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Suzuki reaction

 
Wikipedia: Suzuki reaction

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, and has been extended to incorporate alkyl bromides [3]. Several reviews have been published.[4][5][6]

The Suzuki reaction

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 Suzuki-Miyaura reaction. It is also often referred to as "Suzuki Coupling".

Contents

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 transmetalation[7] with the boron-ate complex 6 forms the organopalladium species 8. Reductive elimination of the desired product 9 restores the original palladium catalyst 1.

The mechanism of the Suzuki reaction

Oxidative addition

Oxidative addition proceeds with retention of stereochemistry with vinyl halides, while giving inversion of stereochemistry with allylic and benzylic halides.[8] The oxidative addition initially forms the cis-palladium complex, which rapidly isomerizes to the trans-complex.[9]

Reductive elimination

Using deuterium-labelling, Ridgway et al. have shown the reductive elimination proceeds with retention of stereochemistry.[10]

Scope

Recent applications of the Suzuki–Miyaura cross-coupling reaction in organic synthesis has been summarized by Kotha and co-workers.[11] With a novel organophosphine ligand (SPhos), a catalyst loading of down to 0.001 mol% has been reported [12]:

Suzuki Reaction Catalyst Loading Barder 2005

See also

References

  1. ^ Miyaura, N. et al. Tetrahedron Lett. 1979, 3437.
  2. ^ Miyaura, N.; Suzuki, A. Chem. Commun. 1979, 866.
  3. ^ http://pubs.acs.org/cgi-bin/abstract.cgi/jacsat/2002/124/i46/abs/ja0283899.html
  4. ^ Suzuki, A. Pure Appl. Chem. 1991, 63, 419-422. (Review)
  5. ^ Miyaura, N.; Suzuki, A. Chem. Rev. 1995, 95, 2457-2483. (Review, doi:10.1021/cr00039a007)
  6. ^ Suzuki, A. J. Organometallic Chem. 1999, 576, 147–168. (Review)
  7. ^ Matos, K.; Soderquist, J. A. J. Org. Chem. 1998, 63, 461–470. (doi:10.1021/jo971681s)
  8. ^ Stille, J. K.; Lau, K. S. Y. Acc. Chem. Res. 1977, 10, 434–442. (doi:10.1021/ar50120a002)
  9. ^ Casado, A. L.; Espinet, P. Organometallics 1998, 17, 954–959.
  10. ^ Ridgway, B. H.; Woerpel, K. A. J. Org. Chem. 1998, 63, 458–460. (doi:10.1021/jo970803d)
  11. ^ Recent applications of the Suzuki–Miyaura cross-coupling reaction in organic synthesis Sambasivarao Kotha, Kakali Lahiri and Dhurke Kashinath Tetrahedron 2002, 48, 9633-9695 doi:10.1016/S0040-4020(02)01188-2
  12. ^ 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

External links


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