(1R,2S,4S,4aS,8S,8aS)-4-Hydroxy-8,8a-dimethyl-10-oxo-2,3,4,7,8,8a-hexahydro-1H-4a,1-(epoxymethano)naphthalen-2-yl acetate

The title compound, C15H20O5, presents a bisnorsesquiterpene skeleton, with a trans-decaline backbone constrained by the lactone bridge. The α-hydroxy substituent and the methyl group belonging to the two decaline rings are in axial positions, whereas the other methyl group and the acyl group occupy the sterically preferred equatorial positions. The molecular structure is stabilized by an intramolecular C—H...O hydrogen bond. In the crystal, molecules are linked into chains along [010] by O—H...O hydrogen bond