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Transmetalation (alt. spelling: transmetallation) is a type of organometallic reaction that involves the transfer of ligands from one metal to another. It has the general form: M 1 –R + M 2 –R′ → M 1 –R′ + M 2 –R
The mechanism of the Stille reaction has been extensively studied. [11] [23] The catalytic cycle involves an oxidative addition of a halide or pseudohalide (2) to a palladium catalyst (1), transmetalation of 3 with an organotin reagent (4), and reductive elimination of 5 to yield the coupled product (7) and the regenerated palladium catalyst (1).
Pd(TFA) 2 is another reactive catalyst for transmetallation of ArGeEt 3. It has an electron-deficient Pd center and provides thermodynamic driving force by forming TFA–GeEt 3. Based on this strategy, an oxidative C–O cross-coupling method catalyzed by Pd(TFA) 2 was reported. The reaction proceeded through a Pd(II)/Pd(IV) catalytic cycle.
The Suzuki reaction or Suzuki coupling is an organic reaction that uses a palladium complex catalyst to cross-couple a boronic acid to an organohalide. [1] [2] [3] It was first published in 1979 by Akira Suzuki, and he shared the 2010 Nobel Prize in Chemistry with Richard F. Heck and Ei-ichi Negishi for their contribution to the discovery and development of noble metal catalysis in organic ...
That the substrate must contain acidic hydrogens adjacent to the ether oxygen was a significant limitation of the original reaction. Thus, the development of transmetallation methods that allowed the selective generation of carbanions from carbon-tin bonds represented a profound methodological advance.
The reaction is named after Ei-ichi Negishi who was a co-recipient of the 2010 Nobel Prize in Chemistry for the discovery and development of this reaction. Negishi and coworkers originally investigated the cross-coupling of organoaluminum reagents in 1976 initially employing Ni and Pd as the transition metal catalysts, but noted that Ni ...
An important synthetic application using such dialkylboranes, such as diethylborane, is the transmetallation of the organoboron compounds to form organozinc compounds. [9] [10] Some diaryl and dialkylboranes are well known. Dimesitylborane is a dimer (C 6 H 2 Me 3) 4 B 2 H 2). It reacts only slowly with simple terminal alkenes.
Organogallium compounds can be synthesized by transmetallation, for example the reaction of gallium metal with dimethylmercury: 2Ga + 3Me 2 Hg → 2Me 3 Ga + 3 Hg. or via organolithium compounds or Grignards: GaCl 3 + 3MeMgBr → Me 3 Ga + 3MgBrCl. The electron-deficient nature of gallium can be removed by complex formation, for example