双阳离子型室温离子液体中Suzuki偶联反应研究

Suzuki Cross-Coupling Reactions in Dicationic Room Temperature Ionic Liquid

合成了具有钳子型的双咪唑阳离子核的室温离子液体2,它的相转变温度为-51℃,热力学分解温度为412℃,利用该离子液体作反应溶剂研究了不同钯催化剂PdCl2,Pd(OAc)2,Pd-NHC配合物3存在下的Suzuki偶联反应.结果表明:在NaOAc作碱,0.5 mol%的Pd-NHC配合物3存在下溴代苯衍生物与苯硼酸反应具有较高的活性,产率可以达到85%以上,Pd-NHC配合物3催化剂能更好地负载在钳子型双阳离子核室温离子液体2中,该反应体系能重复循环使用多次,且分离简单、重现性强、环境友好.

Room temperature ionic liquid （RTIL） 2 with pincer bisimidazole cationic nuclei was prepared. Its phase transition and thermal decomposition temperature are --51 and 412 ℃, respectively. Suzuki reactions have been studied when different catalyst PdCI2, Pd（OAc）2, Pd-N-heterocyclic carbene complex 3 were used in RTIL 2. The results indicate that aryl bromide can react with phenylboronic acid in the yield of over 85% in the presence of NaOAc and 0.5 mol% Pd-NHC 3, and the load- ing capability of Pd-NHC 3 in RTIL 2 is best. This high efficient catalytic system is environmentally benign, recoverable and easily separated with products.