Fischer Indole Synthesis

Fischer Indole Synthesis

Overall Reaction

This oldest indole synthesis method transforms aryl hydrazones to indoles and requires elevated temperatures and the addition of Brønsted or Lewis acids.

This reaction is good for preparing 2-, 3-, 5-and 7-substituted indoles but is poorer for the preparation of 4- and 6-substituted indoles, due to lack of regioselectivity.

Mechanism of Fischer Indole Synthesis