Theoretical Evaluation of the Global and Local Electrophilicity Patterns to Characterize Hetero Diels-Alder Cycloaddition in the Synthesis of Isoxazolo[4,5-e](1,2,3,4-tetrazine)

A series Of Substituted dienophiles 1-10 and three 1,2-diazadienes namely D-1, D-27 D-3 were chosen to understand the reactivity and selectivity of Diels-Alder cycloaddition. The global and local electrophilicity patterns have been evaluated on a series of cycloaddition reactions to assess the reaction pathways (NDAC/IEDDAC) using the absolute scale of electrophilicity proposed by Parr et al. Regional electrophilicity at the active sites of the reagents involved in Diels-Alder processes has been described on a quantitative basis using, local or regional electrophilicity index i.e. Fukui function. Good qualitative/quantitative comparison was found between Molecular energy gaps and global electronic parameters, which has been employed to assess the cycloaddition pathways successfully.