Transition-state structure for the neutral water-catalyzed hydrolysis of ethyl trifluorothiolacetate

Venkatasubban, K. S.; Davis, Kenneth R.; Hogg, John L.

doi:10.1021/ja00487a026

Cited by 18 publications

(16 citation statements)

References 4 publications

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“…However, the overall trend is the presence of a halogen atom lowers normalΔnormal‡G∘, which corresponds to the higher kfalse(Tfalse). This is in line with other esters [4], [5], [6] as mentioned in the introduction. Furthermore, a heavier halogen atom raises kfalse(Tfalse) which agrees with the result by Schmeer and Sturm [12].…”

Section: Resultssupporting

confidence: 82%

“…The rate constant is higher when halogenated substitution is introduced to the ester. For instance, the alkyl- and aryl-substituted trifluoroacetates (with , ngoodbreakafter=3, 4, and 5) has an order of 10badbreakafter−6 [4], chloromethyl chloroacetate has an order of 10badbreakafter−5 [5], while ethyl trifluorothiolacetate () has a rate constant with an order of 10badbreakafter−3 [6].…”

Section: Introductionmentioning

confidence: 99%

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The transition state conformational effect on the activation energy of ethyl acetate neutral hydrolysis

Rusydi

Aisyah

Fadilla

et al. 2019

Heliyon

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We report a first-principles study on ethyl acetate neutral hydrolysis in which we focus on the activation energy variation resulting from the conformational effect in the transition state. We use the conformers of ethyl formate, ethyl acetate, ethyl fluoroacetate, and ethyl chloroacetate as the ester models and one water molecule with a one-step reaction mechanism. We also consider the long-range interaction and the surrounding water in the form of PCM. Our results show that the various conformers yield a significant range of activation energy. Moreover, the gauche conformer has lower activation energy than the trans conformer. The activation energy in its own right is lowered by the halogen atoms. Finally, we remark that the long-range correction and PCM stabilize the transition state geometry but raise the activation energy.

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Section: Resultssupporting

confidence: 82%

Section: Introductionmentioning

confidence: 99%

The transition state conformational effect on the activation energy of ethyl acetate neutral hydrolysis

Rusydi

Aisyah

Fadilla

et al. 2019

Heliyon

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“…A stepwise mechanism involving at least two water molecules in the transition state has been proposed for neutral hydrolysis (eq 3). 26 Our previous PIX and KIE experiments are consistent with this prevailing mechanism. 10 The PIX experiment again indicated that formation of the tetrahedral intermediate is rate-determining (k h /k ex > 25).…”

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confidence: 76%

A Mechanistic Study of Thioester Hydrolysis with Heavy Atom Kinetic Isotope Effects

et al. 2015

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The carbonyl-C, carbonyl-O, and leaving-S kinetic isotope effects (KIEs) were determined for the hydrolysis of formylthiocholine. Under acidic conditions, (13)k(obs) = 1.0312, (18)k(obs) = 0.997, and (34)k(obs) = 0.995; for neutral conditions, (13)k(obs) = 1.022, (18)k(obs) = 1.010, and (34)k(obs) = 0.996; and for alkaline conditions, (13)k(obs) = 1.0263, (18)k(obs) = 0.992, and (34)k(obs) = 1.000. The observed KIEs provided helpful insights into a qualitative description of the bond orders in the transition state structure.

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“…The water-catalyzed hydrolysis of esters and related carboxylic acid derivatives in aqueous solutions is thought to proceed via a three-proton transition state involving two water molecules as shown below …”

mentioning

confidence: 99%

Transition State Structure for the Water-Catalyzed Hydrolysis of p-Nitrophenyl Trifluoroacetate in Acetonitrile

et al. 1998

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The neutral hydrolysis of p-nitrophenyl trifluoroacetate in acetonitrile solvent has been studied by varying the molarities of water from 1.0 to 5.0 at 25 degrees C. The reaction is found to be third order in water. The reaction is also third order in D(2)O and in methanol when D(2)O and methanol replace water as the solvent. The kinetic solvent isotope effect is (kH(2)O/kD(2)O) = 2.90 +/- 0.12. Proton inventories at each molarity of water studied are consistent with an eight-membered cyclic transition state model. In this model, three protons undergo bonding changes. Such an eight-membered transition state model can easily accommodate linear hydrogen bonds for the three transferred protons. These results are consistent with the experimental findings of Bell and Critchlow(1) on the reversible addition of water to 1,3-dichloroacetone in dioxane and the theoretical findings of Wolfe and co-workers(2) on the hydration of formaldehyde.

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Transition-state structure for the neutral water-catalyzed hydrolysis of ethyl trifluorothiolacetate

Cited by 18 publications

References 4 publications

The transition state conformational effect on the activation energy of ethyl acetate neutral hydrolysis

The transition state conformational effect on the activation energy of ethyl acetate neutral hydrolysis

A Mechanistic Study of Thioester Hydrolysis with Heavy Atom Kinetic Isotope Effects

Transition State Structure for the Water-Catalyzed Hydrolysis of p-Nitrophenyl Trifluoroacetate in Acetonitrile

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