Photoinduced Transition‐Metal and External Photosensitizer Free Benzylic Fluorination of Unactivated Alkylarenes

A green and efficient protocol for the direct monofluorination of unactivated alkylarenes under visible‐light irradiation has been developed, without any extraneous transition‐metal catalysts or photosensitizers. This method is compatible with a broad spectrum of functional groups, including carboxylic and alcoholic scaffolds, under mild reaction conditions. Gram‐scale synthesis of a fluorine‐containing pharmaceutical analogue was successfully executed, underscoring the strategy's reliability and practicality. Furthermore, mechanistic studies suggest that a single‐electron transfer mechanism might be responsible for the generation of the benzylic radicals in initiation step. The photocatalytic monofluorination of unactivated alkylarenes, potentially initiated via a single‐electron transfer, offers a highly efficient and selective pathway with excellent substrate compatibility, enabling the scale‐up synthesis of pharmaceutical molecules. Omitting transition‐metal catalysts and photosensitizers simplifies late‐stage drug modification and the purification process.