Electronic structures of vinylazide, vinylnitrene and 2H-azirine. Mechanism of the reaction from vinylazide to 2H-azirine

The mechanism of the conversion of vinylazides into 2H-azirines is examined by use of ab initio MO calculations. It is ascertained that vinylnitrenes have very weak bonds between the vinylazides and nitrogen molecule parts. It seems to decompose readily into the two fragments. This is one of the most characteristic features of vinylazides. The reaction is shown to proceed with N2 at the tail of the vinylnitrene part. This mechanism accounts well for experimental results of the reaction.