Mechanism of Palladium-Catalyzed Suzuki–Miyaura Reactions: Multiple and Antagonistic Roles of Anionic “Bases” and Their Countercations

Authors

  • Dr. Christian Amatore,

    Corresponding author
    1. Ecole Normale Supérieure, Département de Chimie, UMR CNRS-ENS-UPMC 8640, 24 Rue Lhomond, 75231 Paris Cedex 5 (France)
    • Ecole Normale Supérieure, Département de Chimie, UMR CNRS-ENS-UPMC 8640, 24 Rue Lhomond, 75231 Paris Cedex 5 (France)

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  • Dr. Gaëtan Le Duc,

    1. Ecole Normale Supérieure, Département de Chimie, UMR CNRS-ENS-UPMC 8640, 24 Rue Lhomond, 75231 Paris Cedex 5 (France)
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  • Dr. Anny Jutand

    Corresponding author
    1. Ecole Normale Supérieure, Département de Chimie, UMR CNRS-ENS-UPMC 8640, 24 Rue Lhomond, 75231 Paris Cedex 5 (France)
    • Ecole Normale Supérieure, Département de Chimie, UMR CNRS-ENS-UPMC 8640, 24 Rue Lhomond, 75231 Paris Cedex 5 (France)

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Abstract

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 Ar′B(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+).

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