Ab Initio Calculation of Thermodynamic and Kinetic Quantities for 1,3-Dipolar Cycloadditions of Benzonitrile Oxide with Various Dipolarophiles

Abstract

Ab initio molecular orbital calculations have been used to investigate the structures and transition states of 1,3-dipolar cycloadditions between benzonitrile oxide with ethylene, acrylonitrile, tetracyanoethylene and cyclopentene. Geometry optimisations and energy calculations were performed with RHF/6–31G*//RHF/6–31G* in each case. Calculation of vibrational frequencies permitted computation of the enthalpies, Gibbs free energies and rate constant of reactions. Cycloadditions of 1,3-dipolar benzonitrile oxide with electron-poor dipolarophiles have higher rates and lower thermodynamic stability than with other dipolarophiles.