Site-Selective\nPyridine Carbamoylation Enabled by\nConsecutive Photoinduced Electron Transfer

The development of innovative approaches for synthesizing\namide\nmotifs is consistently in high demand. Herein, we successfully employ\nreadily available oxamic acids as carbamoyl radical precursors to\ncouple with pyridinium salts under metal-free conditions, selectively\nintroducing the amide group into pyridine architectures. The key innovation\nlies in the successful integration of an acridinium-based photocatalyst,\nwhich enables the formation of amide bonds through a consecutive photoinduced\nelectron transfer process. This open-shell strategy exhibits remarkable\ntolerance toward a wide range of functional groups. Furthermore, the\napplicability of this method has been extended to complex motifs,\ndemonstrating its versatility. Importantly, this approach serves as\na complementary strategy to classical amidation synthesis, offering\npotential advantages such as improved selectivity and expanded synthetic\npossibilities.