Palladium Nanoparticles Supported on Sulfonic Acid Functionalized Silica as Trifunctional Heterogeneous Catalysts for Heck and Suzuki Reactions

The arylation of acrylates and boronic acids with anilines, through insitu generated aryl diazonium salts, was successfully achieved by using trifunctional heterogeneous catalysts bearing BrOnsted acid and metal active sites. The trifunctional materials were prepared by adsorption of palladium nanoparticles, generated by reduction of a solution of Pd(OAc)(2) onto a commercially available sulfonic acid functionalized silica. These new trifunctional catalysts act as a 1)proton donor for the diazotization step, 2)counterion for the diazonium salt, and 3)Pd source for the coupling step. This unprecedented strategy, features mild and safe conditions as hazardous aryl diazonium salts are generated in situ and only produces environmentally friendly byproducts such as tBuOH, H2O, and N-2.