C-H cycloamination of N-aryl-2-aminopyridines and N-arylamidines catalyzed by an in situ generated hypervalent iodine(III) reagent.

A metal-free synthesis of diversified pyrido[1,2-a]benzimidazoles and 1H-benzo[d]imidazoles from N-aryl-2-aminopyridines and N-arylamidines has been developed. The C-H cycloamination reaction was catalyzed by hypervalent iodine(III) species generated in situ from iodobenzene (catalytic) and peracetic acid (stoichiometric). The reaction proceeded smoothly at ambient temperature to provide the corresponding N-heterocycles in good to excellent yields.