著者

原 修 中尾 一成 棚田 喜久 西尾 東 松原 淳 横川 文明 濱田 康正 塩入 孝之

出版者

天然有機化合物討論会

雑誌

天然有機化合物討論会講演要旨集

巻号頁・発行日

no.32, pp.617-624, 1990-09-25

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Calyculins having high cytotoxicity were isolated from the marine sponge Discordermia calyx in the Gulf of Sagami. Calyculin A (1), the major cytotoxic constituent, has 15 chiral centers, a spiroketal bearing phosphate, an oxazole ring, and a nitrile conjugated with all (E)-tetraene. However, its absolute stereostructure has remained uncovered. Interestingly, calyculin A (1) exhibits antitumor activity against Ehrlich and P-388 leukemia in mice. Its unique complex structure as well as its intriguing biological activity led us to investigate the total synthesis of 1, which will determine the absolute configuration of 1 as well. Retrosynthetic analysis has revealed that 1 would be constructed from four fragments A, B, C, and D, shown in Chart 1. Fragments A and B could be prepared by stereoselective reduction of tetronic acid derivatives 11 and 24, respectively. Fragments C and D were prepared from amino acids utilizing the methodology developed by us earlier.