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

Organic & Biomolecular Chemistry Pub Date: 2018-04-03 DOI: 10.1039/C8OB00535D

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.

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