Hydrolysis of acetaldehyde diethyl acetal and ethyl vinyl ether: secondary kinetic isotope effects in water and aqueous dioxane and the stability of the ethoxyethyl cation

1984 ◽  
Vol 106 (23) ◽  
pp. 7140-7143 ◽  
Author(s):  
A. J. Kresge ◽  
Daniel P. Weeks
Keyword(s):  
Vinyl Ether ◽  
Isotope Effects ◽  
Kinetic Isotope Effects ◽  
Ethyl Vinyl Ether ◽  
Diethyl Acetal ◽  
Aqueous Dioxane ◽  
Ethyl Vinyl ◽  
Kinetic Isotope ◽  
The Stability ◽  
Hydrolysis Of

Vinyl ether hydrolysis. XIII. The failure of I-strain to produce a change in rate-determining step

1980 ◽  
Vol 58 (2) ◽  
pp. 124-129 ◽  
Author(s):  
Y. Chiang ◽  
W. K. Chwang ◽  
A. J. Kresge ◽  
S. Szilagyi
Keyword(s):  
Vinyl Ether ◽  
Acid Catalysis ◽  
Isotope Effects ◽  
Kinetic Isotope Effects ◽  
Mineral Acid ◽  
Buffer Solutions ◽  
Rate Determining Step ◽  
Kinetic Isotope ◽  
Acetic Acid Buffer ◽  
Hydrolysis Of

Rates of hydrolysis of 1-ethoxy-3,3,5,5-tetramethylcyclopentene and 1-methoxy-2,3,3,5,5-pentamethylcyclopentene measured in mineral acid and formic and acetic acid buffer solutions show general acid catalysis and give large kinetic isotope effects in the normal direction (kH/kD > 1). This indicates that these reactions proceed by the conventional mechanism for vinyl ether hydrolysis in which proton transfer from the catalyzing acid to the substrate is rate-determining, and that the I-strain in these substrates is insufficiently great to shift the reaction mechanism to rapidly reversible substrate protonation followed by rate-determining hydration of the ensuing cationic intermediate.

α-DEUTERIUM KINETIC ISOTOPE EFFECTS IN SOLVOLYSES OF endo-NORBORNYL p-BROMOBENZENESULFONATE

1965 ◽  
Vol 43 (8) ◽  
pp. 2254-2258 ◽  
Author(s):  
C. C. Lee ◽  
Edward W. C. Wong
Keyword(s):  
Acetic Acid ◽  
Formic Acid ◽  
Isotope Effects ◽  
Kinetic Isotope Effects ◽  
Aqueous Dioxane ◽  
Kinetic Isotope ◽  
Different Temperatures

endo-Norbornyl-2-d p-bromobenzenesulfonate was synthesized and the isotope effects, as measured by kH/kD, were determined over a range of temperatures for solvolyses in 30% water – 70% dioxane, acetic acid, and formic acid. Values of kH/kD are of the order of 1.20. The data appear to indicate slightly higher isotope effects as the solvents are changed from aqueous dioxane to acetic acid to formic acid, as well as somewhat higher isotope effects at lower temperatures. Possible mechanistic implications of these results are presented. Relative titrimetric acetolysis rates, kexo/kendo, at different temperatures, and enthalpies and entropies of activation for these acetolyses are evaluated and discussed.

ALPHA-SECONDARY DEUTERIUM KINETIC ISOTOPE EFFECTS FOR HYDROLYSIS OF TREHALOSE BY TREHALASE

2002 ◽  
Author(s):  
Jin-Ha Lee ◽  
Mamoru Nishimoto ◽  
Masayuki Okuyama ◽  
Haruhide Mori ◽  
Atsuo Kimura ◽  
...  
Keyword(s):  
Isotope Effects ◽  
Kinetic Isotope Effects ◽  
Kinetic Isotope ◽  
Hydrolysis Of

Transition-state structure for the hydronium-ion-promoted hydrolysis of α-d-glucopyranosyl fluoride

2015 ◽  
Vol 93 (4) ◽  
pp. 463-467 ◽  
Author(s):  
Jefferson Chan ◽  
Ariel Tang ◽  
Andrew J. Bennet
Keyword(s):  
Transition State ◽  
Kinetic Isotope Effect ◽  
Bond Cleavage ◽  
Isotope Effects ◽  
Kinetic Isotope Effects ◽  
Theoretical Modelling ◽  
Kinetic Isotope ◽  
Hydronium Ion ◽  
Anomeric Carbon ◽  
Hydrolysis Of

The transition state for the hydronium-ion-promoted hydrolysis of α-d-glucopyranosyl fluoride in water has been characterized by combining multiple kinetic isotope effect measurements with theoretical modelling. The measured kinetic isotope effects for the C1-deuterium, C2-deuterium, C5-deuterium, anomeric carbon-13, and ring oxygen-18 are 1.219 ± 0.021, 1.099 ± 0.024, 0.976 ± 0.014, 1.014 ± 0.005, and 0.991 ± 0.013, respectively. The transition state for the hydronium ion reaction is late with respect to both C–F bond cleavage and proton transfer.

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