Unusual deactivation in the asymmetric hydrogenation of itaconic acid

Schmidt, Thomas; Baumann, Wolfgang; Drexler, Hans‐Joachim; Heller, Detlef

doi:10.1016/j.jorganchem.2010.12.020

Cited by 11 publications

(9 citation statements)

References 30 publications

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“…Deactivation is not limited to the bisphosphine/diamine-Ru catalysts. It has also been documented with other catalysts and reactions in solution, as in the case of a [Rh(DIPAMP)(MeOH)2]BF4 complex in solution used to catalyze the asymmetric hydrogenations of C-C double bonds [9]. Deactivation has also been reported during C-C coupling with a [(PtBu3)-PdBr]2 catalyst [10], and olefin hydroamination catalyzed by PtBr2/Br − [11].…”

Section: Synthesis Of the Complexesmentioning

confidence: 92%

Chiral Catalyst Deactivation during the Asymmetric Hydrogenation of Acetophenone

Ruelas-Leyva

Fuentes

2017

Catalysts

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Asymmetric hydrogenation in solution catalyzed by chiral catalysts is a powerful tool to obtain chiral secondary alcohols. It is possible to reach conversions and enantiomeric excesses close to 99%, but that frequently requires the use of non-optimal amounts of catalysts or long reaction times. That is in part caused by the lack of kinetic information needed for the design of large-scale reactors, including few reported details about catalyst deactivation. In this work, we present a kinetic model for the asymmetric hydrogenation in solution of acetophenone, a prochiral substrate, catalyzed by different bisphosphine-diamine Ru complexes. The experimental data was fitted with a first order model that includes first order deactivation of the catalyst and the presence of residual activity. The fit of the experimental data is very good, and an analysis of the kinetic and deactivation parameters gives further insight into the role of each ligand present in the Ru catalysts. This is the first report of a kinetic analysis of homogenous complexes' catalysis including an analysis of their deactivation.

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Section: Synthesis Of the Complexesmentioning

confidence: 92%

Chiral Catalyst Deactivation during the Asymmetric Hydrogenation of Acetophenone

Ruelas-Leyva

Fuentes

2017

Catalysts

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“…[32] We extended the here-reported novel concept of bidirectional enantioselectivity to (Z)-methyl-a-acetamidocinnamate derivatives 4 bearing either electron-withdrawing or -donating substituents at the phenyl group, dimethyl itaconate (6), and methyl-a-acetamidoacrylate (8). [32] We extended the here-reported novel concept of bidirectional enantioselectivity to (Z)-methyl-a-acetamidocinnamate derivatives 4 bearing either electron-withdrawing or -donating substituents at the phenyl group, dimethyl itaconate (6), and methyl-a-acetamidoacrylate (8).…”

Section: Methodsmentioning

confidence: 99%

Temperature‐Controlled Bidirectional Enantioselectivity in a Dynamic Catalyst for Asymmetric Hydrogenation

Storch

Trapp

2015

Angew Chem Int Ed

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Asymmetric catalysis using enantiomerically pure catalysts is one of the most widely used methods for the preparation of enantiomerically pure compounds. The separate synthesis of both enantiomerically pure compounds requires tedious and time-consuming preparation of both enantiomerically pure catalysts or chiral separation of the racemic products. Here, we report a stereochemically flexible diastereomeric rhodium(I) catalyst for asymmetric hydrogenations of prochiral (Z)-α-acetamidocinnamates and α-substituted acrylates, which changes its enantioselectivity depending on the temperature to produce each enantiomerically pure compound in high yield with constant high enantioselectivity over time. The same axially chiral rhodium(I) catalyst produces (R)-phenylalanine derivatives in enantiomeric ratios of up to 87:13 (R/S) at low temperature and up to 3:97 (R/S) of the corresponding S enantiomers after re-equilibration of the same catalyst at elevated temperature.

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“…This represents a dead-end of the catalytic cycle because oxidative addition of molecular hydrogen is formally not possible on a Rh(III) complex. The inactive species has been thoroughly characterized and its molecular structure was unambiguously assigned by X-ray analysis [219,220]. Its rate of formation is influenced by substrate concentration, temperature, hydrogen pressure, and the presence of additives, either acidic or basic.…”

Section: Catalyst Deactivation Due To Irreversible Reactions Of the Amentioning

confidence: 99%

Activation, Deactivation and Reversibility Phenomena in Homogeneous Catalysis: A Showcase Based on the Chemistry of Rhodium/Phosphine Catalysts

et al. 2019

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In the present work, the rich chemistry of rhodium/phosphine complexes, which are applied as homogeneous catalysts to promote a wide range of chemical transformations, has been used to showcase how the in situ generation of precatalysts, the conversion of precatalysts into the actually active species, as well as the reaction of the catalyst itself with other components in the reaction medium (substrates, solvents, additives) can lead to a number of deactivation phenomena and thus impact the efficiency of a catalytic process. Such phenomena may go unnoticed or may be overlooked, thus preventing the full understanding of the catalytic process which is a prerequisite for its optimization. Based on recent findings both from others and the authors’ laboratory concerning the chemistry of rhodium/diphosphine complexes, some guidelines are provided for the optimal generation of the catalytic active species from a suitable rhodium precursor and the diphosphine of interest; for the choice of the best solvent to prevent aggregation of coordinatively unsaturated metal fragments and sequestration of the active metal through too strong metal–solvent interactions; for preventing catalyst poisoning due to irreversible reaction with the product of the catalytic process or impurities present in the substrate.

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Unusual deactivation in the asymmetric hydrogenation of itaconic acid

Cited by 11 publications

References 30 publications

Chiral Catalyst Deactivation during the Asymmetric Hydrogenation of Acetophenone

Chiral Catalyst Deactivation during the Asymmetric Hydrogenation of Acetophenone

Temperature‐Controlled Bidirectional Enantioselectivity in a Dynamic Catalyst for Asymmetric Hydrogenation

Activation, Deactivation and Reversibility Phenomena in Homogeneous Catalysis: A Showcase Based on the Chemistry of Rhodium/Phosphine Catalysts

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