研究者詳細 - 髙村　浩由

論文 - 髙村　浩由

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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

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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

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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

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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

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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

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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

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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

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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

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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

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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

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