Regioselective Fischer indole route to 3-unsubstituted indoles

…, DL Hughes, DR Bender, AM DeMarco…

Index: Zhao; Hughes; Bender; DeMarco; Reider Journal of Organic Chemistry, 1991 , vol. 56, # 9 p. 3001 - 3006

Full Text: HTML

Citation Number: 34

Abstract

Use of Eaton's reagent (P206/MeS08H) as acid catalyst in the Fischer indole reaction using methyl ketones provides unprecedented regiocontrol to form the 3-unsubstituted indoles. In several instances where the harshness of the reagent causes decomposition and low yields, dilution in sulfolane or dichloromethane results in far less degradation and higher yields of indoles. Steric effeds and the acidity of the medium are the two major factors that control ...