Alkyltriflones in the Ramberg–Bäcklund Reaction: An Efficient and Modular Synthesis of <i>gem</i>-Difluoroalkenes

Abstract

The unprecedented synthesis of gem-difluoroalkenes through the Ramberg–Bäcklund reaction of alkyl triflones is described herein. Structurally diverse, fully substituted gem-difluoroalkenes that are difficult to prepare by other methods can be easily prepared from readily available triflones by treatment with specific Grignard reagents. Experimental and computational studies provide insight into the unique and critical role of the Grignard reagent, which serves both as a base to remove the α-proton and as a Lewis acid to assist C–F bond activation.