Substituent effects on the rate of formation of azomethine ylides. A computational investigation

Abstract

The effect of substituents on the rate of conrotatory thermal cleavage of aziridine has been studied at the MP2(Full)/6-311++G(d,p)//MP2(Full)/6-31+G(d) level and also using SCS-MP2 methodology. While the parent compound has a high free energy of activation (194.6 kJ mol⁻¹), this value could be drastically lowered by substituent effects. Anionic species were found to be particularly effective in increasing the calculated reaction rate. The potential utility of this approach in 1,3-dipolar cycloaddition is discussed.