Kericembrenolides A, B, C, D, and E, five new cytotoxic cembrenolides from the Okinawan soft coral Clavularia koellikeri.

Abstract

Five new cytotoxic cembrenolides, kericembrenolies A (7__∼), B (8__∼), C(9__∼), D (10__∼), and E (11__∼), having an α-methylene-γ-lactone moiety were isolated together with neodolabelline (5__∼) and neodolabellenol (6__∼) from the Okinawan soft coral Clavularia koellikeri. Their absolute configurations were determined on the basis of chemical and physicochemical evidence.