Electrochemical oxidation enables aromatic C–H amination with dual mechanisms

Abstract The selective amination of aromatic C–H bonds is a powerful strategy to access aryl amines, functionalities found in many pharmaceuticals and agrochemicals. Despite advances in the field, a platform for the direct, selective C–H amination of electronically diverse (hetero)arenes, particularly electron-deficient (hetero)arenes, remains an unaddressed fundamental challenge.1-10 In addition, many (hetero)arenes present difficulty in common selective pre-functionalization reactions, such as halogenation11, or metal-catalyzed borylation12 and silylation13. Here, we report a general solution to these limitations that enables selective C–H amination across a comprehensive scope of (hetero)arenes. Key to this strategy’s success is the oxidative generation of highly electrophilic N-radical dications from bicyclic tertiary amines (DABCO) that reacts across a wide range of arenes with high selectivity. Notably, this platform constitutes the first anodically generated N-radical cations that engage in aromatic C–H amination over well-reported hydrogen atom transfer (HAT) with weak C­–H bonds.14-16 This C–­H amination reaction that allows selective functionalization of both electron-rich and deficient arenes, as well as pyridines, is a rarity in the general area of non-directed aromatic C–H functionalization.1-4 This sustainable electrochemical DABCOylation reaction provides access to many complex drug-like aryl- and pyridinylpiperazines with high functionality tolerance, chemoselectivity, and site-selectivity.17