Fritsch–Buttenberg–Wiechell rearrangement

The Fritsch - Butt -Wiechell rearrangement was named after their discoverers Paul Ernst Moritz Fritsch, William Paul Buttenberg and Henry G. Wiechell. This is a chemical reaction in which a 1,1 -diaryl -2-bromo -alkene is reacted in a rearrangement reaction to a 1,2- diaryl alkyne compound. The reaction is carried out with a strong base, such as alkoxides.

The rearrangement reaction is also possible with alkyl substituents.

Reaction mechanism

The base deprotonates the vinylic hydrogen atom and α - elimination is a vinyl carbene or Vinylcarbenoid formed. A 1,2- alkyl migration form the desired 1,2- dialkyl alkyne.