Mitchell等報(bào)導(dǎo)了用dppb作鈀的配體，能夠有效地催化氯代芳雜類同芳基硼酸進(jìn)行Suzuki反應(yīng)，產(chǎn)率高達(dá)98%; 之后Wang Shen等用三環(huán)已基磷(PCy3)作鈀的配體，發(fā)現(xiàn)此配體催化劑能夠最有效地激活芳氯鍵，這可能是由于三環(huán)已基磷比三苯基磷有更多的電子，因而可以增加鈀氧化插入芳氯鍵的能力，同時(shí)還發(fā)現(xiàn)在Pd(PCy3)Cl2催化下，鄰對(duì)位吸電子取代芳基氯能更有效的進(jìn)行反應(yīng)。
反應(yīng)實(shí)例
The following is a typical experimental procedure. Amixture of methyl trarts-3shlorociunamate (entry 18, Table 2) (393.2 mg, 2mmol), dichlorobis(tricyclobezylphosphine) palladium(73.8 mg, 0.10 mol),phenylboronic acid (292.6 mg. 2.4 mmol), and cesium fluoride (607 mg, 4.0 mmol)in 1-methyl-2-pyrrolidinone (NMP, 5 mL)was degassed by purging with nitrogen. The mixture was then heated at 100 ℃for 10 hours. The mixture was then partitioned between ethyl acetate (90 mL)and water (20 mL). The organic layer was separated, washed with water, dried,and concentrated} The residue was then purified by column chromatographyeluting with 50/50/5 toluene/hexane/ether to give the coupled product (466mg.98%).
【TetrahedronLetter: Vol. 38, No. 32,pp. 5575-5578, 1997】
1.0 equiv of aryl chloride, 1.5 equiv of boronic acid,3.0 equiv of KF, cat. Pd(OAc)2 , cat. (two ligands per Pd center), THF (1 mL per mmol of aryl chloride), room temperature.Reaction times have not been minimized.
【W(wǎng)olfe,J. P.; Buchwald, S. L. Angew. Chem., Int. Ed. Engl. 1999, 38,2413–2416.】
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