A MEDT STUDY OF THE MECHANISM AND SELECTIVITY OF THE HETERO-DIELS–ALDER REACTION BETWEEN 3-BENZOYLPYRROLO[1,2-c][1,4]-BENZOXAZINE-1,2,4-TRIONE AND VINYL ACETATE

Abstract

The chemo-, regio-, and stereoselectivity of the hetero-Diels–Alder reaction between 3-benzoylpyrrolo[1,2-c][1,4]benzoxazine-1,2,4-trione and vinyl acetate, has been investigated within molecular electron density theory at the B3LYP/6-311(d,p) level of theory. The conceptual density functional theory reactivity indices, as well as the activation and reaction energies have been analyzed, and five possible reaction paths for this cycloaddition reaction, resulting from the presence of three heterodiene frameworks in the molecule of the diene reactant have been studied. The conceptual density functional theory analysis indicates that vinyl acetate acts as a nucleophile and 3-benzoylpyrrolo[1,2-c][1,4]benzoxazine-1,2,4-trione acts as a strong electrophile. The computed activation and reaction energies reveal that that this reaction is chemo-, stereo-, and regioselective, which is consistent with the experimental findings. Topological electron localization function analysis was used to look into how the electron densities were reorganized along the preferred reaction path. According to this analysis, the reaction takes place through a two-stage one-step mechanism.