A new method to prepare α,β-unsaturated enol aldehydes is described. 3-Ethoxymethacrolein (1) and 5-formyl-3,4-dihydro-2H-pyran (5) were effectively prepared from enolethers and the Vilsmeier-Haack type complex, derived from cyanuricchloride and DMF. One byproduct, amidine 4, was also characterized.