The anionic ring-opening polymerization of five-membered cyclic carbonates fused to the cyclohexane ring

The anionic polymerization of five-membered cyclic carbonates fused to a cyclohexane ring, that is, the trans-and cis-cyclohexane-1,2-diyl carbonates (trans- and cis-1, respectively), were examined as a model polymerization example to reveal the origin of the unusually good polymerizability of the previously reported methyl 4,6-O-benzylidene-2,3-O-carbonyl-alpha, D-glucopyranoside. The tert-BuOK-initiated anionic polymerization of trans-1 produces polymers with M-n values of 11 000, whereas no polymeric products were obtained from cis-1. The structure of the poly(trans-1) was confirmed by comparison with the model carbonate (2) based on the C-13 NMR spectra as well as the hydrolysis experiments. The poly(trans-1) form essentially consists of polycarbonate units; therefore, the polymerization of trans-1 was not accompanied by any decarboxylation. The thermodynamic parameters for the polymerization of trans-1 were estimated to be Delta H-p degrees = -23 kJ mol(-1) and Delta S-p degrees = 63 JK(-1)mol(-1).