Addition of the oxirane derivatives to CO2 catalyzed by Lewis bases under mild conditions

The addition of the oxirane derivatives to CO2 was found to occur without Lewis acid involvement but requires the presence of the Lewis base. The reaction was carried out at atmospheric pressure by CO2 bubbling through the starting ether in the presence of a source of halide anion or trichloroacetate anion, which provides the formation of ethylenecarbonate derivatives in preparative amounts. The reactivity of halide anions in the addition of the studied oxirane derivatives to CO2 decreases in the order I- > Br- > Cl- > F- >> Cl3CCOO-. The quantum chemical calculations of the reaction of CO2 with epichlorohydrin show that the reaction consists of consecutive processes of nucleophilic addition and nucleophilic ipso-substitution, which explains the catalytic effect of the Lewis bases and the order of their activity.