Catalytic Enantioselective Carbon Insertion into the β-Vinyl C–H Bond of Cyclic Enones

Chiral oxazaborolidinium ion-catalyzed Csp(2)-H functionalization of enones using diazoacetate has been developed. Various β-substituted cyclic enones were synthesized in high yield (up to 99%) with high to excellent enantioselectivity (up to 99% ee). The synthetic utility of this reaction was demonstrated by the formal synthesis of (+)-epijuvabione.