Studies of Australian soft corals. IV. A novel bicyclic diterpene from Lobophytum hedleyi

Abstract

A new bicyclic diterpene, (3E,5E)-2-methyl-6-[(2'R*,4a'S*,8a'R*)-4a'-methyl-8'-methylene-trans-perhydronaphthalen-2'-yl]hepta-3,5-dien-2-ol (1), is reported as the major terpenoid component from Lobophytum hedleyi. It represents the first non-cembranoid diterpene to be reported from soft corals. A minor component in the coral is tentatively identified as the 7-hydroxy derivative of (1). Evidence for the structure of (1) is mainly spectroscopic but final proof rests on degradation and conversion into a known compound.