Effect of halogens on the activity of halonitrobenzenes in reactions with carbanions

Mąkosza, Mieczysław; Lobanova, O. V.; Kwast, Andrzej

doi:10.1016/j.tet.2004.01.038

Cited by 16 publications

(20 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…[24] For identification of the VNS products and quantitative analysis of the mixtures produced in the competitive experiments, samples of all expected products were synthesized in advance by preparative-scale VNS reaction of 1 with individual nitroarenes. Most of these VNS products have been described in our earlier papers.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Substituent Effects on the Electrophilic Activity of Nitroarenes in Reactions with Carbanions

Błażej

Mąkosza

2008

Chemistry A European J

View full text Add to dashboard Cite

The effect on electrophilic activity of substituents located para, ortho, and meta to the nitro group of nitrobenzenes was determined by using vicarious nucleophilic substitution of hydrogen (VNS) with the carbanion of chloromethyl phenyl sulfone (1) as the model process. Values for the relative activities of substituted nitroarenes are given relative to nitrobenzene, which was taken as the standard. This process was chosen as a model reaction because it meets key criteria, such as the wide range of substituents that can be present on the nitrobenzene ring, a low sensitivity to steric hindrance, and in particular the possibility of ensuring conditions in which the overall relative rates of reaction in competitive experiments are equal to the relative rates of nucleophilic addition. The values of relative rates of addition, which were taken to be a measure of electrophilic activity, were determined by competitive experiments in which pairs of nitroarenes competed for the VNS reaction with carbanion of 1. A comprehensive set of data for effects of substituents on the electrophilic activity of nitroarenes is presented for the first time.

show abstract

Section: Resultsmentioning

confidence: 99%

“…These conditions are essentially the same as reported earlier. [24] The procedure for the competitive experiments is shown in simplified way in Scheme 3.…”

Section: Resultsmentioning

confidence: 99%

Substituent Effects on the Electrophilic Activity of Nitroarenes in Reactions with Carbanions

Błażej

Mąkosza

2008

Chemistry A European J

View full text Add to dashboard Cite

show abstract

“…Protonation of the adducts led to the elimination of nitrous acid and formation of 1,3,5-trisubstituted benzenes as the products of a nucleophilic cine-substitution of the nitro group. Mąkosza et al 19 performed kinetic experiments for vicarious nucleophilic substitution of 2-chloronitrobenzene, 4-chloro-nitrobenzene, 2,4-dichloronitrobenzene, 2,4,6-trichloronitrobenzene, 2-bromonitrobenzene and 4-bromonitrobenzene by treating these compounds with chloromethyl phenyl sulfone in dimethylformamide in the presence of an excess of potassium t-butoxide at -40 °C. They measured the relative rates of formation of σ adducts obtained by nucleophilic addition of carbanions to nitroarenes.…”

Section: Introductionmentioning

confidence: 99%

cine- and tele-Substitution reactions: review of work from 2002-2016

Suwiński¹

2017

Arkivoc

View full text Add to dashboard Cite

This report brings new facts and achievements on the cine-and tele-substitutions reactions published in the last fifteen years. The reactions occurred primarily in such systems as nitroarenes, metal homoarene complexes, and five-or six-membered heteroarenes. Sometimes similar reactions were also observed in other systems, including non-aromatic. cine-and tele-Substitution reactions are presented here independently of their mechanisms.

show abstract

“…Analogous substituent effects on the electrophilic activities of nitro-substituted benzenoid arenes have already been studied earlier. [13,14] Results and Discussion Product studies: As shown previously, the anion of chloromethyl phenyl sulfone (1 À ) undergoes VNS reactions with a broad variety of electron-deficient arenes [15,16] and was used as a substrate in earlier mechanistic studies. [7-10, 13, 14] Accordingly, it was chosen as the reference nucleophile also in this work.…”

Section: Introductionmentioning

confidence: 99%

Reactions of Nitroheteroarenes with Carbanions: Bridging Aromatic, Heteroaromatic, and Vinylic Electrophilicity

Seeliger

Błażej

Bernhardt

et al. 2008

Chemistry A European J

View full text Add to dashboard Cite

The relative rate constants for the vicarious nucleophilic substitution (VNS) of the anion of chloromethyl phenyl sulfone (1-) with a variety of nitroheteroarenes, for example, nitropyridines, nitropyrroles, nitroimidazoles, 2-nitrothiophene, and 4-nitropyrazole, have been determined by competition experiments. It was shown that nitropyridines are approximately four orders of magnitude more reactive than nitrobenzene. Among the five-membered heterocycles 2-nitrothiophene is the most active followed by nitroimidazoles and 4-nitropyrazole. Nitropyrroles are the least electrophilic nitroheteroarenes with reactivities comparable to nitrobenzene. Quantum chemically calculated methyl anion affinities (B3LYP/6-311G(d,p)//B3LYP/6-31G(d)) of the nitroarenes correlated only moderately with the partial relative rate constants. The correlation of these activities with the LUMO energies of nitroarenes is even worse. By measuring the second-order rate constants of the addition of 1- to nitroarenes and to diethyl arylidenemalonates 10, it was possible to link the electrophilic reactivities of nitroheteroarenes with the comprehensive electrophilicity scale based on the linear-free-energy-relationship log k(20 degrees C)=s(N+E).

show abstract

Effect of halogens on the activity of halonitrobenzenes in reactions with carbanions

Cited by 16 publications

References 14 publications

Substituent Effects on the Electrophilic Activity of Nitroarenes in Reactions with Carbanions

Substituent Effects on the Electrophilic Activity of Nitroarenes in Reactions with Carbanions

cine- and tele-Substitution reactions: review of work from 2002-2016

Reactions of Nitroheteroarenes with Carbanions: Bridging Aromatic, Heteroaromatic, and Vinylic Electrophilicity

Contact Info

Product

Resources

About