The Suzuki reaction is the organic reaction of an aryl- or vinyl-boronic acid with an aryl- or vinyl-halide catalyzed by a palladium(0) complex.[1][2] It is widely used to synthesize poly-olefins, styrenes, and substituted biphenyls. Several reviews have been published.[3][4][5]
The reaction also works with pseudohalides, such as triflates (OTf), instead of halides, and also with boron-esters instead of boronic acids.
- Relative reactivity: R2-I > R2-OTf > R2-Br >> R2-Cl
First published in 1979 by Akira Suzuki, the Suzuki reaction couples boronic acids (containing an organic part) to halides. The reaction relies on a palladium catalyst such as tetrakis(triphenylphosphine)palladium(0) to effect part of the transformation. The palladium catalyst (more strictly a pre-catalyst) is 4-coordinate, and usually involves phosphine supporting groups. In many publications this reaction also goes by the name Miyaura-Suzuki reaction. It is also often referred to as "Suzuki Coupling".
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Reaction mechanism
The mechanism of the Suzuki reaction is best viewed from the perspective of the palladium catalyst. The first step is the oxidative addition of palladium to the halide 2 to form the organo-palladium species 3. Reaction with base gives intermediate 4, which via transmetallation[6] with the boron-ate complex 6 forms the organopalladium species 8. Reductive elimination of the desired product 9 restores the original palladium catalyst 1.
Oxidative addition
Oxidative addition proceeds with retention of stereochemistry with vinyl halides, while giving inversion of stereochemistry with allylic and benzylic halides.[7] The oxidative addition initially forms the cis-palladium complex, which rapidly isomerizes to the trans-complex.[8]
Reductive elimination
Using deuterium-labelling, Ridgeway et al. have shown the reductive elimination proceeds with retention of stereochemistry.[9]
Scope
With a novel organophosphine ligand, a catalyst loading of up to 0.001 mol% has been reported [10]:
References
- ^ Miyaura, N. et al. Tetrahedron Lett. 1979, 3437.
- ^ Miyaura, N.; Suzuki, A. Chem. Commun. 1979, 866.
- ^ Suzuki, A. Pure Appl. Chem. 1991, 63, 419-422. (Review)
- ^ Miyaura, N.; Suzuki, A. Chem. Rev. 1995, 95, 2457-2483. (Review, doi:10.1021/cr00039a007)
- ^ Suzuki, A. J. Organometallic Chem. 1999, 576, 147–168. (Review)
- ^ Matos, K.; Soderquist, J. A. J. Org. Chem. 1998, 63, 461–470. (doi:10.1021/jo971681s)
- ^ Stille, J. K.; Lau, K. S. Y. Acc. Chem. Res. 1977, 10, 434–442. (doi:10.1021/ar50120a002)
- ^ Casado, A. L.; Espinet, P. Organometallics 1998, 17, 954–959.
- ^ Ridgway, B. H.; Woerpel, K. A. J. Org. Chem. 1998, 63, 458–460. (doi:10.1021/jo970803d)
- ^ Catalysts for Suzuki-Miyaura Coupling Processes: Scope and Studies of the Effect of Ligand Structure Timothy E. Barder, Shawn D. Walker, Joseph R. Martinelli, and Stephen L. Buchwald J. AM. CHEM. SOC. 2005, 127, 4685-4696 doi:10.1021/ja042491j
