Alkaline salt-catalyzed aza Diels–Alder reactions of Danishefskys diene with imines in water under neutral conditions

Two- or three-component aza Diels–Alder reactions of Danishefskyʹs 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.