Visible-Light-Induced Photocatalyst-Free Intramolecular sp3 C−H Oxidation of 2-Alkyl Benzamides

A new amidyl radical-mediated intramolecular 2‑alkyl benzamide oxidation reaction was developed under mild photochemical conditions. This Hofmann–Löffler–Freytag (HLF) type reaction involved the formation of intramolecular sp3 CO bonds via a different pathway than the construction of CN bonds in classic and modified HLF reactions. The oxidation proceeded smoothly at room temperature without any photocatalyst, and the desired products were provided in moderate to excellent yields with exclusive chemoselectivity.