Transition‐Metal‐Catalyzed C−H Bond Functionalization of Arenes/Heteroarenes via Tandem C−H Activation and Subsequent Carbene Migratory Insertion Strategy.

The past decade has witnessed tremendous developments in transition‐metal‐catalyzed C−H bond activation and subsequent carbene migratory insertion reactions, thus assisting in the construction of diverse arene/heteroarene scaffolds. Various transition‐metal catalysts serve this purpose and provide efficient pathways for an easy access to substituted heterocycles. A brief introduction to metal‐carbenes has been provided along with key mechanistic pathways underlying the coupling reactions. The purpose of this review is to provide a concise knowledge about diverse directing group‐assisted coupling of varied arenes/heteroarenes and acceptor‐acceptor/donor‐acceptor diazo compounds. The review also highlights the synthesis of various carbocycles and fused heterocycles through diazo insertion pathways, via C−C, C−N and C−O bond forming reactions. The mechanism usually involves a C−H activation process, followed by diazo insertion leading to subsequent coupling. [ABSTRACT FROM AUTHOR]