A Highly Active Catalytic System For Suzuki-Miyaura Cross-coupling Reaction In Water

Using water instead of conventinal organic solvent in organic synthesis is much cheaper and environmental friendly,and consequently,it's of great significance for the development of green chemistry.Suzuki-Miyaura cross-coupling reaction is an important method for the synthesis of bis-aryl compounds.Since the discovery of the reaction,Chemists has been trying to change the reaction conditions,in expect to make the reaction substrates much broader,the reaction conditions milder,the tolerance of the functional groups much better,and the solvent much greener.There has been several reports on the Suzuki-Miyaura cross-coupling reaction could be carried out in water,and condition generally used was a mixed system of water and an organic solvent,or the catalytic reaction performed with a water-soluble ligand,or in the presence of phase transfer reagent.But the reaction substrates were mainly concentrated to aryl iodides and aryl bromides,while so far the report on aryl and heteroaryl chlorides as the substrates for Suzuki-Miyaura cross-coupling reaction in water has not still been common.Hydration of C-C triple bonds to give substituted ketones or aldehydes is of fundamental importance in synthetic organic chemistry.Alkynes are many synthetic precursor of the functional group-containing compounds.So the hydration of alkynes is an important method for the synthesis of many useful carbonyl compounds.The metal mostly used for the hydration of alkynes mainly include Ag,Pt,Ru,Au,etc.In recent years,catalyzing hydration of alkynes utilizing the gold heterocyclic carbene(NHC)as catalyst has been much more studied.According to these studies,a highly active catalytic system was developed for the Suzuki-Miyaura cross-coupling reaction of aryl and heteroaryl chlorides in water.Four Au-phosphine complexes were synthesized,and these complexs were characterized by 1H NMR,31P NMR,elemental analysis and X-ray single crystal diffraction,furthermore,complex 2 was used for the catalytic hydration of alkynes.The main details are as follows:[1]A highly active Pd(OAc)2/(2-mesitylindenyl)dicyclohexylphosphine/Me(Octyl)3 N+Cl-/K3PO4 · 3H2O catalyst system was developed,the catalytic system was very effective for the Suzuki-Miyaura cross-coupling reaction of aryl and heteroaryl chlorides with arylboronic acid in water.[2]Four gold phosphine complexs were Synthesized and characterized by 1H NMR,31P NMR,elemental analysis,furthermore,complexs 2 and 4 were characterized by X-ray crystal diffraction,and the catalytic activity of complex 2 was tested for hydration of alkyne,the results showed that it was very effective.