High diastereoselectivity induced by intermolecular hydrogen bonding in [3+2] cycloaddition reaction: experimental and computational mechanistic approaches

Abstract

A diastereoselective [3 + 2] cycloaddition of N-aryl substituted maleimides with N, a-diphenyl nitrone possessing 11-hydroxyundecyloxy as a flexible substituent was performed. Experimental and comprehensive mechanistic density functional theory studies reveals that intermolecular H-bonding and steric repulsive interaction predominate exo-Z and exo-E cycloaddition transition states, respectively. The reaction proceeded smoothly depending on the reactants and gave a good yield of (syn) cis-isoxazolidine or (anti) trans-isoxazolidine as a single diastereomer.