【摘要】 芳基钯(Ⅱ)化合物(PPh3)2Pd(Ar)Br(1a~1e)与苯硼酸(2)经Suzuki偶联反应定量合成了一系列取代联苯(3a~3e),其结构经1H NMR确证。考察了辅助膦配体、反应温度、反应溶剂、反应时间、原料配比及芳环上取代基对偶联反应的影响。实验结果表明,在最佳反应条件[1 1 mmol,n(1)/n(2)=1/1,不加膦配体,甲苯/水为溶剂,于60℃~90℃反应3 h~24 h]下,可定量生成3;过量辅助膦配体和低反应温度不利于偶联反应中金属转移和还原消除的顺利进行,收率较低;芳环上带有吸电子基团时则有利于金属转移和还原消除,收率较高。更多还原

【Abstract】 A series of substituted diphenyls(3a ~ 3e) were synthesized by Suzuki coupling reaction of(PPh3)2Pd(Ar) Br(1a ~ 1e) with phenylboronic acid(2) under the optimum reaction conditions[1 1mmol,n(1) /n(2) = 1 /1,without auxiliary phosphine ligand,using toluene and H2O as a mixture solvent,at 60 ℃ ~ 90 ℃ for 3 h ~ 24 h].The structures were confirmed by1H NMR.The results showed that additional auxiliary phosphine ligand and low reaction temperature were unfavorable to the transmetallation and reductive elimination process,deduced from the lower coupling yield,while the electron withdrawing substituent on the aryl unit could accelerate the aforementioned process,indicative of the higher coupling yield.更多还原