Combining ATRP and “Click” Chemistry:  a Promising Platform toward Functional Biocompatible Polymers and Polymer Bioconjugates

The bromine chain-ends of well-defined poly(oligo(ethylene glycol) acrylate) (POEGA) (Mn = 6850 g·mol-1, Mw/Mn = 1.21) prepared using ATRP were successfully transformed into various functional end groups (ω-hydroxy, ω-amino, and ω-Fmoc-amino acid) via a two step pathway: (1) substitution of the bromine terminal atom by an azide function, (2) 1,3-dipolar cycloaddition of the terminal azide and functional alkynes (propargyl alcohol, propargylamine, and N-α-(9-fluorenylmethyloxycarbonyl)-l-propargylglycine). The efficient “click” cycloaddition was confirmed in all cases by 1H NMR or SEC−UV analysis. Moreover, this two-step synthetic strategy was also studied for preparing polymer-b-oligopeptide bioconjugates. Well-defined POEGA-b-GGRGDG was obtained in high yields via the “click” ligation of the azido functional POEGA and the alkyne functional oligopeptide GGRGDG.