No abstract

The substituents on the diene and/or dienophile can contribute to the decrease or increase of this energy. However, there are other artifices to catalyze chemical reactions, in particular the Diels-Alder reactions, such as, for example, the application of an electric field on the reaction axis. The existence of an external electric field (EEF), properly oriented, has the potential to further stabilize or destabilize these charge transfer contributors and thus influence the energy. So, the goal of this study was to compare the activation energies of the Diels-Alder reaction between ethylene and nitrosoethylene, using an electric field, Lewis acid (BH3) as catalysts and the influence of substituents. All calculations were performed with Gaussian09 software, the compounds were fully optimized using the restricted Hartree-Fock method with the basis set 6-31G, single-point energies determined with MP3 method and basis set 6-31G. The effects of EEFs were studied using the “Field = M ± N” keyword with F values (F=±0,125 au and ±0,080 au) along the preferred axis. The lowest activation barrier is encountered when the electric field is applied, followed by the use of borane as the Lewis acid.