(7aR)-1-[(2R,5S,E)-6-Hy­droxy-5,6-dimethyl­hept-3-en-2-yl]-7a-methyl­hexa­hydro-1H-inden-4(2H)-one

The chiral title compound, C(19)H(32)O(2), contains a [4.3.0]-bicyclic moiety in which the shared C—C bond presents a trans configuration and a side chain in which the C=C double bond shows an E conformation. The conformations of five- and six-membered rings are envelope (with the bridgehead atom bearing the methyl substituent as the flap) and chair, respectively, with a dihedral angle of 4.08 (17)° between the idealized planes of the rings. In the crystal, the mol­ecules are self-assembled via classical O—H⋯O hydrogen bonds, forming chains along [112]; these chains are linked by weak non-classical C—H⋯O hydrogen bonds, giving a two-dimensional supra­molecular structure parallel to (010). The absolute configuration was established according to the configuration of the starting material.