A study of the dependence of substituted N,N-acyl defended keto stabilized sulfur ylides structure on their transformations by means of quantum chemistry

The effect of substituents and the nature of imide groups on the behavior of N,N-acyl defended carbonyl stabilized sulfur ylides was investigated. The comparison of Gibbs free energies of reactions obtained at the B3LYP/6-31G(d,p) level shows that the Wittig and the Corey-Chaykovsky reactions are least profitable for all considered ylides. It is found that the thermodynamic preference of methylthio pyrrolisindiones formation grows with temperature while formation of linear products does not depend on temperature. The presence of substituent in the β-position and the nature of the cyclic imide group have considerable influence on the preferable transformations of ylides.