Cyclic Carbonate Formation in Water

Continuing the theme for the use of carbon dioxide, this paper (S Zhang et al, Tet Lett, 2009, 50 (4), 423) describes the reaction of epoxides with carbon dioxide in water with catalytic amount of ionic liquid to prepare cyclic carbonates.  The reaction worked best for terminal epoxides, such as butene oxide or styrene oxide, and gave yields of >83%.  Cyclohexene oxide gave just 47% yield.

A particularly interesting aspect of the paper is the fact that in the absence of water the product yields were significantly inferior (about 20-30% yields) and the authors propose a mechanism to explain the enhanced reaction in the presence of water.  

In conclusion, this paper shows again that carbon dioxide is a viable reagent and also outlines how the combined use of ionic liquid and water could enhance chemical reactivity.