(1R,4R,6S,7S)-5,5-Di-chloro-1,4,8,8-tetra-methyl-tri-cyclo-[5.4.1(1,7).0(4,6)]dodecan-12-one

The title compound, C16H24Cl2O, was synthesized in three steps from β-himachalene (3,5,5,9-tetra-methyl-2,4a,5,6,7,8-hexa-hydro-1H-benzo-cyclo-heptene), which was isolated from essential oil of the Atlas cedar (cedrus atlantica). The asymmetric unit contains two independent mol-ecules with similar conformations. Each mol-ecule is built up from two fused seven-membered rings and an additional three-membered ring arising from the reaction of himachalene with di-chloro-carbene. The dihedral angles between the mean planes of the two seven-membered rings are 75.03 (9) and 75.02 (9)° in the two independent mol-ecules.