Enantiomerically pure synthesis of [beta]-substituted [gamma]-butyrolactones: A key intermediate to concise synthesis of pregabalin

The synthesis of enantiomerically pure [beta]- substituted [gamma]-butyrolactones carried out by employing nucleophilic cyclopropane ring opening of bicyclic lactone followed by decarbethoxylation is presented. The method could be applied to synthesize an anticonvulsant drug, pregabalin (S)-3-isobutyl-[gamma]-aminobutyric acid, for the treatment of peripheral neuropathic pain.