(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, C₁₉H₃₂O₂, 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.

[(2S,3aR,6aR)-5-Oxohexa­hydro­furo[3,2-b]furan-2-yl]methyl acetate

The title compound, C₉H₁₂O₅, is a bicyclic lactone, presenting a 2,6-dioxabi­cyclo­[3.3.0]octan-3-one skeleton, which was obtained through an intra­molecular lactonization. The bicyclic lactone presents a cis ring-junction and a 1,5-trans-substituted tetra­hydro­furan. Both five-membered rings are in twisted envelope conformations with one of the fused C atoms as the flap. The dihedral angle between the mean planes of the bicyclic lactone residue, defined by the di­hydro­furan-2(3H)-one and the tetra­hydro­furan rings, is 69.5 (2)°. The atoms of the ester chain are coplanar [maximum deviation = 0.013 (2) Å]. The absolute structure was not determined.

(1S,2S,5S)-2-Methyl-3-oxo-5-(prop-1-en-2-yl)cyclo­hexane-1-carbo­nitrile

The mol­ecule of the title compound, C₁₁H₁₅NO, contains a cyclo­hexa­none ring, three defined stereocenters and an exocyclic double bond. The crystal structure is the result of a study on the Michael addition reaction of (S)-carvone with sodium cyanide using ionic liquids as the reaction medium and so the absolute configuration is known from the chemistry. The six-membered ring is in a chair conformation.