Mechanism of one oxygen atom transfer from oxo (salen) manganese(V) complex to olefins

Article abstract of DOI:10.1016/0040-4020(95)00904-3

In the Mn-salen catalyzed asymmetric epoxidation of some olefins, non-linear relationship between reaction temperature and entioselectivity was observed. For example, the epoxidation of 1,3-cycloalkadiene with complex 3a as a catalyst showed the maximum enantioselectivity at 0°C. It was also found that the electronic nature of the aromatic substituent in the salen ligand affects enantioselectivity but its effect does not necessarily correspond to the Hammet's σ-values. Based on these new experimental results, we propose a reaction mechanism which proceeds through metallaoxetane intermediate, for one oxygen atom transfer reaction from oxo (salen) manganese(V) complex to olefins.