研究者詳細 - 髙村　浩由

論文 - 髙村　浩由

分割表示 68 件中 41 - 60 件目／全件表示 >>

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

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