(1S,3R,8R,9S,11R)-2,2-Di­bromo-10,10-di­chloro-3,7,7,11-tetra­methyl­tetra­cyclo­[6.5.0.0(1,3).0(9,11)]trideca­ne

The title compound, C(17)H(24)Br(2)Cl(2), was synthesized from β-himachalene (3,5,5,9-tetra­methyl-2,4a,5,6,7,8-hexa­hydro-1H-benzo­cyclo­heptene), which was isolated from the essential oil of the Atlas cedar (Cedrus Atlantica). The mol­ecule contains fused six-, seven- and two three-membered rings. The six-membered ring has a half-chair conformation, while the seven-membered ring displays a boat conformation. The absolute structure was unambiguously established from anomalous dispersion effects. The crystal packing exhibits no short inter­molecular contacts.