Phenyliodine Diacetate-Mediated Intramolecular C(sp2)-H Amidation for 1,2-Disubstituted Benzimidazole Synthesis under Metal-Free Conditions

A transition metal-free, hypervalent iodine(III) reagent [phenyliodine diacetate (PIDA)]-mediated C(sp(2))-H amidation in trifluoroethanol (TFE) has been developed. The intramolecular coupling methodology presented here provides a direct access to 1,2-disubstituted multifunctional benzimidazoles in good to excellent yields. The reactions were performed in the open air and at ambient temperature, and were found to be eco-friendly and atom-economical.