Kinetics of the Reaction between a Vinyl Fluoride and Sodium Ethoxide

Silversmith, Ernest F.; Smith, D. A.

doi:10.1021/jo01097a027

Cited by 17 publications

(8 citation statements)

References 2 publications

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“…groups enhance the nucleophilic rather than the electrophilic reactivity of the double bond. The nucleophilic addition-elimination mechanism observed in the reaction of the related l,l-diaryl-2-haloethylenes with ethoxide ion [25][26][27] showed different kinetic behavior than our compounds. By using the Hammet equation for this reaction, 10sAr2 values at 120°are 120 and 1.8 1.…”

Section: Discussionmentioning

confidence: 85%

Vinylic cations form solvolysis. I. Trianisylvinyl halide system

Rappoport¹,

Gal²

1969

J. Am. Chem. Soc.

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phonium salts which can undergo further decomposition to tetracovalent phosphorus compounds. Experimental SectionMaterials. The starting phosphines were prepared by standard techniques or purchased when possible. Their 1H and 31P nmr spectra agreed with literature values.Reactions. Equimolar quantities (ca. 5 X mol of the phosphine and diethyl peroxide) were allowed to react in methylene chloride. Usually the reactants were cooled to at least 0" before mixing. The reactions were monitored by 1H and 31P nmr spectroscopy. In those studies in which other solvents were used the methylene chloride was evaporated at room temperature in cucuo and the residue was dissolved in the appropriate solvent. Benzoic acid was added to each reaction mixture and the formation of ethyl benzoate was demonstrated by glpc.formed by exchange. Once again the compound 19 is quite unstable and it decomposes readily to tetracovalent phosphorus compounds.The relative instability of the compounds with amino nitrogen bonded to phosphorus is not unexpected. Amino nitrogen can stabilize a positive charge on phosphorus and therefore enhance dissociation to phos-Abstract: Solvolysis of trianisylvinyl chloride (1-CI) and bromide (1-Br) and of l-anisyl-2,2-diphenylvinyl bromide (7) in 80% ethanol follows a first-order course in the substrate, is independent of the concentration of added sodium hydroxide, and is only slightly dependent on that of added p-toluenethiolate ion. The solvolysis of 1-Br is 1.75 times faster than that of a-bromo-p-methoxystyrene, excluding the addition-elimination mechanism. The similar rates for 1-Br and 7 point to the absence of P-aryl participation. The Grunwald-Winstein nz values of 0.34-0.53 and the kl-B,/kl.CI value of 58 at 120" are discussed in terms of intermediate vinylic cations in the solvolysis. The reactivity difference between a-bromostyrene and a-phenylethyl bromide is entirely due to activation energy difference. Vinylic and saturated cations are compared.inylic cations were studied very little until recent V years. Lately, they were suggested as intermediates in electrophilic additions to allenes and acetylenes (eq l),* in the deamination of vinylamine~,~ or in the reaction of 2-oxazolidones in basic solution4 or vinyltriazenes in acidic solution5 (eq 2). Ions with contributing vinylic cation structures were observed by nmr,6 and solvolysis products of acetylenic sulfonates ( I ) Presented in part at

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Section: Discussionmentioning

confidence: 85%

Vinylic cations form solvolysis. I. Trianisylvinyl halide system

Rappoport¹,

Gal²

1969

J. Am. Chem. Soc.

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“…An examination of the data indicates that the reaction is probably overall second order, first order in 1,1-diary 1-2-bromoethene and probably first order in base in agreement with previously reported results. 13 The rate constants for p-CF3 and m-CF3 were obtained in anhydrous diglyme at 0°; however, for m-F, rearrangement occurred under these conditions. A "corrected" rate constant26 for substitution when m-F was used is given.…”

Section: Resultsmentioning

confidence: 95%

“…(Ar)2C --CH (X) OR -> (Ar)2C=CHOR + X" (2b) elimination of bromide to produce a diaryl alkyl vinyl ether. [13][14][15][16][17][18] An examination of available data concerning substituent effects on the elimination-rearrangement16 •17-19 and our work on the substitution reactions indicates that a minimum could be obtained in the Hammett plot. The effect of substituents on the eliminationrearrangement reaction and the substitution reaction are described and the combined substituent effects are examined in terms of their effect on the Hammett plot.…”

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confidence: 99%

Nonlinear Hammett plot. Substituent effects in the substitution and elimination-rearrangement reactions of 1,1-diaryl-2-bromoethenes with potassium tert-butoxide in an aprotic solvent

Bender¹,

Thippeswamy²,

Rellahan³

1970

J. Org. Chem.

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A series of 1, l-diaryl-2-bromoethenes was synthesized and allowed to react with potassium ¿-butoxide in anhydrous diglyme at 0°. The substitution products were isolated by solvent extraction and column chromatography and identified by nuclear magnetic resonance spectrometry and elemental analysis. The elimination-rearrangement products were identified by ultraviolet spectrophotometry. The rate constants for the rearrangements step were calculated by the time-ratio method. An increase in electron-withdrawing character of the substituent caused the elimination-rearrangement reaction to proceed slower and the substitution reaction to proceed faster. None of the compounds tested underwent both reactions. The Hammett reaction constant, p, was found to be

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“…Thus both the perfluoro and 1,2-dichloro alicyclic olefins undergo a similar SN2 for the first step by what is believed to be an addition-elimination mechanism (1,5). The second methoxide ion must go via another addition-elimination with the perfluorocyclic olefin, while it is known that the 1,2-&hloro derivative undergoes an Sx2' (6) as the second step.…”

Section: Discussionmentioning

confidence: 98%

“…The second methoxide ion must go via another addition-elimination with the perfluorocyclic olefin, while it is known that the 1,2-&hloro derivative undergoes an Sx2' (6) as the second step. The difference is that a vinyl fluoride is much more reactive towards nucleophilic dis-placement than a vinyl chloride (5). Another factor is steric hindrance.…”

Section: Discussionmentioning

confidence: 99%

The Reaction of Methoxide Ion With Perfluorocyclopentene

Stockel¹,

Beachem²,

Megson³

1964

Can. J. Chem.

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A B S T R A C T T h e reaction o f methoxide ion with perfluorocyclopentene gave two major components. These have been identified as 1-fluoro-2-methoxyhexaAuorocyclopentene ( I I f ) and 1,2-dimethoxyhexafluorocyclopentene (IIe).A third component (3-methoxy-2,4,4,5,5-pentaAuoro-2-cyclopenten-l-one ( V I I ) ) was isoIated and a structure is proposed based on n.m.r. evidence.A list o f carbon-carbon double bond stretch frequencies is given for a number of 1,2-disubstituted perfluorocycloper~ter~es which follow the electronegativities o f the atoms adjacent t o the double bond.

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Kinetics of the Reaction between a Vinyl Fluoride and Sodium Ethoxide

Cited by 17 publications

References 2 publications

Vinylic cations form solvolysis. I. Trianisylvinyl halide system

Vinylic cations form solvolysis. I. Trianisylvinyl halide system

Nonlinear Hammett plot. Substituent effects in the substitution and elimination-rearrangement reactions of 1,1-diaryl-2-bromoethenes with potassium tert-butoxide in an aprotic solvent

The Reaction of Methoxide Ion With Perfluorocyclopentene

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