Fischer Indolization of N^α-Alkyl-2-allylphenylhydrazones

Abstract

Fischer indolization of the hydrazones of 8-allyl-1-amino-, 1, 2, 3, 4-tetrahydroquinoline and related compounds was investigated. Fischer indolization induced Cope rearrangement of the allyl group and acid-catalyzed intramolecular cycloaddition between the hydrazonyl group and the vinyl group. The base treatment of the latter reaction product caused eliminative ring-opening of the adduct and led to the formation of an indoline skeleton bearing a 2-ketoalkyl group at the C-2 position.