Copper-Catalyzed Oxidative Cross-Dehydrogenative Coupling/Oxidative Cycloaddition: Synthesis of 4-Acyl-1,2,3-Triazoles.

A copper-catalyzed three-component reaction of methyl ketones, organic azides, and various one-carbon (C1) donors was developed that provides 4-acyl-1,2,3-triazoles in moderate to good yields. While DMF, DMA, TMEDA, or DMSO can serve as the C1 donor, best yields were obtained using DMF. The transformation is proposed to proceed via an oxidative C-H/C-H cross-dehydrogenative coupling followed by an oxidative 1,3-dipolar cycloaddition.