著者

亀谷 哲治 津吹 政可 日暮 勝之 加藤 正 本多 利雄

出版者

天然有機化合物討論会実行委員会

雑誌

天然有機化合物討論会講演要旨集 27 (ISSN:24331856)

巻号頁・発行日

pp.176-183, 1985-09-07 (Released:2017-08-18)

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The stereocontrolled synthesis of steroid side chain has been developed. The major interest has been forcused on the synthesis of the side chain of ecdysone as well as crustecdysone from 20-oxosteroid via furan derivatives. Reduction of the olefin (21) over palladium-carbon afforded the (20S)-20-furylsteroid (22), stereoselectively, whose hydrogenation over rhodium-alumina, followed by ruthenium tetroxide oxidation and treatment with methylmagnesium bromide, gave the triols (28) and (29) having an ecdysone-type side chain, respectively. The stereoselective reduction of the lactone (33) as a key reaction to give the δ-lactone (35) and the γ-lactone (36), under various conditions has also been investigated. Grignard reaction of both lactones with methylmagnesium bromide led to the synthesis of the tetraol (37) possessing a crustecdysone side chain. The total synthesis of 2-deoxycrustecdysone (3) has also been achieved by application of the above method.

著者

末宗 洋 上野 貢嗣 川原 哲也 小田 晃造 舟越 和久 酒井 浄

出版者

天然有機化合物討論会実行委員会

雑誌

天然有機化合物討論会講演要旨集 27 (ISSN:24331856)

巻号頁・発行日

pp.108-114, 1985-09-07 (Released:2017-08-18)

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In the synthesis of natural products consisting of the basic structure of cyclopentane ring, variously functionalized cyclopentanones are required as starting materials. Previously, we succeeded in a simple, highly stereospecific synthesis of the cis-3,4-disubstituted cyclopentanones by the mild reaction with RhCl(PPh_3)_3. By the application of this newer cyclization reaction, we have succeeded in the synthesis of cis,cis-dihydronepetalactone, prostanoic acid, 8-isoprostanoic acid, (+)-brefeldin A and carbacyclin in the optically active form from limonene or Corey lactone. These compounds were synthesized via the following key steps. 1) 3-(3-Oxobutyl)cyclopentanone was easily converted to the deconjugated bicyclic enone (3→4). 2) The regioselective alkylation of limonene was performed by using s-BuLi-TMEDA (1→8). 3) The cis-3,4-disubstituted cyclopentanone from limonen-10-ol could be converted to the trans-3,4-disubstituted cyclo-pentanone by the epimerization (15→16, 22→23).