Intramolecular Fischer Indole Synthesis and its Combination with an Aromatic [3,3]-Sigmatropic Rearrangement for the Preparation of Tricyclic Benzo[cd]indoles

Abstract

At the end of the tether: Aryl hydrazides that have carbonyl groups tethered at the para position of the aromatic ring undergo an intramolecular Fischer indolization reaction to give the corresponding indolophanes. Strategic insertion of a double bond in the tether enables a tandem aromatic [3,3] sigmatropic rearrangement reaction to occur to give tricyclic benzo[cd]indoles.