A carbonate ester is a functional group in organic chemistry consisting of a carbonyl group flanked by two alkoxy groups. The general structure of these carbonates is R1O(C=O)OR2 and they are related to esters R1O(C=O)R and ethers R1OR2 and also to the inorganic carbonates.
Carbonate esters are used as protecting group for diols. A classic reagent is phosgene but more user friendly reagents exist such as carbonyl diimidazole. Ethylene carbonate and Propylene carbonate are used as a solvent. Dimethyl carbonate is used as a methylating reagent.
Laboratory methods for the synthesis of carbonate ester in the laboratory are:
- from the corresponding diols.
- by double oxidation of ketones in a Baeyer-Villiger rearrangement
- by reaction of an epoxide with carbon dioxide catalysed by a zinc halide