Studies of Australian soft corals. VIII. A chemical and crystallographic study of a novel bicyclic diterpene alcohol with a rearranged skeleton from an unknown species of soft coral

Abstract

The structure of a novel bicyclic diterpene alcohol is reported and shown to be (3Z,5E,9E,1R*,-7R*,12aR*)-1-isopropyl-6,10,12a-trimethyl- 1,2,4,7,8,11,12,12a-octahydrocyclopentacycloundecen-7-ol(1a). It is structurally related to the known diterpene (2) from Dollabella californica. However, in (1a), there has been a methyl migration resulting in a rearranged isoprenoid skeleton. The structure was solved by single-crystal X-ray analysis, after spectroscopic analysis failed to yield an unambiguous structure.