Fischer indole synthesis – [3,3]-sigmatropic rearrangement

A [3,3]-sigmatropic rearrangement is a key step in the Fischer indole synthesis

Click the structures and reaction arrows in sequence to view the 3D models and animations respectively

The Fischer indole synthesis is a famous method of making biologically important indoles. A key step involves a [3,3]-sigmatropic rearrangement where the sigma bond that breaks is between two nitrogen atoms. The sigma bond that forms links two rings with a C-C bond.

Ionic reaction steps are not shown which constitute the remainder of the Fischer indole synthesis.

Richard Windsor – Undergraduate Final Year Project 2008

G. R. Humphrey and J. T. Kuethe, Chem. Rev., 2006, 106, 2875–2911.