Synthesis of carbazoles via one-pot copper-catalyzed amine insertion into cyclic diphenyleneiodoniums as a strategy to generate a drug-like chemical library

Carbazoles have attracted high interest among synthetic chemists due to their unique structural features and potential pharmacological activities. Compared to linear aryliodoniums, cyclic diphenyleneiodoniums are more inert and have not attracted much attention to their application as building blocks. Employing our synthetic strategy, diversified carbazoles can be efficiently obtained from a single cyclic diphenyleneiodonium under mild conditions. The reactions catalyzed by cop- per(II) acetate have provided a variety of carbazoles in modest to good yields with a broad range of amines including anilines, aliphatic amines and sulfon amides. Moreover, one of the obtained carbazoles has displayed an outstanding ability to protect HT-22 neuronal cells from the damage induced by neurotoxins glutamate and homocysteic acid.