A Formal Total Synthesis of the Sesterterpenoid (±)-Dysidiolide and Approaches to the Syntheses of (±)-6-Epi-, (±)-15-Epi-, and (±)-6,15-Bisepidysidiolide

A formal total synthesis of the sesterterpenoid (+/-)-dysidiolide (1), a structurally novel sponge metabolite that inhibits the cdc25A protein phosphatase, and approaches to the syntheses of (+/-)-15-epi- (34), (+/-)-6-epi- (36), and (+/-)-6, 15-bisepidysidiolide (39) are described.