Polymer- and Ionic Liquid-Containing Palladium: Recoverable Soluble Cross-Coupling Catalysts

Phosphine, palladacycle, and N-heterocyclic carbene palladium complexes are highly active homogeneous catalysts that can promote a wide range of CC and CN cross-coupling reactions. An evolution from homogeneous catalysis has been to anchor these complexes in a platform in such a way that the catalytic reaction still occurs in homogeneous phase, but the palladium complex can be recovered at the end of the reaction and reused to promote consecutive reactions. In the present review we describe those strategies to develop palladium complexes anchored to soluble polymers and ionic liquids showing the advantages and limitations of this approach to develop recyclable palladium catalysts.