Asymmetric anionic polymerization of alkyl-substituted N,N-diphenylacrylamide derivatives

Abstract

Five novel N,N-diphenylacrylamide derivatives bearing alkyl groups on a phenyl group were synthesized and polymerized with a chiral anionic initiator, the complex of (-)-sparteine and fluorenyllithium, in toluene at low temperature. Both position and size of the alkyl-substituents greatly affected the tacticity and optical activity of the polymer obtained. N,N-Di-4-tolylacrylamide gave a polymer possessing the highest isotacticity (m=72%) and specific rotation ([α]36525=-423°), which may be attributed to the chiral conformation of the main-chain. The asymmetric anionic polymerization of N-phenyl-N-(4-tolyl)acrylamide gave a chloroform-soluble polymer which was found to contain a polymer of high specific rotation ([α]36525=-1122°) and isotacticity (m=94%) through fractionation by GPC.