Palladium versus copper-catalyzed N-arylation towards an efficient access to polysubstituted dibenzophenanthrolines and carbazoles

The double amination of meta-diiodo and dibromobenzenes by anthranilic acid derivatives is described using palladium and/or copper catalysis. The resulting symmetrical and unsymmetrical phenylene diamines are key precursors to polyfunctional dibenzophenanthroline carboxaldehydes. In contrast, when ortho-dibromo benzene is used as substrate, the Pd-mediated process affords exclusively the functional carbazole.