Abstract

The Diels-Alder reaction of methyl 2-(4-methylphenyl)-2H-azirine-3-carboxylate (dienophile), with four dienes namely 1-methoxy-1,3-butadiene D-1, cyclopentadiene D-2, penta-1,3-diene D-3, and 1-acetoxy-1,3-butadiene D-4 has been studied using DFT method at B3LYP/6-31G* level of theory. A novel approach of using global and local electrophilicity patterns was evoked to interpret the electrophilic/nucleophilic behavior of dienes and dienophile in polar hetero-Diels-Alder cycloaddition. Moreover, regional nucleophilicity has been evaluated using local nucleophilicity descriptor Nk, whereas regional electrophilicity at the active sites of the interactive species involved in hetero-Diels-Alder processes has been quantitatively interpreted using local electrophilicity index ωk.

Keywords: Electrophilicity index, 2H-azirine, Fukui functions, Hetero-Diels-Alder reaction, DFT, electrophilic/nucleophilic behavior, photochemical excitation, dienophile, regioselective addition, cyclopentadiene