Partial kinetic ‘resolution’ resulting from a deuterium isotope effect
Abstract
The ‘racemate’1A/1B cyclises on heating to the enol 5via an ‘ene’ reaction; at two-thirds completion, the recovered enone 1A/1B has [α]D–62°(1B has [α]D–132°); kinetic ‘resolution’ results from a deuterium isotope effect for the cyclisation (kH/kDca. 1.8); the absolute stereochemistry of compound 6a is determined by X-ray analysis.