Ionic Liquids In Suzuki Coupling Reaction

Many natural products containing the unit of biaryls are the importantconstitutional units of pharmaceuticals and functional materials. Suzuki reaction iswidely established as a powerful tool to synthesize biaryls due to its high efficiency,low cost and mild condition. Current study focused on the Suzuki reaction is to exploreinexpensive, environmentally friendly, efficient and recyclable catalytic system. As agreen solvent, ionic liquid (IL) instead of traditional organic solvent can be used inSuzuki reaction smoothly. In this paper, three new ionic liquid systems of Suzukireactions were developed by Pd/C catalyst and Nickel catalyst.First of all, a new system of ionic liquid as solvent, Suzuki reaction catalyzed byPd/C was developed. The reaction conditions including the ratio of ionic liquids andwater, the amount of catalyst, temperature, base and atmosphere were investigatedcarefully. The optimized process conditions were developed. Eighteen compounds ofbiaryls were successfully synthesized under the best conditions. Meanwhile catalyst andsolvent can be recycled five times.Secondly, use IL/PEG/H2O as solvent, an efficient and recyclable protocol to theSuzuki reaction was developed. Considered the influence of catalyst, temperature, baseand atmosphere, the optimized conditions were developed. By this mild conditions andhigh catalytic efficiency system, twenty-five compounds of biaryls were successfullysynthesized. Catalyst and solvent can be recycled four times without loss of activity.Thirdly, the catalytic system of nickel-catalyzed Suzuki reaction in ionic liquidwas developed. Confirmed optimum conditions after screening and comparing,Twenty-one biphenyl compounds were successfully synthesized. And six biphenylcompounds were synthesized by aryl methanesulfonates and arylboronic acid under thisoptimum condition. The reaction was low cost and environmentally friendly.