(1S,3R,8R,9S,11R)-2,2,10,10-Tetra­chloro-3,7,7,11-tetra­methyl­tetra­cyclo­[6.5.0.0^1,3.0^9,11]trideca­ne

The title compound, C₁₇H₂₄Cl₄, 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 is built up from fused six- and seven-membered rings and two three-membered rings from the reaction of β-himachalene with dichloro­carbene. The six-membered ring shows a chair conformation, whereas the seven-membered ring displays a boat conformation.