Synthesis of boltorn 1,2,3-triazole dendrimers by click chemistry

Abstract

Second-, third-, and fourth-generation hyperbranched aliphatic polyols namely Boltorn® H20, Boltorn H30, and Boltorn H40 were endcapped with azido and activated acetylenic groups in good to excellent yields (75–95%) following an acid catalyzed procedure. The resultant terminally functionalized dendritic azido and acetylenic groups undergo 1,3-dipolar cycloaddition using methyl (or ethyl) propiolate and benzyl azide, respectively, under catalytic or noncatalytic conditions below 40 °C to yield 1,2,3-triazole dendrimeric polymers in 82–95% yield, under extremely mild conditions that could be applied for compounds sensitive to acid, base, or heat. The dendritic azido and activated acetylenic derivatives may act as novel scaffolds to tune the mechanical properties of different polymers.