Theoretical evaluation of global and local electrophilicity patterns to characterize hetero-Diels-Alder cycloaddition of three-membered 2H-azirine ring system.

Present communication elicits an interesting interaction between 2H-azirine and a number of electron rich and electron deficient dienes. A series of substituted 2H-azirine 1-10, and three dienes namely cyclopentadiene D-1, furfural D-2, and dinitrofuran D-3 were chosen to investigate and critically review the reactivity and selectivity of Diels-Alder cycloaddition strategy. The global and local electrophilicity patterns have been evaluated to interpret the electrophilic/nucleophilic behavior of dienes D-1 to D-3 and dienophiles 1-10, in polar Diels-Alder cycloaddition, using the DFT method at the B3LYP/6-31G* level of theory. Regional nucleophilicity have been evaluated using local nucleophilicity descriptor N(k) (Perez, P.; Domingo, L. R.; Duque-Norena, M.; Chamorro, E. J. Mol. Struct. THEOCHEM 2009, 895, 86-91), and regional electrophilicity at the active sites of the interactive species involved in Diels-Alder processes have been described on a quantitative basis using local electrophilicity index omega(k).