Solventless Suzuki-Coupling reactions on palladium doped potassium fluoride alumina

Reactions of boronic acids with organic halides in the presence of palladium catalysts, the Suzuki Reaction, play an important role in modern organic chemistry. Numerous organic syntheses performed in the presence of alumina, Al₂O₃, exist in the literature. It has been found that the Suzuki-Coupling reaction can be carried out on commercially available alumina doped with potassium fluoride, 40% by weight, in the complete absence of organic solvents. This new solid phase synthesis is convenient, efficient, and environmentally friendly. The effects of substrate, temperature, reactant ratio, base, catalyst concentration, and the unique character of the KF/Al₂O₃ solid are presented. The development of a completely recyclable catalytic medium and the use of microwave irradiation with this methodology is also demonstrated.