Asymmetric radical polymerization of N-butadiene 1-carboxylyl S(−)- α-phenyl ethyl amine

Abstract

N-butadiene 1-carboxylyl S(−)- α-phenyl ethyl amine (Bu-1-CPA) was prepared and polymerized in various solvents such as acetonitrile, dimethylformamide (DMF), methanol, dioxane and benzene at 50° using AIBN as initiator. From the i.r. spectra of the polymers, it was confirmed that poly(Bu-1-CPA) was composed of trans 1,4-units. The polymer produced in DMF showed constant optical activity around [ α] D − 10° ( c = 1.0 in DMF) but the polymers obtained in the other solvents showed different optical activity, suggesting that the degree of asymmetric induction depended upon the solvent used during polymerization. From results for the copolymerization of Bu-1-CPA with styrene, it was similarly found that the asymmetric induction occurred in the backbone chain. The proposed mechanism for asymmetric induction involves polymerization via amide-iminol type prototropic tautomerism of Bu-1-CPA.