Efficient Synthesis of 4-Cyano 2,3-Dihydrooxazoles by Direct Amination of 2-Alkylidene 3-Oxo Nitriles

The addition of N-protected O-sulfonyl hydroxylamine derivatives on 2-alkylidene 3-oxo nitriles gives 2,5-disubstituted 4cyano 2,3-dihydrooxazoles (4-oxazolines) by a practical and efficient synthetic procedure under very mild conditions in high yields. Likely, the formation of N,O-heterocycles proceeds through a domino reaction involving a fast rearrangement of unstable 2-acyl 2-cyano aziridines.