Synthesis and Application of N-Heterocyclic Carbene-Palladium Ligands with Glycerol Dendrons for the Suzuki-Miyaura Cross-Coupling in Water

Highly active glycerol-dendron-supported N-heterocyclic carbene-palladium catalysts with catalytic sites at the core position were obtained with an efficient modular synthesis. A symmetrical ligand structure was designed to build a larger micro-environment by increasing the number of dendron generations. The catalytic activity was tested in Suzuki-Miyaura cross-coupling reactions. Deprotection of the dendritic supported catalysts allowed the catalytic reaction to take place in neat water, which is highly desirable for a more sustainable processing. A positive dendritic effect was observed for coupling of activated and nonactivated bromoaryls.