Palladium-Catalyzed Cascade Process Consisting of Isocyanide Insertion and Benzylic C(sp³)–H Activation: Concise Synthesis of Indole Derivatives

Synthesis of the indole skeleton was achieved using a Pd-catalyzed cascade process consisting of isocyanide insertion and benzylic C(sp3)–H activation. It was found that slow addition of isocyanide is effective for reducing the amount of catalyst needed and Ad2PnBu is a good ligand for C(sp3)–H activation. The construction of the tetracyclic carbazole skeleton was also achieved by a Pd-catalyzed domino reaction incorporating alkyne insertion.