A Novel Catalytic Route to Polymerizable Bicyclic Cyclic Carbonate Monomers from Carbon Dioxide

A new catalyticroute has been developedforthe couplingof epoxidesand CO2affordingpolymer-izable six-memberedbicycliccarbonates.Cyclic epoxidesequippedwith aβ-positionedOH group can be trans-formedinto structurallydiversebicycliccyclic carbo-nates in good yields and with high selectivity.Key to thechemo-selectivityis the differencebetweenthe reactivityofsyn- andanti-configuredepoxyalcohols,with thelatter leadingto six-memberedring carbonateformationin the presenceof a binaryAlIIIaminotriphenolatecomplex/DIPEAcatalyst.X-ray analysesshow that theconversionof thesyn-configuredsubstrateevolvesvia astandarddoubleinversionpathwayprovidinga five-memberedcarbonateproduct,whereastheanti-isomerallows for activationof the oxiraneunit of the substrateoppositeto the pendentalcohol.The potentialuse ofthese bicyclicproductsis shownin ring-opening poly-merizationofferingaccess to rigid polycarbonates with improved thermal resistance.