Polar Diels-Alder Reactions Developed in a Protic Ionic Liquid: 3-Nitroindole as Dienophile. Theoretical Studies Using DFT Methods

Author(s): Claudia D. D. Rosa, Carla M. Ormachea, Ana S. Sonzogni, Maria N. Kneeteman, Luis R. Domingo, Pedro M. E. Mancini.

Journal Name:Letters in Organic Chemistry

Volume 9 , Issue 10 , 2012

Abstract:

N-Tosyl-3-nitroindole reacts with moderate and strong nucleophilic dienes in a polar Diels-Alder reaction using protic ionic liquid (PIL) [HMIM][BF4] as reaction media. In the cases in which the diene has oxygenated substituents, the PIL favors the aromatization of the formal [4+2] cycloadducts. Although the presence of the PIL in the reactions of Ntosyl- 3-nitroindole as electrophile shows a clear tendency to the aromatization of the [4+2] cycloadducts, we observed that the neoteric solvent did not increase the yields in relation to a molecular solvent. Part of this work is specifically concerned with theoretical studies using DFT reactivity indices. The global and local electrophilicity and nucleophilicity indices were calculated for N-tosyl-3-nitroindole, and the dienes used in this study. For the studied reactions, the regioselectivity involved in the polar Diels-Alder reaction is well predicted.

Keywords: Dienophile, Diels-Alder, nitroindole, protic ionic liquid

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Article Details

VOLUME: 9
ISSUE: 10
Year: 2012
Page: [691 - 695]
Pages: 5
DOI: 10.2174/157017812803901845
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