Standard Article

Hegedus Indole Synthesis

Published Online: 15 SEP 2010

DOI: 10.1002/9780470638859.conrr302

Comprehensive Organic Name Reactions and Reagents

Comprehensive Organic Name Reactions and Reagents

How to Cite

2010. Hegedus Indole Synthesis. Comprehensive Organic Name Reactions and Reagents. 302:1358–1362.

Publication History

  1. Published Online: 15 SEP 2010

Abstract

The palladium (II) complex–catalyzed oxidative N-heterocyclization of o-allylaniline or o-aminostyrenes and the palladium-catalyzed intramolecular cyclization of o-halo N-allylaniline are included in the indole derivatives reactions which is referred to as the Hegedus indole synthesis also known as the Hegedus cyclization. Several features of this reaction have been discussed. This reaction is not restricted to nitrogen nucleophiles and it works for oxygen nucleophiles as well. For the preparation of an indole from o-halo N-allylaniline, the iodo aromatics give good yields of indole in the presence of Pd(OAc)2 and Et3N in CH3CN at 110°C for 72 h but it is found necessary to add fresh catalyst periodically. Further this reaction has been explored to form 3-methylindole in higher yields and under milder conditions without using a phosphine ligand. This reaction has been applied in various organic syntheses.

Keywords:

  • indole;
  • tris(3-sulfonatophenyl)phosphine sodium salt (TPPTS) ligand;
  • palladium complex;
  • o-halo-N-allylanilines cyclization