Sesterterpenes. 1. Stereospecific construction of the ceroplastol and ophiobolin ring systems via a common bicyclic intermediate

The ring systems present in the two major classes of ophiobolane sesterterpenes have been obtained via a common bicyclic intermediate. In each case, the eight-membered ring was constructed by fragmentation of an appropriately functionalized bicyclo(3.3.1)nonane ring system.