Unveiling substituent effects
in [3+2] cycloaddition reactions
of benzonitrile N-oxide
and benzylideneanilines
from the molecular electron density theory perspective

2023 vol 2 issue 1
Full paper

A. Mondal, H. A. Mohammad-Salim, N. Acharjee

Pages 75-92


The zw- type [3+2] cycloaddition (32CA) reactions of benzonitrile N-oxide with a series of substituted benzylideneanilines have been studied within the Molecular Electron Density Theory (MEDT) at the B3LYP/6-31G(d) computational level. The presence of dimethylamino and methoxy substituents in the aromatic rings of benzylideneaniline makes the reaction more facile relative to the unsubstituted one, while the electron withdrawing nitro substituents relatively induce minimal changes in the energy profile complying with the experimentally observed reaction rates. The presence of non-bonding electron density at the nitrogen atom and the formation of pseudoradical centre at the carbon atom of benzonitrile N-oxide characterise the difference in electronic structure of the TSs relative to the reagents, while the topological analysis of the electron localization function (ELF) and the atoms-in-molecules (AIM) reveal no covalent bond formation at the early TSs. The present MEDT study analyses the experimentally observed substituent effects and complete regioselectivity in the studied 32CA reactions.

benzonitrile N-oxide, benzylideneanilines, electron localization function, [3+2] cycloaddition reactions, MEDT

First published: 23.03.2023