Well-defined glycopolymers from RAFT polymerization: Poly(methyl 6-O-methacryloyl-α-D-glucoside) and Its Block Copolymer with 2-Hydroxyethyl Methacrylate

The glycomonomer methyl 6-O-methacryloyl-α-D-glucoside was prepared by lipase-catalyzed transesterification of vinyl methacrylate with methyl α-D-glucoside in dry acetonitrile. The desired 6-O regioisomer was obtained in good yield and its structure confirmed by ¹H- ¹H and ¹H-¹³C correlation NMR spectroscopy. Reversible addition-fragmentation chain transfer (RAFT) polymerization of the unprotected monomer was performed directly in aqueous solution using (4-cyanopentanoic acid)-4-dithiobenzoate as the chain transfer agent to give poly(methyl 6-O-methacryloyl-α-D-glucoside) with M_n between 16 and 103 kDa (¹H NMR) and polydispersities as low as 1.10. Chain extension of one of these polymers with 2-hydroxyethyl methacrylate afforded the novel hydrophilic-hydrophilic block copolymer poly [(methyl 6-O-methacryloyl-α-D-glucoside)-block-(2-hydroxyethyl methacrylate)].