Synlett 2019; 30(03): 245-251
DOI: 10.1055/s-0037-1610336
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© Georg Thieme Verlag Stuttgart · New York

Modern Annulation Strategies for the Synthesis of Cyclo[b]fused Indoles

Edgar Haak*
Otto von Guericke University Magdeburg, Universitätsplatz 2, 39106 Magdeburg, Germany   Email: Edgar.Haak@ovgu.de
› Author Affiliations
This work was supported by the German Research Foundation DFG (265182801).
Further Information

Publication History

Received: 24 August 2018

Accepted after revision: 05 November 2018

Publication Date:
13 December 2018 (online)


Abstract

2,3-Annulated indoles exhibit a broad spectrum of biological activities. Various annulation strategies are applied to generate these scaffolds from prefunctionalized aniline or indole derivatives. Only a few methodologies allow the direct annulation of indole itself, often associated with regioselectivity issues or restrictions on available substitution patterns. More recently, ruthenium-catalyzed cascade transformations of readily available propargyl alcohols have been applied to the selective synthesis of various cyclo[b]fused indoles directly from indole. These efficient processes provide rapid access to intricate molecular structures from simple starting materials and facilitate the preparation of drug-like molecules.