Metal-free C(sp2)–H functionalization of azoles: K2CO3/I2-mediated oxidation, imination, and amination

Abstract

The direct C2−H oxidation and imination of a wide variety of azoles was achieved by using a commercially available simple K₂CO₃/I₂ reagent combination. The iodinated azole adduct, produced via the in situ generation of N-heterocyclic carbene, is the key intermediate for C2−H oxidation, imination, and amination of azoles. Significantly, these reactions proceed under mild conditions with high to excellent yields, are scalable to large quantity and exhibit a broad substrate scope. Interestingly, this direct C2−H imination method allowed us to access various pharmacologically active N⁶-alkyl or N⁶-aryl substituted benzimidazoquinazolinone scaffolds through intramolecular C−H imination in a sequential one-pot reaction.