Theoretical analysis of mechanism, regio- and stereoselectivity of 1, 3-dipolar cycloaddition of cyclic nitrone and substituted alkenes by DFT method.

Abstract This study presents a theoretical investigation of the 1,3-dipolar cycloaddition between cyclic nitrone a1 and substituted alkene b1. The mechanism, regioselectivity, and stereoselectivity of this 13DC reaction were analyzed using transition state theory and reactivity indices obtained from conceptual density functional theory (DFT) with DFT methods at B3LYP/6-31G(d) level of theory. The results indicate that this cycloaddition reaction proceeds via a synchronous one-step mechanism, exhibiting a non-polar nature and significant activation energies. These theoretical results are in agreement with the experimental observations. Moreover, topological analyses such as ESP, RDG-NCI, and ELF were employed to determine active sites, distinguish hydrogen bonds, van der Waals interactions, and steric repulsive interactions, and predict electron localization, respectively.