Stereospecific anionic polymerization of alpha-(alkylthiomethyl) acrylatesand alpha-(2-thienylmethyl) acrylate

Novel alpha-substituted acrylates having various functional groups containi ng a sulfur atom at the alpha-position, such as benzyl alpha-(butylthiometh yl)acrylate, benzyl alpha-(t-butylthiomethyl)acrylate, benzyl alpha-(benzyl thiomethyl)acrylate, benzyl alpha-(triphenylmethylthiomethyl)acrylate, ethy l alpha-(2-thienylmethyl)acrylate, benzyl alpha-(benzylsulfinylmethyl)acryl ate, and benzyl alpha-(benzylsulfonylmethyl)acrylate, were synthesized, and polymerizability and stereoregularity of the obtained polymers using lithi um reagents were investigated. In the anionic polymerization of alpha-(alky lthiomethyl)acrylates and ethyl a-(2-thienylmethyl)acrylate in toluene, hig hly isotactic polymers were obtained in good yields. A bulky alpha-substitu ent, triphenylmethylthiomethyl group, prevents polymerization. The anionic polymerization of alpha-(alkylthiomethyl)acrylates in tetrahydrofuran (THF) resulted in low yields and isotacticities, ethyl alpha-(2-thienylmethyl)ac rylate gave an isotactic polymer in a good yield. A side reaction, the elim ination of alkylthiolate anion from the propagating end, seems to take plac e in the polymerization of alpha-(alkylthiomethyl)acrylates in THF.