Mechanistic Study of the Carbonylation of Aziridines to β-Lactams: Alkylation, Solvent and Molecular NaBr and MgO Clusters Catalysts Effects.

Using first principles methodology, we show that molecular NaBr and MgO nanoclusters are efficient ecofriendly and transition metal free catalysts for the carbonylation of aziridines to β-lactams. Multi-step mechanisms are proposed, where the activation energies of the rate-determining step are strongly lowered compared to gas phase reaction, exhibiting, however, a unique step. Also, these reactions are viewed to be favored thermodynamically in the presence of these catalysts and also in solvents, in particular in methanol. We suggest thus the use of NaBr and MgO nanoclusters for these reactions. Besides, the present findings allow to explain the experimentally observed regioselectivity of carbonylation of aziridines reactions, where CO is added on the more substituted C of aziridine three-membered ring. In sum, our work should motivate the use of such ecofriendly catalysts for carbonylation reactions without using transition metal catalysts.