Visible-Light-Induced Defluorinative Giese Reaction of gem -Difluorides via the ConPET Process: A Route to tert -Alkyl Fluorides

The activation of C(sp³)-F bonds, particularly the selective activation of polyfluorinated compounds, is an important yet challenging topic in organic synthesis. Herein, we report a metal-free, visible-light-induced defluorinative Giese reaction of gem-difluorides, providing a straightforward approach to tert-alkyl fluorides. This protocol is characterized by mild and redox-neutral conditions, excellent functional group compatibility, and high atom efficiency. Mechanistic studies and DFT calculations suggest that the key fluorobenzyl radical intermediate is formed via a consecutive photoinduced electron transfer (ConPET) process. This intermediate then undergoes radical addition, followed by a hydrogen atom transfer (HAT) process, to yield the final product rather than undergoing classical protonation.