Organocuprates initiated anionic living polymerization of tert-butyl methacrylate

We report organocuprates initiated anionic polymerizations of various alpha,beta-unsaturated ester monomers in tetrahydrofuran (THF) under various conditions. It was found that catalysts prepared by reaction of CuI with methyllithium (MeLi) very effectively cause the polymerization of meth(acrylate) monomers. At molar ratio of [MeLi] to [CuI] higher than 2 the polymerization of t-butyl methacrylate (TBMA) proceeded quantitatively in THF at 0-45 degrees C to afford high molecular weight poly(t-butyl methacrylate) (PTBMA) with extremely narrow molecular weight distribution (MWD) (M-w/M-n=1.0(5)-1.1(7)). Initiator efficiency was less than 10% and highest at about [MeLi]/[Cul]=4.0. The post-polymerization proved the livingness of the polymerization of TBMA caused by lithium methylcuprate in THF at 0 degrees C. The active species for the polymerization of TBMA was thought to be higher cuprate, such as Li2Cu(CH3)(3). For the polymerizations of other methacrylates and I-butyl acrylate lithium methylcuprate initiators effectively afforded the polymers but with very bread MWD.