One-Pot Cascade Synthesis of Substituted Carbazoles from Indoles, Ketones, and Alkenes Using Oxygen as the Oxidant.

An efficient one-pot two-step indole-to-carbazole strategy has been developed. This transition metal-free methodology uses oxygen as the sole oxidant and starts from cheap and readily available indoles, ketones, and alkenes. The present protocol efficiently enables the assembly of a diverse array of substituted carbazole products with good regioselectivity and broad tolerance of functional groups.