Mechanism of solvolysis of substituted benzoyl halides

Song, Byeong Doo; Jencks, William P.

doi:10.1021/ja00204a021

Cited by 105 publications

(130 citation statements)

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“…15 For SN1 reaction, a value of kF/kCl = 10 -6 -10 -7 was observed in 4-(N,N-dimethylamino)benzoyl halide solvolyses 16 and a low value of kF/kCl = 1.3 × 10 -4 was also observed for acetyl halide solvolyses in 75% acetone. 15 These values reflect an appreciable ground-state stabilization for the fluoride 17 and the need to break a strong carbon-fluorine bond in the rate determining step.…”

Section: Discussionmentioning

confidence: 98%

Correlation of the Rates of Solvolysis of Methyl Fluoroformate Using the Extended Grunwald-Winstein Equation

Lee¹,

Rhu²,

Kyong³

et al. 2009

Bulletin of the Korean Chemical Society

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The specific rates of solvolysis of methyl fluoroformate have been measured at 40.0 o C in several hydroxylic solvents. Analysis with the extended Grunwald-Winstein equation leads to sensitivities toward changes in solvent nucleophilicity (l) of 1.33 ± 0.10 and toward changes in solvent ionizing power (m) 0.73 ± 0.06. For methanolysis, a solvent deuterium isotope effect of 3.98 is compatible with the incorporation of general-base catalysis into the substitution process. For four representative solvents, studies were made at several temperatures and activation parameters determined. These observations are also compared with those previously reported for alkyl halogenoformate esters and mechanistic conclusions are drawn.

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Section: Discussionmentioning

confidence: 98%

Correlation of the Rates of Solvolysis of Methyl Fluoroformate Using the Extended Grunwald-Winstein Equation

Lee¹,

Rhu²,

Kyong³

et al. 2009

Bulletin of the Korean Chemical Society

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“…This is especially so when the attack is at an acyl carbon. For S N 1 reaction, a value as low as 10 -7 was observed in 4-(N,Ndimethylamino)benzoyl halide solvolyses [18] and a low value of 1.3·10 -4 was also observed for acetyl halide solvolyses in 75% acetone [17]. These values reflect an appreciable ground-state stabilization for the fluoride [19] and the need to break a strong carbon-fluorine bond in the rate determining step.…”

Section: Discussionmentioning

confidence: 99%

Rate and Product Studies of Solvolyses of Benzyl Fluoroformate

Kyong

Ryu

Kevill

2006

IJMS

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Abstract:The specific rates of solvolysis of benzyl fluoroformate have been measured in several hydroxylic solvents at 25.0 °C. For methanolysis, the solvent deuterium isotope effect and activation parameters were determined and activation parameters were also determined for solvolyses in ethanol and 80% ethanol. For several of the binary hydroxylic solvents, measurement of product ratios allowed selectivity values to be determined. An extended Grunwald-Winstein treatment of the data led to sensitivities to changes in solvent nucleophilicity and ionizing power. Comparison with previously determined specific rates for solvolysis of the chloroformate gave fluorine/chlorine rate ratios greater than unity. All of the determinations made were consistent with an addition-elimination (associationdissociation) mechanism, with addition rate-determining.

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“…Thus, in the reaction conditions used, both compounds are susceptible to nucleophilic attack on the sp 2 imino carbon of the benzisothiazolyl system, and the reaction might be accelerated in the presence of perchlorate salts, if the mechanism operating is sensitive to the solvent ionizing power [30]. Degradation of the two potential ligands possibly induced by the oxidative nature of the perchlorate ligand, can explain the failure on coordination of iron(II) with the benzisothiazole-tetrazolyl derivatives.…”

Section: Resultsmentioning

confidence: 99%