Visible‐Light‐Mediated Nitrogen‐Centered Radical Strategy: Preparation of 3‐Acylated Spiro[4,5]trienones

Abstract A nitrogen‐centered radical strategy for the preparation of 3‐acylated spiro[4,5]trienones via visible‐light‐mediated acylation/ ipso ‐cyclization of alkynes with acyl oxime esters is reported. The alkyl‐ and aryl‐substituted acyl radicals, which generate from the cleavage of carbon‐carbon σ ‐bonds in acyl oxime esters via nitrogen‐centered radical pathway, attack the carbon‐carbon triple bonds in propiolamides and then undergo ipso ‐cyclization. This method provides a way for the construction of 3‐acyl‐substituted spiro[4,5]trienones, which can introduce aryl‐ or alkyl‐substituted acyl into spiro[4,5]trienone skeletons. magnified image