Unexpected 1,2,3-triazole formation in the reaction of diethylaluminum azide with a’- amino a,b-unsaturated ketones.

4-Acyl-1H-1,2,3-triazoles are formed from diethylaluminum azide and -(N,N-dibenzylamino)-,-unsaturated ketones by [3+2] cycloaddition of azide, followed by 1,5 hydride transfer to the carbon of the triazoline side chain and fragmentation of the tertiary amino group promoted by coordination of the latter to the Lewis acid. The structure of a triazole product is confirmed by X-ray crystallography.