Electrochemically catalyzed synthesis of cyclic carbonates from CO2 and propargyl alcohols

A convenient and efficient electrochemical method has been developed for the synthesis of the alpha-alkylidene cyclic carbonates from carbon dioxide (CO2) and propargyl alcohols at room temperature. The electrosynthesis was successfully carried out with a copper anode and a nickel cathode in an undivided cell containing n-Bu4NBr-MeCN electrolyte with a constant current under 3 MPa pressure of CO2, and the a-alkylidene cyclic carbonates were obtained in good to excellent isolated yields in the secondary and tertiary terminal propargylic alcohols cases. The experimental results show that the electrogenerated Cu+ ions and strong bases in situ could efficiently catalyze or promote the coupling reaction under the cooperation of electrolytic medium MeCN and supporting electrolyte n-Bu4NBr. The plausible mechanism of the coupling reaction was also discussed briefly. (c) 2010 Elsevier Ltd. All rights reserved.