Photochemical Aminomethylation of C(sp 3 )–H Bonds via Hydrogen Atom Transfer

Direct installation of an aminomethyl group onto aliphatic C–H bonds provides an attractive route to valuable amine-containing building blocks but remains challenging with conventional polar approaches. Here, we report a photochemical aminomethylation of C(sp3)–H bonds enabled by hydrogen atom transfer (HAT). Photoexcited benzophenone directly abstracts hydrogen from αamino, α-oxy, and α-thio C–H bonds, generating carbon-centered radicals that are intercepted by an in situ-formed N-protected formimine. This strategy provides direct access to protected vicinal diamines, amino alcohol derivatives, and related aminomethylated products without requiring prefunctionalization of the C–H donor. Notably, the C–H substrate can be employed as the limiting reagent, while selective radical generation suppresses overfunctionalization. Translation to continuous flow reduces reaction times from 20 h to 3 h, while improving yields for the investigated substrates, and enables scalable synthesis. Subsequent deprotection and functionalization further demonstrate the synthetic utility of the resulting aminomethylated products.