Trialkylsilyl-Protected Functional Initiators for Stereospecific Anionic Polymerization of Methacrylates

Abstract

Anionic polymerizations of methyl methacrylate with trialkylsilyl-protected lithium benzylamides were conducted in the presence of aluminum compounds such as n-Bu₃Al. When the Me₃Si-protected amide was used, the carbonyl attack took place to some extent to form a methacrylamide derivative with slightly lower initiator efficiency (∼0.9). In the case of i-Pr₃Si-protected amide, the carbonyl addition was completely suppressed. The obtained polymers had narrow molecular weight distribution and carried benzylamino end-group, as revealed by NMR analysis, which is readily accessible for further chemical transformations such as acylation with acryloyl chloride and debenzylation with H₂/Pd-C. Difuntional initiators with protected groups were also examined.