Kinetic studies of reactions of 4‐nitrobenzofuroxan with carbanions derived from benzyltriflones in methanol

Asghar, Basim H.

doi:10.1002/kin.20621

Cited by 5 publications

(1 citation statement)

References 39 publications

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“…Nucleophilic triflylation was widely used for the preparation of different benzyl triflones, ,,− allyl triflones, as well as propargyl triflones (Scheme ). Besides the common triflinate salts, the combination of triflates with amines could be used to generate the triflinate anion (eq b, Scheme ). , …”

Section: Synthesis Of C–so2cf3 Compoundsmentioning

confidence: 99%

Synthetic Methods for Compounds Having CF₃–S Units on Carbon by Trifluoromethylation, Trifluoromethylthiolation, Triflylation, and Related Reactions

2014

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Section: Synthesis Of C–so2cf3 Compoundsmentioning

confidence: 99%

Synthetic Methods for Compounds Having CF₃–S Units on Carbon by Trifluoromethylation, Trifluoromethylthiolation, Triflylation, and Related Reactions

2014

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Nucleophilic Reactivities of Bis‐Acceptor‐Substituted Benzyl Anions

2017

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The kinetics of the reactions of bis‐acceptor‐substituted benzyl anions (PhCXY–, X,Y = CN, CO2Et, COPh, SO2Ph) with benzhydrylium ions and quinone methides (reference electrophiles) have been determined in dimethyl sulfoxide solution at 20 °C. The reactions follow second‐order kinetics, first order with respect to the electrophile and first order with respect to the carbanion. The addition of 18‐crown‐6 ether, which efficiently coordinates to the anions' counter ions K+, did not affect the kinetics, which indicates that the measured rate constants refer to the reactivities of the nonpaired carbanions. Comparison with the reactivities of the structurally analogous secondary carbanions HCXY– shows that replacement of H at the carbanionic center by Ph reduces the nucleophilic reactivities towards a reference benzhydrylium ion by factors in the range of only 1.2 (X,Y = SO2Ph) to 6 (X,Y = CO2Et). The plots of lg k2 versus the electrophilicity parameters E of the reference electrophiles are linear, thereby indicating that the correlation lg k2(20 °C) = sN(E + N), which characterizes nucleophiles by the two solvent‐dependent parameters sN and N and electrophiles by the parameter E, is applicable. In this way, it becomes possible to integrate these carbanions into our comprehensive nucleophilicity scale, which provides a direct comparison of the nucleophilic reactivities of different families of compounds.

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Reactions of Substituted Phenylnitromethane Carbanions with Aromatic Nitro Compounds in Methanol: Carbanion Reactivity, Kinetic, and Equilibrium Studies

Asghar

2014

Int J of Chemical Kinetics

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The feasibility of carrying out nucleophilic addition from electron‐deficient heteroaromatics has been addressed through a detailed investigation of the interaction of a two 7‐substituted‐nitrobenzofurazan (R = OMe 2a; R = Cl 2b) with a series of substituted‐nitroaryl anions (X = 4‐NO2 1a; X = 3‐NO2 1b; X = 4‐CN 1c; X = 4‐Br 1d), all reactions first lead to the quantitative formation of the σ‐adducts 3a–d and 4a–d arising from covalent addition of the nucleophile to the C‐5 carbon. The rate and equilibrium constants for the formation of σ‐adducts 3a–d and 4a–d (k5, K5) together with the rate constants for their decomposition (k−5) have been determined in methanol at 25°C, allowing a determination of intrinsic rate constants, k0 = 0.03, the lower k0 value reflects the very strong salvation by methanol of the negative charge on the nitro group. The discovery of a linear correlation between the E and pKaMeOH parameters allows a calibration of the electrophilicity power of 2a and 2b, E = −11.67 and −10.29, respectively. Applying the general approach to nucleophilicity/electrophilicity recently developed by Mayr et al. through the relationship log k = s(E + N), a successful ranking of our nitroaryl anions 1a–d on the general nucleophilicity scale (N) has been carried out. The N values of 1a–d are found to cover a range from 15.78 to 16.69. The results are compared with previously reported data in water and DMSO.

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Kinetic studies of reactions of 4‐nitrobenzofuroxan with carbanions derived from benzyltriflones in methanol

Cited by 5 publications

References 39 publications

Synthetic Methods for Compounds Having CF₃–S Units on Carbon by Trifluoromethylation, Trifluoromethylthiolation, Triflylation, and Related Reactions

Synthetic Methods for Compounds Having CF₃–S Units on Carbon by Trifluoromethylation, Trifluoromethylthiolation, Triflylation, and Related Reactions

Nucleophilic Reactivities of Bis‐Acceptor‐Substituted Benzyl Anions

Reactions of Substituted Phenylnitromethane Carbanions with Aromatic Nitro Compounds in Methanol: Carbanion Reactivity, Kinetic, and Equilibrium Studies

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Kinetic studies of reactions of 4‐nitrobenzofuroxan with carbanions derived from benzyltriflones in methanol

Cited by 5 publications

References 39 publications

Synthetic Methods for Compounds Having CF3–S Units on Carbon by Trifluoromethylation, Trifluoromethylthiolation, Triflylation, and Related Reactions

Synthetic Methods for Compounds Having CF3–S Units on Carbon by Trifluoromethylation, Trifluoromethylthiolation, Triflylation, and Related Reactions

Nucleophilic Reactivities of Bis‐Acceptor‐Substituted Benzyl Anions

Reactions of Substituted Phenylnitromethane Carbanions with Aromatic Nitro Compounds in Methanol: Carbanion Reactivity, Kinetic, and Equilibrium Studies

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Synthetic Methods for Compounds Having CF₃–S Units on Carbon by Trifluoromethylation, Trifluoromethylthiolation, Triflylation, and Related Reactions

Synthetic Methods for Compounds Having CF₃–S Units on Carbon by Trifluoromethylation, Trifluoromethylthiolation, Triflylation, and Related Reactions