Marine Terpenes and Terpenoids. XIII. Isolation of a New Dihydrofuranocembranoid, Sarcophytonin E, from the Sarcophyton sp. Soft Coral of Okinawa

抄録

A new dihydrofuranocembranoid, sarcophytonin E (1a), was isolated from the Sarcophyton sp. soft coral of Chatan, Okinawa. The structure of 1a was derived from the spectroscopic data, and was confirmed by correlation with the known compound 16-deoxosarcophine (2a). Compound 1a was found to be converted, on storage, to the butenolide 3a. The proton nuclear magnetic resonance spectra of the 2-methoxy-2-trifluoromethylphenylacetic acid esters of 1a and 3a indicated that they are enantiomerically pure, and showed our previous assumption, that the cembranoids isolated from this soft coral are enantiomeric mixtures, to be incorrect.