Versatile synthesis of functionalized β- and γ-carbolines via Pd-catalyzed C–H addition to nitriles/cyclization sequences

The first example of versatile synthesis of functionalized β-carbolines and γ-carbolines via redox-free Pd-catalyzed C-H addition of indole to nitrile/cyclization sequences is reported. A wide range of functionalized β-carbolines and γ-carbolines can be prepared from readily accessible indoles and nitriles in good to excellent yields under the optimal conditions.