THEORETICAL STUDY ON HYDROLYSIS MECHANISM OF β-PHOSPHOLACTAMS

Abstract

The neutral hydrolysis mechanisms of a simple β-phospholactam with and without water-assisted reaction have been studied by using quantum chemical method at HF/6-31G**, MP2/6-31G** and B3LYP/6-31G** levels, respectively. The reaction can proceed by two different mechanisms: concerted and stepwise. There are two pathways in stepwise, i.e. pathway a and b, and the energy barriers of them are close. The energy barriers of water-assisted hydrolysis of β-phospholactam are obviously lower than those of no-water-assisted hydrolysis system. The energy barriers of stepwise mechanism are much lower than those of the concerted pathway in both cases. The solvent effects have been considered by means of a polarizable continuum model. The hydrolysis mechanism of β-phospholactam with that of the β-lactam and β-sultam was compared.