Crystal structure and absolute configuration of 2α,6,6,8-tetramethyltricyclo[6.2.1.0]undecan-7β-yl p-bromobenzoate

Abstract

The crystal structure of the p-bromobenzoate ester of a new tricyclic sesquiterpene alcohol isolated from Eremophila georgei, C₂₂H₂₉BrO₂, has been determined from X-ray diffractometer data by the heavy-atom method and refined by least squares to R 0.049 for 1 689 reflections. Crystals of the derivative are monoclinic, space group P2₁, a= 6.341 (2), b= 15.560(4), c= 20.475(4)Å, β= 95.19(2)°, Z= 4. There are two molecules in the asymmetric unit. The absolute configuration suggested for the tricyclic skeleton is the enantiomer of that reported for khusimol p-bromobenzoate.