Efficient synthesis of biscarbazoles by palladium-catalyzed twofold C–N coupling and C–H activation reactions†
Abstract
A new and efficient strategy for the synthesis of 3,9′- and 2,9′-biscarbazoles was developed. Our strategy relies on the cyclization of 1,1′-biphenyl-2,2′-diyl bis(trifluoromethanesulfonate) with 4- or 3-anisidine, transformation of the methoxy to a triflate group and subsequent oxidative Pd-catalyzed cyclization with various anilines.