A New Synthetic Route to β-Unsubstituted β-Lactones by Intramolecular Cyclization

When carboxylic acids β-substituted by a tert-butoxy group were treated with thionyl chloride, an intermediate acyl chloride β-substituted by a hydroxyl group was likely formed. Its subsequent intramolecular cyclization produced novel β-lactones in one step. Two enantiomerically enriched lactones could be prepared via intermediates obtained by enzymatic hydrolysis.