The observed regioselectivity in [3 + 2] cycloaddition reactions (32CA) between ethyl vinyl ether (2) and substituted α-alkoxynitrones (1a, 1b) was studied theoretically using the conceptual density functional theory (CDFT) method at B3LYP/6–31 + + G(d, p) computational level. The regioselectivity and stereoselectivity of this 32CA reaction are rationalized by computations of activation energy calculations, Fukui FMO analysis, and local reactivity indices derived from CDFT in both the ground and transitions states. Analysis of the Fukui and CDFT indices allows the recognition of the nitrones as TACs participating in zwitterionic zw-type 32CA polar reactions and highly dependent on the electrophilic/nucleophilic character of the reactants. Thermodynamic and kinetic parameters of the putative ortho/meta species were determined to describe the preferred regioisomer. The TS obtained results suggest that the reactions proceed via a one-step mechanism that preferentially leads to the ortho-exo stereoisomer over the endo one. Both electronic and steric effects affect the stereoselectivity of these reactions. The results show that the experimental trends in the relative reactivity and regioselectivity of these reactions are correctly predicted using the computational CDFT method. [ABSTRACT FROM AUTHOR]