Lewis-Acid-Catalyzed Decarboxylative Annulation of 2-Aminoindole-3-Carboxylate with Ynals Involving [3 + 2] Spirocycloaddition and 2,3-Aza Migration
摘要:
2-Aminoindole-3-carboxylates undergo a Lewis-acid-catalyzed decarboxylative annulation with ynals to afford dihydro-chromeno-fused delta-carbolines through a 2,3-aza migration, via a spirocyclic intermediate generated from an initial [3 + 2] spirocycloaddition. Bronsted acid interference changes the path from a [3 + 2] to a [4 + 2] addition. 2-Aminoindoles without an ester functional group at C3 underwent a different condensation, followed by hetero-Diels Alder reaction to generate chromeno-fused alpha-carbolines.
Diversity-Oriented Synthesis of Polycyclic Indoles: Brønsted or Lewis Acid Catalyzed Three-Component Reaction for the Synthesis of α-Carbolines and Pyrimidoindoles
作者:Rajesh K. Arigela、Ravi Kumar、Srinivas Samala、Sahaj Gupta、Bijoy Kundu
DOI:10.1002/ejoc.201402633
日期:2014.9
diversity-oriented synthesis of pyrido- and pyrimido-indoles from an acid-catalyzed three component (3C) reaction involving ethyl 2-amino-1H-indole-3-carboxylates, arylaldehydes, and terminal alkynes. In the presence of a Bronsted acid such as trifluoroacetic acid (TFA), the 3C reaction furnished a mixture of pyrido- and pyrimido-indoles, whereas when catalyzed by Yb(OTf)3 as a Lewis acid, pyrimidoindoles
Three-component tandem reaction involving acid chlorides, terminal alkynes, and ethyl 2-amino-1H-indole-3-carboxylates: synthesis of highly diversified pyrimido[1,2-a]indoles via sequential Sonogashira and [3+3] cyclocondensation reactions
作者:Sahaj Gupta、Sudhir K. Sharma、Anil K. Mandadapu、Harsh M. Gauniyal、Bijoy Kundu
DOI:10.1016/j.tetlet.2011.06.021
日期:2011.8
A simple, highly efficient three-component reaction involving acid chlorides, terminal alkynes, and ethyl 2-amino-1H-indole-3-carboxylates, for the synthesis of highly diversified pyrimido[1,2-a]indoles has been described. The salient feature of the reaction involves sequential Sonogashira and [3+3] cyclocondensation reactions. (C) 2011 Elsevier Ltd. All rights reserved.