Fragilide B:: A novel briarane-type diterpenoid with a S-cis diene moiety

A novel chlorinated briarane derivative, fragilide B (1), was isolated from the Formosan gorgonian coral Junceella fragilis. Fragilide B (1) possesses a s-cis diene moiety in the structure. The structure of 1 was elucidated by interpretation of spectral data and further supported by molecular mechanics calculations.