- Amide Synthesis via Aminolysis of Ester or Acid with an Intracellular Lipase
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A unique lipase (SpL) from Sphingomonas sp. HXN-200 was discovered as the first intracellular enzyme for the aminolysis of ester or acid to produce amide. Reactions of a series of esters and amines with SpL gave the corresponding amides 3a-g in high yield with high activity. SpL also showed high enantioselectivity and high activity for enantioselective ester aminolysis, producing amides (R)-3h-j in high ee from the corresponding racemic ester or amine. Moreover, SpL was found to be highly active for the aminolysis of carboxylic acid, which was generally considered infeasible with the known aminolysis enzymes. The aminolysis of several carboxylic acids afforded the corresponding amides 3a, 3d, 3k, 3l, and 3n in good yield. The intracellular SpL was expressed in Escherichia coli cells to give an efficient whole-cell biocatalyst for amide synthesis. Remarkably, high catalytic activity was observed in the presence of water at 2-4% (v/v) for free enzyme and 16% (v/v) for whole cells, respectively. Accordingly, E. coli (SpL) wet cells were used as easily available and practical catalysts for the aminolysis of ester or acid, producing a group of useful and valuable amides in high concentration (up to 103 mM) and high yield. The newly discovered intracellular SpL with unique properties is a promising catalyst for green and efficient synthesis of amides.
- Zeng, Shichao,Liu, Ji,Anankanbil, Sampson,Chen, Ming,Guo, Zheng,Adams, Joseph P.,Snajdrova, Radka,Li, Zhi
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p. 8856 - 8865
(2018/09/06)
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- Stereospecific Nucleophilic Substitution with Arylboronic Acids as Nucleophiles in the Presence of a CONH Group
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Stereospecific nucleophilic substitution was achieved for the first time with arylboronic acids as nucleophiles. This transition-metal-free coupling between chiral α-aryl-α-mesylated acetamides and arylboronic acids provided access to a series of chiral α,α-diaryl acetamides with excellent enantioselectivity and moderate to good yields. The CONH functionality proved to be crucial for bridging the reactants and promoting the reaction. Efficient syntheses of a cannabinoid CB1 receptor ligand, the antidepressant (S)-diclofensine, and a key chiral building block of the inhibitor implitapide were successfully accomplished by using this method.
- Tian, Duanshuai,Li, Chengxi,Gu, Guoxian,Peng, Henian,Zhang, Xumu,Tang, Wenjun
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supporting information
p. 7176 - 7180
(2018/05/29)
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- Enantioselective Iridium-Catalyzed Hydrogenation of α-Keto Amides to α-Hydroxy Amides
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A highly enantioselective iridium-catalyzed hydrogenation of α-keto amides to form α-hydroxy amides has been achieved with excellent results (up to >99% conversion and up to >99% ee, TON up to 100?000). As an example, this protocol was applied to the synthesis of (S)-4-(2-amino-1-hydroxyethyl)benzene-1,2-diol, the enantiomer of norepinephrine, which is widely used as an injectable drug for the treatment of critically low blood pressure. Density functional theory (DFT) calculations were also carried out to reveal the reaction mechanism.
- Gu, Guoxian,Yang, Tilong,Yu, Ouran,Qian, Hua,Wang, Jiang,Wen, Jialin,Dang, Li,Zhang, Xumu
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supporting information
p. 5920 - 5923
(2017/11/10)
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- Amidation of unactivated ester derivatives mediated by trifluoroethanol
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A catalytic amidation protocol mediated by 2,2,2-trifluoroethanol has been developed, facilitating the condensation of unactivated esters and amines, furnishing both secondary and tertiary amides. The complete scope and limitations of the method are described, along with modified conditions for challenging substrates such as acyclic secondary amines and chiral esters with retention of chiral integrity.
- McPherson, Christopher G.,Caldwell, Nicola,Jamieson, Craig,Simpson, Iain,Watson, Allan J. B.
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supporting information
p. 3507 - 3518
(2017/04/26)
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- Enantioselective Synthesis of α-Hydroxy Amides and β-Amino Alcohols from α-Keto Amides
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Synthesis of enantiomerically enriched α-hydroxy amides and β-amino alcohols has been accomplished by enantioselective reduction of α-keto amides with hydrosilanes. A series of α-keto amides were reduced in the presence of chiral CuII/(S)-DTBM-SEGPHOS catalyst to give the corresponding optically active α-hydroxy amides with excellent enantioselectivities by using (EtO)3SiH as a reducing agent. Furthermore, a one-pot complete reduction of both ketone and amide groups of α-keto amides has been achieved using the same chiral copper catalyst followed by tetra-n-butylammonium fluoride (TBAF) catalyst in presence of (EtO)3SiH to afford the corresponding chiral β-amino alcohol derivatives.
- Mamillapalli, N. Chary,Sekar, Govindasamy
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supporting information
p. 18584 - 18588
(2016/01/25)
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- Catalytic chemical amide synthesis at room temperature: One more step toward peptide synthesis
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An efficient method has been developed for direct amide bond synthesis between carboxylic acids and amines via (2-(thiophen-2-ylmethyl)phenyl)boronic acid as a highly active bench-stable catalyst. This catalyst was found to be very effective at room temperature for a large range of substrates with slightly higher temperatures required for challenging ones. This methodology can be applied to aliphatic, α-hydroxyl, aromatic, and heteroaromatic acids as well as primary, secondary, heterocyclic, and even functionalized amines. Notably, N-Boc-protected amino acids were successfully coupled in good yields with very little racemization. An example of catalytic dipeptide synthesis is reported.
- Mohy El Dine, Tharwat,Erb, William,Berhault, Yohann,Rouden, Jacques,Blanchet, Jér?me
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p. 4532 - 4544
(2015/05/13)
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- B(OCH2CF3)3-mediated direct amidation of pharmaceutically relevant building blocks in cyclopentyl methyl ether
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The use of B(OCH2CF3)3 for mediating direct amidation reactions of a wide range of pharmaceutically relevant carboxylic acids and amines is described, including numerous heterocycle-containing examples. An initial screen of solvents for the direct amidation reaction suggested that cyclopentyl methyl ether, a solvent with a very good safety profile suitable for use over a wide temperature range, was an excellent replacement for the previously used solvent acetonitrile. Under these conditions amides could be prepared from 18 of the 21 carboxylic acids and 18 of the 21 amines examined. Further optimisation of one of the low yielding amidation reactions (36% yield) via a design of experiments approach enabled an 84% yield of the amide to be obtained.
- Karaluka, Valerija,Lanigan, Rachel M.,Murray, Paul M.,Badland, Matthew,Sheppard, Tom D.
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supporting information
p. 10888 - 10894
(2015/11/17)
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- PRODUCTION METHOD FOR HYDROXY-CARBOXYLIC ACID AMIDE COMPOUND, AND NOVEL ARYLBORONIC ACID COMPOUND
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A method for production of hydroxycarboxylic acid amide compounds, comprising performing amide condensation between an α- or β-hydroxycarboxylic acid compound and an amine compound in the presence as a catalyst of an alkylboronic acid represented by R3B(OH)2 (wherein R3 is a primary alkyl group) or an arylboronic acid compound to produce a hydroxycarboxylic acid amide compound, the arylboronic acid compound being represented by Formula (1): (in Formula (1), -(CH2)nNR1R2 is bonded at an ortho position or a para position, n is 1 or 2, R1 is a tertiary alkyl group, R2 is a secondary or tertiary alkyl group, and -NR1R2 may be a ring).
- -
-
Paragraph 0045; 0047
(2015/01/18)
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- Sulfated tungstate: A highly efficient catalyst for transamidation of carboxamides with amines
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An environmentally benign protocol for the transamidation of carboxamides with amines using sulfated tungstate, as a heterogeneous catalyst, has been developed. The method has been successfully applied to the synthesis of a wide range of aromatic and aliphatic amides and phthalimides. Efficient transformation, mild reaction conditions, easy product isolation and the potential reusability of the catalyst are attractive features.
- Pathare, Sagar P.,Jain, Ashish Kumar H.,Akamanchi, Krishnacharya G.
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p. 7697 - 7703
(2013/06/27)
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- Biocatalytic reduction of α-keto amides to (R)-α-hydroxy amides using Candida parapsilosis ATCC 7330
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Biocatalytic reduction of primary and secondary α-keto amides was accomplished using whole cells of Candida parapsilosis ATCC 7330. The primary (R)-α-hydroxy amides were obtained in good enantiomeric excess (up to 94%) and conversion (88-99%) as compared to the secondary (R)-α-hydroxy amides.
- Stella, Selvaraj,Chadha, Anju
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p. 345 - 352
(2013/01/15)
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- A new chemoenzymatic approach to the synthesis of chiral 4-aryl-1,4-dihydro-2H-isoquinolines via the enzymatic resolution of 2-acetyl-4-phenyl-1,4-dihydro-2H-isoquinolin-3-one
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A new chemoenzymatic method is proposed for the synthesis of enantiomerically pure 4-phenyl-1,4-dihydro-2H-isoquinolines based on the enzymatic kinetic resolution of 2-acetyl-4-phenyl-1,4-dihydro-2H-isoquinolin-3- one. For the enzymatic resolution of the racemic substrate, readily available 'home made' animal liver acetone powders (LAPs) were used. Excellent enantioselectivity, exceeding 500, was achieved in a short reaction time upon application of turkey liver acetone powder as the biocatalyst. Reduction of obtained product led to the formation of amine (R)-1, which is hardly available using standard procedures. These results show that N-acetyl lactams are a new type of substrate for enzymatic biotransformations.
- Koszelewski, Dominik,Cwiklak, Malgorzata,Ostaszewski, Ryszard
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p. 1256 - 1261
(2012/11/07)
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- Asymmetric aerobic oxidation of α-hydroxy acid derivatives catalyzed by reusable, polystyrene-supported chiral N-salicylidene oxidovanadium tert-leucinates
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The direct immobilization of two different C-5-propargyl ether-modified, chiral N-salicylidene vanadyl(V) tert-leucinates onto 4-azidomethyl-substituted polystyrene by click chemistry was examined. Among the eight different solvents investigated, the resulting polystyrene-supported catalysts promote the asymmetric, aerobic oxidation of α-hydroxy (thio)esters and amides with enantioselectivities of up to 99% ee (selectivity factor up to 41) in chloroform. These polystyrene-supported catalysts can be readily recovered by filtration and reused for at least four consecutive runs without discernible loss of reactivity and enantioselectivity.
- Salunke, Santosh B.,Babu, N.Seshu,Chen, Chien-Tien
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supporting information; experimental part
p. 1234 - 1240
(2011/06/26)
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- Asymmetrie aerobic oxidation of α-hydroxy acid derivatives by C 4-symmetric, vanadate-centered, tetrakisvanadyl(V) clusters derived from N-salicylidene-α-aminocarboxylates
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(Chemical Equation Presented) A series of chiral vanadyl(V) methoxides bearing 3-t-butyl-5-substituted N-salicylene-L-valinate and L-t-leucinate as chiral auxiliaries has been prepared. In all cases except the 3,5-di-t-butyl analogue, they exist as monomers both in solution and in the single crystal state. In the case of the 3,5-di-t-butyl analogue, the architectural nature of the vanadyl(V) complex highly depends on the base used during the complex formation event. A pentanuclear C4-symmetric complex was formed when potassium salts were employed instead of the corresponding sodium salts. A central vanadate(V) unit serves to grip four identical chiral monomelic vanadyl(V) units together, by which a potassium ion sits on top of the four flanking units through carbonyl coordinations and serves to hold the whole cluster by cooperation with the central vanadate(V) unit. In comparison with the corresponding monomelic vanadyl(V) methoxide complex, the cluster complex was utilized to facilitate the asymmetric aerobic oxidations of various racemic α-hydroxyesters, -amides, and -thioesters with excellent selectivity factors (krel 40 to >500).
- Chen, Chien-Tien,Bettigeri, Sampada,Weng, Shiue-Shien,Pawar, Vijay D.,Lin, Ya-Hui,Liu, Cheng-Yuan,Lee, Way-Zen
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p. 8175 - 8185
(2008/02/13)
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- A density functional study of the hydrogenation of ketones catalysed by neutral rhodium-diphosphane complexes
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The potential energy profile of RhI-catalysed hydrogenation of ketones has been computed for the simple model system [Rh{H3POCH 2CH2N(H)PH3}(Cl)] using DFT calculations. The general sequence of the catalytic cycle involves coordination of the carbonyl derivative to the neutral RhI complex followed by oxidative addition of molecular hydrogen providing rhodium dihydride intermediates. The latter are converted into alkoxy hydrides by a migratory insertion reaction. Reductive elimination of the alcohol and substitution of the latter by the incoming substrate completes the catalytic cycle. Intermediates and transition states of all catalytic steps have been located. Two isomeric derivatives bearing the model substrate have been found for the [Rh{H3POCH2CH 2N(H)PH3}(Cl)(H2CO)] complex. Eight diastereomeric pathways have been followed for the cis addition of molecular hydrogen to [Rh{H3POCH2CH2N(H)PH 3}(Cl)(H2CO)] leading to eight distinct isomeric dihydride intermediates. Four dihydride complexes can be considered as the more accessible compounds. The site preference for migratory insertion and transition states discriminates the main path of the catalytic reaction. Migratory insertion to form the alkoxy hydride constitute the turn over limiting step of the process. The potential energy profile has been found to be smooth without excessive activation barriers. Wiley-VCH Verlag GmbH & Co. KGaA, 2006.
- Agbossou-Niedercorn, Francine,Paul, Jean-Francois
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p. 4338 - 4348
(2008/03/27)
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- New diphosphinite ligands derived from mannitol for rhodium catalyzed enantioselective hydrogenation of ketones
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We have developed new electron rich chiral bisphosphinites from mannitol. The new ligands have been found to be efficient chiral auxiliaries for rhodium catalyzed hydrogenation of functionalized ketones leading to hydroxy compounds in up to 86% ee. (C) 2000 Elsevier Science Ltd.
- Naili, Said,Suisse, Isabelle,Mortreux, André,Agbossou, Francine,Ait Ali, Mustapha,Karim, Abdallah
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p. 2867 - 2870
(2007/10/03)
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- Enantioselective hydrogenation of functionalized ketones. Synthesis and application of new chiral aminophosphine-phosphinite ligands
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The chiral new aminophosphine-phosphinites (AMPP's 1-7) have been synthesised and applied successfully in the enantioselective hydrogenation of dihydro-4,4-dimethyl-2,3-furandione 8, N-benzylbenzoylformamide 9, and ethylpyruvate 10 providing the hydroxy products in up to 97, 95, and 80% ee, respectively.
- Pasquier, Corinne,Eilers, Jürgen,Reiners, Iris,Martens, Jürgen,Mortreux, André,Agbossou, Francine
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p. 1162 - 1164
(2007/10/03)
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- Enantioselective hydrogenation of α- and β-functionalized ketones by Ru(II){AMPP} catalysts
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Neutral ruthenium complexes bearing aminophosphine-phosphinite ligands have been applied in the enantioselective hydrogenation of α- (5-7) and β- (8-10) functionalized ketones. The corresponding hydroxycompounds are produced with enantiomeric excesses up to 63 and 85% respectively for the two types of substrates.
- Hapiot, Frederic,Agbossou, Francine,Mortreux, Andre
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p. 2881 - 2884
(2007/10/03)
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- The anticonvulsant activities of functionalized N-benzyl 2-acetamidoacetamides. The importance of the 2-acetamido substituent
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Recent studies have demonstrated that substituted N-benzyl 2-acetamidoacetamides provide significant protection against maximal electroshock (MES)-induced seizures in mice and rats. In this study, we investigated whether the 2-acetamido moiety was necessary for anticonvulsant activity. Ten derivatives of the known anticonvulsant, N-benzyl 2-acetamido-2-phenylacetamide were prepared in which the 2-acetamido group was replaced by hydrogen, methyl, oxygen, and halogen substituents. Evaluation of these compounds in the MES-induced seizure test demonstrated that both the hydroxy and the methoxy compounds provided full protection against MES-induced seizures in mice given ip at 100 mg/g. Moreover, evaluation of the individual stereoisomers for the hydroxy compound showed that the principal activity resided in the (R)-isomer. These findings demonstrated that the 2-acetamido substituent is important but not obligatory for the prevention of MES-induced seizures. Further supporting evidence was provided by comparing the pharmacological activities of N-benzyl 2,3-dimethoxypropionamide with N-benzyl 2-acetamido-3-methoxypropionamide. The ED50 value for the former in the MES test was 3.0 mg/kg (ip), which compared favorably with phenobarbital (ED50=22 mg/kg), but the ED50 value for N-benzyl 2-acetamido-3-methoxypropionamide was 8.3 mg/kg.
- Choi, Daeock,Stables, James P.,Kohn, Harold
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p. 2105 - 2114
(2007/10/03)
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- Rhodium(I) bis(aminophosphane) complexes as catalysts for asymmetric hydrogenation of activated ketones
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The synthesis of new homochiral bis(aminophosphanes) (BAMP) 1-5 and their application in rhodium based asymmetric hydrogenation of dihydro-4,4-dimethyl-2,3-furandione 12 and N-benzylbenzoylformamide 14 are presented. Under mild conditions, the hydrogenations led to high enantiomeric excesses (up to 87% and 75% ere respectively for both substrates).
- Roucoux, Alain,Suisse, Isabelle,Devocelle, Marc,Carpentier, Jean-Francois,Agbossou, Francine,Mortreux, Andre
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p. 379 - 382
(2007/10/03)
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- Catalytic asymmetric hydrogenation of activated keto compounds by some homogeneous and silica-supported di(μ-carboxylato)bis(aminophosphinephosphinite)dirhodium complexes
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New soluble and silica-supported rhodium complexes have been synthesized and tested as catalyst precursors for the enantioselective hydrogenation of α-ketoesters and an α-ketoamide. The homogeneous catalysts have been found to be efficient in terms of activity and asymmetric induction (up to 94% enantiomeric excess). On the other hand, the heterogenized systems exhibited lower performances and were gradually deactivated.
- Carpentier,Agbossou,Mortreux
-
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- BICHEP-Ru complexes, highly efficient catalysts for asymmetric hydrogenation of carbonyl compounds
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Newly prepared [RuX(p-cymene)(bichep)]X (X = I, Cl) and Ru(OAc)2(bichep) (bichep = 2,2'-bis(dicyclohexylphosphino)-6,6'-dimethyl-1,1'-biphenyl) proved to be highly efficient catalysts for asymmetric hydrogenation of carbonyl compounds bearing phenylglyoxyloyl group under mild conditions.
- Chiba,Miyashita,Nohira,Takaya
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p. 2351 - 2354
(2007/10/02)
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- New alkylarylamidophosphinephosphinites as chiral diphosphines for asymmetric hydrogenation of activated keto compounds
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Syntheses of new easily accessible chiral alkylarylamidophosphinephosphinite chelating ligands are described. Their rhodium complexes [Rh(L2*)Cl]2 are highly effective precursors for the catalytic asymmetric hydrogenation of functionalized ketones. Ketopantoyllactone and N-benzylphenyl glyoxamide are converted to the corresponding alcohols up to 96 and 79.6% ee respectively.
- Roucoux,Agbossou,Mortreux,Petit
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p. 2279 - 2282
(2007/10/02)
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- Synthesis of chiral Rh-bichep complexes, highly efficient catalysts for asymmetric hydrogenations
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Chiral cationic and neutral Rh complexes RhX(bichep)(nbd) (X=Cl,ClO4; NBD=norbornadiene;bichep=2,2′-bis(dicyclohexylphosphino)-6,6'-dimethyl-l, r-biphenyl) are highly active and excellent catalysts for enantioselective hydrogenation of prochiral olefms and ketones under mild reaction conditions.
- Chiba, Takeshi,Miyashita, Akira,Nohira, Hiroyuki,Takaya, Hidemasa
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p. 4745 - 4748
(2007/10/02)
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- New Chiral Mixed AMPP Ligands and their Use in Asymmetric Hydrogenation of Activated Ketones on Rhodium Catalysts
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Chiral bidentate aminophosphinephosphinites (AMPP) ligands bearing different substituents at the aminophosphine and the phosphinite moieties are prepared in a one pot synthesis from aminoalcohols.Their use in asymmetric hydrogenation of activated ketones is described.Upon analysis of these results, it is suggested that the phosphinamido group governs both the activity and the enantioselectivity of this reaction.
- Hatat, Corinne,Kokel, Nicolas,Mortreux, Andre,Petit, Francis
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p. 4139 - 4142
(2007/10/02)
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- Asymmetric Reduction of Functionalized Ketones with a Sodium Borohydride-(L)-Tartaric Acid System
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The sodium borohydride-(L)-tartaric acid system is effective for the asymmetric reduction of prochiral ketones if they are functionalized on the α- or β-carbon with a group that can chelate to the chirally modified borohydride.
- Yatagai, Masanobu,Ohnuki, Takashi
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p. 1826 - 1828
(2007/10/02)
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- ASYMMETRIC HYDROGENATION OF ACTIVATED KETO COMPOUNDS CATALYZED BY NEW CHIRAL PERALKYL-AMPP RHODIUM COMPLEXES
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Readily available peralkyl aminophosphinephosphinite ligands (alkyl-AMPP) give neutral rhodium complexes active for the catalytic reduction of some activated ketones under atmospheric hydrogen pressure at ambient temperature (ee=80percent).
- Hatat, Corinne,Karim, Abdallah,Kokel, Nicolas,Mortreux, Andre,Petit, Francis
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p. 3675 - 3678
(2007/10/02)
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- NEW ENTRY TO THE PREPARATION OF CHIRAL BIS(DICYCLOHEXYLPHOSPHINO)ALKANE DERIVATIVES. USE FOR RHODIUM-CATALYZED HYDROGENATION OF CARBONYL COMPOUNDS
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Conversion has been achieved of two representative chiral diphosphines, (-)-DIOP and (S,S)-Chiraphos, into the corresponding bis(dicyclohexylphosphino)alkane derivatives, the latter being used for chiral ligands of the rhodium(I) catalyst in the homogeneous hydrogenation of prochiral carbonyl compounds.
- Yamamoto, Keiji,Saeed-Ur-Rehman
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p. 1603 - 1606
(2007/10/02)
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