A One-Pot Copper-Catalyzed 3-Fold C-N Bond Coupling Strategy to the Synthesis of Substituted Benzimidazoles

An efficient, one-pot copper catalyzed 3-fold C-N bond-coupling strategy leading to pharmaceutically relevant benzimidazole heterocycles is reported. Our strategy involves a copper catalyzed intramolecular C-N coupling of N,N'-bis(2-bromophenyl)formamidine to provide 1-(2-bromophenyl)-1H-benzimidazole which upon intermolecular coupling with 2-amino pyridines and a cascade sp(2) C-H amination furnished a range of benzimidazo[1,2-a]benzimidazoles.