Stereospecific anionic polymerization and copolymerization of 1,1-diphenylethyl methacrylate

1,1-Diphenylethyl methacrylate (DPEMA), which is a new methacrylic ester, was synthesized and polymerized by n-butyllithium (n-BuLi) in toluene and THF. The triad tacticity of the polymers was determined from the n.m.r. spectrum of poly(methyl methacrylate) (PMMA) which was derived from them. A highly stereoregular polymer was not formed either in toluene or in THF by n-BuLi between ?78° and 30°C. In toluene, the tacticity depended very much on the polymerization temperature, and unexpectedly, the polymer obtained at ?78°C was rich in syndiotacticity. The polymers obtained in THF were atactic regardless of the temperature. A highly isotactic polymer was formed with Grignard reagents. DPEMA (M₁) was also copolymerized with methyl methacrylate (MMA), diphenylmethyl methacrylate (DPMMA), and trityl methacrylate (TrMA) (M₂) in toluene and THF with n-BuLi; the tacticity of the copolymers was determined. Generally, the stereoregularity of the copolymers was lower than those of the M₂ homopolymers. In the copolymerization with MMA monomer reactivity ratios were also determined.