Cationic polymerization of α·β-disubstituted olefins. Part XI. Polymerization of 2-chloroethyl propenyl ether catalyzed by BF3·O(C2H5)2

2-Chloroethyl propenyl ether (CEPE) was synthesized, and its cationic polymerizability by BF₃·O(C₂H₅)₂ and the steric structure of the resulting polymer were studied. In the polymerization in toluene at ?78°C, the rate of consumption of monomers decreased in the following order: cis-CEPE > 2-chloroethyl vinyl ether > trans-CEPE. The steric structure of the β-methyl group of the resulting polymer was determined quantitatively on the basis of the NMR spectrum of the β-methyl protons decoupled from β-methine protons. In the polymerization of CEPE in toluene at ?78°C, the polymer obtained from trans-CEPE was rich in threo-meso structure whilst cis-CEPE gave a polymer containing almost the same amount of threo-meso and erythro-meso structures. With methylene chloride as solvent, the amount of threo-meso structure increased and that of erythro-meso structure decreased for the polymer obtained from cis-CEPE. The steric structure of the polymer obtained from trans-CEPE was independent of the nature of the solvent used. The effect of polymerization temperature on the steric structure of the polymers was also investigated.