Salamé, A.; Rio, J.; Ciofini, I.; Perrin, L.; Grimaud, L.; Payard, P.-A. Copper-Catalyzed Homocoupling of Boronic Acids: A Focus on B-to-Cu and Cu-to-Cu Transmetalations. Molecules2022, 27, 7517.
Salamé, A.; Rio, J.; Ciofini, I.; Perrin, L.; Grimaud, L.; Payard, P.-A. Copper-Catalyzed Homocoupling of Boronic Acids: A Focus on B-to-Cu and Cu-to-Cu Transmetalations. Molecules 2022, 27, 7517.
Salamé, A.; Rio, J.; Ciofini, I.; Perrin, L.; Grimaud, L.; Payard, P.-A. Copper-Catalyzed Homocoupling of Boronic Acids: A Focus on B-to-Cu and Cu-to-Cu Transmetalations. Molecules2022, 27, 7517.
Salamé, A.; Rio, J.; Ciofini, I.; Perrin, L.; Grimaud, L.; Payard, P.-A. Copper-Catalyzed Homocoupling of Boronic Acids: A Focus on B-to-Cu and Cu-to-Cu Transmetalations. Molecules 2022, 27, 7517.
Abstract
Controlling and understanding Cu-catalyzed homocoupling reaction is crucial to prompt the development of efficient Cu-catalyzed cross-coupling reactions. The presence of a coordinating base (hydroxide, methoxide) enables the B-to-Cu(II) transmetalation from aryl boronic acid to CuIICl2 in methanol, through formation of a mixed Cu-(μ-OH)-B intermediates. A second B-to-Cu transmetalation to form bis-aryl Cu(II) complexes is disfavored. Instead, organocopper(II) dimers undergo a coupled transmetalation-electron-transfer (TET) allowing the formation of a bis-organocopper(III) complexes readily promoting reductive elimination. Based on this mechanism some guidelines are suggested to control the undesired formation of homocoupling product in Cu-catalyzed cross-coupling reactions.
Chemistry and Materials Science, Theoretical Chemistry
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