Chiral phosphine ligands

Arao, Takafumi; Kondo, Kazuhiro; Aoyama, Toyohiko published the artcile< Asymmetric construction of quaternary carbon stereocenter by Pd-catalyzed intramolecular α-arylation>, Name: (S)-(-)-2,2′-Bis(diphenylphosphino)-5,5′,6,6′,7,7′,8,8′-octahydro-1,1′-binaphthyl, the main research area is quaternary carbon stereocenter palladium catalyzed intramol arylation; enantioselective indolone preparation palladium catalyzed.

The catalyst comprised of Pd(OAc)2 and H8-BINAP provides good reaction conversions for a catalytic enantioselective intramol. α-arylation of N-(2-bromophenyl)-N-methyl-2-arylpropanamides. The corresponding 3-substituted indol-2-ones are formed with up to 68% enantioselectivity.

Chemical & Pharmaceutical Bulletin published new progress about Arylation (intramol.). 139139-93-8 belongs to class chiral-phosphine-ligands, and the molecular formula is C44H40P2, Name: (S)-(-)-2,2′-Bis(diphenylphosphino)-5,5′,6,6′,7,7′,8,8′-octahydro-1,1′-binaphthyl.

Referemce:
Phosphine ligand,
Chiral phosphine ligands in asymmetric synthesis. Molecular structure and absolute configuration of (1,5-cyclooctadiene)-(2S,3S)-2,3-bis(diphenylphosphino)butanerhodium(I) perchlorate tetrahydrofuran solvate

Das, Mrinal K.; Kumar, Nivesh; Bisai, Alakesh published the artcile< Catalytic Asymmetric Total Syntheses of Naturally Occurring Amarylidaceae Alkaloids, (-)-Crinine, (-)-epi-Crinine, (-)-Oxocrinine, (+)-epi-Elwesine, (+)-Vittatine, and (+)-epi-Vittatine>, Quality Control of 152140-65-3, the main research area is asym catalytic total synthesis Amaryllidaceae alkaloid; crinine catalytic asym total synthesis decarboxylative allylation; epi crinine catalytic asym total synthesis decarboxylative allylation; oxocrinine catalytic asym total synthesis decarboxylative allylation; elwesine epi catalytic asym total synthesis decarboxylative allylation; vittatine catalytic asym total synthesis decarboxylative allylation.

An expeditious approach to catalytic enantioselective total syntheses of crinine-type Amaryllidaceae alkaloids has been accomplished via a Pd-catalyzed enantioselective decarboxylative allylation of allylenol carbonates as a key step (up to 96% ee). Using this strategy, collective total syntheses of Amaryllidaceae alkaloids such as (-)-epi-elwesine I (R = OH, R1 = R2 = H), (-)-crinine I (R = H, R1 = OH, R22 = bond), (-)-epi-crinine I (R = OH, R1 = H, R22 = bond), (-)-oxocrinine I (RR1 = O, R22 = bond), and (-)-buphanisine I (R = H, R1 = OH, R22 = bond) have been accomplished. Gratifyingly, naturally occurring Amaryllidaceae alkaloids such as (+)-vittatine II (R = OH, R1 = H, R22 = bond), (+)-epi-vittatine II (R = H, R1 = OH, R22 = bond), and (+)-epi-elwesine II (R = R2 = H, R1 = OH) have also been achieved by switching the antipode of the ligand used in the catalytic enantioselective step.

Organic Letters published new progress about Allylation catalysts, stereoselective (decarboxylative). 152140-65-3 belongs to class chiral-phosphine-ligands, and the molecular formula is C54H42N2O2P2, Quality Control of 152140-65-3.

Referemce:
Phosphine ligand,
Chiral phosphine ligands in asymmetric synthesis. Molecular structure and absolute configuration of (1,5-cyclooctadiene)-(2S,3S)-2,3-bis(diphenylphosphino)butanerhodium(I) perchlorate tetrahydrofuran solvate

Siu, Eulalia; Won, Keehoon; Park, Chan Beum published the artcile< Electrochemical Regeneration of NADH Using Conductive Vanadia-Silica Xerogels>, Reference of 606-68-8, the main research area is electorchem NADH regeneration vanadia silica xerogel.

Elec. conductive sol-gel matrixes have been first introduced in order to enhance the efficiency of electrochem. NADH regeneration systems for biocatalysis. Vanadia-silica mixed gels as conductive sol-gels were synthesized using vanadium (V) oxytripropoxide (VOTP) and tetra-Me orthosilicate (TMOS) as precursors. Direct electrochem. reductions of NAD+ were carried out in the presence of vanadia-silica xerogels using unmodified platinum electrodes. Vanadia-silica gels from higher ratios of VOTP to TMOS could effectively improve electrochem. generations of NADH from NAD+. Direct electrochem. regenerations of NADH were coupled to the synthesis of L-glutamate from α-ketoglutarate catalyzed by glutamate dehydrogenases (GDH). In this case, vanadia-silica gels were used as matrixes for enzyme encapsulation, as opposed to serving as additives. When GDH were entrapped in “”nonconductive”” silica gels, synthesized using only TMOS, in the control experiment, the initial supply of NADH exhausted quickly and a final conversion of 30% was obtained. However, the use of conductive vanadia-silica gels with encapsulated GDH resulted in complete conversion of α-ketoglutarate to L-glutamate. A turnover number of a cofactor was also enhanced 3-fold by the application of conductive vanadia-silica gels.

Biotechnology Progress published new progress about Electrochemical reduction. 606-68-8 belongs to class chiral-phosphine-ligands, and the molecular formula is C21H27N7Na2O14P2, Reference of 606-68-8.

Referemce:
Phosphine ligand,
Chiral phosphine ligands in asymmetric synthesis. Molecular structure and absolute configuration of (1,5-cyclooctadiene)-(2S,3S)-2,3-bis(diphenylphosphino)butanerhodium(I) perchlorate tetrahydrofuran solvate

Kita, Yusuke; Hida, Shoji; Higashihara, Kenya; Jena, Himanshu Sekhar; Higashida, Kosuke; Mashima, Kazushi published the artcile< Chloride-Bridged Dinuclear Rhodium(III) Complexes Bearing Chiral Diphosphine Ligands: Catalyst Precursors for Asymmetric Hydrogenation of Simple Olefins>, Electric Literature of 139139-93-8, the main research area is diarylalkane enantioselective preparation; diarylalkene enantioselective hydrogenation rhodium catalyst; asymmetric catalysis; hydrogenation; reaction mechanisms; rhodium.

Efficient rhodium(III) catalysts were developed for asym. hydrogenation of simple olefins. A series of chloride-bridged dinuclear rhodium(III) complexes were synthesized from the rhodium(I) precursor [RhCl(cod)]2, chiral diphosphine ligands, and hydrochloric acid. Complexes from the series acted as efficient catalysts for asym. hydrogenation of (E)-prop-1-ene-1,2-diyldibenzene and its derivatives without any directing groups, in sharp contrast to widely used rhodium(I) catalytic systems that require a directing group for high enantioselectivity. The catalytic system was applied to asym. hydrogenation of allylic alcs., alkenylboranes, and unsaturated cyclic sulfones. Control experiments support the superiority of dinuclear rhodium(III) complexes over typical rhodium(I) catalytic systems.

Angewandte Chemie, International Edition published new progress about Aryl alkenes Role: RCT (Reactant), RACT (Reactant or Reagent). 139139-93-8 belongs to class chiral-phosphine-ligands, and the molecular formula is C44H40P2, Electric Literature of 139139-93-8.

Referemce:
Phosphine ligand,
Chiral phosphine ligands in asymmetric synthesis. Molecular structure and absolute configuration of (1,5-cyclooctadiene)-(2S,3S)-2,3-bis(diphenylphosphino)butanerhodium(I) perchlorate tetrahydrofuran solvate

Saba, Tony; Li, Jianwei; Burnett, Joseph W. H.; Howe, Russell F.; Kechagiopoulos, Panagiotis N.; Wang, Xiaodong published the artcile< NADH Regeneration: A Case Study of Pt-Catalyzed NAD+ Reduction with H2>, Formula: C21H27N7Na2O14P2, the main research area is TEM hydrogenation catalyst platinum; NAD hydrogenation NMR NADH platinum magnesium catalyst nicotinamide silica.

This study shows the importance of resolving catalytic performance in the regeneration of the reduced form of NAD (NADH) through activity measurements based on NAD+ conversion and the closure of mass balance via byproduct quantification. This approach is applied to assess the performance of supported platinum catalysts with varying points of zero charge, utilizing H2 as a reductant. It was found that Pt/SiO2, which exhibits a net neg. charge under the reaction conditions, outperforms the neutral Pt/C and pos. charged Pt/MgO because of the favorable electrostatic attraction between the catalyst surface and pos. charged (+1) nicotinamide ring. NMR spectroscopy identifies side-products formed during NAD+ hydrogenation.

ACS Catalysis published new progress about Hydrogenation. 606-68-8 belongs to class chiral-phosphine-ligands, and the molecular formula is C21H27N7Na2O14P2, Formula: C21H27N7Na2O14P2.

Referemce:
Phosphine ligand,
Chiral phosphine ligands in asymmetric synthesis. Molecular structure and absolute configuration of (1,5-cyclooctadiene)-(2S,3S)-2,3-bis(diphenylphosphino)butanerhodium(I) perchlorate tetrahydrofuran solvate

Okamoto, Ryuichi; Okazaki, Eri; Noguchi, Keiichi; Tanaka, Ken published the artcile< Rhodium-catalyzed olefin isomerization/enantioselective intramolecular Alder-ene reaction cascade>, HPLC of Formula: 139139-86-9, the main research area is dihydrobenzofuran dihydronaphthofuran derivative enantioselective synthesis; enyne olefin isomerization Alder ene reaction Rh chiral ligand.

The olefin isomerization/enantioselective intramol. Alder-ene reaction cascade was achieved by using a cationic rhodium(I)/(R)-BINAP complex as a catalyst. A variety of substituted dihydrobenzofurans e. g., I and dihydronaphthofurans e. g., II were obtained from phenol- or naphthol-linked 1,7-enynes, resp., with good yields and ee values.

Organic Letters published new progress about Alkenynes Role: RCT (Reactant), SPN (Synthetic Preparation), RACT (Reactant or Reagent), PREP (Preparation). 139139-86-9 belongs to class chiral-phosphine-ligands, and the molecular formula is C44H40P2, HPLC of Formula: 139139-86-9.

Referemce:
Phosphine ligand,
Chiral phosphine ligands in asymmetric synthesis. Molecular structure and absolute configuration of (1,5-cyclooctadiene)-(2S,3S)-2,3-bis(diphenylphosphino)butanerhodium(I) perchlorate tetrahydrofuran solvate

Kishore, Nand; Holden, Marcia J.; Tewari, Yadu B.; Goldberg, Robert N. published the artcile< A thermodynamic investigation of some reactions involving prephenic acid>, Application of C21H27N7Na2O14P2, the main research area is thermodn prephenate dehydratase dehydrogenase.

Calorimetric enthalpies of reaction have been measured for the following enzyme-catalyzed reactions at the temperature 298.15 K: prephenate(aq) = phenylpyruvate(aq) + carbon dioxide(aq), prephenate(aq) + NADox(aq) + H2O(l) = 4-hydroxyphenylpyruvate(aq) + NADred(aq) + carbon dioxide(aq). Here, NADox and NADred are, resp., the oxidized and reduced forms of β-NAD. The enzymes that catalyze these resp. reactions, prephenate dehydratase and prephenate dehydrogenase, were prepared by expression of the appropriate plasmids using the techniques of mol. biol. The calorimetric measurements together with the equilibrium modeling calculations lead to a standard molar enthalpy change ΔrHom = -(126±5) kJ·mol-1 for the reference reaction: prephenate2-(aq) = phenylpyruvate-(aq) + HCO3-(aq). Similarly, ΔrHom = -(74±3) kJ·mol-1 for the reference reaction: prephenate2-(aq) + NADox-(aq) + H2O(l) = 4-hydroxyphenylpyruvate-(aq) + NADred2-(aq) + HCO3-(aq) + H+(aq). Both results pertain to T = 298.15 K and ionic strength I = 0. Benson estimates for the entropies lead to approx. values of the equilibrium constants K ≈ 1×1026 and K ≈ 1×1012, resp., for the above two reference reactions. (c) 1999 Academic Press.

Journal of Chemical Thermodynamics published new progress about Equilibrium constant. 606-68-8 belongs to class chiral-phosphine-ligands, and the molecular formula is C21H27N7Na2O14P2, Application of C21H27N7Na2O14P2.

Referemce:
Phosphine ligand,
Chiral phosphine ligands in asymmetric synthesis. Molecular structure and absolute configuration of (1,5-cyclooctadiene)-(2S,3S)-2,3-bis(diphenylphosphino)butanerhodium(I) perchlorate tetrahydrofuran solvate

Frattini, Domenico; Hyun, Kyuhuan; Kwon, Yongchai published the artcile< Direct electrochemistry of lactate dehydrogenase in aqueous solution system containing L(+)-lactic acid, β-nicotinamide adenine dinucleotide, and its reduced form>, HPLC of Formula: 606-68-8, the main research area is lactic acid nicotinamide adenine dinucleotide lactate dehydrogenase electrochem.

Using lactate dehydrogenase (LDH) for lactate detection in biosensors is fascinating but still challenging because in-situ bioelectrochem. sensors are still at the research stage due to the lack of reliable information about the direct electrochem. of systems not involving redox mediators. To provide reliable information, the direct electrochems. of aqueous solution systems containing L(+)-lactic acid (Lac), β-NAD (NAD+) and its reduced form (NADH) is investigated using (i) free-standing LDH and (ii) LDH immobilized on carbon nanotubes (CNT). Results show that there is one peak for NADH oxidation and one peak for the NAD+ reduction while the conversion of lactate is observed in the aqueous solution In addition, the peak for NADH oxidation may disappear or be shifted irreversibly. As a result, the detection of lactate relies on the type of solution The conventional mechanisms explaining these phenomena are too superficial and hard to interpret, thus, in this work, we suggest a new interpretation method explaining the empirical behavior of lactate detection. In this prospect, the role of chem. equilibrium related to the conversion of lactate into pyruvate that is catalyzed by LDH is important and this is sequentially elucidated, while the rate-determining step for lactate detection is suggested.

Journal of Industrial and Engineering Chemistry (Amsterdam, Netherlands) published new progress about Carbon nanotubes. 606-68-8 belongs to class chiral-phosphine-ligands, and the molecular formula is C21H27N7Na2O14P2, HPLC of Formula: 606-68-8.

Referemce:
Phosphine ligand,
Chiral phosphine ligands in asymmetric synthesis. Molecular structure and absolute configuration of (1,5-cyclooctadiene)-(2S,3S)-2,3-bis(diphenylphosphino)butanerhodium(I) perchlorate tetrahydrofuran solvate

Kashima, Kenichi; Ishii, Masahiro; Tanaka, Ken published the artcile< Synthesis of Pyridylphosphonates by Rhodium-Catalyzed [2+2+2] Cycloaddition of 1,6- and 1,7-Diynes with Diethyl Phosphorocyanidate>, Formula: C44H40P2, the main research area is diyne cycloaddition enantioselective phosphorocyanidate preparation pyridylphosphonate fluorescence.

The convenient and atom-economical synthesis of substituted bicyclic pyridylphosphonates was achieved by the cationic Rh(I)/H8-binap-complex-catalyzed [2+2+2] cycloaddition of 1,6- and 1,7-diynes with di-Et phosphorocyanidate. These reactions may proceed via an azarhodacyclopentadiene intermediate in addition to the rhodacyclopentadiene intermediate.

European Journal of Organic Chemistry published new progress about Alkadiynes Role: RCT (Reactant), RACT (Reactant or Reagent). 139139-93-8 belongs to class chiral-phosphine-ligands, and the molecular formula is C44H40P2, Formula: C44H40P2.

Referemce:
Phosphine ligand,
Chiral phosphine ligands in asymmetric synthesis. Molecular structure and absolute configuration of (1,5-cyclooctadiene)-(2S,3S)-2,3-bis(diphenylphosphino)butanerhodium(I) perchlorate tetrahydrofuran solvate

Tabuchi, Sho; Hirano, Koji; Miura, Masahiro published the artcile< Palladium-Catalyzed Asymmetric Benzylic Alkylation of Active Methylene Compounds with α-Naphthylbenzyl Carbonates and Pivalates>, Reference of 139139-93-8, the main research area is palladium catalyst asym benzylic alkylation active methylene compound; asymmetric catalysis; kinetic resolution; ligand effects; palladium; synthetic methods.

A Pd/(R)-H8-BINAP-catalyzed asym. benzylic alkylation of active methylene compounds has been developed. The reaction proceeds without the use of an external base, and the starting racemic diarylmethyl carbonates are converted into the optically active coupling products which contain the benzylic chiral stereocenter by a dynamic kinetic asym. transformation (DYKAT). Addnl., with suitable carbonates bases, the same palladium catalysis allows the corresponding pivalates to be adopted in the same DYKAT process.

Angewandte Chemie, International Edition published new progress about Active methylene compounds Role: RCT (Reactant), RACT (Reactant or Reagent). 139139-93-8 belongs to class chiral-phosphine-ligands, and the molecular formula is C44H40P2, Reference of 139139-93-8.

Referemce:
Phosphine ligand,
Chiral phosphine ligands in asymmetric synthesis. Molecular structure and absolute configuration of (1,5-cyclooctadiene)-(2S,3S)-2,3-bis(diphenylphosphino)butanerhodium(I) perchlorate tetrahydrofuran solvate