- DEVICE AND METHOD FOR EVALUATING ORGANIC MATERIAL FOR ORGANIC SOLAR CELL
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Provided are a novel 1,2-bis(dialkylphosphino)-4,5-(methylenedioxy)benzene derivative that forms a metal complex having particularly high asymmetry induction capacity and catalytic activity on β-dehydroamino acids, a method for manufacturing the same, a metal complex having this 1,2-bis(dialkylphosphino)-4,5-(methylenedioxy)benzene derivative as a ligand, and an asymmetric hydrogenation method using this metal complex. A 1,2-bis(dialkylphosphino)-4,5-(methylenedioxy)benzene derivative represented by general formula (1). (In the formula, R1 and R2 represent an alkyl group having 1-10 carbon atoms, and R1 and R2 have different numbers of carbon atoms.)
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Paragraph 0082; 0083; 0084; 0085; 0086
(2014/08/07)
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- METHOD FOR PRODUCING OPTICALLY ACTIVE 1,2-BIS(DIALKYLPHOSPHINO)BENZENE DERIVATIVE
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An industrially advantageous method for producing an optically active 1,2-bis(dialkylphosphino)benzene derivative of the present invention is provided. The method is characterized in that a phosphine-borane compound represented by the following general formula (1) is subjected to a deboronation reaction, followed by lithiation, then the reaction product is subjected to reaction with an alkyldihalogenophosphine represented by RaPX′2, and thereafter the reaction product is subjected to reaction with a Grignard reagent represented by RbMgX″ to produce an optically active 1,2-bis(dialkylphosphino)benzene derivative (A). R1 and R2 respectively represent an alkyl group having 1 to 8 carbon atoms, and the number of carbon atoms is different between R1 and R2. Ra is either R1 or R2 and Rb is the other of R1 and R2. X, X′, and X″ each represent a halogen atom.
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Paragraph 0068; 0069; 0070; 0071; 0072; 0073
(2013/07/19)
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- Three-hindered quadrant phosphine ligands with an aromatic ring backbone for the rhodium-catalyzed asymmetric hydrogenation of functionalized alkenes
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The three-hindered quadrant phosphine ligands (R)-1-tert- butylmethylphosphino-2-(di-tert-butylphosphino)benzene ((R)-3H-BenzP*) and (R)-2-tert-butylmethylphosphino-3-(di-tert-butylphosphino)quinoxaline ((R)-3H-QuinoxP*) exhibited good to excellent enantioselectivities in the rhodium-catalyzed asymmetric hydrogenation of selected dehydroamino acid derivatives, enamides, and ethenephosphonates.
- Zhang, Zhenfeng,Tamura, Ken,Mayama, Daisuke,Sugiya, Masashi,Imamoto, Tsuneo
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experimental part
p. 4184 - 4188
(2012/06/18)
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- Rigid P-chiral phosphine ligands with tert -butylmethylphosphino groups for rhodium-catalyzed asymmetric hydrogenation of functionalized alkenes
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Both enantiomers of 2,3-bis(tert-butylmethylphosphino)quinoxaline (QuinoxP*), 1,2-bis(tert-butylmethylphosphino)benzene (BenzP*), and 1,2-bis(tert-butylmethylphosphino)-4,5-(methylenedioxy)benzene (DioxyBenzP*) were prepared in short steps from enantiopure (S)- and (R)-tert-butylmethylphosphine-boranes as the key intermediates. All of these ligands were crystalline solids and were not readily oxidized on exposure to air. Their rhodium complexes exhibited excellent enantioselectivities and high catalytic activities in the asymmetric hydrogenation of functionalized alkenes, such as dehydroamino acid derivatives and enamides. The practical utility of these catalysts was demonstrated by the efficient preparation of several chiral pharmaceutical ingredients having an amino acid or a secondary amine component. A rhodium complex of the structurally simple ligand BenzP* was used for the mechanistic study of asymmetric hydrogenation. Low-temperature NMR studies together with DFT calculations using methyl α-acetamidocinnamate as the standard model substrate revealed new aspects of the reaction pathways and the enantioselection mechanism.
- Imamoto, Tsuneo,Tamura, Ken,Zhang, Zhenfeng,Horiuchi, Yumi,Sugiya, Masashi,Yoshida, Kazuhiro,Yanagisawa, Akira,Gridnev, Ilya D.
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supporting information; experimental part
p. 1754 - 1769
(2012/03/11)
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- Enantiopure 1,2-Bis(tert-butylmethylphosphino)benzene as a highly efficient ligand in rhodium-catalyzed asymmetric hydrogenation
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Figure Presented. An electron-rich P-stereogenic bisphosphine ligand named "BenzP" was conveniently prepared from o-dibromobenzene and enantiopure tert-butylmethylphosphine-borane. Its rhodium complex exhibited excellent enantioselectivities of up to 99.9% and high catalytic activity of up to 10000 h-1 TOF in asymmetric hydrogenations of various functionalized alkenes.
- Tamura, Ken,Sugiya, Masashi,Yoshida, Kazuhiro,Yanagisawa, Akira,Imamoto, Tsuneo
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supporting information; experimental part
p. 4400 - 4403
(2010/12/25)
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- Monodentate Phosphoramidites: A Breakthrough in Rhodium-Catalysed Asymmetric Hydrogenation of Olefins
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Monodentate phosphoramidites based on BINOL or substituted BINOL are excellent ligands for the rhodium-catalysed asymmetric hydrogenation of olefins. Very high enantioselectivities were obtained with MonoPhos (7a) the simplest member of this class, a ligand that is prepared in a single step from BINOL and HMPT. Turnover numbers up to 6000 have been obtained in the hydrogenation of dehydroamino acid derivatives. Enantioselectivities in the hydrogenation of dehydroamino acids are solvent dependent; in non-protic solvents they range from 95-99%. Itaconic acid and its dimethyl ester could be hydrogenated with 96 and 94% e.e., respectively. Hydrogenation of aromatic enamides gave the corresponding acylated amines in 86-94% e.e. Several analogous phosphoramidite ligands have been pre-pared. Surprisingly, bidentate ligands gave poorer results, both in terms of rate as well as enantioselectivity. Taddol-based phosphoramidites led to poor e.e. and slow rates. Methyl substituents at the 3,3′-position of BINOL led to a sharply reduced rate and a somewhat lower enantioselectivity. Bromo substituents at the 6,6′-position led to a slightly reduced rate but little effect was seen on enantioselectivity. Use of octahydro-MonoPhos (11) gave results that were very similar to those obtained with 7a. The rate of the reaction is dependent on the hydrogen pressure, however, the enantioselectivity is not affected. The rate of the dehydroamino acid hydrogenation also increases if the ligand to rhodium ratio is reduced from 2.2 to 1.5 or even to 1.0; yet, there is no deleterious effect on the enantioselectivity. Catalytic activity ceases with L/Rh = 3 when dehydroamino acid derivatives were used as substrate. The reaction shows a positive non-linear effect, which confirms the presence of Rh-complexes with more than one ligand. Following the hydrogenation of methyl 2-acetamidocinnnamate with Rh(nbd)2BF4/7a by electrospray mass spectrometry showed the presence of several rhodium species. Notable are the presence of [Rh(7a)]3+ and [Rh(7a)]4+. There is at present insufficient evidence to conclude if the active catalytic species carries one or two ligands. In view of the low cost of MonoPhos this invention might well lead to a broader application of asymmetric olefin hydrogenation for the production of enantiopure amino acids and amines.
- Van Den Berg, Michel,Minnaard, Adriaan J.,Haak, Robert M.,Leeman, Michel,Schudde, Ebe P.,Meetsma, Auke,Feringa, Ben L.,De Vries, André H. M.,Maljaars, C. Elizabeth P.,Willans, Charlotte E.,Hyett, David,Boogers, Jeroen A. F.,Henderickx, Hubertus J. W.,De Vries, Johannes G.
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p. 308 - 323
(2007/10/03)
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- Retention and selectivity of teicoplanin stationary phases after copper complexation and isotopic exchange
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Teicoplanin is a macrocyclic glycopeptide that is highly effective as a chiral selector for LC enantiomeric separations. Two possible interaction paths were investigated and related to solute retention and selectivity: (1) interactions with the only teicoplanin amine group and (2) role of hydrogen bonding interactions. Mobile phases containing 0.5 and 5 mM copper ions were used to try to block the amine group. In the presence of copper ions, it was found that the teicoplanin stationary phase has a decreased ability to separate most underivatized racemic amino acids. However, it maintained its ability to separate enantiomers that were not α - amino acids. It is established that there is little copper - teicoplanin complex formation. The effect of Cu2+ on the enantioseparation of some α - amino acids appears to be due to the fact that these solutes are good bidentate ligands and form complexes with copper ions in the mobile phase. Isotopic exchange with deuterium oxide was performed using acetonitrile - heavy water mobile phases. It was found that the retention times of all amino acids were lower with deuterated mobile phases. The retention times of polar or apolar molecules without amine groups were higher with deuterated mobiles phases. In all cases, the enantio-selectivity factors were unaffected by the deuterium exchange. It is proposed that the electrostatic interactions are decreased in the deuterated mobile phases and the solute-accessible stationary-phase volume is somewhat swollen by deuterium oxide. The balance of these effects is a decrease in the amino acid retention times and an increase in the apolar solute retention time. The enantio-selectivity factors of all of the molecules remain unchanged because all of the interactions are changed equally. We propose a new global quality criterion (the E factor) for comparing and evaluating enantiomeric separations.
- Berthod,Valleix,Tizon,Leonce,Caussignac,Armstrong
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p. 5499 - 5508
(2007/10/03)
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