Journal of Polymer Science Part A: Polymer Chemistry, Vol.51, No.21, 4667-4674, 2013
V-Shaped Graft Copolymers via Triple Click Reactions: Diels-Alder, Copper-Catalyzed Azide-Alkyne Cycloaddition, and Nitroxide Radical Coupling
We report here a simple and universal synthetic pathway covering triple click reactions, Diels-Alder, copper-catalyzed azide-alkyne cycloaddition (CuAAC), and nitroxide radical coupling (NRC), to prepare well-defined graft copolymers with V-shaped side chains. The Diels-Alder click reaction between the furan protected-maleimide-terminated poly(ethylene glycol) (PEG) and a trifunctional core (1) carrying an anthracene, alkyne, and bromide was carried out to yield the corresponding -alkyne- and -bromide-terminated PEG (PEG-alkyne/Br) in toluene at 110 degrees C. Subsequently, the polystyrene or polyoxanorbornene with pendant azide functionality as a main backbone is reacted with the PEG-alkyne/Br and 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO)-terminated poly(epsilon-caprolactone) using the CuAAC and NRC reactions in a one-pot fashion in N,N-dimethylformamide at room temperature to result in the target V-shaped graft copolymers. (c) 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 4667-4674
Keywords:click chemistry;copper-catalyzed azide-alkyne cycloaddition (CuAAC);Diels-Alder;graft copolymers;nitroxide radical coupling (NRC);poly(epsilon-caprolactone) (PCL);poly(ethylene glycol) (PEG);polyoxanorbornene (PONB);polystyrene (PS);triple click reactions;V-shaped graft copolymers