Recent Advances in Photocatalytic C–N Bond Coupling Reactions

Catalytic C–N bond formation is one of the major research topics in synthetic chemistry owing to the ubiquity of amino groups in natural products, synthetic intermediates and pharmaceutical agents. In parallel with well-established metal-catalyzed C–N bond coupling protocols, photocatalytic reactions have recently emerged as efficient and selective alternatives for the construction of C–N bonds. In this review, the progress made on photocatalytic C–N bond coupling reactions between 2012 and February 2020 is summarized. 1 Introduction 1.1 General Mechanisms for Photoredox Catalysis 1.2 Pioneering Work 2 C(sp2)–N Bond Formation 2.1 Protocols Involving an External Oxidant 2.2 Oxidant-Free Protocols 3 C(sp3)–N Bond Formation 3.1 Direct Radical–Radical Coupling 3.2 Addition Reactions to Alkenes 3.3 Reductive Amination of Carbonyl Compounds 3.4 Decarboxylative Amination 4 Cyclization Reactions 4.1 C(sp2)–N Heterocycle Formation 4.2 C(sp3)–N Heterocycle Formation 5 Other Examples 6 Conclusion and Outlook