Coupling Reaction of CO2 with Epoxides by Binary Catalytic System of Lewis Acids and Onium Salts

Abstract

Various off-the-shelf Lewis acids in conjunction with various onium salts are screened for coupling reaction of <TEX>$CO_2$</TEX> with epoxides. Among the tested ones, <TEX>$VCl_3/n-Bu_4NOAc$</TEX>, <TEX>$VCl_3/(n-Bu_4NCl$</TEX> or PPNCl), <TEX>$FeCl_3/ n-Bu_4NOAc$</TEX>, and <TEX>$FeCl_3/ n-Bu_4NOAc$</TEX>are proved to be highly active. Propylene oxide, epichlorohydrin, styrene oxide, and cyclohexene oxide can be converted over 90% yields to the corresponding cyclic carbonates without the use of organic solvents under mild conditions by 0.1-1.0 mol% catalyst charge.