Quantum-chemical investigation of the mechanism of reaction between 1,2-dialkyldiaziridines and heterocumulenes

By quantum-chemical method in the framework of the density functional theory [B3LYP/6-31G(d)] a mechanism of reaction between 1,2-dialkyldiaziridines and ketenes CH2=C=O, PhCH=C=O, and aroyl isocyanates was investigated. The fragment Ph-CH-C(O) in the intermediate governing the cleavage of the N-N bond of the diaziridine ring is virtually planar leading to a considerable loosening of the bond. In the intermediate governing the cleavage of the C-N bond of the ring the fragment Ph-C(O)-N-C(O) is nonplanar resulting in significantly lesser loosening of the N-N bond and in the C-N-opening of the diaziridine ring. The calculated thermodynamical parameters are well consistent with the experimental data on the reactivity.