Mechanism and Linear Free Energy Relationships in Michael‐Type Addition of 4‐Substituted Anilines to Activated Olefin in Acetonitrile |
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Authors: | N Dhahri T Boubaker R Goumont |
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Institution: | 1. Laboratoire CHPNR, Faculté des Sciences de Monastir, Université de Monastir, , 5019 Monastir, Tunisia;2. Institut Lavoisier de Versailles UMR 8180, Université de Versailles 45, , 78035 Versailles Cedex, France |
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Abstract: | Kinetic studies for the Michael‐type reactions of ethyl‐3‐(4′‐N,N‐dimethylaminophenyl)‐2‐(nonafluorobutane)sulfonylpro‐penoate 1 with 4‐X‐substituted anilines 2a–e (X = OCH3, CH3, H, F, and Cl) have been investigated in acetonitrile at 20°C. A quadratic dependence of the pseudo–first‐order rate constants (kobsd) versus 2a–e ] has been observed and has been interpreted in terms of a dimer nucleophile mechanism. The finding of a relatively large negative ρ value (?3.09) for the Hammett plot suggests that the intermediate ( I± ) is highly zwitterionic in nature. A linear correlation (r2 = 0.9989) between the Hammett's substituent constants σ and nucleophilicity parameters N of 4‐X‐substituted anilines in acetonitrile has been observed. The electrophilicity parameters E of the olefin 1 is evaluated, using the correlations σ versus N and log k versus σ and compared with the electrophilicities of analogously Michael acceptors. |
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