研究者詳細 - 門田　功

論文 - 門田　功

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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

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

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

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

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

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 査読

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 査読

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）

(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

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

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 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

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

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

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 査読

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 査読

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

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

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.

DOI： 10.1021/jo701352

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

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.

DOI： 10.1016/j.tetlet.2006.11.058

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

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.

DOI： 10.3987/COM-07-S(W)39

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

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

P-141 Convergent Synthesis of Hemibrevetoxin B

Ishitsuka Yukako, Abeda Touchy, Nagata Ryoko, Kadota Isao, Yamamoto Yoshinori

International Symposium on the Chemistry of Natural Products 2006 "P - 141" 2006年7月

P-140 Synthesis of the IJK Ring Segment of Yessotoxin

Abe Takashi, Sato Yuki, Kadota Isao, Yamamoto Yoshinori

International Symposium on the Chemistry of Natural Products 2006 "P - 140" 2006年7月

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

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

P-31 ブレベトキシンBの全合成(ポスター発表の部)

高村浩由, 西井広樹, 石岡裕貴, 門田功, 山本嘉則

天然有機化合物討論会講演要旨集 ( 47 ) 325 - 330 2005年9月

記述言語：日本語出版者・発行元：天然有機化合物討論会

Brevetoxin B (1), a potent neurotoxin, was isolated from the red tide organism Gymnodinium breve Davis in 1981. The unique structural features and biological activity of this molecule have attracted the attention of synthetic chemists. We have already reported the efficient method for the convergent synthesis of polycyclic ethers via the intramolecular allylation and subsequent ring-closing metathesis. Herein we report the convergent total synthesis of 1 based on our own methodology. The reaction of the bicyclic compound 9, prepared from the known compound 6, with the allylic silane 10 in the presence of TMSOTf gave the desired product 11, stereoselectively. The JK ring segment 3 was synthesized in 11 steps including one-carbon elongation from 11. Palladium-catalyzed coupling of the ketene acetal triflate 15 and the organozinc reagent 16 gave the enol ether 17, which was converted to the diene 22. The construction of the A ring via ring-closing metathesis afforded the ABC ring segment 4. The chlorosulfide 4 was treated with the alcohol 5 in the presence of AgOTf and DTBMP to give the O,S-acetal 24. Intramolecular allylation of 26 using AgOTf as a Lewis acid provided the desired product 27, stereoselectively. Chemoselective reduction of the olefinic moiety in the E ring of 29 was carried out under the condition of the diimide reduction to afford 30. The heptacyclic compound 30 was converted to the alcohol 2 in 6 steps including one-carbon elongation. The alcohol 2 and the carboxylic acid 3 were connected successfully by Yamaguchi conditions to give the ester 33. The construction of the polycyclic framework of 1 was performed via the intramolecular allylation and subsequent ring-closing metathesis to yield 38. After the TBS and TBDPS protecting groups were removed using HF・pyr, chemoselective oxidation of the allylic moiety with MnO_2 furnished brevetoxin B (1). The synthetic brevetoxin B exhibited spectroscopic data identical with those of natural brevetoxin B.

DOI： 10.24496/tennenyuki.47.0_325

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

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

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