Facile synthesis of the azocino[4,3-b]indole framework of strychnopivotine and other Strychnos alkaloids

Abstract

[Figure not available: see fulltext.]A new synthetic route to the 1,5-methanoazocino[4,3-b]indole is described. The aim of the present study is to provide a tetracyclic skeleton for the synthesis of pentacyclic Strychnos alkaloids (tubifolidine and strychnopivotine). Starting from a carbazole derivative, the ring closure was achieved by an intramolecular aldol reaction. The final product was obtained in 45% in the overall yield over 7 steps. © 2016, Springer Science+Business Media New York.