Hiyama coupling
Abstract
The Hiyama coupling is a palladium-catalyzed cross-coupling reaction in which an aryl, or vinyl halide (R1-X, where X = I, Br, Cl) reacts with an organosilane in the presence of a fluoride source or a base to form a new C-C bond.
Keywords
Aryl halide, Vinyl halide, Organosilane, Cross coupling
Category
Organometallic catalysis
Mechanism
The Hiyama coupling begins with the oxidative addition of an aryl or vinyl halide to the palladium(0) complex (1). In parallel, the organosilane is activated by a fluoride source (tetrabutylammonium fluoride, TBAF) or a base (-OR) through a nucleophilic attack at silicon, generating a hypervalent pentacoordinate silicate anion. This activated species then undergoes transmetalation with the palladium(II) complex, transferring its organic group R2 to the palladium center while releasing the halide ligand (2). Finally, reductive elimination from the palladium(II) complex affords the desired cross-coupled product and regenerates the palladium(0) catalyst (3).
Recent review
Komiyama, T.; Minami, Y.; Hiyama, T. Recent Progress in the Cross-Coupling Reaction Using Triorganosilyl-Type Reagents. Synlett. 2017, 28, 1873-1884.