1-[(1S,6R,7S,9R)-8,8-Di­bromo-5,5,9-tri­methyl­tri­cyclo­[4.4.0.1^7,9]decan-1-yl]ethanone

The title compound, C₁₆H₂₄Br₂O, was synthesized by three steps from β-himachalene (3,5,5,9-tetra­methyl-2,4a,5,6,7,8-hexa­hydro-1H-benzo­cyclo­heptene), which was isolated from essential oil of the Atlas cedar cedrus atlantica. The asymmetric unit contains two independent mol­ecules with almost identical conformations. Each mol­ecule is built up from two fused six-membered rings, one having a chair conformation and the other a boat conformation, and an additional three-membered ring arising from the reaction of himachalene with di­bromo­carbene. In the crystal, there are no significant intermolecular interactions present. The absolute structure of the title compound was confirmed by resonance scattering.

(1R,4R,6S,7R)-5,5-Di­bromo-1,4,8,8-tetra­methyl­tri­cyclo­[5.4.1.0^4,6]dodecan-12-one

The title compound, C₁₆H₂₄Br₂O, was synthesized from the reaction of β-himachalene (3,5,5,9-tetra­methyl-2,4a,5,6,7,8-hexa­hydro-1H-benzo­cyclo­heptene), which was isolated from Atlas cedar (Cedrus atlantica). The asymmetric unit contains two independent mol­ecules with similar conformations. Each mol­ecule is built up from two fused seven-membered rings and an additional three-membered ring. In both mol­ecules, one of the seven-membered rings has a chair conformation, whereas the other displays a screw-boat conformation.