Enantioconvergent Synthesis of (-)-α-Cuparenone Involving Chiral Inversion of a Ketone Intermediate

Abstract
The acid (-)-2 was converted to the ketone (-)-6. Unsaturated ketone (+)-14 was synthesised from (-)-6. The ketone (+)-7 prepared from the acid (+)-3 on 1,2-ketone transposition, furnished the optical antipode (-)-6.