(1S,3R,8R,9R,10S)-2,2-Dibromo-3,7,7,10-tetra­methyl-9β,10β-ep­oxy-3,7,7,10-tetra­methyl­tricyclo­[6.4.0.0^1,3]dodeca­ne

The title compound, C₁₆H₂₄Br₂O, 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- and seven-membered rings, each linked to a three-membered ring. The six-membered ring has a half-chair conformation, while the seven-membered ring displays a chair conformation. The dihedral angle between the mean planes through the six- and seven-membered rings is 39.55 (12)°. The two three-membered rings, linked to the six- and seven-membered rings, are nearly perpendicular to the six-membered ring, making dihedral angles of 78.6 (2) and 80.5 (2)°, respectively. The absolute structure was established unambiguously from anomalous dispersion effects. In the crystal, each mol­ecule is linked to its symmetry-equivalent partner by C—H...O hydrogen bonds, forming zigzag chains parallel to [100].

2,2-Dichloro-3,7,7,11-tetra­methyl-10-aza­tetra­cyclo­[6.5.0.0^1,3.0^9,11]trideca­ne

The title compound, C₁₆H₂₅Cl₂N, 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 linked to two three-membered rings. The six-membered ring shows a half-chair conformation, whereas the seven-membered ring displays a boat conformation. The dihedral angle between the mean planes through the six- and seven-membered rings is 59.8 (2)°. The two three-membered rings lie to one side and each is nearly perpendicular to the six-membered ring, forming dihedral angles of 83.2 (2) and 86.0 (2)°. The absolute structure was established unambiguously from anomalous dispersion effects. No specific inter­molecular inter­actions are noted in the crystal structure.

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

The title compound, C₁₇H₂₄Br₂Cl₂, 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 asymmetric unit contains two independent mol­ecules. Each mol­ecule is built up from fused six-, seven- and two three-membered rings. In both mol­ecules, the six-membered ring has a half-chair conformation, whereas the seven-membered ring displays a boat conformation. No specific inter­molecular inter­actions are noted in the crystal packing.

(1S,3R,8R)-2,2-Di­chloro-3,7,7,10-tetra­methyl­tri­cyclo­[6.4.0.0^1,3]dodec-9-en-11-one

The title compound, C₁₆H₂₂Cl₂O, 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 arising from the reaction of himachalene with di­chloro­carbene. The six-membered ring has an envelope conformation, with the C atom belonging to the three-membered ring forming the flap, whereas the seven-membered ring displays a screw-boat conformation; the dihedral angle between the rings (all atoms) is 59.65 (14)°.