Rearrangements and proton transfer in nitrones by quantum chemistry and molecular dynamics

The structures of intermediates and transition states in rearrangement reactions of nitrone to amide via oxaziridine were calculated at the unrestricted B3LYP level of theory using the 6-31G(d,p) basis set. The same processes were studied by the method of direct molecular dynamics. Both methods reveal two reaction channels from cyclic oxaziridine to amide. One is via the acyclic structure C(O)H2NH with eclipsed NH and CO and then through the intermediate HC(OH)NH to amide. The other channel, from oxaziridine, is via the structure C(O)H2NH and then directly to the amide product.