Contribution of reactivity indexes in the formation of β-lactams through [2+2] cycloaddition between substituted ketenes and imines

Abstract A quantum computational study has been performed at B3LYP/6-311G++(d, p) level to investigate mechanistic details of [2+2] cycloaddition reaction between substituted ketenes and imines. The global electrophilicity index, defined within the conceptual density functional theory (DFT), was used to distinguish the electrophilic and nucleophilic components of cycloaddition reaction on a unique scale of electrophilicity. In order to evaluate the feasibility of cycloaddition, the activation energies (B3LYP/6-311G(d)) have also been determined. An interesting interaction between a series of substituted ketenes (electrophiles) 1 – 10 , and imines (nucleophiles) 1–3 , has been deduced in order to rationalize these results.