New P-chirogenic diphosphines and their use in catalytic asymmetric reactions

Imamoto, Tsuneo

doi:10.1351/pac200173020373

Cited by 32 publications

(15 citation statements)

References 10 publications

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“…Note that (S,S)-tBu-BisP* and (R,R)-t-Bu-MiniPHOS constitute almost the same stereochemical environment around the stereogenic phosphorus centers, although the respective absolute configurations are different. The stereochemical sense of the hydrogenation is consistent with the results obtained for the hydrogenation of ␣-acylaminoacrylic acid derivatives and enamides (27)(28)(29)(30)(31). These facts suggest that the benzoate oxygen atom like amide oxygen interacts coordinatively with rhodium metal to control the stereoselection.…”

Section: Methodssupporting

confidence: 86%

“…These ligands form five-or four-membered C 2 -symmetric chelates, and it is expected that the imposed asymmetric environment is responsible for high enantioselectivity in catalytic asymmetric reactions. The synthetic utility of these ligands, especially of t-Bu-BisP* and t-Bu-MiniPHOS, has been proven in a few representative asymmetric catalyses (27)(28)(29)(30)(31)(32)(33).…”

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confidence: 99%

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Asymmetric hydrogenation of α,β-unsaturated phosphonates with Rh-BisP* and Rh-MiniPHOS catalysts: Scope and mechanism of the reaction

Gridnev

Yasutake

Imamoto

et al. 2004

Proc. Natl. Acad. Sci. U.S.A.

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Optically active 1,2-bis(alkylmethylphosphino)ethanes and bis(alkylmethylphosphino)methanes are unique diphosphine ligands combining the simple molecular structure and P-stereogenic asymmetric environment. This work shows that these ligands exhibit excellent enantioselectivity in rhodium-catalyzed asymmetric hydrogenation of ␣,␤-unsaturated phosphonic acid derivatives. The enantioselective hydrogenation mechanism elucidated by NMR study is also described. The ␣-hydroxy-and ␣-aminophosphonic acids have an extremely rich and varied spectrum of biological activity (1, 2) that is stipulated by their ability to act as antagonists for amino acids inhibiting enzymes involved in the amino acids' metabolism. They can be used as herbicides (3, 4), antiviral drugs (5), antibiotics (6), and neurodrugs (7). Being able to affect the biological activity of cells (8), some of them can inhibit HIV protease (9) and alanine racemase (alafosfalin) (10). Peptide ␣-hydroxyphosphonates are known to be rennin inhibitors (11).The biological activity of the phosphonic acids highly depends on the absolute configuration of its ␣-chiral center. An excellent example is alafosfalin, [N-(L-alanyl)-L-1-aminoethyl]phosphonic acid (S,R)-diastereomer. Only this diastereomer unlike (R,R)-, (S,S)-, and (R,S)-diastereomers shows high antibacterial activity (12, 13).Development of the synthesis of optically active ␣-hydroxyand ␣-aminophosphonic acids has begun only recently (2, 15). ʈ Processes applying the catalytic amounts of the source of chirality are especially attractive. Thus, hydrophosphonylation of imines catalyzed by heterobimetallic complexes Ln-K-BINOL (16) and hydrophosphonylation of aldehydes catalyzed by analogous complexes Al-Li-BINOL (17) give the ␣-amino-and ␣-hydroxyphosphonic acids, respectively, with high enantiomeric excesses (ee's). Furthermore, the catalytic asymmetric Michael addition to ␣,␤-unsaturated phosphonates (18, 19) and the allylation reaction of ␣-acetylamino-␤-ketophosphonates (20) have been successfully used for the synthesis of phosphonic acid derivatives with the stereogenic centers in the ␣-or ␤-position.Another convenient approach to the synthesis of the acids is the asymmetric hydrogenation of the corresponding unsaturated precursors. By this means, the phosphorus analogs of ␣-aminoor ␣-hydroxycarboxylic acids were obtained with up to 96% ee by using the Rh complexes of chiral phosphine ligands such as (Ϫ)-BPPM (2S,4S) (21) and DuPHOS (22). Noyori and coworkers reported that ␣-substituted ␤-ketophosphonates were subjected to enantio-and diastereoselective hydrogenation by the use of the BINAP-Ru(II) complex to give the corresponding ␤-hydroxyphosphonates with exceedingly high ee's (94-98%) (23,24). Also worth mentioning is that optically active ␣-arylsubstituted ethylphosphonates, phosphorus analogs of 2-arylpropionic acids, were produced by Ir-and Ru-catalyzed asymmetric hydrogenation of ethenylphosphonates (25,26).On the other hand, we previously designed and synthesized new bidentate phosphine ligands, (S,S...

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Section: Methodssupporting

confidence: 86%

mentioning

confidence: 99%

Asymmetric hydrogenation of α,β-unsaturated phosphonates with Rh-BisP* and Rh-MiniPHOS catalysts: Scope and mechanism of the reaction

Gridnev

Yasutake

Imamoto

et al. 2004

Proc. Natl. Acad. Sci. U.S.A.

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“…Briefly, the parahydrogen gas is used in a chemical reaction (hydrogenation) to produce the PASADENA precursors. In order to preserve the spin correlation between the protons immediately after hydrogenation a rhodium catalyst [22,23] is used, which transfers the protons as a unit on to the precursor, without scrambling. The chemistry takes place during 4 s, at an elevated temperature (60°C) in a reactor where a solution containing both precursor and catalyst (constituted in ultrapure water (Millipore Super-Q Plus System); final pH 7.8) is injected, into an atmosphere of 10 bar pressure of parahydrogen gas.…”

Section: Pasadena Hyperpolarizationmentioning

confidence: 99%

Towards hyperpolarized 13C-succinate imaging of brain cancer

Bhattacharya

Chekmenev

Perman

et al. 2007

Journal of Magnetic Resonance

210

255

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We describe a novel (13)C enriched precursor molecule, sodium 1-(13)C acetylenedicarboxylate, which after hydrogenation by PASADENA (Parahydrogen and Synthesis Allows Dramatically Enhanced Nuclear Alignment) under controlled experimental conditions, becomes hyperpolarized (13)C sodium succinate. Fast in vivo 3D FIESTA MR imaging demonstrated that, following carotid arterial injection, the hyperpolarized (13)C-succinate appeared in the head and cerebral circulation of normal and tumor-bearing rats. At this time, no in vivo hyperpolarized signal has been localized to normal brain or brain tumor. On the other hand, ex vivo samples of brain harvested from rats bearing a 9L brain tumor, 1 h or more following in vivo carotid injection of hyperpolarized (13)C sodium succinate, contained significant concentrations of the injected substrate, (13)C sodium succinate, together with (13)C maleate and succinate metabolites 1-(13)C-glutamate, 5-(13)C-glutamate, 1-(13)C-glutamine and 5-(13)C-glutamine. The (13)C substrates and products were below the limits of NMR detection in ex vivo samples of normal brain consistent with an intact blood-brain barrier. These ex vivo results indicate that hyperpolarized (13)C sodium succinate may become a useful tool for rapid in vivo identification of brain tumors, providing novel biomarkers in (13)C MR spectral-spatial images.

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“…11,21,30,31 With diethyl succinate, we transfer the spin order to the 13 C labeled carbonyl using radio frequency pulses. 11,32 We generate diethyl 1- 13 C 2,3-d 2 -succinate using hydrogenation of diethyl 1- 13 C 2,3-d 2 -fumarate (Figure 1).…”

Section: Introductionmentioning

confidence: 99%

Real-Time Molecular Imaging of Tricarboxylic Acid Cycle Metabolism in Vivo by Hyperpolarized 1-¹³C Diethyl Succinate

et al. 2011

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The Krebs tricarboxylic acid cycle (TCA) is central to metabolic energy production and is known to be altered in many disease states. Real time molecular imaging of TCA cycle in vivo will be important in understanding the metabolic basis of several diseases. Positron emission tomography (PET) using FDG-glucose (2-[18F]fluoro-2-deoxy-D-glucose) is already being used as a metabolic imaging agent in clinics. However, FDG-glucose does not reveal anything past glucose uptake and phosphorylation. We have developed a new metabolic imaging agent, hyperpolarized diethyl 1-13C 2,3-d2 succinate, that allows for real time in vivo imaging and spectroscopy of the TCA cycle. Diethyl succinate can be hyperpolarized using parahydrogen induced polarization (PHIP) in an aqueous solution with signal enhancement of 5000 compared to Boltzmann polarization. 13C magnetic resonance spectroscopy (MRS) and magnetic resonance imaging (MRI) were achieved in vivo seconds after injection of 10 to 20 μmol of hyperpolarized diethyl succinate into normal mice. The downstream metabolites of hyperpolarized diethyl succinate were identified in vivo as malate, succinate, fumarate and aspartate. The metabolism of diethyl succinate was altered after exposing the animal to 3-nitropropionate, a known irreversible inhibitor of succinate dehydrogenase. Based on our results, hyperpolarized diethyl succinate allows for in real time in vivo MRI and MRS with a high signal to noise ratio and with visualization of multiple steps of the TCA cycle. Hyperpolarization of diethyl succinate and its in vivo applications may reveal an entirely new regime wherein the local status of TCA cycle metabolism is interrogated on the time scale of seconds to minutes with unprecedented chemical specificity and MR sensitivity.

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New P-chirogenic diphosphines and their use in catalytic asymmetric reactions

Cited by 32 publications

References 10 publications

Asymmetric hydrogenation of α,β-unsaturated phosphonates with Rh-BisP* and Rh-MiniPHOS catalysts: Scope and mechanism of the reaction

Asymmetric hydrogenation of α,β-unsaturated phosphonates with Rh-BisP* and Rh-MiniPHOS catalysts: Scope and mechanism of the reaction

Towards hyperpolarized 13C-succinate imaging of brain cancer

Real-Time Molecular Imaging of Tricarboxylic Acid Cycle Metabolism in Vivo by Hyperpolarized 1-¹³C Diethyl Succinate

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New P-chirogenic diphosphines and their use in catalytic asymmetric reactions

Cited by 32 publications

References 10 publications

Asymmetric hydrogenation of α,β-unsaturated phosphonates with Rh-BisP* and Rh-MiniPHOS catalysts: Scope and mechanism of the reaction

Asymmetric hydrogenation of α,β-unsaturated phosphonates with Rh-BisP* and Rh-MiniPHOS catalysts: Scope and mechanism of the reaction

Towards hyperpolarized 13C-succinate imaging of brain cancer

Real-Time Molecular Imaging of Tricarboxylic Acid Cycle Metabolism in Vivo by Hyperpolarized 1-13C Diethyl Succinate

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Product

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Real-Time Molecular Imaging of Tricarboxylic Acid Cycle Metabolism in Vivo by Hyperpolarized 1-¹³C Diethyl Succinate