A Sugar Decorated Macromolecular Bottle Brush by Carbohydrate-Initiated Cationic Ring-Opening Polymerization

The capability of a range of protected glucose- (Glc), galactose- (Gal), and fructose- (Fru) based tosylates and triflates to initiate the living cationic ring-opening polymerization of 2-ethyl-2-oxazoline (EtOx) was investigated by detailed kinetic studies utilizing 1H and 19F NMR spectroscopy and SEC as well as MALDI and ESI TOF mass spectrometry. The Glc and Gal tosylates and a sterically hindered Fru triflate revealed slow and incomplete initiation, whereas the Glc and Gal triflates resulted in living polymerizations. Well-defined Glc as well as Gal α-end-functionalized PEtOx was obtained after deprotection. Functionalization of the living oxazolinium chain ends with methacrylate anions resulted in a macromonomer that was applied for RAFT polymerization. Deprotection resulted in a comb polymer that is selectively functionalized with Glc at the ends of all side chains (DPbackbone = 13, DPside chains = 10, PDI = 1.11).