Metal-free cross-dehydrogenative C–N coupling of azoles with xanthenes and related activated arylmethylenes

Abstract

A metal-free C(sp³)–H/N–H cross-coupling of azoles with xanthenes and related activated arylmethylenes is presented. Both the use of azoles and the activation pattern of C(sp³)–H sources are essential for this transformation. In the presence of 2.0 equiv of benzoyl peroxide (BPO), methylenes bearing a heteroatom-bridged bisaryl group reacted with various azolic N–H sources to afford C–N bond forming products in usually excellent or quantitative yields, and the diphenylmethane and methylenes coactivated by a phenyl group and an adjacent heteroatom are less reactive. Mechanistic investigations suggest that a radical/radical cross-coupling pathway might be involved.

Graphical Abstract

Keywords:

• Amination
• C–N coupling
• cross-dehydrogenative coupling
• radical reaction

Additional information

Funding

We gratefully acknowledge the financial support from the National Natural Science Foundation of China (21702083), the General Projects of Yunnan Education Department (2017ZZX093), the Program for Innovative Research Team (in Science and Technology) in Universities of Yunnan Province, and the Yunnan Ten Thousand Talent Program for Young Top-Notch Talents.