The Fritsch-Buttenberg-Wiechell rearrangement, named for Paul Ernst Moritz Fritsch, 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
This rearrangement is also possible with alkyl substituents.
The strong base deprotonates the vinylic hydrogen
, which after alpha-elimination
forms a vinyl carbene
. A 1,2-aryl migration forms the desired product, the 1,2-diaryl-alkyne.
One study explored this reaction for the synthesis of novel polyynes