Synlett 2015; 26(05): 604-608
DOI: 10.1055/s-0034-1379950
letter
© Georg Thieme Verlag Stuttgart · New York

Target cum Flexibility: Synthesis of Indolo[1,2-b]isoquinoline Derivatives via Cobalt-Catalyzed [2+2+2] Cyclotrimerization

Anuradha Swami
Division of Organic Chemistry, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune 411 008, India   Email: vr.chepuri@ncl.res.in
,
Chepuri V. Ramana*
Division of Organic Chemistry, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune 411 008, India   Email: vr.chepuri@ncl.res.in
› Author Affiliations
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Publication History

Received: 03 October 2014

Accepted after revision: 26 November 2014

Publication Date:
12 January 2015 (online)


Abstract

A modular approach for the synthesis of small molecules having the unnatural 6,11-dihydroindolo[1,2-b]isoquinoline tetracyclic core has been documented. An acid-catalyzed Friedel–Crafts-type C2-alkylation of N-propargyl indole with a suitably activated alkynol has been used to prepare the key indole-derived diynes. The cobalt-catalyzed [2+2+2] cyclotrimerization of these diynes has been studied with various internal/terminal alkynes and with nitriles.

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