Palladium-catalyzed amination and cyclization to heteroannellated indoles and carbazoles

New ortho-bromodiarylamines in the benzob]thiophene series were prepared by palladium-catalyzed amination, either in the benzene or in the thiophene ring. These were submitted to palladium-catalyzed cyclization, under different required conditions, to give several differently substituted thieno3,2-c] or 2,3-b]carbazoles and indolo3,2-b]benzob]thiophenes. This constitutes a novel synthetic route to both tetracyclic systems.