論文 - 高尾　賢一

Total Syntheses of (+)-Aquatolide and Related Humulanolides

Takao K., Kai H., Yamada A., Fukushima Y., Komatsu D., Ogura A., Yoshida K.

Angewandte Chemie - International Edition （Angewandte Chemie - International Edition）  58 （ 29 ） 9851 - 9855 2019年

ISSN  14337851

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© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim The short, efficient total synthesis of (+)-aquatolide was achieved by a biomimetic transannular [2+2] photocycloaddition, and provides the first example of constructing a 5/5/4/8-ring system from asteriscunolides. Furthermore, the reaction leading to a 5/4/4/7-ring system, the originally proposed structure of aquatolide, was also developed. This strategy achieved syntheses of five more humulanolides, (−)-asteriscunolides A, C, D, and I, and (+)-tetradehydroasteriscanolide.

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Identification of topoisomerases as molecular targets of cytosporolide C and its analog

Otake K., Yamada K., Miura K., Sasazawa Y., Miyazaki S., Niwa Y., Ogura A., Takao K., Simizu S.

Bioorganic and Medicinal Chemistry （Bioorganic and Medicinal Chemistry）  27 （ 15 ） 3334 - 3338 2019年

ISSN  09680896

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© 2019 Elsevier Ltd Cytosporolide (Cytos) A–C, isolated from the fungus Cytospora sp., have anti-microbial activity, but their molecular targets in mammalian cells are unknown. We have previously reported the total synthesis of Cytos A by biomimetic hetero-Diels-Alder reaction. In this study, to examine the novel bioactivity of Cytos, we synthesized Cytos C and measured cell growth-inhibiting activities of 7 compounds, including Cytos A and C, in several human cancer cell lines. Among these compounds, Cytos C and tetradeoxycytosporolide A (TD-Cytos A), a model compound for the synthesis of Cytos A, had anti-proliferative effects on cancer cells, and TD-Cytos A exhibited stronger activity than Cytos C. In vitro topoisomerase-mediated DNA relaxing experiments showed that TD-Cytos A inhibited the activities of topoisomerase I and II, whereas Cytos C targeted only topoisomerase I. These data suggest that the anti-proliferative activities of Cytos correlate with the inhibition of topoisomerases and implicated TD-Cytos A as a novel anti-cancer drug that suppresses the activities of topoisomerase I and II.

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Studies toward the synthesis of perforatumone: Synthesis of the 7-OXABICYCLO[4.2.1]NONANE-8,9-DIONE CORE

Nakajima T., Takiguchi K., Yoshida K., Ogura A., Takao K.

Heterocycles （Heterocycles）  99 （ 1 ） 661 - 668 2019年

ISSN  03855414

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© 2019 The Japan Institute of Heterocyclic Chemistry. Construction of the unique bridged bicyclic skeleton, 7-oxabicyclo[4.2.1]nonane-8,9-dione, of perforatumone was achieved. Key steps included a Dieckmann-type condensation, a Claisen rearrangement, and an intramolecular Michael reaction.

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Enantioselective Total Synthesis of (-)-Misramine

Yoshida K., Fujino Y., Takamatsu Y., Matsui K., Ogura A., Fukami Y., Kitagaki S., Takao K.

Organic Letters （Organic Letters）  20 （ 16 ） 5044 - 5047 2018年08月

ISSN  15237060

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© 2018 American Chemical Society. The enantioselective total synthesis of an unusual pentacyclic proaporphine alkaloid, (-)-misramine, was achieved. The synthetic strategy relied on an enantioselective intramolecular Friedel-Crafts-type 1,4-addition using an asymmetric organocatalyst to construct a spiroindane skeleton containing an all-carbon quaternary stereocenter and a double reductive amination of the keto-aldehyde to form a piperidine ring toward the end of the synthesis. This work is the first example of asymmetric synthesis of a proaporphine alkaloid.

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Total Synthesis of Clavilactones

Takao K., Mori K., Kasuga K., Nanamiya R., Namba A., Fukushima Y., Nemoto R., Mogi T., Yasui H., Ogura A., Yoshida K., Tadano K.

Journal of Organic Chemistry （Journal of Organic Chemistry）  Vol.83 （ 13 ） 7060 - 7075 2018年07月

研究論文（学術雑誌）, 共著, 査読有り,  ISSN  00223263

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Copyright © 2018 American Chemical Society. Clavilactones A, B, and D are epidermal growth factor receptor tyrosine kinase inhibitors that were isolated from cultures of the fungus Clitocybe clavipes. Here, we report full details of the total synthesis of these clavilactones. A key feature of our synthetic approach is a ring-opening/ring-closing metathesis strategy that allows the concise transformation of a cyclobutenecarboxylate into a γ-butenolide. Coupled with enantioselective Ti/BINOL-catalyzed alkynylation of a multisubstituted benzaldehyde and ring-closing metathesis of a diene-bearing silylene acetal to construct the 10-membered carbocycle, this strategy enabled the total synthesis of the natural enantiomers (+)-clavilactone A and (-)-clavilactone B. In addition, the correct structure of clavilactone D was determined by the synthesis of two newly proposed structures. This research resulted in the asymmetric synthesis of the revised (+)-clavilactone D.

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Synthesis and Evaluation of Biological Activities of Vibsanin A Analogs

Wataru Matsuki, So Miyazaki, Keisuke Yoshida, Akihiro Ogura, Yukiko Sasazawa, Ken-ichi Takao, and Siro Simizu

Bioorg. Med. Chem. Lett. Vol.27   4536 - 4539 2017年10月

研究論文（学術雑誌）, 共著, 査読有り

Total Synthesis and Structural Revision of Clavilactone D

Ken-ichi Takao, Ryuichi Nemoto, Kento Mori, Ayumi Namba, Keisuke Yoshida, and Akihiro Ogura

Chem. Eur. J. Vol.23   3828 - 3831 2017年03月

研究論文（学術雑誌）, 共著, 査読有り

Kinetically Controlled α-Selective O-Glycosylation of Phenol Derivatives Using 2-Nitroglycals by a Bifunctional Chiral Thiourea Catalyst

Keisuke Yoshida, Yohei Kanoko, and Ken-ichi Takao

Asian J. Org. Chem. Vol.5   1230 - 1236 2016年10月

研究論文（学術雑誌）, 共著, 査読有り

Stereoselective Construction of All-Carbon Quaternary Stereocenters by Allylboration of Chiral Aldehydes: Synthesis of a Fragment of (+)-Vibsanin A

Akihiro Sakama, Yoshiyasu Nishimura, Yuko Motohashi, Keisuke Yoshida, and Ken-ichi Takao

Tetrahedron Vol.72   5465 - 5471 2016年09月

研究論文（学術雑誌）, 共著, 査読有り

Enantioselective Organocatalytic Construction of Spiroindane Derivatives by Intramolecular Friedel–Crafts-type 1,4-Addition

Keisuke Yoshida, Yukihiro Itatsu, Yuta Fujino, Hiroki Inoue, and Ken-ichi Takao

Angew. Chem. Int. Ed. Vol.55   6734 - 6738 2016年06月

研究論文（学術雑誌）, 共著, 査読有り

Organocatalytic Regioselective Chlorosilylation of Oxirane Derivatives: Mild and Effective Insertion of Bulky Silyl Chloride by Using 4-Methoxypyridine N-Oxide

Keisuke Yoshida, Hina Suzuki, Hiroki Inoue, Kohei Matsui, Yuta Fujino, Yohei Kanoko, Yukihiro Itatsu, and Ken-ichi Takao

Adv. Synth. Catal. Vol.358   1886 - 1891 2016年06月

研究論文（学術雑誌）, 共著, 査読有り

Identification of a seco-clavilactone B as a small-molecule actin polymerization inhibitor

So Miyazaki, Yukiko Sasazawa, Takuma Mogi, Takehiro Suzuki, Keisuke Yoshida, Naoshi Dohmae, Ken-ichi Takao, and Siro Simizu

FEBS Lett. Vol.590   1163 - 1173 2016年04月

研究論文（学術雑誌）, 共著, 査読有り

Amine-Free Silylation of Alcohols under 4-Methylpyridine N-Oxide-Catalyzed Conditions

Keisuke Yoshida, Yuta Fujino, Yukihiro Itatsu, Hiroki Inoue, Yohei Kanoko, and Ken-ichi Takao

Tetrahedron Lett. Vol.57   627 - 631 2016年02月

研究論文（学術雑誌）, 共著, 査読有り

連続オレフィンメタセシス反応を用いた天然物の全合成

高尾賢一・吉田圭佑・只野金一

有機合成化学協会誌 Vol.73   1192 - 1199 2015年12月

研究論文（学術雑誌）, 共著, 査読有り

Total Synthesis of (+)-Cytosporolide A via a Biomimetic Hetero-Diels–Alder Reaction

Ken-ichi Takao, Shuji Noguchi, Shu Sakamoto, Mizuki Kimura, Keisuke Yoshida, and Kin-ichi Tadano

J. Am. Chem. Soc. Vol.137   15971 - 15977 2015年12月

研究論文（学術雑誌）, 共著, 査読有り

Total Synthesis of (+)-Vibsanin A

Ken-ichi Takao, Kohei Tsunoda, Takuya Kurisu, Akihiro Sakama, Yoshiyasu Nishimura, Keisuke Yoshida, and Kin-ichi Tadano

Org. Lett. Vol.17   756 - 759 2015年02月

研究論文（学術雑誌）, 共著, 査読有り

An Access to the 13-Membered Cyclophane Substructure in GKK1032As: An Intramolecular 1,4-Addition Approach

Satoka Nagai, Yuka Yamagishi, Yuta Shimizu, Ken-ichi Takao, and Kin-ichi Tadano

Heterocycles Vol.90   819 - 826 2015年01月

研究論文（学術雑誌）, 共著, 査読有り

Catalytic Silylation of Secondary Alcohols by Pyridine N-Oxide Derivative

Keisuke Yoshida and Ken-ichi Takao

Tetrahedron Lett. Vol.55   6861 - 6863 2014年12月

研究論文（学術雑誌）, 共著, 査読有り

Total Synthesis of (+)-Clavilactone A and (–)-Clavilactone B by Ring-Opening/Ring-Closing Metathesis

Ken-ichi Takao, Ryuki Nanamiya, Yuuki Fukushima, Ayumi Namba, Keisuke Yoshida, and Kin-ichi Tadano

Org. Lett. Vol.15   5582-5585 2013年11月

研究論文（学術雑誌）, 共著, 査読有り

Synthetic Studies of the Spirocyclic Cyclohexene Part of Versipelostatin, a Novel GRP78/Bip Molecular Chaperone Downregulator

Shu Sasaki, Suguru Samejima, Tomoki Uruga, Kai Anzai, Natsumi Nishi, Eriko Kawakita, Ken-ichi Takao, and Kin-ichi Tadano

J. Antibiot. Vol.66   147-154 2013年03月

研究論文（学術雑誌）, 共著, 査読有り