The absolute configuration of (+)-isocamphenilanic acid by X-ray analysis and of (–)-camphene

Abstract

The absolute configuration of (+)-isocamphenilanic acid (3,3-dimethylnorbornane-exo-2-carboxylic acid)(2; R = OH) has been defined by an X-ray crystallographic examination of the p-bromophenacyl ester. Degradation of this (+)-acid by the Cope procedure proceeds by normal cis-elimination to furnish (–)-camphene, but is in conflict with the reported chemical conversion of (–)-camphene into (–)-camphene into (–)-isocamphenilanic acid.