Synthesis of Carbazoles and Dibenzofurans via Cross-Coupling of o-Iodoanilines and o-Iodophenols with Silylaryl Triflates and Subsequent Pd-Catalyzed Cyclization.

An efficient route to a variety of carbazoles and dibenzofurans has been developed. It involves the reaction of o-iodoanilines or o-iodophenols with silylaryl triflates in the presence of CsF to afford the N- or O-arylated products, which are subsequently cyclized using a Pd catalyst to carbazoles and dibenzofurans in good to excellent yields. By using this methodology, the carbazole alkaloid mukonine has been synthesized in 76% overall yield in three steps.