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

A base-promoted denitrogenative coupling of nonactive <i>N</i>(1)-aryl-1,2,3-triazoles with nucleophiles of ketones was developed, enabling the assembly of (<i>Z</i>)-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 <i>in situ</i>. This process affords a highly efficient and straightforward means to construct functionalized (<i>Z</i>)-β-enaminones with a broad substrate scope and excellent yields, by employing readily available <i>N</i>(1)-aryl-1,2,3-triazoles and ketones as starting materials.