Mechanism of Palladium-Catalyzed Suzuki-Miyaura Reactions: Multiple and Antagonistic Roles of Anionic "Bases" and Their Countercations
Mechanism of Palladium-Catalyzed Suzuki-Miyaura Reactions: Multiple and Antagonistic Roles of Anionic "Bases" and Their Countercations
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DOI：
10.1002/chem.201300177
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发表时间：
2013-07-29
影响因子：
4.3
通讯作者：
Jutand, Anny
中科院分区：
文献类型：
--
作者：
Amatore, Christian;Le Duc, Gaetan;Jutand, Anny
在Suzuki-Miyaura反应中，阴离子碱F-和OH-（作为其本身使用或由水中的CO32-生成）发挥多种拮抗作用。两个是正的：1)在决定速率的步骤（rds）金属转化中形成反式-[Pd(Ar)F(L)(2)]或反式-[Pd(Ar)- (L)(2)(OH)] (L=PPh3)，与ArB（OH)(2)反应；2）催化中间反式-[Pd(Ar)(Ar)(L)(2)]的还原消除。有两个作用是负的：1)形成不活泼的芳基硼酸盐（或氟硼酸盐）和2)通过碱（Na+, Cs+, K+）的反阳离子使[Pd(Ar)(L)(2)(OH)]的OH基团络合。
In Suzuki-Miyaura reactions, anionic bases F- and OH- (used as is or generated from CO32- in water) play multiple antagonistic roles. Two are positive: 1)formation of trans-[Pd(Ar)F(L)(2)] or trans-[Pd(Ar)- (L)(2)(OH)] (L=PPh3) that react with ArB(OH)(2) in the rate-determining step (rds) transmetallation and 2)catalysis of the reductive elimination from intermediate trans-[Pd(Ar)(Ar)(L)(2)]. Two roles are negative: 1)formation of unreactive arylborates (or fluoroborates) and 2)complexation of the OH group of [Pd(Ar)(L)(2)(OH)] by the countercation of the base (Na+, Cs+, K+).