Palladium-Catalyzed Cross-Coupling of 1-Aminoazoles with Aryl Chlorides: Application to the Synthesis of Unsymmetrical N,N′-Diaryl-1-aminoindoles

An efficient method for the selective mono-N-arylation of 1-aminoazoles to provide a range of N-aryl-1-aminoazoles in good yields is described. This process based on the use of tris(dibenzylideneacetone)dipalladium associated to Xphos as the catalyst system is general, and allows the coupling to proceed, for the first time, with a variety of cheaper and less reactive aryl chlorides. The sequential combination of selective monoarylation using aryl chlorides and a second N-arylation reaction using (hetero)aryl bromides and iodides proved to be useful for the rapid construction of non-symmetrical N,N'-diaryl-1-aminoindoles in good yields.