CATIONIC POLYMERIZATION OF ANETHOLE AND ITS MODEL REACTION - STEREOCHEMICAL APPROACH TO THE PROPAGATION MECHANISM

The stereochemistry in the cationic polymerization of anethole, a β-substituted styrene, was investigated to clarify the propagation mechanism. The addition of acetaldehyde dimethyl acetal to anethole (acetal addition) was also studied as a model reaction. C NMR spectra showed that trans-anethole gave stereoregular polymers and that cis-isomer did not, indicating that the steric structure of the polymers depended on the geometrical structure of the monomer rather than on the polymerization conditions employed. On the other hand, the stereospecificity of the acetal addition was not very high even in the best case with trans-anethole (76∧#x0025; specificity). These results suggest that the structure of the attacking carbocation plays an important role in controlling the steric structure of products. © 1979 The Society of Polymer Science, Japan.