Unexpected Direct Synthesis of N ‐Vinyl Amides through Vinyl Azide–Enolate [3+2] Cycloaddition

The unexpected synthesis of industrially important N ‐vinyl amides directly from aldehydes and α,β‐unsaturated N ‐vinyl amides from esters is reported. This reaction probably proceeds through an initial [3+2] azide–enolate cycloaddition involving a vinyl azide generated in situ. A survey of the reaction scope and preliminary mechanistic findings supported by quantum computational analysis are reported, with implications for the future development of atom‐efficient amide synthesis. Intriguingly, this study suggests that (cautious) reevaluation of azidoethene as a synthetic reagent may be warranted.