Silica-Supported Palladium-Based Catalysts for Clean Synthesis

Research into supported palladium complexes is described. The complexes are immobilised on porous silica supports using both grafting and templated sol-gel techniques. The resultant complexes are efficient catalysts for various C-C bond forming reactions, including Heck, Suzuki and allylic substitution. The catalysts are stable and can be easily recovered and reused, making them suitable for cleaner processing. Catalysts based on palladium (Pd) have provid-ed some of the most effective and exciting transformations in organic chemistry. A wide range of couplmg reactions are known, including the Heck (1-3), Suzuki (4-6) and Sonagashira reac-tions 0, all of which are efficient and have excellent generality. Other transformations such as hydrogenations and nucleophilic attack on allylic electrophiles are also widely used. Carbonylations represent a further class of reactions where carbo