A convergent approach to biocompatible polyglycerol "click" dendrons for the synthesis of modular core-shell architectures and their transport behavior.

Dendrimers are an important class of polymeric materials for a broad range of applications in which monodispersity and multivalency are of interest. Here we report on a highly efficient synthetic route towards bifunctional polyglycerol dendrons on a multigram scale. Commercially available triglycerol (1), which is highly biocompatible, was used as starting material. By applying Williamson ether synthesis followed by an ozonolysis/reduction procedure, glycerol-based dendrons up to the fourth generation were prepared. The obtained products have a reactive core, which was further functionalized to the corresponding monoazido derivatives. By applying copper(I)-catalyzed 1,3-dipolar cycloaddition, so-called "click" coupling, a library of core-shell architectures was prepared. After removal of the 1,2-diol protecting groups, water-soluble core-shell architectures 24-27 of different generations were obtained in high yields. In the structure-transport relationship with Nile red we observe a clear dependence on core size and generation of the polyglycerol dendrons.