first enantioselective totalsynthesis of 10-isocyano-4-cadinene, a marine sesquiterpene isolated from nudibranchs of the family Phyllidiidae, was achieved. The cadinene is expected to be a novel nontoxic antifouling agent. In the synthesis, an intermolecular Diels−Alder reaction and a SmI2-induced Barbier-type reaction were employed as key steps. The absoluteconfiguration of 10-isocyano-4-cadinene