Synthesis of Functionalized Cyclic Carbonates by One-Pot Reactions of Carbon Dioxide, Epibromohydrin, and Phenols, Thiophenols, or Carboxylic Acids Catalyzed by Ionic Liquids

The one-pot reactions of CO₂, epibromohydrin, and phenols, thiophenols, or carboxylic acids catalyzed by 1-butyl-3-[(3-hydroxyphenyl)methyl]imidazolium bromide were investigated. Three kinds of cyclic carbonates with ether, thioether, or ester groups were synthesized under mild reaction conditions in good-to-high yields. Reaction-mechanism studies indicated that the proton exchange between the alkoxide formed through the ring-opening reaction of epibromohydrin with 1-bromo-3-phenoxy-2-propanol plays a crucial role in this synthetic route. The catalyst 1-butyl-3-[(3-hydroxyphenyl)methyl]imidazolium bromide was transformed to the corresponding cyclic-carbonate-functionalized ionic liquid during the reaction. This transformation did not affect its catalytic performance in the reaction.