INTERMEDIATES IN THE SYNTHESIS OF CEMBRANE DITERPENES .1.

The molecular structure of rac-(1R,2R,3S,7S)-3-hydroxy-5 -isopropyl-2- methyltricyclo [8.4.0.0(2,7)] tetradeca-4,9-dien-6-one, C18H26O2, has an all-cis ring-fusion tricyclic structure, with an overall distorted hemispherical conformation (the hydroxyl group is opposite the other s ubstituents). The cyclohexenone ring is in a half-chair conformation, the cyclohexene ring is in a distorted half-chair conformation and the cyclohexane ring adopts an almost ideal chair conformation. The molec ules are linked through a hydrogen bond.