Zur Kenntnis der Waldenschen Umkehrung. IV

Fischer, Emil; Scheibler, Helmuth

doi:10.1002/cber.190904201201

Cited by 27 publications

(4 citation statements)

References 6 publications

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“…c Optical purity was determined on the basis of NMR measurement using Eu(facam)3 in CCI4. The values in parentheses are optical purity calculated from the reported specific rotation of the pure enantiomer [[«]20d -21.09°( neat)] (ref 19). d Configuration of ethyl and n-butyl 3-hydroxylbutyrate is unknown.…”

Section: Resultsmentioning

confidence: 99%

Reduction of carbonyl compounds via hydrosilylation. 3. Asymmetric reduction of keto esters via hydrosilylation catalyzed by a rhodium complex with chiral phosphine ligands

Ojima¹,

Kogure²,

Kumagai³

1977

J. Org. Chem.

106

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Asymmetric reduction of -, ß-and -keto esters via hydrosilylation catalyzed by rhodium complexes with chiral phosphines, (+)-BMPP, (+)or (-)-DIOP, was investigated. High optical yields around 80% (72-85% ee) were attained in the case of pyruvates. Clear double asymmetric induction was observed in the asymmetric hydrosilylation of (-)-menthyl phenylglyoxylate. Under optimum conditions, the optical purity of the mandelate was 77%. Transfer hydrogenation instead of hydrosilylation is proposed to be involved in the reaction of an acetoacetate and a benzoylacetate. Asymmetric hydrosilylation of various levulinates followed by acid hydrolysis afforded 4-methyl^butyrolactone (76-85% ee) in nearly quantitative yield. A combination of DIOP ligand with o-naphthylphenylsilane was found to be quite effective for the asymmetric induction. High efficiency of asymmetric induction for the keto esters compared with simple prochiral ketones may be due to an attractive interaction between the ester carbonyl and rhodium center in the transition state. Possible mechanisms for the induction of asymmetry are discussed using Dreiding models of the intermediate -silyloxyalkyl-rhodium complexes.

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Section: Resultsmentioning

confidence: 99%

Reduction of carbonyl compounds via hydrosilylation. 3. Asymmetric reduction of keto esters via hydrosilylation catalyzed by a rhodium complex with chiral phosphine ligands

Ojima¹,

Kogure²,

Kumagai³

1977

J. Org. Chem.

106

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“…Reference compounds of the analytes were obtained from Sigma-Aldrich Chemie GmbH (Taufkirchen, Germany). U-[ 13 C, 15 (Fischer and Scheibler, 1909).…”

Section: Chemicals and Reference Compoundsmentioning

confidence: 99%

Identification of metabolic fluxes in hepatic cells from transient ¹³C‐labeling experiments: Part I. Experimental observations

Hofmann¹,

Maier²,

Niebel³

et al. 2007

Biotech & Bioengineering

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An experimental set-up for acquiring metabolite and transient (13)C-labeling data in mammalian cells is presented. An efficient sampling procedure was established for hepatic cells cultured in six-well plates as a monolayer attached to collagen, which allowed simultaneous quenching of metabolism and extraction of the intracellular intermediates of interest. Extracellular concentrations of glucose, amino acids, lactate, pyruvate, and urea were determined by GC-MS procedures and were used for estimation of metabolic uptake and excretion rates. Sensitive LC-MS and GC-MS methods were used to quantify the intracellular intermediates of tricarboxylic acid cycle, glycolysis, and pentose phosphate pathway and for the determination of isotopomer fractions of the respective metabolites. Mass isotopomer fractions were determined in a transient (13)C-labeling experiment using (13)C-labeled glucose as substrate. The absolute amounts of intracellular metabolites were obtained from a non-labeled experiment carried out in exactly the same way as the (13)C-labeling experiment, except that the media contained naturally labeled glucose only. Estimation of intracellular metabolic fluxes from the presented data is addressed in part II of this contribution.

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“…R-BHB (note that the physiological enantiomer R-BHB is designated as D-BHB in the recent clinical literature. In early publications [11,12] and in the Merck Index, it is called L-BHB) is a physiological ketone body which is in oxidoreduction equilibrium with acetoacetate (AcAc) via R-BHB dehydrogenase. S-BHB is not a natural compound [13].…”

Section: Introductionmentioning

confidence: 99%

Metabolism of R- and S-1,3-butanediol in perfused livers from meal-fed and starved rats

Desrochers

David

Garneau

et al. 1992

Biochemical Journal

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The metabolism of millimolar concentrations of R- or S-1,3-butanediol has been studied in perfused livers from fed and starved rats. Protocols were designed to measure in the same experiment (i) uptake of the diol, (ii) the contribution of the diol to ketogenesis, (iii) the contribution of the diol to total fatty acid plus sterol synthesis, and (iv) conversion of S-1,3-butanediol into S-3-hydroxybutyrate. Our data show that R- and S-1,3-butanediol are taken up by the liver at the same rate. Most of the metabolism of R-1,3-butanediol is accounted for by conversion to the physiological ketone bodies R-3-hydroxybutyrate and acetoacetate. Only 29-38% of S-1,3-butanediol uptake is accounted for by conversion into physiological ketone bodies. The balance of S-1,3-butanediol metabolism is conversion to S-3-hydroxybutyrate, lipids and CO2.

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Zur Kenntnis der Waldenschen Umkehrung. IV

Cited by 27 publications

References 6 publications

Reduction of carbonyl compounds via hydrosilylation. 3. Asymmetric reduction of keto esters via hydrosilylation catalyzed by a rhodium complex with chiral phosphine ligands

Reduction of carbonyl compounds via hydrosilylation. 3. Asymmetric reduction of keto esters via hydrosilylation catalyzed by a rhodium complex with chiral phosphine ligands

Identification of metabolic fluxes in hepatic cells from transient ¹³C‐labeling experiments: Part I. Experimental observations

Metabolism of R- and S-1,3-butanediol in perfused livers from meal-fed and starved rats

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Zur Kenntnis der Waldenschen Umkehrung. IV

Cited by 27 publications

References 6 publications

Reduction of carbonyl compounds via hydrosilylation. 3. Asymmetric reduction of keto esters via hydrosilylation catalyzed by a rhodium complex with chiral phosphine ligands

Reduction of carbonyl compounds via hydrosilylation. 3. Asymmetric reduction of keto esters via hydrosilylation catalyzed by a rhodium complex with chiral phosphine ligands

Identification of metabolic fluxes in hepatic cells from transient 13C‐labeling experiments: Part I. Experimental observations

Metabolism of R- and S-1,3-butanediol in perfused livers from meal-fed and starved rats

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Identification of metabolic fluxes in hepatic cells from transient ¹³C‐labeling experiments: Part I. Experimental observations