Controllable Synthesis of Stereoregular Polyesters by Organocatalytic Alternating Copolymerizations of Cyclohexene Oxide and Norbornene Anhydrides

A facile strategy has been demonstrated for the selective synthesis of highly stereoregular polyesters with cis-2,3-(exo, exo) or trans-2,3-(exo, endo) repeating units by the organocatalysts mediated alternating copolymerization of cyclohexene oxide and norbornene anhydride (NA) stereoisomers. The geometrical structure of polyester can be tuned simply by modulating the type of NA isomers (endo- or exo-NA), monomer feed ratio, and reaction temperature. The cis- (>99%) and trans-polyesters (>99%) exhibit high glass transition temperature up to 129.8 and 115.9 degrees C, respectively. The resulting polyesters provide a versatile platform to incorporate various functional groups through the robust thiol-ene reaction of the pendant norbornenyl groups.