TheFritsch–Buttenberg–Wiechell rearrangement, named for Paul Ernst Moritz Fritsch (1859–1913), Wilhelm Paul Buttenberg, and Heinrich G. Wiechell, is achemical reaction whereby a 1,1-diaryl-2-bromo-alkenerearranges to a 1,2-diaryl-alkyne by reaction with a strong base such as analkoxide.[1][2][3][4]
The Fritsch-Buttenberg-Wiechell rearrangement
This rearrangement is also possible withalkyl substituents.[5]
The strong base deprotonates the vinylichydrogen, which afteralpha elimination forms avinylcarbene. 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
^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.PMID10814340.
^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. TykwinskiJ. Org. Chem.2007, 72, 9622–9629doi:10.1021/jo701810g
