Crystal structure of (4bS,8aR)-1-isopropyl-4b,8,8-trimethyl-7-oxo-4b,7,8,8a,9,10-hexahydro-phenanthren-2-yl acetate

The title compound, C22H28O3, was prepared by a direct acetylation reaction of naturally occurring totarolenone. The molecule contains three fused rings, which exhibit different conformations. The central ring has a half-chair conformation, while the non-aromatic oxo-substituted ring has a screw-boat conformation. In the crystal, molecules are linked by C-H center dot center dot center dot O hydrogen bonds and C-H center dot center dot center dot pi interactions, forming sheets parallel to the bc plane. The carbonyl O atoms and the C atom at the 6-position of the cyclohexene ring are each disordered over two sets of sites with major occupancy components of 0.63 (7) and 0.793 (14), respectively.