Theoretical implications on the [3 + 2] cycloaddition reactions of dibromoformaldoxime and (Z)-, (E)-3-(4-chlorobenzylidene)-1-methylindolin-2-one in terms of FMO, MEDT, and distortion-interaction theories.

Regio- and stereoselectivities of the [3 + 2] cycloaddition reactions of dibromoformaldoxime and (Z)-, (E)-3-(4-chlorobenzylidene)-1-methylindolin-2-one have been investigated using density functional theory. The results show that the experimental observations are predicted correctly by the PBE0-D3BJ/Def2TZVPP level of theory, unlike the frequently employed functional, i.e., B3LYP/6-31G(d). The distortion/interaction analyses revealed that these [3 + 2] cycloaddition reactions are under distortion control, and FMO calculations indicated a dominant HOMOmultiple bond system to LUMOTAC interaction. From the molecular electron density theory perspective, these [3 + 2] cycloaddition reactions show non-polar character and the bromo nitrile oxide under study were classified as zwitterionic species from the topological analysis of the electron localization function (ELF). [ABSTRACT FROM AUTHOR]