Decatungstate-Catalyzed Photochemical Synthesis of Enaminones from Vinyl Azides and Aldehydes

Visible light-induced synthesis of enaminones from vinyl azides and aldehydes under decatungstate photocatalysis was developed. The reaction proceeds via acyl radical generation from aldehyde, followed by its addition to vinyl azide, nitrogen elimination, hydrogen atom abstraction by the intermediate iminyl radical, and tautomerization. Photochemical synthesis was efficiently conducted under both batch and flow conditions. The method can be applied to various vinyl azides and aldehydes and provides the desired products in 15-72% yields.