(1S,2R,7R,8S,10R)-9,9-Di-bromo-2,6,6,10-tetra-methyl-1α,2α-ep-oxy-tri-cyclo-[5.5.0.0(8,10)]dodeca-ne.

The title compound, C16H24Br2O, was synthesized from the reaction of β-himachalene (3,5,5,9-tetra-methyl-2,4a,5,6,7,8-hexa-hydro-1H-benzo-cyclo-heptene), which was isolated from Atlas cedar (Cedrus atlantica) essential oil, after reaction with di-bromo-carbene. The asymmetric unit contains two independent mol-ecules with similar conformations. Each mol-ecule is built up from fused six-and seven-membered rings and two three-membered rings. In both mol-ecules, the six-membered ring has an envelope conformation with the flap provided by the C atom of the ep-oxy ring, whereas the seven-membered ring displays a chair conformation. The crystal packing is governed only by van der Waals inter-actions. The absolute configuration was established from anomalous dispersion effects.