A new synthetic approach to pentacyclic ring, 6,7,14,15-tetrahydro[1,5] diazocino[1,2-a:6,5-a']-8-dihydrodiindole

Abstract

The construction of a new pentacyclic ring system, 6,7,14,15-tetrahydro[1, 5]diazocino[1,2-a:6,5-a'] -8-dihydrodiindole (7) from simple precursors through our new synthetic route was presented to be a facile and concise method for an intramolecular N-alkylation of tosylate 12 which was obtained from N-acylation of indoline 4 with indole acid 9, followed by reduction and tosylation. This new synthetic approach can overcome the disadvantage of uncontrollable intermolecular double N-alkylation of the precursor 3 to produce the unexpected ring system 2. © 2011 The Japan Institute of Heterocyclic Chemistry.