Английская Википедия:Fritsch–Buttenberg–Wiechell rearrangement

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Шаблон:Reactionbox The Fritsch–Buttenberg–Wiechell rearrangement, named for Paul Ernst Moritz Fritsch (1859–1913), Wilhelm Paul Buttenberg, and Heinrich G. Wiechell, is a chemical reaction whereby a 1,1-diaryl-2-bromo-alkene rearranges to a 1,2-diaryl-alkyne by reaction with a strong base such as an alkoxide.[1][2][3][4]

The Fritsch-Buttenberg-Wiechell rearrangement
The Fritsch-Buttenberg-Wiechell rearrangement

This rearrangement is also possible with alkyl substituents.[5]

Reaction mechanism

The strong base deprotonates the vinylic hydrogen, which after alpha elimination forms a vinyl carbene. A 1,2-aryl migration forms the 1,2-diaryl-alkyne product. The mechanism of the FBW rearrangement was a subject of on-surface studies where the vinyl radical was visualised with sub-atomic resolution.[6]

Mechanism of the Fritsch-Buttenberg-Wiechell rearrangement
Mechanism of the Fritsch-Buttenberg-Wiechell rearrangement

Scope

One study explored this reaction for the synthesis of novel polyynes:[7][8]

Fritsch-Buttenberg-Wiechell rearrangement Application
Fritsch-Buttenberg-Wiechell rearrangement Application

See also

References

Шаблон:Reflist

  • Darses, B.; Milet, A.; Philouze, C.; Greene, A. E.; Poisson, J.-F. o., Ynol Ethers from Dichloroenol Ethers: Mechanistic Elucidation Through 35Cl Labeling. Organic Letters 2008, 10 (20), 4445-4447.

Шаблон:Alkynes

  1. Шаблон:Cite journal
  2. Шаблон:Cite journal
  3. Шаблон:Cite journal
  4. Шаблон:Cite journal
  5. Шаблон:Cite journal
  6. Шаблон:Cite journal
  7. One-Pot Formation and Derivatization of Di- and Triynes Based on the Fritsch-Buttenberg-Wiechell Rearrangement Thanh Luu, Yasuhiro Morisaki, Nina Cunningham, and Rik R. Tykwinski J. Org. Chem. 2007, 72, 9622–9629 Шаблон:Doi
  8. The metal acetylide intermediate is captured by electrophile methyl iodide. The reaction product is a biomolecule found in for instance Bidens pilosa