Comparison of mesoporous silica and alumina supports for palladium-catalyzed carbon–carbon coupling reactions: unexpected high acceleration by supported cetyltrimethylammonium bromide

The coupling reaction of p-iodoanisole and phenylboronic acid occurs with high yields in aqueous medium in the presence of palladium complexes with water-soluble phosphine ligands on different mesoporous inorganic supports. Silica and alumina supports were similarly prepared and functionalized with sulfonate groups. The catalyst was immobilized by ion exchange. A novel approach to the amphiphilization of the supports by cetyltrimethylammonium bromide was applied to modify phase transfer steps favorably and to embed the catalyst in this bipolar surface layer. The reaction is accelerated and conversions with these embedded catalysts exceed those in homogeneous systems.