Corymbolone

The title compound, C₁₅H₂₄O₂ [systematic name: (4S,4aR,6R,8aR)-4a-hy­droxy-4,8a-dimethyl-6-(prop-1-en-2-yl)octahydro­naphthalen-1(2H)-one], features two edge-shared six-membered rings with the hydroxyl and methyl substituents at this bridge being trans. One adopts a flattened chair conformation with the C atoms bearing the carbonyl and methyl substituents lying 0.5227 (16) and 0.6621 (15) Å, respectively, above and below the mean plane through the remaining four C atoms (r.m.s. deviation = 0.0145 Å). The second ring, bearing the prop-1-en-2-yl group, has a chair conformation. Supra­molecular helical chains along the b axis are found in the crystal packing, which are sustained by hy­droxy–carbonyl O—H...O hydrogen bonding.

2-[(3S,3aS,5R,8S,8aS)-3,8-Di­methyl­hexa­hydro-1H,4H-3a,8a-ep­oxy­azulen-5-yl]propan-2-ol

Four independent mol­ecules (A–D) comprise the asymmetric unit of the title compound, C₁₅H₂₆O₂, which differ only in the relative orientations of the terminal –C(Me)₂OH groups [e.g. the range of C_methyl­ene—C_methine—C_quaternary—O_hy­droxy torsion angles is 52.7 (7)–57.1 (6)°, where the C_methyl­ene atom is bound to an epoxide C atom]. The five-membered rings adopt envelope conformations, with the methyl­ene C atom adjacent to the methine C atom being the flap atom in each case. In each mol­ecule, the conformation of the seven-membered ring is a half-chair, with the C_methyl­ene—C_methine bond, flanked by methyl­ene C atoms, being the back of the chair. Supra­molecular helical chains along the b axis are found in the crystal packing, sustained by hy­droxy–epoxide O—H...O hydrogen bonding. Mol­ecules of A self-associate into a chain as do those of D. A third independent chain comprising B and C mol­ecules is also formed. The studied crystal is a pseudo-merohedral twin (minor component ca 21%).