研究者詳細 - 髙村　浩由

論文 - 髙村　浩由

分割表示 >> ／全件表示 68 件中 1 - 68 件目

A direct oxidative esterification of aldehydes with alcohols mediated by photochemical C–H bromination 査読

Haru Ando, Sakura Kodaki, Hiroyoshi Takamura, Isao Kadota, Kenta Tanaka

Organic & Biomolecular Chemistry 22 ( 46 ) 9032 - 9035 2024年9月

Synthesis of Ozonides Mediated by Molecular Sieve Under Solvent-Free Conditions 査読

Mohamed R. El-kholany, Nana Kishimoto, Kenta Tanaka, Hiroyoshi Takamura, Isao Kadota

Tetrahedron 134137 - 134137 2024年7月

Total synthesis and structure–antifouling activity relationship of scabrolide F 査読

Hiroyoshi Takamura, Yuki Sugitani, Ryohei Morishita, Takefumi Yorisue, Isao Kadota

Organic & Biomolecular Chemistry 22 ( 28 ) 5739 - 5747 2024年5月

担当区分：筆頭著者,　責任著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Royal Society of Chemistry (RSC)

The details of our total synthesis of scabrolide F are described. The synthetic scabrolide F and its synthetic intermediates exhibited antifouling activity without toxicity.

DOI： 10.1039/d4ob00698d

Strongly reducing helical phenothiazines as recyclable organophotoredox catalysts 査読

Haru Ando, Hiroyoshi Takamura, Isao Kadota, Kenta Tanaka

Chemical Communications 60 ( 36 ) 4765 - 4768 2024年3月

Efficient Method for the Preparation of Ozonides Under Dry Conditions 査読国際共著国際誌

Mohamed R. El-kholany, Nana Kishimoto, Kenta Tanaka, Hiroyoshi Takamura, Isao Kadota

Bulletin of the Chemical Society of Japan 96 ( 12 ) 1316 - 1318 2023年10月

Relative stereochemical determination of the C61–C83 fragment of symbiodinolide using a stereodivergent synthetic approach 査読国際誌

Hiroyoshi Takamura, Kosuke Hattori, Takumi Ohashi, Taichi Otsu, Isao Kadota

Organic & Biomolecular Chemistry 21 ( 44 ) 8837 - 8848 2023年9月

担当区分：筆頭著者,　責任著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Royal Society of Chemistry (RSC)

Stereodivergent synthesis of the C61–C74 and C69–C83 fragments of symbiodinolide elucidated the relative configuration of its C61–C83 fragment.

DOI： 10.1039/d3ob01420g

Chemical synthesis and antifouling activity of monoterpene–furan hybrid molecules 査読国際誌

Hiroyoshi Takamura, Yuya Kinoshita, Takefumi Yorisue, Isao Kadota

Organic & Biomolecular Chemistry 21 ( 3 ) 632 - 638 2023年

Total Synthesis of Scabrolide F 査読国際誌

Hiroyoshi Takamura, Yuki Sugitani, Ryohei Morishita, Isao Kadota

Organic Letters 24 ( 42 ) 7845 - 7849 2022年10月

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

担当区分：筆頭著者,　責任著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：WILEY-V C H VERLAG GMBH

Xylemin (6) and its designed structural analogues 18-23, N-(4-aminobutyl)alkylamines, were synthesized by 2-nitrobenzenesulfonamide (Ns) strategy. Investigation of the improved synthesis of 20-23 resulted in the development of one-step synthesis of these analogues from the commercially available corresponding ketones. Biological assessment of the synthetic molecules elucidated that xylemin (6) and the analogue N-(4-aminobutyl)cyclopentylamine (21) promoted the expression level of thermospermine synthase ACAULIS5 (ACL5) and enhanced xylem formation. In addition, xylemin (6) was found to significantly promote lateral root formation, whereas xylemin analogues 18-23 including 21 did not. These results indicate that the analogue 21 has the potential as a novel inhibitor of thermospermine synthesis to work specifically in xylem differentiation.

DOI： 10.1002/ejoc.202000322

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

Hiroyoshi Takamura, Isao Kadota

Journal of Synthetic Organic Chemistry, Japan 77 ( 12 ) 1190 - 1200 2019年12月

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

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 stereoselective synthesis of the macrolactone core of neopeltolide is described. The tetrahydropyran moiety was constructed via the intramolecular allylation of an alpha-acetoxy ether. A late-stage macrolactonization provided a known synthetic intermediate of neopeltolide. (C) 2018 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.tetlet.2018.12.066

Concise Synthesis of Anticancer Active trans-4-(4-Octylphenyl)prolinol 査読

Hiroyoshi Takamura, Minoru Tanaka, Junki Ando, Aoi Tazawa, Kohei Ishizawa

HETEROCYCLES 99 ( 1 ) 716 - 716 2019年

Stereodivergent and Stereoselective Synthesis of cis- and trans-4-Substituted Prolinols 査読

Hiroyoshi Takamura, Minoru Tanaka, Junki Ando, Aoi Tazawa, Kohei Ishizawa

HETEROCYCLES 99 ( 1 ) 188 - 188 2019年

Formal total synthesis of enigmazole A 査読

Andreas Meissner, Takayuki Kishi, Yuka Fujisawa, Yuto Murai, Hiroyoshi Takamura, Isao Kadota

Tetrahedron Letters 59 ( 51 ) 4492 - 4495 2018年12月

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 stereoselective formal total synthesis of enigmazole A, a marine macrolide isolated from Cinachyrella enigmatica, is described. Lewis acid mediated intramolecular allylation of an alpha-acetoxy ether, prepared from alcohol and carboxylic acid fragments was carried out to construct the methylene THP ring with high stereoselectivity. The late-stage macrolactonization of the corresponding seco-acid provided a known synthetic intermediate of enigmazole A. (C) 2018 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.tetlet.2018.11.017

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

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

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

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

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 A-E 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 A-E ring framework was performed by using the intramolecular allylation of alpha-acetoxy ether followed by ring-closing metathesis.

DOI： 10.1246/bcsj.20170390

Recent topics of the stereodivergent synthesis of natural products 査読

Hiroyoshi Takamura

Tetrahedron Letters 59 ( 11 ) 955 - 966 2018年3月

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

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 alpha-acetoxy ether. The cyclization precursor was prepared from two segments, an alcohol and carboxylic acid derivatives, by esterification followed by reductive acetylation. (C) 2018 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.tetlet.2018.01.034

Total Synthesis of Rhoiptelol B 査読

Isao Kadota, Nobuhiro Tanaka, Hiroyoshi Takamura

HETEROCYCLES 97 ( 2 ) 1157 - 1157 2018年

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 Japan Institute of Heterocyclic Chemistry

A stereoselective total synthesis of rhoiptelol B, a diarylheptanoid isolated from the fruits of Rhoiptelea chiliantha, is described. The tetrahydropyran ring was constructed via an intramolecular allylation methodology.

DOI： 10.3987/com-18-s(t)57

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

Hiroyoshi Takamura, Tomoya Katsube, Kazuki Okamoto, Isao Kadota

CHEMISTRY-A EUROPEAN JOURNAL 23 ( 68 ) 17191 - 17194 2017年12月

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-V C H VERLAG GMBH

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 H-1 and (CNMR)-C-13 data and specific rotation with those of the natural product elucidated the absolute configuration of natural (-)-6-chlorotetrahydrofuran acetogenin 1.

DOI： 10.1002/chem.201704514

Late-Stage Divergent Synthesis and Antifouling Activity of Geraniol–Butenolide Hybrid Molecules

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

Organic and Biomolecular Chemistry 15 ( 26 ) 5549 - 5555 2017年7月

Total Synthesis of Sarcophytonolide H and Isosarcophytonolide D: Structural Revision of Isosarcophytonolide D and Structure-Antifouling Activity Relationship of Sarcophytonolide H

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

ORGANIC LETTERS 18 ( 9 ) 2110 - 2113 2016年5月

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 first total syntheses of sarcophytonolide H and the originally proposed and correct structures of isosarcophytonolide D have been achieved via transannular ring-closing metathesis (RCM). These total syntheses culminated in the stereostructural confirmation of sarcophytonolide H and the reassignment of isosarcophytonolide D, respectively. The antifouling activity of the synthetic sarcophytonolide H and its analogues was also evaluated.

DOI： 10.1021/acs.orglett.6b00737

Inside Back Cover: Stereodivergent Synthesis and Stereochemical Reassignment of the C79-C104 Fragment of Symbiodinolide (Chem. Eur. J. 6/2016)

Hiroyoshi Takamura, Takayuki Fujiwara, Yohei Kawakubo, Isao Kadota, Daisuke Uemura

Chemistry - A European Journal 22 ( 6 ) 2183 - 2183 2016年2月

Chemical control of xylem differentiation by thermospermine, xylemin, and auxin

Kaori Yoshimoto, Hiroyoshi Takamura, Isao Kadota, Hiroyasu Motose, Taku Takahashi

SCIENTIFIC REPORTS 6 2016年2月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：NATURE PUBLISHING GROUP

The xylem conducts water and minerals from the root to the shoot and provides mechanical strength to the plant body. The vascular precursor cells of the procambium differentiate to form continuous vascular strands, from which xylem and phloem cells are generated in the proper spatiotemporal pattern. Procambium formation and xylem differentiation are directed by auxin. In angiosperms, thermospermine, a structural isomer of spermine, suppresses xylem differentiation by limiting auxin signalling. However, the process of auxin-inducible xylem differentiation has not been fully elucidated and remains difficult to manipulate. Here, we found that an antagonist of spermidine can act as an inhibitor of thermospermine biosynthesis and results in excessive xylem differentiation, which is a phenocopy of a thermospermine-deficient mutant acaulis5 in Arabidopsis thaliana. We named this compound xylemin owing to its xylem-inducing effect. Application of a combination of xylemin and thermospermine to wild-type seedlings negates the effect of xylemin, whereas co-treatment with xylemin and a synthetic proauxin, which undergoes hydrolysis to release active auxin, has a synergistic inductive effect on xylem differentiation. Thus, xylemin may serve as a useful transformative chemical tool not only for the study of thermospermine function in various plant species but also for the control of xylem induction and woody biomass production.

DOI： 10.1038/srep21487

Stereodivergent Synthesis and Stereochemical Reassignment of the C79-C104 Fragment of Symbiodinolide

Hiroyoshi Takamura, Takayuki Fujiwara, Yohei Kawakubo, Isao Kadota, Daisuke Uemura

CHEMISTRY-A EUROPEAN JOURNAL 22 ( 6 ) 1984 - 1996 2016年2月

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-V C H VERLAG GMBH

We have synthesized eight possible diastereoisomers 3a-h of the C79-C97 fragment of symbiodinolide (1) in a stereodivergent manner by utilizing a dithiane addition to the aldehyde as a key step. Comparison of the (CNMR)-C-13 chemical shifts of the natural product 1 and the synthetic products 3a-h indicated that the relative stereostructure of this fragment in symbiodinolide (1) is that represented in 3a or f. We have stereodivergently synthesized eight possible diastereoisomers of the C94-C104 fragment 4a-h, and we have compared their (CNMR)-C-13 chemical shifts with those of the natural product, which established the relative stereochemistry of this fragment to be that described in diastereoisomers 4a or e. By combining the stereostructural outcomes of the C79-C97 and C94-C104 fragments, we have proposed four candidate compounds of the C79-C104 fragment 2a-d. We also synthesized diastereoisomers 2a and b (2a in the preceding article; Chem. Eur. J. 2015, DOI: 10.1002/chem.201503880) by a Julia-Kocienski olefination and diastereoisomers 2c and d by a Wittig reaction. By comparing the (CNMR)-C-13 chemical shifts of natural symbiodinolide (1) with those of the synthetic products 2a-d, we have reassigned the stereostructure of the C79-C104 fragment of natural product 1 to be that depicted in diastereoisomer 2b.

DOI： 10.1002/chem.201503881

Stereoselective Synthesis of the Proposed C79-C104 Fragment of Symbiodinolide

Hiroyoshi Takamura, Takayuki Fujiwara, Yohei Kawakubo, Isao Kadota, Daisuke Uemura

CHEMISTRY-A EUROPEAN JOURNAL 22 ( 6 ) 1979 - 1983 2016年2月

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-V C H VERLAG GMBH

Stereoselective and streamlined synthesis of the proposed C79-C104 fragment 2 of symbiodinolide (1), a polyol marine natural product with a molecular weight of 2860, was achieved. In the synthetic route, the proposed C79-C104 fragment 2 was synthesized by utilizing a Julia-Kocienski olefination and subsequent Sharpless asymmetric dihydroxylation as key transformations in a convergent manner. Detailed comparison of the (CNMR)-C-13 chemical shifts between the natural product and the synthetic C79-C104 fragment 2 revealed that the stereostructure at the C91-C99 carbon chain moiety of symbiodinolide (1) should be reinvestigated.

DOI： 10.1002/chem.201503880

Convergent synthesis of the EFGH ring system of ciguatoxin CTX3C

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

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

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

Stereodivergent Synthesis and Relative Stereostructure of the C1–C13 Fragment of Symbiodinolide

Takamura, H, Wada, H, Ogino, M, Kikuchi, T, Kadota, I, Uemura, D

J. Org. Chem. 80 ( 6 ) 3111 - 3123 2015年3月

Stereocontrolled Synthesis of the C1–C17 Fragment of Enigmazole A

Kishi, T, Fujisawa, Y, Takamura, H, Kadota, I

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

Improved Synthesis of the A–E Ring Segment of Ciguatoxin CTX3C

Shiroma, K, Asakura, H, Tanaka, T, Takamura, H, Kadota, I

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

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 ) 2 - 13 2014年

Stereoselective Synthesis of the C79‒C97 Fragment of Symbiodinolide

Takamura, H, Wada, H, Lu, N, Ohno, O, Suenaga, K, Kadota, I

Beilstein J. Org. Chem. 9 1931 - 1935 2013年9月

Total Synthesis, Structural Elucidation, and Structure–Cytotoxic Activity Relationship of (–)-Gummiferol

Takamura, H, Wada, H, Lu, N, Ohno, O, Suenaga, K, Kadota, I

J. Org. Chem. 78 ( 6 ) 2443 - 2454 2013年3月

Total Synthesis of Two Possible Diastereomers of (+)-Sarcophytonolide C and Its Structural Elucidation

Hiroyoshi Takamura, Kohei Iwamoto, Eiji Nakao, Isao Kadota

ORGANIC LETTERS 15 ( 5 ) 1108 - 1111 2013年3月

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 and parallel total syntheses of two possible diastereomers of (+)-sarcophytonolide C have been accomplished. Macrolactonization and transannular ring-closing metathesis (RCM) were the key transformations. Detailed comparisons of their H-1 and C-13 NMR data and specific rotation with those of the natural product allowed the absolute configuration of (+)-sarcophytonolide C to be determined.

DOI： 10.1021/ol400157s

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

Kengo Shiroma, Hiroyoshi Takamura, Isao Kadota

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

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

Stereoselective Synthesis of the C94‒C104 Fragment of Symbiodinolide

Takamura, H, Tsuda, K, Kawakubo, Y, Kadota, I, Uemura, D

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

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

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

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

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

Convergent Synthesis of the HIJKLM Ring System of Ciguatoxin CTX3C

Hiroyoshi Takamura, Naoki Nishiuma, Takashi Abe, Isao Kadota

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

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

Total Synthesis and Absolute Configuration of (–)-Gummiferol

Takamura, H, Wada, H, Lu, N, Kadota, I

Org. Lett. 13 ( 14 ) 3644 - 3647 2011年7月

Stereocontrolled Synthesis and Structural Confirmation of the C14–C24 Degraded Fragment of Symbiodinolide

Takamura, H, Kadonaga, Y, Kadota, I, Uemura, D

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

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

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

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

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

Total synthesis of brevenal

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

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

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

Stereoselective Synthesis of the C14–C24 Degraded Fragment of Symbiodinolide

Takamura, H, Kadonaga, Y, Kadota, I, Uemura, D

Tetrahedron Lett. 51 ( 19 ) 2603 - 2605 2010年5月

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

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

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

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

Determination of absolute configuration of C14-C23 fragment in symbiodinolide

Chunguang Han, Yoshi Yamano, Masaki Kita, Hiroyoshi Takamura, Daisuke Uemura

TETRAHEDRON LETTERS 50 ( 37 ) 5280 - 5282 2009年9月

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 degradation product C14-C23 2 was obtained using ethenolysis with the 2nd-generation Hoveyda-Grubbs catalyst from 62-membered lactone in symbiodinolide (1). The absolute configurations of three chiral centers in fragment 2 were assigned as 17R, 18R, and 21R by a combination of J-based configuration analysis and the Mosher-Riguera method. (c) 2009 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.tetlet.2009.07.014

Stereoselective Synthesis and Absolute Configuration of the C1’-C25’ Fragment of Symbiodinolide

Takamura, H, Murata, T, Asai, T, Kadota, I, Uemura, D

J. Org. Chem. 74 ( 17 ) 6658 - 6666 2009年9月

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

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

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

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

Selective cleavage of primary MPM ethers with TMSI/Et3N

Isao Kadota, Yuji Yamagami, Naoya Fujita, Hiroyoshi Takamura

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

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

Synthesis and Structural Revision of Symbiodinolide C23-C34 Fragment

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

JOURNAL OF ORGANIC CHEMISTRY 74 ( 13 ) 4797 - 4803 2009年7月

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 C23-C34 fragment of symbiodinolide, which possesses the originally proposed stereochemistry, and its diastercomers 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.

DOI： 10.1021/jo900546k

Total Synthesis of Brevenal

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

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

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.

DOI： 10.1021/ol900769d

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

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

TETRAHEDRON LETTERS 50 ( 8 ) 863 - 866 2009年2月

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

Synibiodinolide (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). (C) 2009 Published by Elsevier Ltd.

DOI： 10.1016/j.tetlet.2008.11.056

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

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

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

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.

DOI： 10.3987/COM-08-S(F)26

Stereocontrolled synthesis of the C79-C96 fragment of symbiodinolide

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

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

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.

DOI： 10.1016/j.tetlet.2008.05.078

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

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

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

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

Concise synthesis of a highly functionalized cyclopentane segment: toward the total synthesis of kansuinine A

Kenichiro Shimokawa, Hiroyoshi Takamura, Daisuke Uemura

TETRAHEDRON LETTERS 48 ( 32 ) 5623 - 5625 2007年8月

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

Kansuinine A, isolated from the plant Euphorbia kansui Liou, is one of a series of jatrophane diterpenes that have novel structural features, which include contiguous stereocenters, a highly oxygenated carbon framework, and a tricyclic ring system. We describe here a short and concise synthesis of the cyclopentane segment of kansuinine A via SmI2-mediated cyclization of delta-iodoester as a key construction method. (c) 2007 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.tetlet.2007.06.046

Studies toward the total synthesis of nakiterpiosin: construction of the CDE ring system by a transannular Diels-Alder strategy

Tomonori Ito, Masahiro Ito, Hirokazu Arimoto, Hiroyoshi Takamura, Daisuke Uemura

TETRAHEDRON LETTERS 48 ( 31 ) 5465 - 5469 2007年7月

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 transarmular Diels-Alder (TADA) reaction was applied to the synthesis of the CDE ring system of nakiterpiosin (1). Tetracyclic compound 25 may be a key intermediate in the total synthesis of 1. (c) 2007 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.tetlet.2007.05.174

ブレベトキシンＢの全合成

門田功, 高村浩由

有機合成化学協会誌 65 ( 5 ) 430 - 438 2007年

記述言語：日本語出版者・発行元：The Society of Synthetic Organic Chemistry, Japan

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.

DOI： 10.5059/yukigoseikyokaishi.65.430

その他リンク： https://jlc.jst.go.jp/DN/JALC/00293529271?from=CiNii

Stereoselective construction of the octalin unit of symbioimine using an intramolecular Diels-Alder reaction

Emi Sakai, Keisuke Araki, Hiroyoshi Takamura, Daisuke Uemura

TETRAHEDRON LETTERS 47 ( 36 ) 6343 - 6345 2006年9月

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 octalin unit of symbioimine (1) has been synthesized stereoselectively via an intramolecular Diels-Alder reaction. (c) 2006 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.tetlet.2006.07.012

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

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.

DOI： 10.1021/jo0603025

海洋産ポリ環状エーテル、シガトキシン類の合成研究

高村浩由

有機合成化学協会誌 64, 418-419. ( 4 ) 418 - 419 2006年

記述言語：日本語出版者・発行元：The Society of Synthetic Organic Chemistry, Japan

More than 20, 000 people suffer annually from ciguatera seafood poisoning in tropical and subtropical areas. The principal causative agents, ciguatoxin and its congeners CTX3C and 51-hydroxyCTX3C are extremely potent neurotoxins that bind to voltage-sensitive sodium channels. The extremely limited availability of these ciguatoxins has hampered the detailed biological studies and preparation of anti-ciguatoxin antibodies for detecting these toxins. Therefore the supply of these compounds by the chemical synthesis has been strongly demanded. Furthermore the unique structural features have attracted the attention of the synthetic chemists. This review has briefly focused on the synthetic studies of ciguatoxins in a convergent manner including a total synthesis.

DOI： 10.5059/yukigoseikyokaishi.64.418

Total synthesis of brevetoxin B

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

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

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.

DOI： 10.1021/ja051171c

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

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 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.

DOI： 10.1021/ja036984k

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

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

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 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.

DOI： 10.1021/jo025566f

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

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 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

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

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 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

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

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

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

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

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 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.

DOI： 10.1016/S0040-4039(01)00530-5

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