A theoretical study of the addition mechanism of carbon dioxide to methylamine. Modelling CO2–biotin fixation

Abstract

The addition reaction of carbon dioxide to methylamine, which can be considered as a first step for the modelling of CO₂–biotin fixation, is investigated using an ab initio MO method at HF/6–31G*, MP2/6–31G* levels and CISD calculations. The complete potential energy hypersurface has been explored and the stationary points representing reactants, transition state and product localized and characterized. Analysis of the structural evolution of the system along its reaction path proves that the reaction mechanism is an asynchronous process and the transition state can be described as a four-membered ring where a C–N bond is formed and one proton is transferred.