Enantioselective hydrogenation II. variation of activity and optical yield with experimental variables in methyl pyruvate hydrogenation catalyzed by cinchona-modified platinum/silica (EUROPT-1)

Meheux, P.A.; Ibbotson, A.; Wells, Peter B.

doi:10.1016/0021-9517(91)90297-h

Cited by 117 publications

(18 citation statements)

References 8 publications

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“…[112][113][114] Several other examples describing enantioselective hydrogenations carried out in commercial and non-commercial continuous flow reactors have been reported in the literature. Among them, the hydrogenation of methyl/ethyl pyruvate [38,[115][116][117][118][119][120][121][122][123][124][125][126][127][128][129][130] ketopantolactone, [116,117,119] 2,2,2-trifluoroacetophenone, [121,122,131,132] isopropyl 4,4,4-trifluoroacetoacetate, [133] 1phenyl-1,2-propanedione, [134] methyl/ethyl benzoylformate, [116,117,125,135] ethyl-2-oxo-4-phenylbutyrate [136] and 4-methoxy-6-methyl-2-pyrone, [137] should be mentioned.…”

Section: Enantioselective Hydrogenationmentioning

confidence: 99%

Heterogeneous Catalytic Hydrogenation Reactions in Continuous‐Flow Reactors

2011

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Microreactor technology and continuous flow processing in general are key features in making organic synthesis both more economical and environmentally friendly. Heterogeneous catalytic hydrogenation reactions under continuous flow conditions offer significant benefits compared to batch processes which are related to the unique gas-liquid-solid triphasic reaction conditions present in these transformations. In this review article recent developments in continuous flow heterogeneous catalytic hydrogenation reactions using molecular hydrogen are summarized. Available flow hydrogenation techniques, reactors, commonly used catalysts and examples of synthetic applications with an emphasis on laboratory-scale flow hydrogenation reactions are presented.

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Section: Enantioselective Hydrogenationmentioning

confidence: 99%

Heterogeneous Catalytic Hydrogenation Reactions in Continuous‐Flow Reactors

2011

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“…Nonetheless, heterogeneous chiral catalysts have been synthesized, in particular for the enantioselective hydrogenation of α-ketoesters. For example, the CH 3 –C=O bond in methyl pyruvate (MP) can be enantioselectively hydrogenated to methyl lactate over cinchona-modified catalysts in the so-called Orito reaction where cinchona operates as a one-to-one modifier 12 13 14 15 16 17 18 19 20 21 22 23 24 . In this case, it has been found that hydrogenation rates are substantially increased at chirally modified sites compared with the unmodified catalyst 17 22 24 25 26 27 , thereby enhancing the effect of the diastereomeric interaction to produce enantiomeric excesses (ee) approaching 100%.…”

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confidence: 99%

Enhanced hydrogenation activity and diastereomeric interactions of methyl pyruvate co-adsorbed with R-1-(1-naphthyl)ethylamine on Pd(111)

et al. 2016

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Unmodified racemic sites on heterogeneous chiral catalysts reduce their overall enantioselectivity, but this effect is mitigated in the Orito reaction (methyl pyruvate (MP) hydrogenation to methyl lactate) by an increased hydrogenation reactivity. Here, this effect is explored on a R-1-(1-naphthyl)ethylamine (NEA)-modified Pd(111) model catalyst where temperature-programmed desorption experiments reveal that NEA accelerates the rates of both MP hydrogenation and H/D exchange. NEA+MP docking complexes are imaged using scanning tunnelling microscopy supplemented by density functional theory calculations to allow the most stable docking complexes to be identified. The results show that diastereomeric interactions between NEA and MP occur predominantly by binding of the C=C of the enol tautomer of MP to the surface, while simultaneously optimizing C=O····H2N hydrogen-bonding interactions. The combination of chiral-NEA driven diastereomeric docking with a tautomeric preference enhances the hydrogenation activity since C=C bonds hydrogenate more easily than C=O bonds thus providing a rationale for the catalytic observations.

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“…For both Pt–GDY and Pt–C system, the conversion ratio decreased with the increasing of the initial concentration of EOPB in the range of 0.5–4. 0 mol/L (Figure d), probably because the enhanced adsorption of EOPB will compete with H 2 absorption upon the increasing of the initial concentration . However, for the Pt–GDY system, there is a platform between 1.0 and 2.0 mol/L in which the conversion ratio was almost constant.…”

Section: Resultsmentioning

confidence: 95%

“…The conversion ratio of Pt−GDY system will increase with the increasing of the reaction temperature (Figure 3c), whereas for the Pt−C system, the conversion ratio reached the highest at 40 °C, then dropped to about 25%, which is due to the less binding stability of the reagents with the Pt nanoparticles. 57,58 Therefore, the introduction of GDY as the catalyst support definitely increases the interaction between Pt NPs and the reactants.…”

Section: Acs Applied Materials and Interfacesmentioning

confidence: 99%

A Novel Graphdiyne-Based Catalyst for Effective Hydrogenation Reaction

Shên

Shi

2018

ACS Appl. Mater. Interfaces

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The platinum nanoparticles (Pt NPs) hybrided with nanostructured carbon materials with high stability are important for catalyzing hydrogenation reaction. Here we reported the fabrication of ultrastable Pt NPs anchored on graphdiyne, in which the strong interactions induced by the porous graphdiyne can prevent the thermal migration of Pt nanoparticles on the graphdiyne surface, exploiting the strong charge transfer interactions from Pt NPs to GDY substrate to tune the electron density of Pt NPs. Pt NPs catalyst with size of 2-3 nm showed high performance on hydrogenation of aldehydes and ketones to the corresponding alcohols compared with commercial Pt-C. Our results indicated that graphdiyne is a promising substrate for constructing metal nanoparticle-based heterogeneous catalysts, especially for those requiring strong interactions between metal nanoparticles and reactants.

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Enantioselective hydrogenation II. variation of activity and optical yield with experimental variables in methyl pyruvate hydrogenation catalyzed by cinchona-modified platinum/silica (EUROPT-1)

Cited by 117 publications

References 8 publications

Heterogeneous Catalytic Hydrogenation Reactions in Continuous‐Flow Reactors

Heterogeneous Catalytic Hydrogenation Reactions in Continuous‐Flow Reactors

Enhanced hydrogenation activity and diastereomeric interactions of methyl pyruvate co-adsorbed with R-1-(1-naphthyl)ethylamine on Pd(111)

A Novel Graphdiyne-Based Catalyst for Effective Hydrogenation Reaction

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