title: Three roles for the fluoride ion in palladium-catalyzed Hiyama reactions: transmetalation of [ArPdFL₂] by Ar'Si(OR)₃.
abstract: From the kinetic data on the transmetalation/reductive elimination in fluoride-promoted Hiyama reactions, obtained using electrochemical techniques, it has been established that fluoride ions play three roles. F(-) reacts with trans-[ArPdBrL2] (L=PPh3) to form trans-[ArPdFL2], which reacts with Ar'Si(OMe)3 in the rate-determining transmetalation, whereas trans-[ArPdBrL2] does not react with Ar'Si(OMe)3. F(-) reacts with Ar'Si(OMe)3 to deliver the unreactive silicate Ar'SiF(OMe)3(-), thus leading to two antagonistic kinetic effects. In addition, F(-) catalyzes the reductive elimination from intermediate trans-[ArPdAr'L2].
authors.affiliation: Ecole Normale Supérieure-PSL Research University, Département de Chimie, Sorbonne Universités, UPMC Univ Paris 06, CNRS UMR 8640 PASTEUR, 24 Rue Lhomond, 75231 Paris Cedex 5 (France). christian.amatore@ens.fr.
authors.forename: Christian
authors.initials: C
authors.lastname: Amatore
authors.forename: Laurence
authors.initials: L
authors.lastname: Grimaud
authors.forename: Gaëtan
authors.initials: G
authors.lastname: Le Duc
authors.forename: Anny
authors.initials: A
authors.lastname: Jutand
keywords: cross-coupling; fluoride; kinetics; palladium; reaction mechanisms