1338348-58-5Relevant academic research and scientific papers
Mechanistic studies and quantification of the electrophilicity of aromatic triflones in σ-complexation and SNAr reactions
Elguesmi, Nizar,Berionni, Guillaume,Asghar, Basim H.
, p. 41 - 47 (2014)
The reactions of anilines (N-nucleophiles) and enamines (C-nucleophiles) with NO2 and SO2CF3 substituted aromatic triflones were investigated spectrophotometrically in acetonitrile at 20 C. We found that the second-order rate constants k1 related to the C-N and C-C bond forming step of these nucleophilic aromatic substitution reactions (SNAr) and σ-complexation reactions follow the three-parameter equation log k(20 C) = sN(N + E), allowing the determination of the electrophilicity E of such aromatic triflones for the first time. The ranking of these neutral electron-deficient compounds on the comprehensive electrophilicity scale defined by Mayr et al. reveals that the most electrophilic triflone, the 1,3,5-tris(trifluoromethanesulfonyl)benzene (TTSB), has an electrophilicity higher than that of the 1,3,5-trinitrobenzene (TNB) the common reference aromatic electrophile in anionic σ-complexation chemistry, by roughly 6 units of E. This finding holds promise for expanding the range of coupling reactions which can be envisioned between this series of electron-deficient neutral aromatics and nucleophiles.
Substituent effects on the reactions of aromatic triflones with para-X-anilines in methanol: Low intrinsic reactivity and transition state imbalances
El Guesmi, Nizar,Boubaker, Taoufik
supporting information; experimental part, p. 255 - 262 (2011/11/12)
A kinetic study is reported for SNAr reactions of 2,4,6-tris(trifluoromethanesulfonyl) anisole 1a with a series of para-X-substituted anilines 2a-e in a methanol solution at various temperatures. The substituent effects on free energy (δ≠G), enthalpy (δ≠H), and entropy (δ≠S) of activation are examined. Aniline addition to triflone 1a is characterized by a βX=0.57, αZ=0.31, and an imbalance of I = αZ-βX=-0.26. The imbalance shows that resonance development lags behind C-N bond formation at the transition state. Interestingly, analysis of the results in terms of Marcus theory reveals that these SNAr are associated with some extremely low intrinsic reactivity (log ko=-1.25
