Fritsch–Buttenberg–Wiechell rearrangement

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]

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.

Scope

One study explored this reaction for the synthesis of novel polyynes:[6][7]

References

  1. ↑ Paul Fritsch (1894). "Ueber die Darstellung von Diphenylacetaldehyd und eine neue Synthese von Tolanderivaten". Justus Liebig's Annalen der Chemie. 279 (3): 319–323. doi:10.1002/jlac.18942790310.
  2. ↑ Buttenberg, W. P. (1894). "Condensation des Dichloracetals mit Phenol und Toluol". Justus Liebig's Annalen der Chemie. 279 (3): 324–337. doi:10.1002/jlac.18942790311.
  3. ↑ Wiechell, H. (1894). "Condensation des Dichloracetals mit Anisol und Phenetol". Justus Liebig's Annalen der Chemie. 279 (3): 337–344. doi:10.1002/jlac.18942790312.
  4. ↑ Köbrich, G. (1965). "Eliminations from Olefins". Angewandte Chemie International Edition. 4: 49–68. doi:10.1002/anie.196500491.
  5. ↑ Rezaei, H.; Yamanoi, S.; Chemla, F.; Normant, J. F. (2000). "Fritsch-Buttenberg-Wiechell Rearrangement in the Aliphatic Series". Org. Lett. 2 (4): 419–421. doi:10.1021/ol991117z.
  6. ↑ 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 doi:10.1021/jo701810g
  7. ↑ The metal acetylide intermediate is captured by electrophile methyl iodide. The reaction product is a biomolecule found in for instance Bidens pilosa

1. 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.

See also

This article is issued from Wikipedia - version of the 9/27/2016. The text is available under the Creative Commons Attribution/Share Alike but additional terms may apply for the media files.