Photo-induced N-Center Radical Catalyzed Direct Hydrogen Atom Transfer Platform for Aliphatic C–H Functionalization

The introduction of diverse functionalities to omnipresent aliphatic C–H bonds is a challenge of notable value in catalysis. Herein, we report a universal platform using readily prepared 9-arylacridine catalysts−a class of neutral, N-centered photocatalysts−that engage aliphatic C–H bonds under mild conditions. This strategy enables the efficient generation of alkyl radicals, allowing various functionalizations of C–H bonds ranging from activated substrates to unativated, gaseous ethane. The platform features broad substrate scope, scalability, and compatibility with transition metal catalysis as well as multicomponent reactions. Its utility is demonstrated in streamlined synthesis of pharmaceutical synthons and late-stage functionalization of bioactive molecules. Detailed mechanistic studies highlight the crucial role of ortho-substituents (e.g. Cl atoms) on the 9-aryl moiety of catalysts, providing a rational basis for current and future catalyst design.