Direct Introduction of an Acetyl Group at the α‐Carbon Atom of an Arene Ring through an Amide Photo‐Fries Rearrangement upon Exposure to UV Light

We employed an amide photo‐Fries rearrangement for the synthesis benzoheterocyclic compounds and found that direct acylation of the α‐carbon atom in an arene ring can occur upon exposure to ultraviolet (UV) light. In this reaction, the N‐acetyl group of amides underwent rearrangement to the α‐position across the bridgehead carbon atom under UV−C light. The reaction conditions were gentle and safe. Moreover, this reaction proves to be more convenient for selectively manipulating benzoheterocyclic compounds in comparison to traditional approaches involving Lewis acid catalysts or anionic reagents.