Stereoregular polymerization of optically active monomers with optically active and inactive catalysts

Mixtures of l- and dl-menthyl methacrylates were polymerized with phenylmagnesium bromide coordinated with l-menthyl ethyl ether, and l- and dl-amylmagnesium bromide as catalysts. The isotacticity of the polymers was decreased by the addition of dl-monomer into l-monomer. From the relationship between the decrease of isotacticity and the increase of heterotacticity and syndiotacticity it is deduced that the isotactic sequences in the polymers are composed of either D or L configurations and not mixtures of D and L sequences. The optical activity of the monomer recovered and that of the polymers showed that the preference of one of the enantiomeric monomers over the other in the polymerization did not occur. The polymers prepared with l- and dl-amylmagnesium bromide had the same stereoregularity.