Computational study of regio- and stereoselectivity in aza-diene cycloadditions with ethyl vinyl ether and methyl acrylate as ethylene derivatives

-pyridine-3-carboxylate β-regioisomer (reaction 2). Conceptual DFT reactivity indices show that 1-aza-butadiene is a strong electrophile, ethyl vinyl ether is a strong nucleophile, and methyl acrylate is a weak nucleophile. Electron localization function and quantum theory of atoms in molecules topological analyses of the electronic structures of the transition state structure reveal a high degree of similarity in their electron density distributions, highlighting the asynchronous nature of the reaction mechanism, a conclusion further supported by BET analysis, favoring a total agreement with experimental findings.