DBU-Catalyzed Alkyne-Imidate Cyclization toward 1-Alkoxypyrazino[1,2- a]indole Synthesis

Alexey A Festa; Rajesh R Zalte; Nikita E Golantsov; Alexey V Varlamov; Erik V Van der Eycken; Leonid G Voskressensky

doi:10.1021/acs.joc.8b01279

DBU-Catalyzed Alkyne-Imidate Cyclization toward 1-Alkoxypyrazino[1,2- a]indole Synthesis

J Org Chem. 2018 Aug 17;83(16):9305-9311. doi: 10.1021/acs.joc.8b01279. Epub 2018 Jul 19.

Authors

Alexey A Festa¹, Rajesh R Zalte¹, Nikita E Golantsov¹, Alexey V Varlamov¹, Erik V Van der Eycken^{1

2}, Leonid G Voskressensky¹

Affiliations

¹ Peoples' Friendship University of Russia (RUDN University) , Miklukho-Maklaya Street 6 , Moscow 117198 , Russian Federation.
² Laboratory for Organic & Microwave-Assisted Chemistry (LOMAC), Department of Chemistry , University of Leuven (KU Leuven) , Celestijnenlaan 200F , B-3001 Leuven , Belgium.

PMID: 29944827
DOI: 10.1021/acs.joc.8b01279

Abstract

1-(Propargyl)indol-2-carbonitriles react with alcohols to afford 1-alkoxypyrazino[1,2- a]indoles under DBU-catalyzed microwave-assisted conditions. The reaction scope includes a wide range of indoles, primary and secondary alcohols, and a thiol. The initial mechanistic study shows that the domino process presumably proceeds through an alkyne-allene rearrangement, imidate formation, and nucleophilic cyclization reaction sequence.