Recent advances in the synthesis of nitrogen heterocycles via Rh(<sc>iii</sc>)-catalyzed chelation-assisted C-H activation/annulation with diazo compounds

Diazo compounds are a class of readily available and versatile reagents in modern organic synthesis that have been used as valuable synthetic building blocks for a diverse range of important organic transformations due to their convenient preparation and high reactivity. In this review, the advancements in the synthesis of nitrogen-containing heterocycles via Rh(iii)-catalyzed chelation-assisted tandem C-H activation/carbene insertion/annulation with diazo compounds as carbene precursors have been summarized. A variety of structurally diverse nitrogen heterocyclic scaffolds, such as indoles, isoindolones, carbazoles, isoquinolines, isoquinolones, 2H-indazoles, indazolones, cinnolines, 2,3-benzodiazepines, azepines, and diazepinones can be easily prepared from different diazo compounds in a highly efficient and environmentally benign manner.