Recent advances in the synthesis of carbazoles from indoles

Carbazoles are privileged nitrogen heterocycles that are present in a wide range of natural products, pharmaceuticals, and functional materials. Due to their wide application, various synthetic strategies are available in the literature using substituted amines or indoles as a substrate. Thus, this review comprehensively highlights the (2015–2019) article that focuses on the synthesis of carbazoles derived from an indole-template through transition-metal catalyzed C–H functionalization, metal-free cyclization, three-component reaction, and electrophilic iodocyclizations. The synthetic strategies described in this review provided diversely substituted carbazoles and few of them have profound pharmacological activity.