macrolide antibiotics are naturally occurring antifungal agents. Members of this class include amphotericin B, which has been used widely to treat systemic fungal infections. A general synthetic strategy has been devised to prepare polyol chains associated with the polyene macrolides. Cyanohydrin acetonide alkylations were used to assemble the carbon skeleton, and a simple modification of the strategy allowed an advanced intermediate to be converted to either the candidin polyol or the nystatin polyol. The candidin polyol was further elaborated to a protected candidin aglycone. This strategy will be applicable to other members of the polyene macrolide natural products.

    DOI: 10.1073/pnas.0401552101

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  • A new approach to the synthesis of cyclic ethers via the intermolecular allylation of alpha-acetoxy ethers and ring-closing metathesis

    Kadota, I, H Uyehara, Y Yamamoto

    TETRAHEDRON   60 ( 34 )   7361 - 7365   2004年8月

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    記述言語:英語   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    A concise synthesis of the isolaurepinnacin skeleton 6 was achieved via the intermolecular allylation of the alpha-acetoxy ether 3 followed by ring-closing metathesis. This methodology was successfully applied to the convergent synthesis of the oxocene 15, an advanced synthetic intermediate for the total synthesis of laurencin. (C) 2004 Elsevier Ltd. All rights reserved.

    DOI: 10.1016/j.tet.2004.05.045

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  • A unified approach to polyene macrolides: Synthesis of candidin and nystatin polyols

    Kadota, I, YQ Hu, GK Packard, SD Rychnovsky

    PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA   101 ( 33 )   11992 - 11995   2004年8月

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    記述言語:英語   出版者・発行元:NATL ACAD SCIENCES  

    Polyene macrolide antibiotics are naturally occurring antifungal agents. Members of this class include amphotericin B, which has been used widely to treat systemic fungal infections. A general synthetic strategy has been devised to prepare polyol chains associated with the polyene macrolides. Cyanohydrin acetonide alkylations were used to assemble the carbon skeleton, and a simple modification of the strategy allowed an advanced intermediate to be converted to either the candidin polyol or the nystatin polyol. The candidin polyol was further elaborated to a protected candidin aglycone. This strategy will be applicable to other members of the polyene macrolide natural products.

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  • A New Approach to the Synthesis of Cyclic Ethers via the Intermolecular Allylation of alpha-Acetoxy Ethers and Ringミclosing Metathesis

    KADOTA I, UYEHARA H, YAMAMOTO Y

    Tetrahedron   60 ( 34 )   7361 - 7365   2004年8月

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  • Allylation of carbon pronucleophiles with alkynes in the presence of palladium/acetic acid catalyst

    NT Patil, Kadota, I, A Shibuya, YS Gyoung, Y Yamamoto

    ADVANCED SYNTHESIS & CATALYSIS   346 ( 7 )   800 - 804   2004年6月

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    記述言語:英語   出版者・発行元:WILEY-V C H VERLAG GMBH  

    We have developed an efficient and ecochemical process for the allylation of carbon pronucleophiles with alkynes. The reaction of alkynes with various active methynes and methylenes in the presence of Pd(PPh3)(4)/acetic acid gave the corresponding allylated products in high yields and high regioselectivities. In the present catalytic system, the key is the use of carboxylic acid which dramatically enhances the rate of the reactions. One of the important features of this process is that neither a leaving group is liberated nor is a stoichiometric amount of base needed to generate the nucleophiles.

    DOI: 10.1002/adsc.200404046

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  • Allylation of carbon pronucleophiles with alkynes in the presence of palladium/acetic acid catalyst

    NT Patil, Kadota, I, A Shibuya, YS Gyoung, Y Yamamoto

    ADVANCED SYNTHESIS & CATALYSIS   346 ( 7 )   800 - 804   2004年6月

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    記述言語:英語   出版者・発行元:WILEY-V C H VERLAG GMBH  

    We have developed an efficient and ecochemical process for the allylation of carbon pronucleophiles with alkynes. The reaction of alkynes with various active methynes and methylenes in the presence of Pd(PPh3)(4)/acetic acid gave the corresponding allylated products in high yields and high regioselectivities. In the present catalytic system, the key is the use of carboxylic acid which dramatically enhances the rate of the reactions. One of the important features of this process is that neither a leaving group is liberated nor is a stoichiometric amount of base needed to generate the nucleophiles.

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  • Palladium-catalyzed intramolecular asymmetric hydroamination of alkynes

    LM Lutete, Kadota, I, Y Yamamoto

    JOURNAL OF THE AMERICAN CHEMICAL SOCIETY   126 ( 6 )   1622 - 1623   2004年2月

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    記述言語:英語   出版者・発行元:AMER CHEMICAL SOC  

    DOI: 10.1021/ja039774g

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  • Palladium-catalyzed intramolecular asymmetric hydroamination of alkynes

    LM Lutete, Kadota, I, Y Yamamoto

    JOURNAL OF THE AMERICAN CHEMICAL SOCIETY   126 ( 6 )   1622 - 1623   2004年2月

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    記述言語:英語   出版者・発行元:AMER CHEMICAL SOC  

    DOI: 10.1021/ja039774g

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  • Convergent synthesis of the A-F ring segment of yessotoxin and adriatoxin

    Isao Kadota, Hirokazu Ueno, Yoshinori Yamamoto

    Tetrahedron Letters   44 ( 50 )   8935 - 8938   2003年12月

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    記述言語:英語   出版者・発行元:Elsevier Ltd  

    A convergent synthesis of the A-F ring segment of yessotoxin and adriatoxin was achieved via the intramolecular allylation of an α-chloroacetoxy ether and subsequent ring-closing metathesis. © 2003 Elsevier Ltd. All rights reserved.

    DOI: 10.1016/j.tetlet.2003.10.010

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  • Convergent synthesis of the A-F ring segment of yessotoxin and adriatoxin

    Kadota, I, H Ueno, Y Yamamoto

    TETRAHEDRON LETTERS   44 ( 50 )   8935 - 8938   2003年12月

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    記述言語:英語   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    A convergent synthesis of the A-F ring segment of yessotoxin and adriatoxin was achieved via the intramolecular allylation of an alpha-chloroacetoxy ether and subsequent ring-closing metathesis. (C) 2003 Elsevier Ltd. All rights reserved.

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  • A simple and practical method for the stereoselective synthesis of (Z)-1-iodo-1-alkenes from 1,1-diiodo-1-alkenes

    Kadota, I, H Ueno, A Ohno, Y Yamamoto

    TETRAHEDRON LETTERS   44 ( 48 )   8645 - 8647   2003年11月

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    記述言語:英語   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    Treatment of the 1,1-diiodo-1-alkenes 8, prepared from the corresponding aldehydes with CI4/PPh3, with Zn-Cu/AcOH in THF-MeOH gave the (Z)-1-iodo-1-alkenes 9, selectively, in good yields. (C) 2003 Elsevier Ltd. All rights reserved.

    DOI: 10.1016/j.tetlet.2003.09.166

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  • A simple and practical method for the stereoselective synthesis of (Z)-1-iodo-1-alkenes from 1,1-diiodo-1-alkenes

    Kadota, I, H Ueno, A Ohno, Y Yamamoto

    TETRAHEDRON LETTERS   44 ( 48 )   8645 - 8647   2003年11月

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    記述言語:英語   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    Treatment of the 1,1-diiodo-1-alkenes 8, prepared from the corresponding aldehydes with CI4/PPh3, with Zn-Cu/AcOH in THF-MeOH gave the (Z)-1-iodo-1-alkenes 9, selectively, in good yields. (C) 2003 Elsevier Ltd. All rights reserved.

    DOI: 10.1016/j.tetlet.2003.09.166

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  • Convergent synthesis of the F-K ring segment of brevetoxin B

    Isao Kadota, Naoko Nishina, Hiroki Nishii, Shigetoshi Kikuchi, Yoshinori Yamamoto

    Tetrahedron Letters   44 ( 43 )   7929 - 7932   2003年10月

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    記述言語:英語   出版者・発行元:Elsevier Ltd  

    A convergent synthesis of the F-K ring segment of brevetoxin B has been achieved via the intramolecular allylation of an α-chloroacetoxy ether and subsequent ring-closing metathesis. © 2003 Elsevier Ltd. All rights reserved.

    DOI: 10.1016/j.tetlet.2003.09.003

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  • Convergent synthesis of the F-K ring segment of brevetoxin B

    Kadota, I, N Nishina, H Nishii, S Kikuchi, Y Yamamoto

    TETRAHEDRON LETTERS   44 ( 43 )   7929 - 7932   2003年10月

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    記述言語:英語   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    A convergent synthesis of the F-K ring segment of brevetoxin B has been achieved via the intramolecular allylation of an alpha-chloroacetoxy ether and subsequent ring-closing metathesis. (C) 2003 Elsevier Ltd. All rights reserved.

    DOI: 10.1016/j.tetlet.2003.09.003

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  • Convergent total syntheses of gambierol and 16-epi-gambierol and their biological activities

    Kadota, I, H Takamura, K Sato, A Ohno, K Matsuda, M Satake, Y Yamamoto

    JOURNAL OF THE AMERICAN CHEMICAL SOCIETY   125 ( 39 )   11893 - 11899   2003年10月

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    記述言語:英語   出版者・発行元:AMER CHEMICAL SOC  

    The convergent total syntheses of gambierol (1) and 16-epi-gambierol (2) have been achieved. The ABC and FGH ring segments 4 and 5 were prepared from known compounds 6 and 13, respectively, by linear manners. The fragments prepared were connected by our own synthetic strategy including the intramolecular allylation of alpha-acetoxy ether followed by ring-closing metathesis to furnish the octacyclic ether 3. The diiodoalkene 45, prepared from 3, was converted to the Z-iodoalkene 50 via a novel and stereoselective hydrogenolysis followed by deprotection. Construction of the triene side chain was performed by the modified Stille coupling of 50 with the Z-vinylic stannane 41 to afford 1. The similar transformations were carried out on the epimeric octacycle 34 to give 2, which showed no toxicity against mice at the concentration of 14 mg/kg.

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  • Convergent total syntheses of gambierol and 16-epi-gambierol and their biological activities

    Kadota, I, H Takamura, K Sato, A Ohno, K Matsuda, M Satake, Y Yamamoto

    JOURNAL OF THE AMERICAN CHEMICAL SOCIETY   125 ( 39 )   11893 - 11899   2003年10月

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    記述言語:英語   出版者・発行元:AMER CHEMICAL SOC  

    The convergent total syntheses of gambierol (1) and 16-epi-gambierol (2) have been achieved. The ABC and FGH ring segments 4 and 5 were prepared from known compounds 6 and 13, respectively, by linear manners. The fragments prepared were connected by our own synthetic strategy including the intramolecular allylation of alpha-acetoxy ether followed by ring-closing metathesis to furnish the octacyclic ether 3. The diiodoalkene 45, prepared from 3, was converted to the Z-iodoalkene 50 via a novel and stereoselective hydrogenolysis followed by deprotection. Construction of the triene side chain was performed by the modified Stille coupling of 50 with the Z-vinylic stannane 41 to afford 1. The similar transformations were carried out on the epimeric octacycle 34 to give 2, which showed no toxicity against mice at the concentration of 14 mg/kg.

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  • Total synthesis of gambierol

    Kadota, I, H Takamura, K Sato, A Ohno, K Matsuda, Y Yamamoto

    JOURNAL OF THE AMERICAN CHEMICAL SOCIETY   125 ( 1 )   46 - 47   2003年1月

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  • Total synthesis of gambierol

    Kadota, I, H Takamura, K Sato, A Ohno, K Matsuda, Y Yamamoto

    JOURNAL OF THE AMERICAN CHEMICAL SOCIETY   125 ( 1 )   46 - 47   2003年1月

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  • Hydroamination of alkynes catalyzed by palladium/benzoic acid

    LM Lutete, Kadota, I, A Shibuya, Y Yamamoto

    HETEROCYCLES   58   347 - 357   2002年11月

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    記述言語:英語   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    The reaction of internal alkynes (1) with amines (2) in the presence of catalytic amount of Pd(PPh3)(4) and benzoic acid in dioxane at 100degreesC gave the allylic amines (3) in good to excellent yields. The intramolecular reaction of alkynes with tethered amino groups (4) gave 2-vinylpyrrolidines and 2-vinylpiperidines (5) in good to excellent yields.

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  • Hydroamination of alkynes catalyzed by palladium/benzoic acid

    LM Lutete, Kadota, I, A Shibuya, Y Yamamoto

    HETEROCYCLES   58   347 - 357   2002年11月

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    記述言語:英語   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    The reaction of internal alkynes (1) with amines (2) in the presence of catalytic amount of Pd(PPh3)(4) and benzoic acid in dioxane at 100degreesC gave the allylic amines (3) in good to excellent yields. The intramolecular reaction of alkynes with tethered amino groups (4) gave 2-vinylpyrrolidines and 2-vinylpiperidines (5) in good to excellent yields.

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  • Concise synthesis of cyclic ethers via the palladium-catalyzed coupling of ketene acetal triflates and organozinc reagents. Application to the iterative synthesis of polycyclic ethers

    Kadota, I, H Takamura, K Sato, Y Yamamoto

    JOURNAL OF ORGANIC CHEMISTRY   67 ( 10 )   3494 - 3498   2002年5月

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    記述言語:英語   出版者・発行元:AMER CHEMICAL SOC  

    The reaction of the ketene acetal triflates 9a-e and a zinc homoenolate 10 in the presence of a catalytic amount of Pd(PPh3)(4) gave the enol ethers 11a-e in good yields. The products were converted to the corresponding cyclic ethers 14a and 14b by hydroboration and lactonization. The present methodology allowed us to synthesize the DE and GH ring segment of gambierol in a concise manner. Iterative syntheses of the polycyclic ethers 26 and 32 are also described.

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  • Concise synthesis of cyclic ethers via the palladium-catalyzed coupling of ketene acetal triflates and organozinc reagents. Application to the iterative synthesis of polycyclic ethers

    Kadota, I, H Takamura, K Sato, Y Yamamoto

    JOURNAL OF ORGANIC CHEMISTRY   67 ( 10 )   3494 - 3498   2002年5月

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    記述言語:英語   出版者・発行元:AMER CHEMICAL SOC  

    The reaction of the ketene acetal triflates 9a-e and a zinc homoenolate 10 in the presence of a catalytic amount of Pd(PPh3)(4) gave the enol ethers 11a-e in good yields. The products were converted to the corresponding cyclic ethers 14a and 14b by hydroboration and lactonization. The present methodology allowed us to synthesize the DE and GH ring segment of gambierol in a concise manner. Iterative syntheses of the polycyclic ethers 26 and 32 are also described.

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  • Convergent synthesis of polycyclic ethers via the intramolecular allylation of alpha-acetoxy ethers and subsequent ring-closing metathesis

    Kadota, I, A Ohno, K Matsuda, Y Yamamoto

    JOURNAL OF THE AMERICAN CHEMICAL SOCIETY   124 ( 14 )   3562 - 3566   2002年4月

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    記述言語:英語   掲載種別:書評論文,書評,文献紹介等   出版者・発行元:AMER CHEMICAL SOC  

    The Lewis acid mediated reaction of a-acetoxy ethers 15-22 gave the corresponding cyclized products 23, 25, 27, 29, 31, 32, 34, and 36 in good yields with high stereoselectivities. Those cyclized products were subjected to ring-closing metathesis to afford the polycyclic ethers 38-42, 44, and 45 in good yields. The usefulness of the present methodology was demonstrated by the convergent synthesis of the CDEF ring system of brevetoxin B (1) and the CDEFG ring system of gambierol (2).

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  • Convergent synthesis of polycyclic ethers via the intramolecular allylation of alpha-acetoxy ethers and subsequent ring-closing metathesis

    Kadota, I, A Ohno, K Matsuda, Y Yamamoto

    JOURNAL OF THE AMERICAN CHEMICAL SOCIETY   124 ( 14 )   3562 - 3566   2002年4月

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    記述言語:英語   掲載種別:書評論文,書評,文献紹介等   出版者・発行元:AMER CHEMICAL SOC  

    The Lewis acid mediated reaction of a-acetoxy ethers 15-22 gave the corresponding cyclized products 23, 25, 27, 29, 31, 32, 34, and 36 in good yields with high stereoselectivities. Those cyclized products were subjected to ring-closing metathesis to afford the polycyclic ethers 38-42, 44, and 45 in good yields. The usefulness of the present methodology was demonstrated by the convergent synthesis of the CDEF ring system of brevetoxin B (1) and the CDEFG ring system of gambierol (2).

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  • Syntheses of the AB and EFGH ring segments of gambierol

    Kadota, I, C Kadowaki, CH Park, H Takamura, K Sato, PWH Chan, S Thorand, Y Yamamoto

    TETRAHEDRON   58 ( 10 )   1799 - 1816   2002年3月

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    記述言語:英語   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    Stereocontrolled syntheses of the AB and EFGH ring systems of gambierol (1) are described. The two key intermediates 3 and 55, representing the AB and EFGH ring frameworks, were prepared from 2-deoxy-D-ribose via linear sequences. Brown's asymmetric allylboration and the intramolecular hetero-Michael reaction were successfully applied to the construction of the A ring moiety. Synthesis of the EFGH ring segment 55 was achieved by the SmI2 mediated reductive cyclization, constructing the EF ring bearing two 1,3-diaxial methyl groups, and the palladium catalyzed coupling of enol triflate and zinc bishomoenolate, making the GH ring moiety. Attempted convergent approaches toward the EFGH ring framework- are also described. (C) 2002 Elsevier Science Ltd. All rights reserved.

    DOI: 10.1016/S0040-4020(02)00039-X

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  • Syntheses of the AB and EFGH ring segments of gambierol

    Kadota, I, C Kadowaki, CH Park, H Takamura, K Sato, PWH Chan, S Thorand, Y Yamamoto

    TETRAHEDRON   58 ( 10 )   1799 - 1816   2002年3月

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    記述言語:英語   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    Stereocontrolled syntheses of the AB and EFGH ring systems of gambierol (1) are described. The two key intermediates 3 and 55, representing the AB and EFGH ring frameworks, were prepared from 2-deoxy-D-ribose via linear sequences. Brown's asymmetric allylboration and the intramolecular hetero-Michael reaction were successfully applied to the construction of the A ring moiety. Synthesis of the EFGH ring segment 55 was achieved by the SmI2 mediated reductive cyclization, constructing the EF ring bearing two 1,3-diaxial methyl groups, and the palladium catalyzed coupling of enol triflate and zinc bishomoenolate, making the GH ring moiety. Attempted convergent approaches toward the EFGH ring framework- are also described. (C) 2002 Elsevier Science Ltd. All rights reserved.

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  • Synthetic studies towards gambierol. Part 1: Synthesis of the AB ring segment

    Isao Kadota, Choul-Hong Park, Kumi Sato, Yoshinori Yamamoto

    Tetrahedron Letters   42 ( 35 )   6195 - 6197   2001年8月

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    The AB ring segment of gambierol (1) was synthesized from 2-deoxy-D-ribose in 23 steps. The key steps were Brown's asymmetric allylboration of the aldehyde 5 and the intramolecular hetero-Michael reaction of 7. © 2001 Elsevier Science Ltd. All rights reserved.

    DOI: 10.1016/S0040-4039(01)01204-7

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  • Synthetic studies towards gambierol. Part 1: Synthesis of the AB ring segment

    Kadota, I, CH Park, K Sato, Y Yamamoto

    TETRAHEDRON LETTERS   42 ( 35 )   6195 - 6197   2001年8月

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    記述言語:英語   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    The AB ring segment of gambierol (1) was synthesized from 2-deoxy-D-ribose in 23 steps. The key steps were Brown's asymmetric allylboration of the aldehyde 5 and the intramolecular hetero-Michael reaction of 7. (C) 2001 Elsevier Science Ltd. All rights reserved.

    DOI: 10.1016/S0040-4039(01)01204-7

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  • Palladium/benzoic acid-catalyzed hydroalkoxylation of alkynes

    Kadota, I, LM Lutete, A Shibuya, Y Yamamoto

    TETRAHEDRON LETTERS   42 ( 35 )   6207 - 6210   2001年8月

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    記述言語:英語   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    The reaction of the internal alkyne 1 with alcohols 2 in the presence of a catalytic amount of Pd(PPh3)(4) and benzoic acid in dioxane at 100 degreesC gave the allylic ethers 3 in good to high yields. The reaction proceeds via the palladium/benzoic acid-catalyzed isomerization of the alkyne 1 to allene 6. followed by the addition of alcohols 2 to the pi -allylpalladium intermediate 7 formed by the hydropalladation of the resulting allene 6. Furthermore. the intramolecular reaction of alkynes having a hydroxy group at the terminus of the carbon chain gave five- and six-membered cyclic ethers in good yields. (C) 2001 Elsevier Science Ltd. All rights reserved.

    DOI: 10.1016/S0040-4039(01)01207-2

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  • Palladium/benzoic acid-catalyzed hydroalkoxylation of alkynes

    Kadota, I, LM Lutete, A Shibuya, Y Yamamoto

    TETRAHEDRON LETTERS   42 ( 35 )   6207 - 6210   2001年8月

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    記述言語:英語   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    The reaction of the internal alkyne 1 with alcohols 2 in the presence of a catalytic amount of Pd(PPh3)(4) and benzoic acid in dioxane at 100 degreesC gave the allylic ethers 3 in good to high yields. The reaction proceeds via the palladium/benzoic acid-catalyzed isomerization of the alkyne 1 to allene 6. followed by the addition of alcohols 2 to the pi -allylpalladium intermediate 7 formed by the hydropalladation of the resulting allene 6. Furthermore. the intramolecular reaction of alkynes having a hydroxy group at the terminus of the carbon chain gave five- and six-membered cyclic ethers in good yields. (C) 2001 Elsevier Science Ltd. All rights reserved.

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  • Synthetic studies towards gambierol. Part 2: Synthesis of the EFGH ring segment

    Kadota, I, C Kadowaki, H Takamura, Y Yamamoto

    TETRAHEDRON LETTERS   42 ( 35 )   6199 - 6202   2001年8月

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    記述言語:英語   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    The EFGH ring segment of gambierol was synthesized from 2-deoxy-D-ribose in 40 steps. The present synthesis includes a SmI2-mediated reductive cyclization and a Pd-catalyzed coupling of enot triflate with a zinc bis-homoenolate as key steps. (C) 2001 Elsevier Science Ltd. All rights reserved.

    DOI: 10.1016/S0040-4039(01)01205-9

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  • Synthetic studies towards gambierol. Part 2: Synthesis of the EFGH ring segment

    Kadota, I, C Kadowaki, H Takamura, Y Yamamoto

    TETRAHEDRON LETTERS   42 ( 35 )   6199 - 6202   2001年8月

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    記述言語:英語   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    The EFGH ring segment of gambierol was synthesized from 2-deoxy-D-ribose in 40 steps. The present synthesis includes a SmI2-mediated reductive cyclization and a Pd-catalyzed coupling of enot triflate with a zinc bis-homoenolate as key steps. (C) 2001 Elsevier Science Ltd. All rights reserved.

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  • Convergent synthesis of polycyclic ethers via the intramolecular allylation of alpha-acetoxy ethers and subsequent ring-closing metathesis: Synthesis of the CDEFG ring system of gambierol

    Kadota, I, A Ohno, K Matsuda, Y Yamamoto

    JOURNAL OF THE AMERICAN CHEMICAL SOCIETY   123 ( 27 )   6702 - 6703   2001年7月

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    記述言語:英語   出版者・発行元:AMER CHEMICAL SOC  

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  • Concise synthesis of cyclic ethers via the palladium-catalyzed coupling of ketene acetal triflates and a zinc homoenolate. Synthesis of the DE and GH ring segments of gambierol

    Kadota, I, H Takamura, K Sato, Y Yamamoto

    TETRAHEDRON LETTERS   42 ( 28 )   4729 - 4731   2001年7月

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    記述言語:英語   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    Concise syntheses: of the DE and GH ring segments of gambierol (1) were achieved by the palladium-catalyzed coupling of ketene acetal triflates and a zinc homoenolate, followed by the hydroboration of the resulting cyclic enol ethers and subsequent lactonization. (C) 2001 Elsevier Science Ltd. All rights reserved.

    DOI: 10.1016/S0040-4039(01)00824-3

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  • Concise synthesis of cyclic ethers via the palladium-catalyzed coupling of ketene acetal triflates and a zinc homoenolate. Synthesis of the DE and GH ring segments of gambierol

    Kadota, I, H Takamura, K Sato, Y Yamamoto

    TETRAHEDRON LETTERS   42 ( 28 )   4729 - 4731   2001年7月

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    記述言語:英語   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    Concise syntheses: of the DE and GH ring segments of gambierol (1) were achieved by the palladium-catalyzed coupling of ketene acetal triflates and a zinc homoenolate, followed by the hydroboration of the resulting cyclic enol ethers and subsequent lactonization. (C) 2001 Elsevier Science Ltd. All rights reserved.

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  • Convergent synthesis of polycyclic ethers via the intramolecular allylation of alpha-acetoxy ethers and subsequent ring-closing metathesis: Synthesis of the CDEFG ring system of gambierol

    Kadota, I, A Ohno, K Matsuda, Y Yamamoto

    JOURNAL OF THE AMERICAN CHEMICAL SOCIETY   123 ( 27 )   6702 - 6703   2001年7月

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    記述言語:英語   出版者・発行元:AMER CHEMICAL SOC  

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  • Synthesis of the A ring segment of gambieric acid

    Isao Kadota, Nao Oguro, Yoshinori Yamamoto

    Tetrahedron Letters   42 ( 21 )   3645 - 3647   2001年5月

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    記述言語:英語  

    The A ring fragment of gambieric acids was stereoselectively synthesized based on an Evans' asymmetric alkylation, Brown's asymmetric crotyl-, allylboration and an intramolecular SN2 reaction. © 2001 Elsevier Science Ltd. All rights reserved.

    DOI: 10.1016/S0040-4039(01)00529-9

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  • Synthesis of the J ring segment of gambieric acid

    Isao Kadota, Hiroyoshi Takamura, Yoshinori Yamamoto

    Tetrahedron Letters   42 ( 21 )   3649 - 3651   2001年5月

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    記述言語:英語  

    The J ring segment 2 of gambieric acid was synthesized stereoselectively by the coupling between the cyclic ether component 3 and the alkenyl iodide 4. The tetrahydropyran 3 was stereoselectively synthesized by the 6-endo-cyclization of a hydroxyepoxide prepared from deoxy-D-ribose. The side chain moiety 4 was prepared by the stereoselective hydrostannation of an internal alkyne. © 2001 Elsevier Science Ltd. All rights reserved.

    DOI: 10.1016/S0040-4039(01)00530-5

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  • Synthesis of the J ring segment of gambieric acid

    Kadota, I, H Takamura, Y Yamamoto

    TETRAHEDRON LETTERS   42 ( 21 )   3649 - 3651   2001年5月

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    記述言語:英語   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    The J ring segment 2 of gambieric acid was synthesized stereoselectively by the coupling between the cyclic ether component 3 and the alkenyl iodide 4. The tetrahydropyran 3 was stereoselectively synthesized by the 6-endo-cyclization of a hydroxyepoxide prepared from deoxy-D-ribose. The side chain moiety 4 was prepared by the stereoselective hydrostannation of an internal alkyne. (C) 2001 Elsevier Science Ltd. All rights reserved.

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  • Synthesis of the A Ring of Gambieric Acid

    KADOTA I, OGURO N, YAMAMOTO Y

    Tetrahedron Lett.   42 ( 21 )   3645 - 3647   2001年

  • A novel convergent approach to trans-fused polyether frameworks based on the reaction of vinylstannanes and triflates and its application to a synthetic study of the EFGH ring system of gambierol

    C Kadowaki, PWH Chan, Kadota, I, Y Yamamoto

    TETRAHEDRON LETTERS   41 ( 30 )   5769 - 5772   2000年7月

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    記述言語:英語   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    A new strategy for the convergent assembly of six-membered polycyclic ether ring fragments has been developed based upon the novel reaction between vinylstannanes with triflates in the presence of a strong base. The application of the present method has allowed for a synthetic study of the EFGH ring of gambierol to be achieved. (C) 2000 Elsevier Science Ltd. All rights reserved.

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  • A novel convergent approach to trans-fused polyether frameworks based on the reaction of vinylstannanes and triflates and its application to a synthetic study of the EFGH ring system of gambierol

    C Kadowaki, PWH Chan, Kadota, I, Y Yamamoto

    TETRAHEDRON LETTERS   41 ( 30 )   5769 - 5772   2000年7月

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    記述言語:英語   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    A new strategy for the convergent assembly of six-membered polycyclic ether ring fragments has been developed based upon the novel reaction between vinylstannanes with triflates in the presence of a strong base. The application of the present method has allowed for a synthetic study of the EFGH ring of gambierol to be achieved. (C) 2000 Elsevier Science Ltd. All rights reserved.

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  • Diastereo- and enantioselective synthesis of beta-amino cyclic ethers via the intramolecular reaction of gamma-alkoxyallylstannane with imine

    JY Park, Kadota, I, Y Yamamoto

    JOURNAL OF ORGANIC CHEMISTRY   64 ( 13 )   4901 - 4908   1999年6月

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    記述言語:英語   出版者・発行元:AMER CHEMICAL SOC  

    The intramolecular Lewis acid mediated cyclization of gamma-alkoxyallylstannanes 1, 2, and 14, bearing a hydrazone group at the terminus of the carbon chain, afforded exclusively the corresponding trans beta-amino cyclic ethers 3a, 4a, and 15, respectively. The Lewis acid mediated cyclization of gamma-alkoxyallylstannane 5, having (R)-(+)-1-phenylethylamine as a chiral auxiliary, afforded exclusively traits beta-amino cyclic ether 6a with very high diastereomeric excess (de) in very high chemical yields. The asymmetric cyclization of gamma-alkoxyallylstannane with imine 7 in the presence of chiral titanium-BINOL complex 9, afforded predominantly cis beta-amino cyclic ether 8b with high enantiomeric excess tee). The chiral Lewis acid mediated cyclization of racemic compound 38 containing phenyl as a substituent afforded cis isomer 39 with very high enantiomeric excess (ee).

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  • Palladium benzoic acid catalyzed hydroamination of alkynes

    Kadota, I, A Shibuya, LM Lutete, Y Yamamoto

    JOURNAL OF ORGANIC CHEMISTRY   64 ( 13 )   4570 - 4571   1999年6月

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    記述言語:英語   出版者・発行元:AMER CHEMICAL SOC  

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  • Palladium benzoic acid catalyzed hydroamination of alkynes

    Kadota, I, A Shibuya, LM Lutete, Y Yamamoto

    JOURNAL OF ORGANIC CHEMISTRY   64 ( 13 )   4570 - 4571   1999年6月

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    記述言語:英語   出版者・発行元:AMER CHEMICAL SOC  

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  • Diastereo- and enantioselective synthesis of beta-amino cyclic ethers via the intramolecular reaction of gamma-alkoxyallylstannane with imine

    JY Park, Kadota, I, Y Yamamoto

    JOURNAL OF ORGANIC CHEMISTRY   64 ( 13 )   4901 - 4908   1999年6月

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    記述言語:英語   出版者・発行元:AMER CHEMICAL SOC  

    The intramolecular Lewis acid mediated cyclization of gamma-alkoxyallylstannanes 1, 2, and 14, bearing a hydrazone group at the terminus of the carbon chain, afforded exclusively the corresponding trans beta-amino cyclic ethers 3a, 4a, and 15, respectively. The Lewis acid mediated cyclization of gamma-alkoxyallylstannane 5, having (R)-(+)-1-phenylethylamine as a chiral auxiliary, afforded exclusively traits beta-amino cyclic ether 6a with very high diastereomeric excess (de) in very high chemical yields. The asymmetric cyclization of gamma-alkoxyallylstannane with imine 7 in the presence of chiral titanium-BINOL complex 9, afforded predominantly cis beta-amino cyclic ether 8b with high enantiomeric excess tee). The chiral Lewis acid mediated cyclization of racemic compound 38 containing phenyl as a substituent afforded cis isomer 39 with very high enantiomeric excess (ee).

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  • Palladium acetic acid catalyzed allylation of some pronucleophiles with simple alkynes

    Kadota, I, A Shibuya, YS Gyoung, Y Yamamoto

    JOURNAL OF THE AMERICAN CHEMICAL SOCIETY   120 ( 39 )   10262 - 10263   1998年10月

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    記述言語:英語   出版者・発行元:AMER CHEMICAL SOC  

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  • Palladium acetic acid catalyzed allylation of some pronucleophiles with simple alkynes

    Kadota, I, A Shibuya, YS Gyoung, Y Yamamoto

    JOURNAL OF THE AMERICAN CHEMICAL SOCIETY   120 ( 39 )   10262 - 10263   1998年10月

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    記述言語:英語   出版者・発行元:AMER CHEMICAL SOC  

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  • Stereocontrolled total synthesis of hemibrevetoxin B

    Kadota, I, Y Yamamoto

    JOURNAL OF ORGANIC CHEMISTRY   63 ( 19 )   6597 - 6606   1998年9月

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    記述言語:英語   出版者・発行元:AMER CHEMICAL SOC  

    The stereocontrolled total synthesis of hemibrevetoxin B (1) has been achieved in 56 steps and 0.75% overall yield from D-mannose. The intramolecular reaction of gamma-alkoxyallylstannane with. aldehyde is a key step for the present total synthesis. Thus, the BF3. OEt2-mediated reaction of 24 gave 6 as a sole product. We encountered difficulty in the synthesis of gamma-alkoxyallylstannane 30 from the corresponding allyl ether 29 in which the gamma-alkoxy substituent became sterically quite bulky. This problem was solved by developing the acetal cleavage method for the synthesis of gamma-alkoxyallylstannanes. The cyclization of 38 proceeded smoothly to give the key intermediate 5 in a highly stereoselective manner. Construction of the alpha-vinyl aldehyde and (Z)-diene moieties were performed using Nicolaou's protocol.

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  • Stereocontrolled total synthesis of hemibrevetoxin B

    Kadota, I, Y Yamamoto

    JOURNAL OF ORGANIC CHEMISTRY   63 ( 19 )   6597 - 6606   1998年9月

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    記述言語:英語   出版者・発行元:AMER CHEMICAL SOC  

    The stereocontrolled total synthesis of hemibrevetoxin B (1) has been achieved in 56 steps and 0.75% overall yield from D-mannose. The intramolecular reaction of gamma-alkoxyallylstannane with. aldehyde is a key step for the present total synthesis. Thus, the BF3. OEt2-mediated reaction of 24 gave 6 as a sole product. We encountered difficulty in the synthesis of gamma-alkoxyallylstannane 30 from the corresponding allyl ether 29 in which the gamma-alkoxy substituent became sterically quite bulky. This problem was solved by developing the acetal cleavage method for the synthesis of gamma-alkoxyallylstannanes. The cyclization of 38 proceeded smoothly to give the key intermediate 5 in a highly stereoselective manner. Construction of the alpha-vinyl aldehyde and (Z)-diene moieties were performed using Nicolaou's protocol.

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  • Synthesis of the E ring of gambierol

    Kadota, I, C Kadowaki, N Yoshida, Y Yamamoto

    TETRAHEDRON LETTERS   39 ( 35 )   6369 - 6372   1998年8月

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    記述言語:英語   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    The synthesis of the E ring of gambierol was achieved from D-ribose via the intramolecular reaction of allylstannane with an aldehyde as a key step. The undesired stereoisomer formed in this reaction was converted to the desired product by using DBU isomerization. (C) 1998 Elsevier Science Ltd. All rights reserved.

    DOI: 10.1016/S0040-4039(98)01311-2

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  • Synthesis of the AB ring system of gambierol

    Kadota, I, CH Park, M Ohtaka, N Oguro, Y Yamamoto

    TETRAHEDRON LETTERS   39 ( 35 )   6365 - 6368   1998年8月

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    記述言語:英語   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    Synthesis of the AB ring system of gambierol (1) was achieved from 2-deoxy-D-ribose. The key steps were the stereoselective allylation of the aldehyde 6, corresponding to the B ring, and the intramolecular hetero-Michael reaction of 9. (C) 1998 Elsevier Science Ltd. All rights reserved.

    DOI: 10.1016/S0040-4039(98)01310-0

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  • Synthesis of the H ring of gambierol

    Kadota, I, A Ohno, Y Matsukawa, Y Yamamoto

    TETRAHEDRON LETTERS   39 ( 35 )   6373 - 6376   1998年8月

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    記述言語:英語   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    Stereoselective synthesis of the H ring of gambierol was achieved from 2-deoxy-D-ribose by using the intramolecular reaction of allylstannane with aldehyde as a key step. Mollified Stille coupling was successfully applied for the construction of the triene side chain. (C) 1998 Elsevier Science Ltd. All rights reserved.

    DOI: 10.1016/S0040-4039(98)01312-4

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  • Synthesis of the H ring of gambierol

    Kadota, I, A Ohno, Y Matsukawa, Y Yamamoto

    TETRAHEDRON LETTERS   39 ( 35 )   6373 - 6376   1998年8月

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    記述言語:英語   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    Stereoselective synthesis of the H ring of gambierol was achieved from 2-deoxy-D-ribose by using the intramolecular reaction of allylstannane with aldehyde as a key step. Mollified Stille coupling was successfully applied for the construction of the triene side chain. (C) 1998 Elsevier Science Ltd. All rights reserved.

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  • Synthesis of the E ring of gambierol

    Kadota, I, C Kadowaki, N Yoshida, Y Yamamoto

    TETRAHEDRON LETTERS   39 ( 35 )   6369 - 6372   1998年8月

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    記述言語:英語   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    The synthesis of the E ring of gambierol was achieved from D-ribose via the intramolecular reaction of allylstannane with an aldehyde as a key step. The undesired stereoisomer formed in this reaction was converted to the desired product by using DBU isomerization. (C) 1998 Elsevier Science Ltd. All rights reserved.

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  • Synthesis of the AB ring system of gambierol

    Kadota, I, CH Park, M Ohtaka, N Oguro, Y Yamamoto

    TETRAHEDRON LETTERS   39 ( 35 )   6365 - 6368   1998年8月

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    記述言語:英語   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    Synthesis of the AB ring system of gambierol (1) was achieved from 2-deoxy-D-ribose. The key steps were the stereoselective allylation of the aldehyde 6, corresponding to the B ring, and the intramolecular hetero-Michael reaction of 9. (C) 1998 Elsevier Science Ltd. All rights reserved.

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  • Asymmetric synthesis of beta-amino cyclic ethers via the intramolecular reaction of gamma-alkoxyallylstannane with chiral imine

    JY Park, CH Park, Kadota, I, Y Yamamoto

    TETRAHEDRON LETTERS   39 ( 13 )   1791 - 1794   1998年3月

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    記述言語:英語   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    The Lewis acid mediated cyclization of gamma-oxygen substituted allylic stannane 1, having a chiral imine group at the terminus of the carbon chain, afforded trans beta-amino cyclic ether 2 with very high to good diastereoselectivities in high chemical yields. (C) 1998 Elsevier Science Ltd. All rights reserved.

    DOI: 10.1016/S0040-4039(97)10866-8

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  • Asymmetric synthesis of beta-amino cyclic ethers via the intramolecular reaction of gamma-alkoxyallylstannane with chiral imine

    JY Park, CH Park, Kadota, I, Y Yamamoto

    TETRAHEDRON LETTERS   39 ( 13 )   1791 - 1794   1998年3月

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    記述言語:英語   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    The Lewis acid mediated cyclization of gamma-oxygen substituted allylic stannane 1, having a chiral imine group at the terminus of the carbon chain, afforded trans beta-amino cyclic ether 2 with very high to good diastereoselectivities in high chemical yields. (C) 1998 Elsevier Science Ltd. All rights reserved.

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  • 21世紀の化学"全合成"

    化学   53 ( 5 )   14   1998年

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  • Chemistry in 21st Century "Total Synthesis"

    Chemistry   53 ( 5 )   14   1998年

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  • Novel route to the synthesis of hydroxylated pyrrolidine derivatives via the intramolecular reaction of gamma-aminoallystannane with aldehyde. Total synthesis of (+)-preussin

    Kadota, I, S Saya, Y Yamamoto

    HETEROCYCLES   46   335 - 348   1997年12月

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    記述言語:英語   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    The thermal cyclization of gamma-aminoallylstannane (8) having an aldehyde group gave beta-hydroxypyrrolidine derivative (9a) as a sole product. This methodology was applied successfully to the total synthesis of (+)-preussin.

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  • Asymmetric total syntheses of hydroxylated piperidine alkaloids via the intramolecular reaction of gamma-aminoallylstannane with aldehyde

    Kadota, I, M Kawada, Y Muramatsu, Y Yamamoto

    TETRAHEDRON-ASYMMETRY   8 ( 23 )   3887 - 3893   1997年12月

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    記述言語:英語   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    Asymmetric total syntheses of (+)-desoxoprosopinine and (-)-desoxoprosophylline were accomplished using L-glutamic acid as the chiral source, in which the intramolecular reaction of a gamma-aminoallylstannane with an aldehyde was used as a key step. (C) 1997 Elsevier Science Ltd. All rights reserved.

    DOI: 10.1016/S0957-4166(97)00563-6

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  • Asymmetric total syntheses of hydroxylated piperidine alkaloids via the intramolecular reaction of gamma-aminoallylstannane with aldehyde

    Kadota, I, M Kawada, Y Muramatsu, Y Yamamoto

    TETRAHEDRON-ASYMMETRY   8 ( 23 )   3887 - 3893   1997年12月

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    記述言語:英語   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    Asymmetric total syntheses of (+)-desoxoprosopinine and (-)-desoxoprosophylline were accomplished using L-glutamic acid as the chiral source, in which the intramolecular reaction of a gamma-aminoallylstannane with an aldehyde was used as a key step. (C) 1997 Elsevier Science Ltd. All rights reserved.

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  • Total synthesis of (+)-desoxoprosopinine via the intramolecular reaction of γ-aminoallylstannane

    Isao Kadota, Miho Kawada, Yoko Muramatsu, Yoshinori Yamamoto

    Tetrahedron Letters   38 ( 42 )   7469 - 7470   1997年10月

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    記述言語:英語  

    A stereoselective total synthesis of (+)-desoxoprosopinine starting from L-glutamic acid as a chiral source was accomplished in which the intramolecular reaction of γ-aminoallylstannane with aldehyde was used as a key step.

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  • Intramolecular reaction of (gamma-alkoxyallyl)stannane with aldehyde: Origin of the stereoselectivities

    Kadota, I, M Kawada, Gevorgyan, V, Y Yamamoto

    JOURNAL OF ORGANIC CHEMISTRY   62 ( 21 )   7439 - 7446   1997年10月

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    記述言語:英語   出版者・発行元:AMER CHEMICAL SOC  

    The intramolecular cyclization of simple acyclic (gamma-alkoxyallyl)stannane aldehydes 1, 2, and 12-15 was investigated to elucidate the relationship between the geometry of the double bond of the allylstannanes, the ring size of cyclic ethers produced by the cyclization, and the procedures for promoting the cyclization. The Lewis acid-mediated cyclization of 1-2, 12-13, and 14-15 gave the trans cyclic ethers 3, 39, and 41, respectively, either predominantly or exclusively irrespective of the geometry of the double bond and of the ring size of the cyclic ethers. The relationship in the thermal cyclization of 1 and 2, which gave the 6-membered cyclic ethers 4 and 3, was straightforward; the Z isomer 1 gave the cis product 4, and the E isomer 2 afforded the trans product 3. However, the relationship in the thermal cyclization of 12 and 13 which afforded the 5-membered cyclic ethers 39 and 40 was different from that expected from the cyclization via the well-accepted cyclic transition state, as observed in the case of 1 and 2. Both the Z (12) and E (13) isomers gave the cis cyclic ether 40 either predominantly or exclusively. The protic acid-mediated (or-catalyzed) cyclization of 12-13 and 14-15 gave the trans cyclic ethers 39 and 41, respectively, regardless of the geometry of the double bonds. On the other hand, the protic acid-promoted cyclization of 1 and 2 was very strange; the Z isomer 1 gave the cis isomer 4, and the E isomer 2 afforded the trans isomer 3. The mechanisms for these cyclization reactions are proposed.

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  • Intramolecular reaction of (gamma-alkoxyallyl)stannane with aldehyde: Origin of the stereoselectivities

    Kadota, I, M Kawada, Gevorgyan, V, Y Yamamoto

    JOURNAL OF ORGANIC CHEMISTRY   62 ( 21 )   7439 - 7446   1997年10月

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    記述言語:英語   出版者・発行元:AMER CHEMICAL SOC  

    The intramolecular cyclization of simple acyclic (gamma-alkoxyallyl)stannane aldehydes 1, 2, and 12-15 was investigated to elucidate the relationship between the geometry of the double bond of the allylstannanes, the ring size of cyclic ethers produced by the cyclization, and the procedures for promoting the cyclization. The Lewis acid-mediated cyclization of 1-2, 12-13, and 14-15 gave the trans cyclic ethers 3, 39, and 41, respectively, either predominantly or exclusively irrespective of the geometry of the double bond and of the ring size of the cyclic ethers. The relationship in the thermal cyclization of 1 and 2, which gave the 6-membered cyclic ethers 4 and 3, was straightforward; the Z isomer 1 gave the cis product 4, and the E isomer 2 afforded the trans product 3. However, the relationship in the thermal cyclization of 12 and 13 which afforded the 5-membered cyclic ethers 39 and 40 was different from that expected from the cyclization via the well-accepted cyclic transition state, as observed in the case of 1 and 2. Both the Z (12) and E (13) isomers gave the cis cyclic ether 40 either predominantly or exclusively. The protic acid-mediated (or-catalyzed) cyclization of 12-13 and 14-15 gave the trans cyclic ethers 39 and 41, respectively, regardless of the geometry of the double bonds. On the other hand, the protic acid-promoted cyclization of 1 and 2 was very strange; the Z isomer 1 gave the cis isomer 4, and the E isomer 2 afforded the trans isomer 3. The mechanisms for these cyclization reactions are proposed.

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  • Total synthesis of (+)-desoxoprosopinine via the intramolecular reaction of gamma-aminoallylstannane

    Kadota, I, M Kawada, Y Muramatsu, Y Yamamoto

    TETRAHEDRON LETTERS   38 ( 42 )   7469 - 7470   1997年10月

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    記述言語:英語   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    A stereoselective total synthesis of (+)-desoxoprosopinine starting from L-glutamic acid as a chiral source was accomplished in which the intramolecular reaction of gamma-aminoallylstannane with aldehyde was used as a key step. (C) 1997 Elsevier Science Ltd.

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  • Stereocontrolled synthesis of polycyclic ethers and related heterocycles via the intramolecular reaction of allylstannanes

    Kadota, I, Y Yamamoto

    JOURNAL OF SYNTHETIC ORGANIC CHEMISTRY JAPAN   55 ( 7 )   619 - 630   1997年7月

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    記述言語:日本語   出版者・発行元:SOC SYNTHETIC ORGANIC CHEM JPN  

    The synthetic reaction using functionalized allylstannanes is widely appreciated as one of the most useful methods for the stereocontrolled C-C bond formation. We now report the stereoselective synthesis of functionalized heterocycles via the intramolecular reaction of allylstannane with aldehydes and imines. The stereocontrolled total synthesis of hemibrevetoxin B was achieved by using the intramolecular reaction of gamma-alkoxyallylstannane with aldehydes. The extension of this methodology led to a new strategy for the stereoselective synthesis of alkaloids such as (+)-desoxoprosopinine and (+)-preussin.

    DOI: 10.5059/yukigoseikyokaishi.55.619

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  • Palladium catalyzed addition of carbon pronucleophiles to conjugated enynes

    Gevorgyan, V, C Kadowaki, MM Salter, Kadota, I, S Saito, Y Yamamoto

    TETRAHEDRON   53 ( 27 )   9097 - 9106   1997年7月

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    記述言語:英語   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    Palladium catalyzed addition of certain carbon pronucleophiles 2 to conjugated enynes 1 afforded the corresponding allenes 3 in good to excellent yields. The most reactive methynes such as methylmalononitrile 2c enabled to undergo double addition leading to alkenes 4. Catalyst optimization supported Pd-2(dba)(3) . CHC3 - dppf combination as the best system among all catalysts tested. The plausible mechanisms for these catalytic reactions were proposed. (C) 1997 Elsevier Science Ltd.

    DOI: 10.1016/S0040-4020(97)00602-9

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  • Palladium catalyzed addition of carbon pronucleophiles to conjugated enynes

    Gevorgyan, V, C Kadowaki, MM Salter, Kadota, I, S Saito, Y Yamamoto

    TETRAHEDRON   53 ( 27 )   9097 - 9106   1997年7月

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    記述言語:英語   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    Palladium catalyzed addition of certain carbon pronucleophiles 2 to conjugated enynes 1 afforded the corresponding allenes 3 in good to excellent yields. The most reactive methynes such as methylmalononitrile 2c enabled to undergo double addition leading to alkenes 4. Catalyst optimization supported Pd-2(dba)(3) . CHC3 - dppf combination as the best system among all catalysts tested. The plausible mechanisms for these catalytic reactions were proposed. (C) 1997 Elsevier Science Ltd.

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  • Regioselective synthesis of 1,3,5-unsymmetrically substituted benzenes via the palladium-catalyzed cyclotrimerization of 1,3-diynes

    A Takeda, A Ohno, Kadota, I, Gevorgyan, V, Y Yamamoto

    JOURNAL OF THE AMERICAN CHEMICAL SOCIETY   119 ( 19 )   4547 - 4548   1997年5月

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    記述言語:英語   出版者・発行元:AMER CHEMICAL SOC  

    DOI: 10.1021/ja970339u

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  • Regioselective synthesis of 1,3,5-unsymmetrically substituted benzenes via the palladium-catalyzed cyclotrimerization of 1,3-diynes

    A Takeda, A Ohno, Kadota, I, Gevorgyan, V, Y Yamamoto

    JOURNAL OF THE AMERICAN CHEMICAL SOCIETY   119 ( 19 )   4547 - 4548   1997年5月

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    記述言語:英語   出版者・発行元:AMER CHEMICAL SOC  

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  • Novel Route to the Synthesis of Hydroxylated Pyrrolidine Perivatives via the Intramolecular Reaction of gamma-Aminoallylstannane with Aldehycle. Total Synthesis of (+)-Preussin

    Heterocycles   46   335 - 348   1997年

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  • Organometallics-Lewis Acid Complex System

    Chemistry and Chemical Industry   50   1486 - 1488   1997年

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  • アリルスズの分子内反応を用いるポリ環状エーテルおよび関連ヘテロ環化合物の立体選択的合成

    門田 功, 山本 嘉則

    有機合成化学協会誌   55 ( 7 )   619 - 630   1997年

  • 有機金属ルイス酸複合系

    化学と工業   50   1486 - 1488   1997年

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  • Intramolecular reaction of oxo-substituted allenyl- and propargylstannane with aldehyde

    Isao Kadota, Daigo Hatakeyama, Katsura Seki, Yoshinori Yamamoto

    Tetrahedron Letters   37 ( 17 )   3059 - 3062   1996年4月

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    記述言語:英語   出版者・発行元:Elsevier Ltd  

    The Lewis acid mediated reactions of allenylstannanes 1 and 13 gave trans cyclic ethers 3a and 14, respectively, with high stereoselectivities. The cyclization to 7 gave trans cyclic ether 9a. The treatment of propargylstannanes 2 and 8 with Lewis acids such as SnCl4, BuSnCl3, and ZnCl2·OEt2 induced isomerization to allenylmetal species, which underwent cyclization to the corresponding 6- and 5-membered cyclic ethers 3 and 9, respectively. The stereoselectivities dependend upon the ring size and Lewis acid utilized.

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  • A general and efficient method for the preparation of gamma-alkoxyallylstannanes via an acetal cleavage

    Kadota, I, T Sakaihara, Y Yamamoto

    TETRAHEDRON LETTERS   37 ( 18 )   3195 - 3198   1996年4月

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    記述言語:英語   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    The reaction of various alcohols and gamma-methoxyallylstannane 3 in the presence of a catalytic amount of CSA afforded mixed acetals in high yields. The treatment of the acetals with TMSI and HMDS produced gamma-alkoxyallylstannanes in high yields via elimination of methanol. Copyright (C) 1996 Elsevier Science Ltd

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  • Intramolecular reaction of gamma-alkoxyallylstannane with hydrazone: Stereoselective synthesis of beta-aminotetrahydro-pyran and -furan

    Kadota, I, JY Park, Y Yamamoto

    CHEMICAL COMMUNICATIONS   ,841-842 ( 7 )   841 - 842   1996年4月

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    記述言語:英語   出版者・発行元:ROYAL SOC CHEMISTRY  

    The Lewis acid mediated cyclization of gamma-oxygen substituted allylic stannanes 1, 2 and 9, bearing a hydrazone group at the terminus of the carbon chain, afforded the corresponding trans-beta-amino cyclic ethers 3a, 4a and 10, respectively, with very high diastereoselectivities in high chemical yields.

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  • Intramolecular reaction of oxo-substituted allenyl- and propargylstannane with aldehyde

    Kadota, I, D Hatakeyama, K Seki, Y Yamamoto

    TETRAHEDRON LETTERS   37 ( 17 )   3059 - 3062   1996年4月

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    記述言語:英語   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    The Lewis acid mediated reactions of allenylstannanes 1 and 13 gave trans cyclic ethers 3a and 14, respectively, with high stereoselectivities. The cyclization fo 7 gave trans cyclic ether 9a. The treatment of propargylstannanes 2 and 8 with Lewis acids such as SnCl4, BuSnCl(3), and ZnCl2 . OEt(2) induced isomerization to allenylmetal species, which underwent cyclization to the corresponding 6- and 5-membered cyclic ethers 3 and 9, respectively. The stereoselectivities depended upon the ring size and Lewis acid utilized. (C) 1996 Elsevier Science Ltd.

    DOI: 10.1016/0040-4039(96)00469-8

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  • Intramolecular reaction of gamma-alkoxyallylstannane with hydrazone: Stereoselective synthesis of beta-aminotetrahydro-pyran and -furan

    Kadota, I, JY Park, Y Yamamoto

    CHEMICAL COMMUNICATIONS   ,841-842 ( 7 )   841 - 842   1996年4月

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    記述言語:英語   出版者・発行元:ROYAL SOC CHEMISTRY  

    The Lewis acid mediated cyclization of gamma-oxygen substituted allylic stannanes 1, 2 and 9, bearing a hydrazone group at the terminus of the carbon chain, afforded the corresponding trans-beta-amino cyclic ethers 3a, 4a and 10, respectively, with very high diastereoselectivities in high chemical yields.

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  • A general and efficient method for the preparation of gamma-alkoxyallylstannanes via an acetal cleavage

    Kadota, I, T Sakaihara, Y Yamamoto

    TETRAHEDRON LETTERS   37 ( 18 )   3195 - 3198   1996年4月

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    記述言語:英語   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    The reaction of various alcohols and gamma-methoxyallylstannane 3 in the presence of a catalytic amount of CSA afforded mixed acetals in high yields. The treatment of the acetals with TMSI and HMDS produced gamma-alkoxyallylstannanes in high yields via elimination of methanol. Copyright (C) 1996 Elsevier Science Ltd

    DOI: 10.1016/0040-4039(96)00493-5

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  • Novel route to the synthesis of hydroxylated piperidine and pyrrolidine derivatives via the intramolecular reaction of gamma-aminoallylstannane with aldehyde

    Kadota, I, M Kawada, S Saya, Y Yamamoto

    TETRAHEDRON LETTERS   37 ( 12 )   2109 - 2112   1996年3月

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    記述言語:英語   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    The Lewis acid mediated intramolecular reaction of gamma-aminoallylstannane 6 gave trans-beta-hydroxypiperidine derivative 7a as a major product. On the other hand, the thermal cyclization of 6 and 8 afforded cis-beta hydroxypiperidine 7b and pyrrolidine derivative 9b, respectively, with very high stereoselectivity.

    DOI: 10.1016/0040-4039(96)00205-5

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  • Novel route to the synthesis of hydroxylated piperidine and pyrrolidine derivatives via the intramolecular reaction of gamma-aminoallylstannane with aldehyde

    Kadota, I, M Kawada, S Saya, Y Yamamoto

    TETRAHEDRON LETTERS   37 ( 12 )   2109 - 2112   1996年3月

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    記述言語:英語   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    The Lewis acid mediated intramolecular reaction of gamma-aminoallylstannane 6 gave trans-beta-hydroxypiperidine derivative 7a as a major product. On the other hand, the thermal cyclization of 6 and 8 afforded cis-beta hydroxypiperidine 7b and pyrrolidine derivative 9b, respectively, with very high stereoselectivity.

    DOI: 10.1016/0040-4039(96)00205-5

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  • Total Synthesis of Hemibrevetoxin B via the Allylic Tin Method

    Main Group Metal Chemistry   19   361 - 366   1996年

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  • Total synthesis of hemibrevetoxin B via the allylic tin methodology

    Kadota, I, Y Yamamoto

    MAIN GROUP METAL CHEMISTRY   19 ( 6 )   361 - 366   1996年

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    記述言語:英語   出版者・発行元:FREUND PUBLISHING HOUSE  

    The total synthesis of Hemibrevetoxin B is described. A new cyclization approach, based on the Lewis acid mediated intramolecular cyclization of the gamma-oxo-substituted allylic tin having an aldehyde group, produced the 6-6-7-7 polycyclic ether skeleton of the natural product with high stereoselectivity. The H-1 and C-13-NMR spectra of synthetic hemibrevetoxin B was identical with those of natural product.

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  • TOTAL SYNTHESIS OF HEMIBREVETOXIN-B

    KADOTA, I, P JUNGYOUL, N KOUMURA, G POLLAUD, Y MATSUKAWA, Y YAMAMOTO

    TETRAHEDRON LETTERS   36 ( 32 )   5777 - 5780   1995年8月

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    記述言語:英語   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    The total synthesis of Hemibrevetoxin B is described. A new cyclization approach, based on the Lewis acid mediated intramolecular cyclization of the gamma-oxo-substituted allylic tin having an aldehyde group, produced the 6-6-7-7 polycyclic ether skeleton of the natural product with high stereoselectivity. The H-1 and C-13-NMR spectra of synthetic hemibrevetoxin B was identical with those of natural product.

    DOI: 10.1016/0040-4039(95)01097-2

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  • TOTAL SYNTHESIS OF HEMIBREVETOXIN-B

    KADOTA, I, P JUNGYOUL, N KOUMURA, G POLLAUD, Y MATSUKAWA, Y YAMAMOTO

    TETRAHEDRON LETTERS   36 ( 32 )   5777 - 5780   1995年8月

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    記述言語:英語   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    The total synthesis of Hemibrevetoxin B is described. A new cyclization approach, based on the Lewis acid mediated intramolecular cyclization of the gamma-oxo-substituted allylic tin having an aldehyde group, produced the 6-6-7-7 polycyclic ether skeleton of the natural product with high stereoselectivity. The H-1 and C-13-NMR spectra of synthetic hemibrevetoxin B was identical with those of natural product.

    DOI: 10.1016/0040-4039(95)01097-2

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  • NICKEL-CATALYZED IMINE ALDOL REACTIONS BETWEEN ACTIVATED IMINES AND PRONUCLEOPHILES

    N SHIDA, Y KUBOTA, H FUKUI, N ASAO, KADOTA, I, Y YAMAMOTO

    TETRAHEDRON LETTERS   36 ( 28 )   5023 - 5026   1995年7月

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    記述言語:英語   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    Treatment of activated imines 1 with carbonyl compounds 2 in the presence of catalytic amounts of NiCl2(PPh(3))(2) or NiBr2(PPh(3))(2) at room temperature affords imine aldol products 3 in high to good yields.

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  • NICKEL-CATALYZED IMINE ALDOL REACTIONS BETWEEN ACTIVATED IMINES AND PRONUCLEOPHILES

    N SHIDA, Y KUBOTA, H FUKUI, N ASAO, KADOTA, I, Y YAMAMOTO

    TETRAHEDRON LETTERS   36 ( 28 )   5023 - 5026   1995年7月

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    記述言語:英語   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    Treatment of activated imines 1 with carbonyl compounds 2 in the presence of catalytic amounts of NiCl2(PPh(3))(2) or NiBr2(PPh(3))(2) at room temperature affords imine aldol products 3 in high to good yields.

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  • ASYMMETRIC DIELS-ALDER REACTIONS OF TMHD-ACRYLATE USING TICL4-CENTER-DOT(ARNHG)(M) COMPLEXED LEWIS-ACIDS

    KADOTA, I, K KOBAYASHI, N ASAO, Y YAMAMOTO

    JOURNAL OF THE CHEMICAL SOCIETY-CHEMICAL COMMUNICATIONS   ,1271-1272 ( 12 )   1271 - 1272   1995年6月

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    記述言語:英語   出版者・発行元:ROYAL SOC CHEMISTRY  

    Diels-Alder reaction of (3R,5S)-5-benzoyloxy-2,2,6,6-tetramethyl-3-heptyl acrylate (TMHD-acrylate) 1 with cyclopentadiene in the presence of TiCl4-(ArnHg)(m) complexed Lewis acids gives (1R,4R,6R)-2-norbomene-6-carboxylate derivative 4 predominantly, whereas the reaction in the presence of TiCl4 alone affords its enantiomer 2 preferentially.

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  • Asymmetric Diels-Alder Reaction of TMHD-acrylate using TiCl4(ArnHg)m Complex Lewis Acids

    Journal of Chemical Society, Chemical Communication   ,1271-1272   1995年

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  • Tri-butylchlorostannane

    Encyclopedia of Reagents for Organic Synthesis   1995年

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  • CHIRAL GAMMA-(TETRAHYDROPYRANYLOXY)ALLYLSTANNANE - A NEW CHIRAL REAGENT FOR THE ASYMMETRIC-SYNTHESIS OF SYN 1,2-DIOLS

    KADOTA, I, K KOBAYASHI, H OKANO, N ASAO, Y YAMAMOTO

    BULLETIN DE LA SOCIETE CHIMIQUE DE FRANCE   132 ( 5-6 )   615 - 623   1995年

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    記述言語:英語   出版者・発行元:EDITIONS SCIENTIFIQUES ELSEVIER  

    (2R,3S)-3-Allyloxy-3,4,5,6-tetrahydro-2H-pyran-2-methanol was prepared in high yield from tri-O-acetyl-D-glucal, an easily available and cheap chiral source. The hydroxyl group was protected as the t-butyldiphenylsilyl ether, and the allyl group was converted to the corresponding allyl stannane via formation of allyl carbanion and subsequent trapping with tributylstannyl chloride. The gamma-alkoxy allyl stannane 1 bearing the (2R,3S)-2-[(t-butyldiphenylsilyloxy)methyl]-3,4,5,6-tetrahydro-2H-pyran-3-yloxy auxiliary at the allyl terminus was prepared by this procedure. The reaction of 1 with aldehydes in the presence of AlCl3 . OEt(2) or AlCl3 gave the corresponding syn adducts 2 with high diastereoselectivities; the ratio of syn/anti > 97:3. The diastereomeric excess of the syn adducts 2, that is, the ratio 2/(2 + the (S,S) isomer of 2), varied from 85 to 94%. Removal of the protecting group of 2 gave the (R,R) diols 3. The high diastereo- and enantioselectivity in the formation of the (R,R) isomer is accounted for by an anti S'(E) transition state 18.

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  • CHIRAL GAMMA-(TETRAHYDROPYRANYLOXY)ALLYLSTANNANE - A NEW CHIRAL REAGENT FOR THE ASYMMETRIC-SYNTHESIS OF SYN 1,2-DIOLS

    KADOTA, I, K KOBAYASHI, H OKANO, N ASAO, Y YAMAMOTO

    BULLETIN DE LA SOCIETE CHIMIQUE DE FRANCE   132 ( 5-6 )   615 - 623   1995年

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    記述言語:英語   出版者・発行元:EDITIONS SCIENTIFIQUES ELSEVIER  

    (2R,3S)-3-Allyloxy-3,4,5,6-tetrahydro-2H-pyran-2-methanol was prepared in high yield from tri-O-acetyl-D-glucal, an easily available and cheap chiral source. The hydroxyl group was protected as the t-butyldiphenylsilyl ether, and the allyl group was converted to the corresponding allyl stannane via formation of allyl carbanion and subsequent trapping with tributylstannyl chloride. The gamma-alkoxy allyl stannane 1 bearing the (2R,3S)-2-[(t-butyldiphenylsilyloxy)methyl]-3,4,5,6-tetrahydro-2H-pyran-3-yloxy auxiliary at the allyl terminus was prepared by this procedure. The reaction of 1 with aldehydes in the presence of AlCl3 . OEt(2) or AlCl3 gave the corresponding syn adducts 2 with high diastereoselectivities; the ratio of syn/anti > 97:3. The diastereomeric excess of the syn adducts 2, that is, the ratio 2/(2 + the (S,S) isomer of 2), varied from 85 to 94%. Removal of the protecting group of 2 gave the (R,R) diols 3. The high diastereo- and enantioselectivity in the formation of the (R,R) isomer is accounted for by an anti S'(E) transition state 18.

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  • Tri-butylchlorostannane

    Encyclopedia of Reagents for Organic Synthesis   1995年

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  • HIGHLY STEREOCONTROLLED FORMAL TOTAL SYNTHESIS OF HEMIBREVETOXIN-B

    Y YAMAMOTO, KADOTA, I

    BULLETIN DES SOCIETES CHIMIQUES BELGES   103 ( 9-10 )   619 - 628   1994年9月

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    記述言語:英語   出版者・発行元:SOC CHIMIQUE BELGIQUE  

    Stereocontrolled synthesis of hemibrevetoxin B framework, 7,7,6,6-tetracyclic ether skeleton, has been accomplished via the intramolecular allylic tin-aldehyde (and ketone) condensation.

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  • ASYMMETRIC-SYNTHESIS OF BETA-ALKOXYCYCLIC ETHERS VIA THE INTRAMOLECULAR CYCLIZATION OF GROUP-14 ALLYLS CONTAINING CHIRAL ACETALS

    KADOTA, I, K MIURA, Y YAMAMOTO

    JOURNAL OF THE CHEMICAL SOCIETY-CHEMICAL COMMUNICATIONS   ,1953-1954 ( 17 )   1953 - 1954   1994年9月

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    記述言語:英語   出版者・発行元:ROYAL SOC CHEMISTRY  

    Treatment of an allylic tin-bearing chiral acetal 1a with TiCl4-PPh(3) gives the (2S, 3R) isomer 2 with high diastereoselectivity (2:3 = 93:7), whereas the reaction of an allylic silane derivative 1f affords predominantly the (2R,3S) isomer 3 (2:3 = 37:63).

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  • ASYMMETRIC-SYNTHESIS OF BETA-ALKOXYCYCLIC ETHERS VIA THE INTRAMOLECULAR CYCLIZATION OF GROUP-14 ALLYLS CONTAINING CHIRAL ACETALS

    KADOTA, I, K MIURA, Y YAMAMOTO

    JOURNAL OF THE CHEMICAL SOCIETY-CHEMICAL COMMUNICATIONS   ,1953-1954 ( 17 )   1953 - 1954   1994年9月

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    記述言語:英語   出版者・発行元:ROYAL SOC CHEMISTRY  

    Treatment of an allylic tin-bearing chiral acetal 1a with TiCl4-PPh(3) gives the (2S, 3R) isomer 2 with high diastereoselectivity (2:3 = 93:7), whereas the reaction of an allylic silane derivative 1f affords predominantly the (2R,3S) isomer 3 (2:3 = 37:63).

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  • Stereocontrolled Synthesis of the 6-7-7-6 Ring System of Polycyclic Ethers via the Intramolecular Reaction with omega-Tributyl stannyl Ether Aldehydes

    Main Group Metal Chemistry   17   269 - 289   1994年

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  • Highly Stereocontrolled Formal Total Synthesis of Hemibrevetoxin B

    Bulletin des Societies Chimiques Belges   103   619 - 629   1994年

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  • Stereocontrolled Synthesis of the 6-7-7-6 Ring System of Polycyclic Ethers via the Intramolecular Reaction with omega-Tributyl stannyl Ether Aldehydes

    Main Group Metal Chemistry   17   269 - 289   1994年

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  • STEREOCONTROLLED SYNTHESIS OF THE HEMIBREVETOXIN RING-SYSTEM VIA AN ALLYLIC TIN METHOD

    KADOTA, I, Y MATSUKAWA, Y YAMAMOTO

    JOURNAL OF THE CHEMICAL SOCIETY-CHEMICAL COMMUNICATIONS   ,1638-1641 ( 21 )   1638 - 1641   1993年11月

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    記述言語:英語   出版者・発行元:ROYAL SOC CHEMISTRY  

    Stereocontrolled synthesis of the 7,7,6,6-tetracyclic ether skeleton of the hemibrevetoxin skeleton has been accomplished via the intramolecular allylic tin-aldehyde (and ketone) condensation.

    DOI: 10.1039/c39930001638

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  • STEREOCONTROLLED SYNTHESIS OF THE HEMIBREVETOXIN RING-SYSTEM VIA AN ALLYLIC TIN METHOD

    KADOTA, I, Y MATSUKAWA, Y YAMAMOTO

    JOURNAL OF THE CHEMICAL SOCIETY-CHEMICAL COMMUNICATIONS   ,1638-1641 ( 21 )   1638 - 1641   1993年11月

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    記述言語:英語   出版者・発行元:ROYAL SOC CHEMISTRY  

    Stereocontrolled synthesis of the 7,7,6,6-tetracyclic ether skeleton of the hemibrevetoxin skeleton has been accomplished via the intramolecular allylic tin-aldehyde (and ketone) condensation.

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  • Cyclic transition state in the acid catalyzed intramolecular allylstannane-aldehyde condensation

    Vladimir Gevorgyan, Isao Kadota, Yoshinori Yamamoto

    Tetrahedron Letters   34 ( 8 )   1313 - 1316   1993年2月

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    記述言語:英語  

    Brφnsted acid catalyzed or Bu4NF-TiCl4 mediated cyclization of (Z)-ω-stannyl ether aldehyde 1a gives 2a, whereas (E)-isomer 1b affords 2b. To explain this stereochemical outcome, a push mechanism is proposed. © 1993.

    DOI: 10.1016/S0040-4039(00)91783-0

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  • CYCLIC TRANSITION-STATE IN THE ACID-CATALYZED INTRAMOLECULAR ALLYLSTANNANE-ALDEHYDE CONDENSATION

    GEVORGYAN, V, KADOTA, I, Y YAMAMOTO

    TETRAHEDRON LETTERS   34 ( 8 )   1313 - 1316   1993年2月

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    記述言語:英語   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    Bronsted acid catalyzed or Bu4NF-TiCl4 mediated cyclization of (Z)-omega-stannyl ether aldehyde 1a gives 2a, whereas (E)-isomer 1b affords 2b. To explain this stereochemical outcome, a push-pull mechanism is proposed.

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  • ASYMMETRIC-SYNTHESIS OF SYN 1,2-DIOLS VIA THE REACTION OF ALDEHYDES WITH CHIRAL GAMMA-(TETRAHYDROPYRANYLOXY)ALLYLSTANNANES

    Y YAMAMOTO, K KOBAYASHI, H OKANO, KADOTA, I

    JOURNAL OF ORGANIC CHEMISTRY   57 ( 26 )   7003 - 7005   1992年12月

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    記述言語:英語   掲載種別:速報,短報,研究ノート等(学術雑誌)   出版者・発行元:AMER CHEMICAL SOC  

    Asymmetric synthesis of syn 1,2-diols 3 has been accomplished via the reaction of the chiral gamma-alkoxy-substituted allylstannane 1 with aldehydes in the presence of AlCl3 or AlCl3.OEt2, followed by a five-step operation to remove the chiral auxiliary.

    DOI: 10.1021/jo00052a002

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  • ASYMMETRIC-SYNTHESIS OF SYN 1,2-DIOLS VIA THE REACTION OF ALDEHYDES WITH CHIRAL GAMMA-(TETRAHYDROPYRANYLOXY)ALLYLSTANNANES

    Y YAMAMOTO, K KOBAYASHI, H OKANO, KADOTA, I

    JOURNAL OF ORGANIC CHEMISTRY   57 ( 26 )   7003 - 7005   1992年12月

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    記述言語:英語   掲載種別:速報,短報,研究ノート等(学術雑誌)   出版者・発行元:AMER CHEMICAL SOC  

    Asymmetric synthesis of syn 1,2-diols 3 has been accomplished via the reaction of the chiral gamma-alkoxy-substituted allylstannane 1 with aldehydes in the presence of AlCl3 or AlCl3.OEt2, followed by a five-step operation to remove the chiral auxiliary.

    DOI: 10.1021/jo00052a002

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  • Diisopropyl Tartrate Modified (E)-gamma-[(Cyclohexyloxy)dimethylsilyl]- and (E)-gamma-(Dimethylphenylsilyl)allylboronates: Chiral Reagents for the Enantio- and Diastereoselective Synthesis of anti-1,2-Diols and 2-Butene-1,4-diols via the Formal alpha-・・・

    Chemtracts: Org. Chem.   5   242 - 245   1992年

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    Diisopropyl Tartrate Modified (E)-gamma-[(Cyclohexyloxy)dimethylsilyl]- and (E)-gamma-(Dimethylphenylsilyl)allylboronates: Chiral Reagents for the Enantio- and Diastereoselective Synthesis of anti-1,2-Diols and 2-Butene-1,4-diols via the Formal alpha- and gamma-Hydroxyallylation of Aldehydes

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  • Diisopropyl Tartrate Modified (E)-gamma-[(Cyclohexyloxy)dimethylsilyl]- and (E)-gamma-(Dimethylphenylsilyl)allylboronates: Chiral Reagents for the Enantio- and Diastereoselective Synthesis of anti-1,2-Diols and 2-Butene-1,4-diols via the Formal alpha-・・・

    Chemtracts: Org. Chem.   5   242 - 245   1992年

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    Diisopropyl Tartrate Modified (E)-gamma-[(Cyclohexyloxy)dimethylsilyl]- and (E)-gamma-(Dimethylphenylsilyl)allylboronates: Chiral Reagents for the Enantio- and Diastereoselective Synthesis of anti-1,2-Diols and 2-Butene-1,4-diols via the Formal alpha- and gamma-Hydroxyallylation of Aldehydes

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  • STEREOCONTROLLED INTRAMOLECULAR CYCLIZATION OF OMEGA-TRIBUTYLSTANNYL ETHER ALDEHYDES - SYNTHESIS OF THE 6.7.7.6 RING-SYSTEM OF POLYCYCLIC ETHERS

    Y YAMAMOTO, J YAMADA, KADOTA, I

    TETRAHEDRON LETTERS   32 ( 48 )   7069 - 7072   1991年11月

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    記述言語:英語   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    The BF3.OEt2 mediated intramolecular cyclization of the gamma-oxo-substituted allylic tin (1) having an aldehyde group at the terminus of the carbon chain proceeded in a stereocontrolled manner to give the 7-membered beta-hydroxy cyclic ether (2a) with high diastereoselectivity. This method was applied for the synthesis of the 6.7.7.6 ring system (3a).

    DOI: 10.1016/0040-4039(91)85042-4

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  • STEREOCONTROLLED INTRAMOLECULAR CYCLIZATION OF OMEGA-TRIBUTYLSTANNYL ETHER ALDEHYDES - SYNTHESIS OF THE 6.7.7.6 RING-SYSTEM OF POLYCYCLIC ETHERS

    Y YAMAMOTO, J YAMADA, KADOTA, I

    TETRAHEDRON LETTERS   32 ( 48 )   7069 - 7072   1991年11月

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    記述言語:英語   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    The BF3.OEt2 mediated intramolecular cyclization of the gamma-oxo-substituted allylic tin (1) having an aldehyde group at the terminus of the carbon chain proceeded in a stereocontrolled manner to give the 7-membered beta-hydroxy cyclic ether (2a) with high diastereoselectivity. This method was applied for the synthesis of the 6.7.7.6 ring system (3a).

    DOI: 10.1016/0040-4039(91)85042-4

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  • SYNTHESIS OF BETA-ALKOXYCYCLIC ETHERS FROM OMEGA-ORGANOMETALLIC ETHER ACETALS - STEREOCONTROL WITH THE COMBINED LEWIS ACID SYSTEM, TITANIUM(IV) CHLORIDE-TRIPHENYLPHOSPHINE

    KADOTA, I, GEVORGYAN, V, J YAMADA, Y YAMAMOTO

    SYNLETT   ,823-824 ( 11 )   823 - 824   1991年11月

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    記述言語:英語   掲載種別:記事・総説・解説・論説等(学術雑誌)   出版者・発行元:GEORG THIEME VERLAG  

    The titanium(IV) chloride-triphenylphosphine mediated intramolecular cyclization of gamma-oxo-substituted allylic silane 1 (4-[3-(trimethylsilyl)-1-propenyloxy]butanal propylene acetal) having an acetal group at the terminus of the carbon chain produced the 6-membered trans isomer 2a [trans-3-(3-hydroxypropoxy)-2-vinyltetrahydropyran] with very high diastereoselectivity in high yield. Highly stereoselective synthesis of seven-and eight-membered rings was also accomplished by the use of titanium(IV) chloride-triphenylphosphine.

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  • A NEW APPROACH TO THE CONSTRUCTION OF BETA-ALKOXY-SUBSTITUTED CYCLIC ETHERS VIA THE INTRAMOLECULAR CYCLIZATION OF OMEGA-TRIALKYLPLUMBYL AND OMEGA-TRIALKYLSTANNYL ETHER ACETALS

    J YAMADA, T ASANO, KADOTA, I, Y YAMAMOTO

    JOURNAL OF ORGANIC CHEMISTRY   55 ( 25 )   6066 - 6068   1990年12月

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    記述言語:英語   掲載種別:記事・総説・解説・論説等(学術雑誌)   出版者・発行元:AMER CHEMICAL SOC  

    DOI: 10.1021/jo00312a003

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  • A NEW APPROACH TO THE CONSTRUCTION OF BETA-ALKOXY-SUBSTITUTED CYCLIC ETHERS VIA THE INTRAMOLECULAR CYCLIZATION OF OMEGA-TRIALKYLPLUMBYL AND OMEGA-TRIALKYLSTANNYL ETHER ACETALS

    J YAMADA, T ASANO, KADOTA, I, Y YAMAMOTO

    JOURNAL OF ORGANIC CHEMISTRY   55 ( 25 )   6066 - 6068   1990年12月

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    記述言語:英語   掲載種別:記事・総説・解説・論説等(学術雑誌)   出版者・発行元:AMER CHEMICAL SOC  

    DOI: 10.1021/jo00312a003

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  • A NOVEL CARBON CARBON BOND-FORMING REACTION OF TRIFLATES WITH COPPER(I)-CATALYZED GRIGNARD-REAGENTS - A NEW CONCISE AND ENANTIOSPECIFIC SYNTHESIS OF (+)-EXO-BREVICOMIN, (5R,6S)-(-)-6-ACETOXY-5-HEXADECANOLIDE, AND L-FACTOR

    H KOTSUKI, KADOTA, I, M OCHI

    JOURNAL OF ORGANIC CHEMISTRY   55 ( 14 )   4417 - 4422   1990年7月

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    記述言語:英語   出版者・発行元:AMER CHEMICAL SOC  

    DOI: 10.1021/jo00301a038

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  • A NOVEL CARBON CARBON BOND-FORMING REACTION OF TRIFLATES WITH COPPER(I)-CATALYZED GRIGNARD-REAGENTS - A NEW CONCISE AND ENANTIOSPECIFIC SYNTHESIS OF (+)-EXO-BREVICOMIN, (5R,6S)-(-)-6-ACETOXY-5-HEXADECANOLIDE, AND L-FACTOR

    H KOTSUKI, KADOTA, I, M OCHI

    JOURNAL OF ORGANIC CHEMISTRY   55 ( 14 )   4417 - 4422   1990年7月

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    記述言語:英語   出版者・発行元:AMER CHEMICAL SOC  

    DOI: 10.1021/jo00301a038

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  • A MILD REDUCTION OF AZOMETHINES WITH ZINC BOROHYDRIDE - SYNTHETIC APPLICATION TO TANDEM ALKYLATION REDUCTION OF NITRILES

    H KOTSUKI, N YOSHIMURA, KADOTA, I, Y USHIO, M OCHI

    SYNTHESIS-STUTTGART   ,401-402 ( 5 )   401 - 402   1990年5月

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    記述言語:英語   出版者・発行元:GEORG THIEME VERLAG  

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  • A MILD REDUCTION OF AZOMETHINES WITH ZINC BOROHYDRIDE - SYNTHETIC APPLICATION TO TANDEM ALKYLATION REDUCTION OF NITRILES

    H KOTSUKI, N YOSHIMURA, KADOTA, I, Y USHIO, M OCHI

    SYNTHESIS-STUTTGART   ,401-402 ( 5 )   401 - 402   1990年5月

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    記述言語:英語   出版者・発行元:GEORG THIEME VERLAG  

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  • A SIMPLE AND EFFICIENT HETEROGENEOUS HYDROLYSIS OF N,N-DIMETHYLHYDRAZONE DERIVATIVES

    H KOTSUKI, A MIYAZAKI, KADOTA, I, M OCHI

    JOURNAL OF THE CHEMICAL SOCIETY-PERKIN TRANSACTIONS 1   ,429-430 ( 2 )   429 - 430   1990年2月

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    記述言語:英語   掲載種別:記事・総説・解説・論説等(学術雑誌)   出版者・発行元:ROYAL SOC CHEMISTRY  

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  • A SIMPLE AND EFFICIENT HETEROGENEOUS HYDROLYSIS OF N,N-DIMETHYLHYDRAZONE DERIVATIVES

    H KOTSUKI, A MIYAZAKI, KADOTA, I, M OCHI

    JOURNAL OF THE CHEMICAL SOCIETY-PERKIN TRANSACTIONS 1   ,429-430 ( 2 )   429 - 430   1990年2月

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    記述言語:英語   掲載種別:記事・総説・解説・論説等(学術雑誌)   出版者・発行元:ROYAL SOC CHEMISTRY  

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  • AN EFFICIENT METHOD FOR THE ALKYLATION OF CHIRAL TRIFLATES WITH ALKYNYLLITHIUM REAGENTS - A HIGHLY CONCISE TOTAL SYNTHESIS OF (+)-PANAXACOL

    H KOTSUKI, KADOTA, I, M OCHI

    TETRAHEDRON LETTERS   31 ( 32 )   4609 - 4612   1990年

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    記述言語:英語   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    DOI: 10.1016/S0040-4039(00)97688-3

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  • AN EFFICIENT METHOD FOR THE ALKYLATION OF CHIRAL TRIFLATES WITH ALKYNYLLITHIUM REAGENTS - A HIGHLY CONCISE TOTAL SYNTHESIS OF (+)-PANAXACOL

    H KOTSUKI, KADOTA, I, M OCHI

    TETRAHEDRON LETTERS   31 ( 32 )   4609 - 4612   1990年

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    記述言語:英語   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    DOI: 10.1016/S0040-4039(00)97688-3

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  • STEREOSELECTIVE REDUCTION OF BICYCLIC KETALS - A NEW, ENANTIOSELECTIVE SYNTHESIS OF ISOLAUREPINNACIN AND LAUTHISAN SKELETONS

    H KOTSUKI, Y USHIO, KADOTA, I, M OCHI

    JOURNAL OF ORGANIC CHEMISTRY   54 ( 21 )   5153 - 5161   1989年10月

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    記述言語:英語   出版者・発行元:AMER CHEMICAL SOC  

    DOI: 10.1021/jo00282a037

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  • STEREOSELECTIVE REDUCTION OF BICYCLIC KETALS - A NEW, ENANTIOSELECTIVE SYNTHESIS OF ISOLAUREPINNACIN AND LAUTHISAN SKELETONS

    H KOTSUKI, Y USHIO, KADOTA, I, M OCHI

    JOURNAL OF ORGANIC CHEMISTRY   54 ( 21 )   5153 - 5161   1989年10月

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    記述言語:英語   出版者・発行元:AMER CHEMICAL SOC  

    DOI: 10.1021/jo00282a037

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  • A NEW EXPEDITIOUS SYNTHESIS OF (+)-EXO-BREVICOMIN VIA EFFICIENT C-C BOND FORMATION OF TRIFLATES

    H KOTSUKI, KADOTA, I, M OCHI

    TETRAHEDRON LETTERS   30 ( 30 )   3999 - 4000   1989年

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    記述言語:英語   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    DOI: 10.1016/S0040-4039(00)99305-5

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  • A Novel Method for Copper(I)-Catalyzed Coupling Reactions of Triflates with Grignard Reagents

    Tetrahedron Letters   30 ( 10 )   1281 - 1284   1989年

  • A New Expeditious Synthesis of (+)-exo-Brevicomin via Efficient C-C Bond Formation of Triflutes

    KOTSUKI H, KADOTA I, OCHI M

    Tetrahedron Letters   30 ( 30 )   3999 - 4000   1989年

  • A NOVEL METHOD FOR COPPER(I)-CATALYZED COUPLING REACTIONS OF TRIFLATES WITH GRIGNARD-REAGENTS

    H KOTSUKI, KADOTA, I, M OCHI

    TETRAHEDRON LETTERS   30 ( 10 )   1281 - 1284   1989年

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    記述言語:英語   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    DOI: 10.1016/S0040-4039(00)72737-7

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  • STEREOSELECTIVE REDUCTION OF BICYCLIC KETALS - AN EFFICIENT SYNTHESIS OF (-)-(R,R)-(CIS-6-METHYLTETRAHYDROPYRAN-2-YL)-ACETIC ACID, AN ENANTIOMER OF CIVET CAT CONSTITUENT

    H KOTSUKI, Y USHIO, KADOTA, I, M OCHI

    CHEMISTRY LETTERS   ,927-930 ( 6 )   927 - 930   1988年6月

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    記述言語:英語   出版者・発行元:CHEMICAL SOC JAPAN  

    DOI: 10.1246/cl.1988.927

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  • STEREOSELECTIVE REDUCTION OF BICYCLIC KETALS - AN EFFICIENT SYNTHESIS OF (-)-(R,R)-(CIS-6-METHYLTETRAHYDROPYRAN-2-YL)-ACETIC ACID, AN ENANTIOMER OF CIVET CAT CONSTITUENT

    H KOTSUKI, Y USHIO, KADOTA, I, M OCHI

    CHEMISTRY LETTERS   ,927-930 ( 6 )   927 - 930   1988年6月

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    記述言語:英語   出版者・発行元:CHEMICAL SOC JAPAN  

    DOI: 10.1246/cl.1988.927

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▼全件表示

受賞

  • 日本化学会進歩賞

    1998年  

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    受賞国:日本国

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  • 日本化学会若い世代の特別講演賞

    1997年  

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    受賞国:日本国

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共同研究・競争的資金等の研究

  • 海産毒シガトキシン類および海洋産マクロライド類の収束的全合成

    研究課題/領域番号:20K05496  2020年04月 - 2023年03月

    日本学術振興会  科学研究費助成事業 基盤研究(C)  基盤研究(C)

    門田 功

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    配分額:4420000円 ( 直接経費:3400000円 、 間接経費:1020000円 )

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  • 分子内アリル化を鍵段階とする海洋産天然物の収束的全合成

    研究課題/領域番号:17K05863  2017年04月 - 2020年03月

    日本学術振興会  科学研究費助成事業 基盤研究(C)  基盤研究(C)

    門田 功

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    配分額:4810000円 ( 直接経費:3700000円 、 間接経費:1110000円 )

    分子内アリル化反応と閉環メタセシスにより、海洋産のポリエーエルであるシガトキシンCTX3CのA-E環部およびH-M環部をそれぞれ立体選択的に合成することができた。さらにエステル縮合と分子内アリル化を行うことによって両者を連結した。また、新たに開発した分子間-分子内ダブルアリル化反応を用いることで、海洋産のTHPマクロライドであるダクチロライドの全合成とエニグマゾールAの形式全合成にも成功した。

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  • エーテル環構築を伴うセグメント連結法を用いた生理活性天然物の収束的合成

    研究課題/領域番号:25410118  2013年04月 - 2016年03月

    日本学術振興会  科学研究費助成事業 基盤研究(C)  基盤研究(C)

    門田 功, 髙村 浩由

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    配分額:5330000円 ( 直接経費:4100000円 、 間接経費:1230000円 )

    海洋生物が生産する二次代謝物は、強力な生理活性を有することから医薬品のリード化合物として注目を集めている。しかし、これらの化合物は天然からの入手が極めて困難であり、化学合成による試料供給が求められている。また、その特異な構造は合成化学者にとっても魅力的なターゲットである。本研究では、分子内アリル化を活用した収束的分子構築法を用い、これら海洋産生理活性天然物の合成について検討した。

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  • 分子内アリル化を基盤とする海産毒シガトキシンおよびブレビシンの合成研究

    研究課題/領域番号:22550036  2010年 - 2012年

    日本学術振興会  科学研究費助成事業 基盤研究(C)  基盤研究(C)

    門田 功

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    配分額:4680000円 ( 直接経費:3600000円 、 間接経費:1080000円 )

    海洋産の渦鞭毛藻が生産するポリ環状エーテル類は、その特異な構造と強力な生理活性から魅力的な合成ターゲットとして興味が持たれている。また、これらの化合物は天然からは極微量しか得られず、生理活性に関する詳細な研究が行われていないため、化学合成による試料供給が重要な課題となっている。本研究では、分子内アリル化反応と閉環メタセシス反応を用いたポリ環状エーテルの収束的合成について検討を行った。

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  • 海洋産ポリ環状エーテルの効率的全合成

    研究課題/領域番号:19350023  2007年 - 2009年

    日本学術振興会  科学研究費助成事業 基盤研究(B)  基盤研究(B)

    門田 功, 高村 浩由

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    配分額:19110000円 ( 直接経費:14700000円 、 間接経費:4410000円 )

    近年、海洋産の生理活性天然物が多くの注目を集めている。中でも、渦鞭毛藻が生産するポリ環状エーテル類は、その特異な構造と強力な生理活性から魅力的かつチャレンジングな合成ターゲットとして興味が持たれている。また、これらの化合物は天然からは極微量しか得られず、生理活性に関する詳細な研究が行われていないため、化学合成による試料供給が重要な課題となっている。本研究では、分子内アリル化反応と閉環メタセシス反応を基盤とする収束的合成法を利用し、ブレベナールおよびシガトキシンCTX3Cの合成研究を行った。

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  • 海洋産ポリ環状エーテルの高効率全合成

    研究課題/領域番号:15750075  2003年 - 2005年

    日本学術振興会  科学研究費助成事業 若手研究(B)  若手研究(B)

    門田 功

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    配分額:3400000円 ( 直接経費:3400000円 )

    昨年に引き続き、赤潮の原因毒であるブレベトキシンBの合成研究を行った。デオキシリボースを光学活性源として、BC環部に相当するα-クロロスルフィドとFG環部アルコールをそれぞれ合成した。両者を銀トリフレートを用いて縮合し、O,S-アセタールを合成した。さらに数段階でアリルスズを導入して分子内アリル化反応のための基質を合成した。この化合物を銀トリフレートで処理したところ84%の収率で環化反応が進行し、目的の化合物が立体選択的に得られてきた。得られた化合物に対し、Grubbs触媒による閉環メタセシスをおこなってB-G環セグメントを得ることができた。さらに数段階を経てA環を構築し、A-G環部とした。これをJK環部に相当するカルボン酸とエステル縮合し、さらに数段階を経て環化前駆体を合成した。この化合物に対して先ほどと同様に分子内アリル化と閉環メタセシスをおこない、ブレベトキシンBのポリエーテル骨格を得ることができた。この化合物に対してラクトン化、脱保護、アリルアルコールの選択的酸化を行い、ブレベトキシンBの全合成を完了した。合成品の各種スペクトルデータは天然のものと完全に一致した。
    また、同様の方法論を用い、イェッソトキシンおよびアドリアトキシンのFGHI環部の収束的合成に成功した。これらの化合物は下痢性貝毒の原因毒として、二枚貝養殖に多きな被害を与えており、ブレベトキシンBと同様深刻な社会問題となっている。本研究により、これら海産毒の活性発現機構に関する研究が進展するものと期待される。

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  • ルイス酸・遷移金属触媒を用いる環境調和型分子変換プロセスの開拓

    研究課題/領域番号:14002001  2002年 - 2006年

    日本学術振興会  科学研究費助成事業 特別推進研究  特別推進研究

    山本 嘉則, 浅尾 直樹, 中村 達, 金 鉄男, 門田 功, PATIL Nitin T., BAJRACHARYA Gan B., 上條 真

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    配分額:585000000円 ( 直接経費:450000000円 、 間接経費:135000000円 )

    π電子配位性ルイス酸触媒およびルイス酸・遷移金属両機能性触媒反応の開発:13族由来のルイス酸のもつC-C多重結合に対する高い親和性を利用し、σ-πキレーションを経る立体制御を達成した。この研究中、二価のパラジウムが遷移金属触媒としてだけではなく、同時にルイス酸触媒としても働くことを見いだし、抗腫瘍物質BCH-2051および抗酸化剤vibsanolの合成に成功した。また、金触媒を用いた反応により、抗生物質(+)-ochromycinoneおよび(+)-rubiginone B2の合成に成功した。
    ビス-π-アリルパラジウム触媒反応の開発:光学活性ビス-π-アリルパラジウム触媒を用い、イミンの不斉アリル化に成功し、さらに抗生物質DMP-777の合成中間体を得ることに成功した。また、関連する反応として、三成分連結によるシアノインドールの新規合成法を開発した。
    C-C多重結合に対するプロ求核体の触媒的付加反応:パラジウム-酢酸触媒を用いると、アミンとアルキンの分子内反応が、含窒素ヘテロ環化合物を高収率で与えることを見いだした。この反応を応用し、インドリジチンアルカロイド209Dの合成に成功した。
    C-H結合の活性化:メチレンシクロプロパンとパラジウム触媒を用い、種々の複素芳香環化合物およびケトン類の触媒的α位アリル化に成功した。一方、メチレンアジリジンを用いると、ピリジン環あるいはベンゼン環を有するピロール誘導体を与えることを見いだした。
    ポリ環状エーテルの高効率全合成:ルイス酸による分子内アリル化反応とルテニウム触媒による閉環メタセシスを組み合わせた収束的分子構築法により、巨大なポリ環状エーテル骨格を有する海産毒ガンビエロールおよびブレベトキシンBの全合成に成功した。

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  • 海洋産ポリ環状エーテルの合成研究

    研究課題/領域番号:12740337  2000年 - 2001年

    日本学術振興会  科学研究費助成事業 奨励研究(A)  奨励研究(A)

    門田 功

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    配分額:2200000円 ( 直接経費:2200000円 )

    まず、ガンビエロールのE環およびH環部の短段階合成について検討した。デオキシリボースから誘導した7員環ラクトンを定法によりケテンアセタールトリフレートとした。これに対し、パラジウム触媒依存下、亜鉛ホモエノレートを作用させることで対応するカップリング生成物を良好な収率で得ることに成功した。得られた生成物は、ハイドロボレーションおよびラクトン化によって、ガンビエロールE環部およびH環部へと変換することができた。今回用いた方法では、アリルスズを用いる従来法に比べて行程数を約3分の2に短縮することができた。次に各セグメントの連結についてのモデル実験を行った。カルボン酸とアルコールから合成したエステルに対し、脱保護、アセタール化、脱離を行いアリルスズを導入した。次にエステル部をDIBALHで還元した後、生じたアルミニウムヘミアセタールを無水酢酸でトラップし、αーアセトキシエーテルを合成した。同様の方法で様々な環化前駆体を合成し、ルイス酸による環化反応を検討した。反応はどの場合も収率良く進行し、目的の化合物が立体選択的に得られてきた。次に得られたジエンに対し、ルテニウム触媒を用いる閉環メタセシスを検討した。この場合も反応は収率良く進行し、様々な大きさのポリ環状エーテルを得ることができた。また、同様の方法論を用いることで、ガンビエロールのCDEFG環部の合成にも成功した。

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  • 海洋産ポリ環状エーテルの合成研究

    研究課題/領域番号:11740341  1999年

    日本学術振興会  科学研究費助成事業 奨励研究(A)  奨励研究(A)

    門田 功

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    配分額:1400000円 ( 直接経費:1400000円 )

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  • 海産毒ガンビエロールの合成研究

    研究課題/領域番号:09740538  1997年 - 1998年

    日本学術振興会  科学研究費助成事業 奨励研究(A)  奨励研究(A)

    門田 功

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    配分額:2100000円 ( 直接経費:2100000円 )

    海産毒ガンビエロールの全合成研究の一環として、AB環、E環、およびH環部の合成を行った。まず、2-deoxy-D-riboseを光学活性源とし、文献記載の方法でB環部に相当する部分を合成した。この化合物に対し、キラルなアリルボランを作用させ、目的のアリル化体をほぼ単一物として得ることができた。さらに分子内ヘテロマイケル反応によって環化を行い、AB環の合成に成功した。7員環エーテルであるE環部は、アリルスズとアルデヒドとの分子内反応を用いて合成した。すなわち、D-riboseから数段階で環化前駆体を合成し、ルイス酸を作用させることにより、高収率で目的のE環部を合成することができた。このとき、かなりの割合で立体異性体が得られてきたが、数段階の操作で目的物に変換することができた。H環部についても同様の方法論を用いた。すなわち、2-deoxy-D-riboseから出発し、アリルスズとアルデヒドとの分子内反応を用いて7員環を合成した。このときには他の立体異性体は全く得られず、目的物のみが単一物として得られてきた。環内に二重結合とメチル基を立体選択的に導入した後、パラジウム触媒による有機スズ化合物とのカップリング反応によって側鎖のトリエン部を構築し、H環部を合成することができた。現在、この様にして合成した各セグメントの連結について検討中である。

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  • キラルβ-ラクタム合成の新手法

    研究課題/領域番号:07044305  1995年

    日本学術振興会  科学研究費助成事業 国際学術研究  国際学術研究

    山本 嘉則, GYOUNG Young, 中村 浩之, 門田 功, 浅尾 直樹, 根本 尚夫

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    カルバペネム系抗生物質は、優れた抗菌力を持つチエナマイシンの発見以来、次世代のβラクタム系抗生物質として注目されている。チエナマイシンはその医薬品化に配合剤が必要とされたが、近年発見された1β-メチルカルバペネムは強い化学的および生物的安定性を持ち、配合剤を用いない形での単独での医薬品化が期待されている。しかし、この1β-メチルカルバペネムは微生物により産生されるものではなく、化学的に合成しなければならず、工業的に大量生産するための効率のよい新規合成法の開発が望まれている。本申請者はこれまでに、光学活性な窒素求核剤の共役エステルへの共役付加とアルドール反応とを組み合わせた三成分連結法について研究を行っており、この合成法を用いチエナマイシンの合成前駆体の不斉合成に成功している。今回、この三成分連結法を用い、四つの連続した不斉点を有する1β-メチルカルバペネムの不斉合成について検討した。
    初めに、γ位にメチル基を有するα,β-不飽和エステル2を用い、その不斉点による不斉誘導を行った。その結果、トランス体のβアミノエステルを立体選択的に得ることに成功した。しかし、その反応では目的とするシス体のβアミノエステル3を、満足できる立体選択性で得ることはできなかった。
    【chemical
    そこで次に、光学活性リチウムアミド1を用いて不斉誘導を行った。その結果、反応は非常に高い立体選択性で進行し、高収率でβアミノエステル3を単一生成物として得ることができた。また、この反応では、出発のα,β-不飽和エステル2のジオメトリーに関係なく、E体、Z体のいずれからも同様の立体選択性で3が得られた。
    次に3からリチウムエノラートを発生させアセトアルデヒドとアルドール反応を行った。種々の添加剤を検討した結果、二塩化エチルアルミニウムを用いたときに最も高い立体選択性で、1β-メチルカルバペネム合成に必要な四つの不斉点を持つアルドール体4を得ることが出来た。さらに4を数ステップの反応により1β-メチルカルバペネムの合成中間体として知られるβ-ラクタム5へと誘導することに成功した。
    光学活性リチウムアミド1の共役付加とそれに続くアルドール反応とを組み合わせた三成分連結法を用いることにより、βラクタム系抗生物質である1β-メチルカルバペネム高効率合成法の開発に成功した。
    【chemical

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  • 海産毒ヘミブレベトキシンBの合成とその生理活性に関する研究

    研究課題/領域番号:07740483  1995年

    日本学術振興会  科学研究費助成事業 奨励研究(A)  奨励研究(A)

    門田 功

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    配分額:800000円 ( 直接経費:800000円 )

    海洋産のポリエーテル系天然物であるヘミブレベトキシンBの合成研究を行った。この化合物は赤潮の原因毒の一つとして渦鞭毛藻の一種Gymnodinium breveから単離された四環性の化合物である。興味深いことにこの魚毒成分は海産ポリエーテルに共通する神経毒性以外に腫瘍細胞に対する活性を示すことが知られており、医薬品への応用も期待されている。本研究では光学活性なd-マンノースから出発し、有機スズ化合物とアルデヒドとの分子内環化反応を利用することによって、ポリエーテル骨格を構築するというルートをとった。その結果、ヘミブレベトキシンBに含まれる四つのエーテル環を全て高立体選択的に合成することに成功した。続いて既知法によって二つの側鎖を導入し、全合成を完了した。今後更に検討を続け、この天然物の大量供給法を確立する。また、その生理活性について詳細な調査を実施し、活性発現機構など生体内での動的挙動についての研究を行う予定である。

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  • 海洋産ポリエーテル系天然物の合成研究

    研究課題/領域番号:06740545  1994年

    日本学術振興会  科学研究費助成事業 奨励研究(A)  奨励研究(A)

    門田 功

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    配分額:900000円 ( 直接経費:900000円 )

    海洋産のポリエーテル系天然物であるヘミブレべトキシンB(1)の合成研究を行った。この化合物は赤潮の原因毒の一つとして渦鞭毛藻の一種Gymnodinium breveから単離された四環性の化合物である。興味深いことにこの魚毒成分は海産ポリエーテルに共通する神経毒性以外に腫瘍細胞に対する活性を示すことが知られており、医薬品への応用も期待されている。本研究では光学活性なd-マンノース2から出発し、有機スズ化合物の分子内環化反応を利用することによって、ポリエーテル骨格を構築するというルートをとった。その結果、ヘミブレベトキシンBに含まれる四つのエーテル環を有する化合物3を高立体選択的に合成することに成功した。今後さらに研究を続け、残る測鎖の導入を行いこの天然物の全合成を目指す。また、合成完了時にはその生理活性についてさらに詳細な調査を実施し、活性発現機構など生体内での動的挙動についての研究を行う予定である。また天然物そのものに対して各種の化学修飾を施し、その生理活性を調べることによって海洋産ポリエーテルの構造活性相関についての研究も行う。

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  • その他の研究制度 

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    資金種別:競争的資金

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    The Other Research Programs 

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    資金種別:競争的資金

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