Copper-catalyzed Z-selective synthesis of acrylamides and polyacrylamides via alkylidene ketenimines

It remains very important to discover and study new fundamental intermediates consisting of carbon and nitrogen as the abundant elements of organic molecules. The unique alkylidene ketenimine could be formed in situ under mild conditions by an unexpected copper-catalyzed three-component reaction of alkyne, azide and water involving a successive cycloaddition, N2 extrusion and carbene-assisted rearrangement. Only Z-α,β-unsaturated amides instead of E-α,β-unsaturated amides or triazoles were acquired from alkylidene ketenimines with excellent selectivities and stereospecificities. In addition, a series of “approximate” alternating copolymers (poly (triazole-alt-Z-acrylamides)) with high Mns and yields were efficiently afforded by multicomponent polymerization through a very simple operation basing on this multicomponent reaction.