Solving the loss of orthogonality during the polyaddition of α‐azide‐ω‐alkyne monomers catalyzed by Cu(PPh3)3Br: Application to the synthesis of high‐molar mass polytriazoles

Abstract

AbstractPolyaddition of an α‐azide‐ω‐alkyne monomer by Cu(PPh3)3Br catalyzed 1,3‐dipolar cycloaddition was thoroughly studied as a model system to investigate the orthogonality of this click chemistry process. Indeed, loss of chain‐end functionality and occurrence of side reactions have a tremendous impact on the molar mass of polymers obtained by step growth polymerization. Particularly, SEC, 1H, and 31P NMR experiments have highlighted the occurrence of a Staudinger side‐reaction between azide chain‐ends and PPh3 from the copper(I) catalyst that dramatically alters Mn of the resulting polytriazoles. A significant enhancement of Mn could be achieved by using an alternative catalyst and optimized experimental conditions, that is, dilution and reaction time. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2470–2476, 2010