Surface‐Driven Keto–Enol Tautomerization: Atomistic Insights into Enol Formation and Stabilization Mechanisms

2018 ◽  
Vol 130 (51) ◽  
pp. 16901-16906 ◽  
Author(s):  
Smadar Attia ◽  
Marvin‐Christopher Schmidt ◽  
Carsten Schröder ◽  
Pascal Pessier ◽  
Swetlana Schauermann
Keyword(s):  
Enol Formation

Reactivity of α-trifluoromethanesulfonyl esters, amides and ketones: Decarboxylative allylation, methylation, and enol formation

2013 ◽  
Vol 153 ◽  
pp. 151-161 ◽  
Author(s):  
Han Il Kong ◽  
Monica A. Gill ◽  
Amy H. Hrdina ◽  
Jennifer E. Crichton ◽  
Jeffrey M. Manthorpe
Keyword(s):  
Decarboxylative Allylation ◽  
Enol Formation

Kinetics of Enol Formation from Reaction of OH with Propene

2009 ◽  
Vol 113 (13) ◽  
pp. 3177-3185 ◽  
Author(s):  
Lam K. Huynh ◽  
Hongzhi R. Zhang ◽  
Shaowen Zhang ◽  
Eric Eddings ◽  
Adel Sarofim ◽  
...  
Keyword(s):  
Kinetics Of ◽  
Enol Formation

Enol Formation and Ring-Opening in OH-Initiated Oxidation of Cycloalkenes

2008 ◽  
Vol 112 (51) ◽  
pp. 13444-13451 ◽  
Author(s):  
Giovanni Meloni ◽  
Talitha M. Selby ◽  
David L. Osborn ◽  
Craig A. Taatjes
Keyword(s):  
Ring Opening ◽  
Enol Formation

In situ preparation of cyclopropanones with the bicyclo[3.1.0]hexan-6-one skeleton (substituted examples of the Loftfield intermediate). Confirmation of a very facile intramolecular alkyl cyclopropanone – dienol rearrangement

1996 ◽  
Vol 74 (1) ◽  
pp. 79-87 ◽  
Author(s):  
T. S. Sorensen ◽  
F. Sun
Keyword(s):  
Nmr Spectroscopy ◽  
Sigmatropic Rearrangement ◽  
Unsaturated Ketone ◽  
Tert Butyl ◽  
H Nmr ◽  
In Situ Preparation ◽  
Rate Determining Step ◽  
Enol Formation ◽  
C Nmr

Four substituted bicyclo[3.1.0]hexan-6-ones (cyclopropanones) were prepared in situ, starting from the corresponding 2,6-dibromocyclohexanone and reductively removing the bromine atoms with the organometallic salt PPN+Cr(CO)4NO− The reaction is essentially instantaneous at −78 or−100 °C, and can be conveniently carried out in an NMR tube for easy characterization of the products by low-temperature 1H and 13C NMR spectroscopy. The1,5-di-tert-butyl and 1-tert-butyl analogs were thermally stable to ca. 0 °C, but the 1-tert-butyl-5-methyl and 1-tert-butyl-5-ethyl derivatives were extremely labile, rearranging at ca. −80 °C into a cross-conjugated enol, where the methyl (or ethyl) substituent was converted into an exomethylene group. These enols were also characterized as in situ species using 1H and 13C NMR spectroscopy, and by allowing the enol → α,β-unsaturated ketone rearrangement to take place at about 25 °C. The mechanism of the enol formation was investigated using a 1 -tert-butyl-5-CD3 analog, and the kH/kD ratio for enol formation was determined to be 6 ± 2. From this, the rate-determining step in the enol formation was postulated as a C-H → H-O transfer of a hydrogen atom in a cyclohexyl oxyallyl intermediate. The 1,5-di-tert-butylbicyclohexanone shows dynamic 1H NMR line broadening, the origin of which is also proposed to involve a cyclohexyl oxyallyl intermediate. Key words: cyclopropanone, oxyallyl, bicyclo[3.1.0]hexan-6-one, dienol, sigmatropic rearrangement.

ChemInform Abstract: Reactivity of α-Trifluoromethanesulfonyl Esters, Amides and Ketones: Decarboxylative Allylation, Methylation, and Enol Formation.

ChemInform ◽  
2014 ◽  
Vol 45 (17) ◽  
pp. no-no
Author(s):  
Han Il Kong ◽  
Monica A. Gill ◽  
Amy H. Hrdina ◽  
Jennifer E. Crichton ◽  
Jeffrey M. Manthorpe
Keyword(s):  
Decarboxylative Allylation ◽  
Enol Formation

Einfluß der Enolisierung auf die Reduktion von β Ketocarbonsäure-Derivaten mit Zinkborhydrid / Influence of the Enol Formation on the Reduction of β-Keto Carboxylic Acid Derivatives by Zinc Borohydride

1991 ◽  
Vol 46 (12) ◽  
pp. 1713-1719 ◽  
Author(s):  
Herbert Meier ◽  
Volker Krause
Keyword(s):  
Hydrogen Bonding ◽  
Carboxylic Acid ◽  
Structure Determination ◽  
Intramolecular Hydrogen Bonding ◽  
Steric Effects ◽  
Group A ◽  
Hydroxy Compounds ◽  
Intramolecular Hydrogen ◽  
Enol Formation

Depending on the keto-enol equilibrium 1 ⇄ 2 reduction of the esters and the amides 1/2 a—g with Zn(BH4)2/ZnCl2 attacks either at the CO or at the CO2R group. A high diastereoselectivity (98:2 or more) is observed for the formation of the β-hydroxy compounds 3a,b,c,e,f in favour of the erythro forms. As to the structure determination of 3, different steric effects and different intramolecular hydrogen bonding have to be considered, leading to different rotameric populations.

Fluorometric Analysis for N'-Formylkynurenine in Plasma and Urine

1974 ◽  
Vol 20 (7) ◽  
pp. 765-768 ◽  
Author(s):  
T Buxton ◽  
G G Guilbault
Keyword(s):  
Quantitative Method ◽  
Fluorometric Method ◽  
Neutral Compound ◽  
Fluorometric Analysis ◽  
Enol Formation

Abstract We describe a fluorometric method of analysis for N'-formylkynurenine. The method depends on the rate of enol formation when a solution of the compound is made basic. The enol is more fluorescent than the neutral compound. The increase in fluorescence is measured, with use of 430-nm emission and 319-nm excitation wavelengths. This method is applied to the determination of N'-formylkynurenine in protein-free filtrates of plasma or urine. To our knowledge, this is the first quantitative method for determination of N'-formylkynurenine.

Surface‐Driven Keto–Enol Tautomerization: Atomistic Insights into Enol Formation and Stabilization Mechanisms

2018 ◽  
Vol 57 (51) ◽  
pp. 16659-16664 ◽  
Author(s):  
Smadar Attia ◽  
Marvin‐Christopher Schmidt ◽  
Carsten Schröder ◽  
Pascal Pessier ◽  
Swetlana Schauermann
Keyword(s):  
Enol Formation
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