Photochemical strategies for C–N bond formation via metal catalyst-free (hetero) aryl C(sp2)–H functionalization

Abstract

The development of efficient and mild methods to assemble C–N bonds represents an important and appealing goal in modern synthetic chemistry. Recently, (hetero) aryl C(sp²)–H functionalization involving a radical process has emerged as an ideal and powerful route to construct C–N bonds, along with diminished cost and waste. As a simple and green methodology, photocatalysis offers selective and efficient access to the generation of radical species. This review presents state-of-the-art examples of photochemical strategies for C–N bond formation via metal catalyst-free (hetero) aryl C(sp²)–H functionalization since 2015. The discussion is divided into six sections according to the type of nitrogen sources and emphasis is placed on the related reaction mechanisms.