Electrosynthesis of enantiomerically pure cyclic carbonates from CO2 and chiral epoxides

• Enantiomerically pure cyclic carbonates were electrosynthesized under mild condition.
• High conversion, selectivity and excellent ee value were obtained.
• The regioselectivity has been firstly studied by the DFT calculation.
• Electroreduced CO2 and Mg2 + played an important role in the synthesis process.

In this paper, the one-step synthesis of enantiomerically pure cyclic carbonates has been developed by electrolyzing the chiral epoxides and CO2 (0.1 MPa, rt) in an undivided cell with a 316 stainless steel (SS) cathode and a Mg sacrificial anode containing TEAI–MeCN as supporting electrolyte and solvent with a constant current. To deeply understand this reaction, the effects of various synthesis conditions were investigated using R-styrene oxide as the model compound. Under the optimized conditions, the maximum conversion is 67% with 96% selectivity and 98.8% ee value for R-styrene carbonate. Finally, the reaction mechanism has been proposed by comparative electrolysis and DFT calculation.