Biosynthetic studies of marine lipids 10. Double side chain extension in the triply alkylated sponge sterol xestosterol

Abstract

Xestosterol, a triply alkylated marine sponge sterol, with a symmetrically extended side chain is shown to be efficiently biosynthesized by the sponge Xestospongia testudinaria via a nonstereoselective SAM biomethylation and 1,2-hydrogen shift. De novo biosynthesis via mevalonate, rarely demonstrated in sponges, has also been demonstrated.