α-Trifluoromethyl Alkenes as Fluorinated Linchpins in Photochemical C–H/C–C Functionalization

Abstract

Photochemical activation of C–H and C–C bonds has emerged as a powerful strategy for accessing fluorinated molecules from simple feedstocks under mild conditions. In this context, α-trifluoromethyl alkenes have evolved into versatile fluorinated linchpins, because radical addition to these activated alkenes can be directed toward either defluorinative alkylation to furnish gem-difluoroalkenes or hydroalkylation to give trifluoromethylated alkanes. This review highlights representative photochemical studies that illustrate how radical generation through C–H and C–C activation, together with control over the fate of the post-addition intermediate, governs product selectivity. Rather than offering a comprehensive survey, we emphasize the mechanistic logic and design principles underlying radical addition, radical-polar crossover, HAT, and EDA-complex activation. We also discuss recent contributions from our group that extend this chemistry to carboxylic acids, ketones, peptides, amides, and hydrocarbons, underscoring the growing utility of α-trifluoromethyl alkenes in fluorine editing, late-stage diversification, and biomolecule modification. Overall, these studies establish α-trifluoromethyl alkenes as programmable fluorinated linchpins for the selective construction of diverse fluorinated architectures.