Conjugate addition of arylboronic acids to α,β-unsaturated carbonyl compounds in aqueous medium using Pd(ii) complexes with dihydroxy-2,2′-bipyridine ligands: homogeneous or heterogeneous nano-catalysis?

Abstract

The conjugate addition of arylboronic acids to α,β-unsaturated carbonyl compounds in water under air has been studied using a series of palladium(II) derivatives containing symmetrically disubstituted-2,2′-bipyridine ligands. Among them, best results were obtained with complex [PdCl2{3,3′-(OH)2-2,2′-bipy}] (2a), which selectively provides the desired addition products in good to high yields under mild conditions. Catalytically active palladium nanoparticles are formed in the course of the reactions. In the presence of sodium dodecyl sulfate (SDS) these nanoparticles can be stabilized and recycled.