Isolation of (−)-cyatha-3,12-diene, a common biosynthetic intermediate of cyathane diterpenoids, from an erinacine-producing basidiomycete, Hericium erinaceum, and its formation in a cell-free system

Cyatha-3,12-diene, a diterpene hydrocarbon having a 5–6–7-membered tricyclic skeleton, has been isolated for the first time from an erinacine-producing basidiomycete, Hericium erinaceum YB4-6237. This hydrocarbon had been formulated by Ayer et al. as a common biosynthetic intermediate of cyathane diterpenoids. Its stereo-structure, including the absolute configuration, has been unambiguously confirmed by its semi-synthesis from erinacine P, and its cell-free conversion from all-trans-geranylgeranyl diphosphate was demonstrated.