α-Trifluoromethyl alkenes as fluorinated linchpins in photochemical C-H/C-C functionalization.

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.