A computational study of 1,3-dipolar cycloadditions of nitrile oxides with dienes

Abstract

Density functional theory calculations at the M06-2X level of theory were employed to study the reactivity and regioselectivity of 1,3-dipolar cycloaddition reactions of nitrile oxides with cyclodienes. Calculated relative activation free energies reproduce the experimentally observed product ratios. The electronic energies of activation are found to be mainly controlled by distortion energies required to achieve the transition states. Both electronic and steric effects influence regioselectivities. Theoretical predictions were performed on previous experimental data and analyzed with the use of the distortion/interaction model. The obtained results will help in obtaining a better understanding of the factors that affect the relative cycloaddition rate.