STEREOELECTIVE CATIONIC POLYMERIZATION OF PROPENYL ETHER BY ASYMMETRIC CATALYSTS

In the reported experiments, racemic cis- and trans-1-methylpropyl propenyl ether and racemic 1-methylpropyl vinyl ether were polymerized by asymmetric alkoxyaluminum dichlorides. In the polymerization of racemic cis-1-methylpropyl propenyl ether in toluene at minus 78 degree C, the polymer obtained a positive optical activity, and the residual monomers were converted by BF//3OEt//2 into a polymer having a negative optical activity. Thus, the stereoelective polymerization of racemic cis-1-methylpropyl propenyl ether was beyond any doubt attained in homogeneous cationic polymerization. In the polymerization of the trans isomer by the same catalyst, an optically active polymer was hardly formed. In the polymerization of racemic-1-methylpropyl vinyl ether which has no beta -methyl group, stereoelectivity was not observed at all.