[5+1] cycloaddition of C,N-cyclic N'-acyl azomethine imines with isocyanides.

A catalyst-free [5 + 1] cycloaddition reaction between isocyanides and C,N-cyclic N'-acyl azomethine imines as the "isocyanophile" leading to novel heterocycles has been developed. These reactions proceeded quickly and cleanly to afford the corresponding imin-1,3,4-oxadiazin-6-one derivatives in high to excellent yields. A wide range of C,N-cyclic N'-acyl azomethine imines and isocyanides were applicable to this reaction.