Base-Promoted Denitrogenative Coupling of Nonactive 1,2,3-Triazoles with Ketones: Stereospecific Access to ( Z )-β-Enaminones

A base-promoted denitrogenative coupling of nonactive N(1)-aryl-1,2,3-triazoles with nucleophiles of ketones was developed, enabling the assembly of (Z)-β-enaminones at ambient temperature with complete stereoselectivity. Mechanistic studies indicate that the transformation proceeds through denitrogenative ring opening of the triazole to generate a ketenimine intermediate, followed by nucleophilic addition of the α-carbanion of the ketone generated in situ. This process affords a highly efficient and straightforward means to construct functionalized (Z)-β-enaminones with a broad substrate scope and excellent yields, by employing readily available N(1)-aryl-1,2,3-triazoles and ketones as starting materials.