A general and expedient synthesis of 5- and 6-membered cyclic carbonates by palladium-catalyzed oxidative carbonylation of 1,2- and 1,3-diols

We present a general, practical, and efficient approach to 5- and 6-membered organic carbonates by palladium-catalyzed direct oxidative carbonylation of 1,2- and 1,3 diols,respectively.Reactions were carried out at 100 C in N,N-dimethylacetamideas the solvent under 20 atm (at 25 C; 1 atm=101.3 kPa) of a 4:1 v/v CO/air mixture in the presence of 0.5–2 mol% of PdI2 and KI (KI/PdI2 molar ratio=10). Excess dehydrating agent, such as trimethyl orthoacetate, was necessary in several cases to obtain appreciable results. The method could also be appliedto the synthesis of a high-value-added glycerol carbonatefrom glycerol, a readily available raw material. When applied to a-d-glucose, a double carbonylation process took place, with direct formation of a-d glucofuranose 1,2:5,6 dicarbonate.