Alkaline salt-catalyzed aza Diels-Alder reactions of Danishefsky's diene with imines in water under neutral conditions.

Two- or three-component aza Diels-Alder reactions of Danishefsky's diene with imines or aldehydes and amines in water took place smoothly under neutral conditions in the presence of a catalytic amount of an alkaline salt such as sodium triflate to afford dihydro-4-pyridones in high yields.