- Quinone Reduction by Organo-Osmium Half-Sandwich Transfer Hydrogenation Catalysts
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Organo-osmium(II) 16-electron complexes [OsII(η6-arene)(R-PhDPEN)] (where η6-arene =para-cymene or biphenyl) can catalyze the reduction of prochiral ketones to optically pure alcohols in the presence of a hydride source. Such complexes can achieve the conversion of pyruvate to unnatural http://www.w3.org/1999/xlinkd-lactate in cancer cells. To improve the catalytic performance of these osmium complexes, we have introduced electron-donor and electron-acceptor substituents (R) into thepara(R1) ormeta(R2) positions of the chiral R-phenyl-sulfonyl-diphenylethylenediamine (R-PhDPEN) ligands and explored the reduction of quinones, potential biological substrates, which play a major role in cellular electron transfer chains. We show that the series of [OsII(η6-arene)(R-PhDPEN)] derivatives exhibit high turnover frequencies, enantioselectivities (>92%), and conversions (>93%) for the asymmetric transfer hydrogenation (ATH) of acetophenone-derived substrates and reduce duroquinone and menadione to their di-alcohol derivatives. Modeling of the catalysis using density functional theory (DFT) calculations suggests a mechanism involving formic acid deprotonation assisted by the catalyst amine groups, phenyl-duroquinone stacking, hydride transfer to OsII, possible CO2coordination, and tilting of the η6-arene ring, followed by hydride transfer to the quinone. These findings not only reveal subtle differences between Ru(II) and Os(II) catalysts, but also introduce potential biological applications.
- Bolitho, Elizabeth M.,Coverdale, James P. C.,Sadler, Peter J.,Schünemann, Volker,Wolny, Juliusz A.,Worby, Nathan G.
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p. 3012 - 3023
(2021/09/13)
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- Enantioselective Hydroboration of Ketones Catalyzed by Rare-Earth-Metal Complexes Supported with Phenoxy-Functionalized TsDPEN Ligands
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Six novel chiral rare-earth-metal complexes bearing the phenoxy-functionalized TsDPEN ligand H3L1 (H3L1 = N-((1R,2R)-2-((3,5-di-Tert-butyl-2-hydroxybenzyl)amino)-1,2-diphenylethyl)-4-methylbenzenesulfonamide) were synthesized successfully and well characterized. The solid-state structures of four tetranuclear rare-earth-metal complexes [RE2L13]2 (RE = Nd (1), Sm (2), Eu (3), Gd (4)) and the dual-core yttrium complex Y2L13 (5) were determined by X-ray diffraction, respectively. The structure of lanthanum complex 6 was speculated by the 1H DOSY spectroscopy in THF-d8 together with DFT calculations. Complexes 1-5 were employed to catalyze the enantioselective hydroboration of ketones and α,β-unsaturated ketones using pinacolborane (HBpin) as a reductant, and complex 1 gave better outcomes in comparison to the others. The corresponding secondary alcohols were obtained in excellent yields and moderate ee values. The same results were also achieved using the combined catalyst system of the neodymium amide Nd[N(SiMe3)2]3 with the phenoxy-functionalized TsDPEN ligand H3L1 in a 1:1.5 molar ratio.
- Yu, Qishun,Lu, Chengrong,Zhao, Bei
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supporting information
p. 2529 - 2537
(2021/07/28)
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- Ruthenium(II)-Catalyzed Enantioselective ?-Lactams Formation by Intramolecular C-H Amidation of 1,4,2-Dioxazol-5-Ones
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We report the Ru-Catalyzed enantioselective annulation of 1,4,2-Dioxazol-5-Ones to furnish ?-Lactams in up to 97% yield and 98% ee via intramolecular carbonylnitrene C-H insertion. By employing chiral diphenylethylene diamine (dpen) as ligands bearing electron-Withdrawing arylsulfonyl substituents, the reactions occur with remarkable chemo- A nd enantioselectivities; the competing Curtius-Type rearrangement was largely suppressed. Enantioselective nitrene insertion to allylic/propargylic C-H bonds was also achieved with remarkable tolerance to the Ca?C and Ca‰iC bonds.
- Xing, Qi,Chan, Chun-Ming,Yeung, Yiu-Wai,Yu, Wing-Yiu
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supporting information
(2019/03/11)
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- Ruthenium(II)-Catalyzed Enantioselective γ-Lactams Formation by Intramolecular C-H Amidation of 1,4,2-Dioxazol-5-ones
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We report the Ru-catalyzed enantioselective annulation of 1,4,2-dioxazol-5-ones to furnish γ-lactams in up to 97% yield and 98% ee via intramolecular carbonylnitrene C - H insertion. By employing chiral diphenylethylene diamine (dpen) as ligands bearing electron-withdrawing arylsulfonyl substituents, the reactions occur with remarkable chemo- and enantioselectivities; the competing Curtius-type rearrangement was largely suppressed. Enantioselective nitrene insertion to allylic/propargylic C - H bonds was also achieved with remarkable tolerance to the C=C and C=C bonds.
- Xing, Qi,Chan, Chun-Ming,Yeung, Yiu-Wai,Yu, Wing-Yiu
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supporting information
p. 3849 - 3853
(2019/04/25)
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- A four-hydrogenated 1, 8 - naphthyridine apperception composition preparation method and its prepared chiral products
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The invention discloses a preparation method of a tetrahydro 1, 8-naphthyridine compound. The preparation method comprises the following steps: under the existence of a chiral catalyst, enabling a compound with the structure shown in the formula (1) (in the description) and hydrogen to be subjected to addition reaction, wherein the chiral catalyst is a coordination compound with the structure shown in the formula (2) (in the description). The invention further provides a chiral product of the tetrahydro 1, 8-naphthyridine compound, prepared through the preparation method. According to the invention, the proper compound with the structure shown in the formula (1) (in the description) is used as a substrate, and the proper coordination compound with the structure shown in the formula (2) (in the description) is used as the chiral catalyst to perform selective hydrogenation reduction on 1, 8-naphthyridine compound with the structure shown in the formula (1) by adopting hydrogen, so that the chiral product of the tetrahydro 1, 8-naphthyridine compound is prepared with low cost. The chiral product of the tetrahydro 1, 8-naphthyridine compound can be used as a biologically active compound and a structural building block of a chiral drug.
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Paragraph 0137; 0173
(2018/03/26)
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- O-bicyclic amine compounds as well as preparation method and chiral products thereof
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The invention relates to the field of asymmetric synthesis methods, and discloses a preparation method of o-bicyclic amine compounds. The method comprises the step of enabling a compound having a structure as shown in a formula (1) and hydrogen to be subjected to an addition reaction in presence of a chiral catalyst, wherein the chiral catalyst is a complex having a structure as shown in a formula (2). The invention also provides chiral products of the o-bicyclic amine compounds prepared by the method, and the o-bicyclic amine compounds. After the method is adopted, the selective hydrogenation reduction of the compound having the structure as shown in the formula (1) is realized by using the hydrogen, so that octahydrogenated products, i.e., the o-bicyclic amine compounds shown in a formula (4) are produced with low cost. The formula (1), the formula (2) and the formula (4) are described in the description.
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Paragraph 0196-0197
(2017/11/04)
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- A four-hydrogenated 1, 5 - naphthyridine apperception composition preparation method and its prepared chiral products
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The invention discloses a method for preparing a tetrahydro-1,5-naphthyridine compound. The method comprises the following steps: carrying out an addition reaction between a compound with the structure shown as a formula (1) and hydrogen in the presence of a chiral catalyst, wherein the chiral catalyst is a coordination complex with a structure shown as a formula (2). The invention also provides a chiral product of the tetrahydro-1,5-naphthyridine compound prepared by the method. The proper compound with the structure shown as the formula (1) is selected as a substrate, the proper coordination complex with the structure shown as the formula (2) is selected as the chiral catalyst, and selective hydrogenation reduction of the 1,5-naphthyridine compound with the structure shown as the formula (1) is realized by adopting hydrogen, so that the chiral product of the tetrahydro-1,5-naphthyridine compound is prepared at low cost. The chiral product of the tetrahydro-1,5-naphthyridine compound prepared by the invention can serve as a structure block of bioactive compounds and chiral drugs.
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Paragraph 0174
(2017/08/25)
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- PH-independent transfer hydrogenation in water: Catalytic, enantioselective reduction of β-keto esters
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A pH-independent asymmetric transfer hydrogenation of β-keto esters in water with formic acid/sodium formate is described. The reaction is conducted open to air and gives access to β-hydroxy esters in excellent yields and selectivities.
- Ariger, Martin A.,Carreira, Erick M.
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supporting information
p. 4522 - 4524
(2012/10/29)
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- Enantioselective Michael addition of ketones to maleimides catalyzed by bifunctional monosulfonyl DPEN salt
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An unprecedented enantioselective Michael addition of various ketones to maleimides catalyzed by a simple bifunctional primary amine, monosulfonyl DPEN salt, is reported and provides the desired adducts in good to excellent yields (up to 99%) with excellent enantioselectivities (up to 99%).
- Yu, Feng,Sun, Xiaomin,Jin, Zhichao,Wen, Shigang,Liang, Xinmiao,Ye, Jinxing
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supporting information; experimental part
p. 4589 - 4591
(2010/11/18)
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- Asymmetric Syn-selective Henry reaction catalyzed by the sulfonyldiamine-CuCl-pyridine system
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(Chemical Equation Presented) A catalytic asymmetric Henry reaction has been developed with use of a sulfonyldiamine-CuCl complex as a catalyst. A series of new binaphthyl-containing sulfonyldiamine ligands (2a-h) were readily synthesized in two steps starting from commercially available chiral 1,2-diamines. The (R,R)-diamine-(R)-binaphthyl ligand (2d)-CuCl complex smoothly catalyzed the enantioselective Henry reaction with the assistance of pyridine to give the corresponding adduct with high enantiomeric excess (up to 93%). Moreover, the 2d-CuCl-pyridine system promotes the diastereoselective Henry reaction in syn-selective manner to give the adduct in up to 99% yield with 92:8 synlanti selectivity. The enantiomeric excess of the syn-adduct was 84% ee.
- Arai, Takayoshi,Takashita, Ryuta,Endo, Yoko,Watanabe, Masahiko,Yanagisawa, Akira
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p. 4903 - 4906
(2008/12/20)
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