Metal‐Free Photoinduced Defluorinative Carboxylation of Trifluoromethylalkenes with Formate

Abstract Herein, we report an efficient protocol in which formate is used as a precursor of the CO 2 radical anion for the photoinduced defluorocarboxylation of α‐trifluoromethylstyrene. A wide range of gem ‐difluorovinylacetic acids bearing a variety of functional groups were successfully obtained in the absence of metal catalysts. The synthetic value of this protocol was highlighted by successful gram‐scale synthesis and late‐stage modification for complex biologically active molecules. This protocol provides a complementary method that extends the range of currently available methodologies for accessing the structurally versatile gem ‐difluoroalkenes.