Isolation of (+)-fusicocca-2,10(14)-diene, a 5-8-5 tricyclic diterpene hydrocarbon biosynthetically related to the fusicoccin aglycon from Fusicoccum amygdali and confirmation of its structure by total synthesis

(+)-Fusicocca-2,10(14)-diene, a double bond isomer of the putative fusicoccin biosynthetic intermediate, i.e., fusicocca-1,10(14)-diene, was isolated for the first time as a main hydrocarbon constituent from the fusicoccin-producing fungus Fusicoccum amygdali, and its stereostructure including absolute configuration was unambiguously confirmed by total synthesis.