Betaine-Catalyzed Synthesis of Cyclic Carbonates

Significance

The betaine 1 catalyzed activation of carbon dioxide towards epoxide opening is reported. Under the developed reaction conditions, different epoxides could be converted into the corresponding cyclic carbonates very efficiently. Catalyst 1 and its para-isomer exhibited superior performance compared to other examined betaine structures. The CO₂ adduct (A) proved to be preferably formed and isolable at lower temperatures, whereas at increased temperatures the ­tendency towards decarboxylation was higher. Determination of the temperature-activity correlation showed that for successful reaction towards epoxide opening temperatures above 70 ˚C were necessary.