Crystal structure of (1S,3R,8R,9S,10R)-10-bromomethyl-2,2-dichloro-9,10-epoxy-3,7,7-trimethyltricyclo[6.4.0.01,3]-dodecane

Abstract

The title compound, C16H23BrCl2O, was synthesized in three steps 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 two fused six- and seven-membered rings, each linked to a three-membered ring. The six-membered ring has a screw-boat conformation, whereas the seven-membered ring displays a twist-boat conformation. The absolute structure was established unambiguously from anomalous dispersion effects.