(1S,3R,8R)-2,2-Dibromo-10-bromo­methyl-3,7,7-trimethyl­tricyclo­[6.4.0.0(1,3)]dodec-9-ene

The title compound, C(16)H(23)Br(3), 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 an additional three-membered ring from the reaction of himachalene with dibromo­carbene. The six-membered ring has an envelope conformation (the flap atom being the C atom shared with the three-membered ring, whereas the seven-membered ring displays a screw boat conformation; the dihedral angle between the rings (defined by the near coplanar atoms) is 56.5 (2)°.