- Mechanistically Guided One Pot Synthesis of Phosphine-Phosphite and Its Implication in Asymmetric Hydrogenation
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Although hybrid bidentate ligands are known to yield highly enantioselective products in asymmetric hydrogenation (AH), synthesis of these ligands is an arduous process. Herein, a one pot, atom-economic synthesis of a hybrid phosphine-phosphite (L1) is reported. After understanding the reactivity difference between an O-nucleophile versus C-nucleophile, one pot synthesis of Senphos (L1) was achieved (72 %). When L1 was treated with [Rh], 31P NMR revealed bidentate coordination to Rh. Senphos, in the presence of rhodium, catalyzes the AH of Methyl-2-acetamido-3-phenylacrylate and discloses an unprecedented turn over frequency of 2289, along with excellent enantio-selectivity (92 %). The generality is demonstrated by hydrogenating an array of alkenes. The AH operates under mild conditions of 1–2 bar H2 pressure, at room temperature. The practical relevance of L1 is demonstrated by scaling-up the reaction to 1 g and by synthesizing DOPA, a drug widely employed for the treatment of Parkinson's disease. Computational insights indicate that the R isomer is preferred by 3.8 kcal/mol over the S isomer.
- Sen, Anirban,Kumar, Rohit,Pandey, Swechchha,Vipin Raj,Kumar, Pawan,Vanka, Kumar,Chikkali, Samir H.
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supporting information
(2022/01/11)
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- Concise synthesis and applications of enantiopure spirobiphenoxasilin-diol and its related chiral ligands
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The development of chiral architectures for chiral ligand and catalyst discovery is essential for asymmetric catalysis. Herein, we report the concise synthesis of a Si-centered spirocyclic skeleton, spirobiphenoxasilin-diol (SPOSiOL), and its derived chiral ligands. Using the chemical resolution method, the optical SPOSiOL could be obtained in high yield on a gram scale. Preliminary studies indicated that this ligand scaffold has great potential in transition metal-catalyzed asymmetric reactions. This finding further highlights that the Si-centered spirocyclic scaffolds are of great value in asymmetric catalysis. This journal is
- Liu, Tao,Wang, Biqin,Wang, Peng,Wu, Yichen,Xu, Wen-Qiang,Yang, Lei
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supporting information
p. 13365 - 13368
(2021/12/17)
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- Diaza-Crown Ether-Bridged Chiral Diphosphoramidite Ligands: Synthesis and Applications in Asymmetric Catalysis
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A small library of diaza-crown ether-bridged chiral diphosphoramidite ligands was prepared. In the rhodium-catalyzed asymmetric hydrogenation and hydroformylation reactions, these ligands exhibited distinct properties in catalytic activity and/or enantioselectivity. Hydrogenated products with opposite absolute configurations could be obtained in high yields with excellent ee values by utilizing (S,S)-L1 and (S,S)-L3, respectively. Meanwhile, the addition of alkali metal cations caused variations in catalytic outcomes, showing the supramolecular tunability of these Rh/diphosphoramidite catalytic systems.
- Luo, Yier,Ouyang, Guanghui,Tang, Yuping,He, Yan-Mei,Fan, Qing-Hua
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p. 8176 - 8184
(2020/07/15)
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- Development of robust heterogeneous chiral rhodium catalysts utilizing acid?base and electrostatic interactions for efficient continuous-flow asymmetric hydrogenations
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Heterogeneous chiral Rh catalysts based on acid?base and electrostatic interactions have been developed. The robust catalysts demonstrate high activity and selectivity in the continuous-flow asymmetric hydrogenation of a wide variety of enamides and dehyd
- Saito, Yuki,Kobayashi, Shu
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supporting information
p. 16546 - 16551
(2020/11/09)
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- Asymmetric Synthesis of Chiral Spiroketal Bisphosphine Ligands and Their Application in Enantioselective Olefin Hydrogenation
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A series of chiral spiroketal bisphosphine ligands containing 1,1′-spirobi(3H,3′H)isobenzofuran backbones was accessed through asymmetric synthesis and subsequently tested in enantioselective Rh-catalyzed hydrogenation of α-dehydroamino acid esters. The l
- Huang, Jian,Hong, Mao,Wang, Chuan-Chuan,Kramer, S?ren,Lin, Guo-Qiang,Sun, Xing-Wen
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p. 12838 - 12846
(2018/10/15)
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- Catalytic Arylhydroxylation of Dehydroalanine in Continuous Flow for Simple Access to Unnatural Amino Acids
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This report discloses the first example of catalytic arylhydroxylation of dehydroalanine with aryldiazonium salts. Aryldiazonium salts, which are generated from aniline precursors under partially aqueous conditions in continuous flow, efficiently reacted with dehydroalanine in the presence of 10–15 mol % ferrocene to furnish α-hydroxyarylalanine derivatives (up to 82 % yield). The reactions proceeded with regioselectivity, broad functional group tolerance, and without polymerization of the dehydroalanine. Furthermore, the products were used to access α-unnatural amino acids, important targets with application in drug development.
- Khan, R. Kashif M.,Zhao, Yang,Scully, Tal D.,Buchwald, Stephen L.
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supporting information
p. 15215 - 15218
(2018/09/25)
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- Site- and Stereoselective Chemical Editing of Thiostrepton by Rh-Catalyzed Conjugate Arylation: New Analogues and Collateral Enantioselective Synthesis of Amino Acids
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The synthesis of complex, biologically active molecules by catalyst-controlled, selective functionalization of complex molecules is an emerging capability. We describe the application of Rh-catalyzed conjugate arylation to the modification of thiostrepton, a complex molecule with potent antibacterial properties for which few analogues are known. By this approach, we achieve the site- and stereoselective functionalization of one subterminal dehydroalanine residue (Dha16) present in thiostrepton. The broad scope of this method enabled the preparation and isolation of 24 new analogues of thiostrepton, the biological testing of which revealed that the antimicrobial activity of thiostrepton tolerates the alteration of Dha16 to a range of amino acids. Further analysis of this Rh-catalyzed process revealed that use of sodium or potassium salts was crucial for achieving high stereoselectivity. The catalyst system was studied further by application to the synthesis of amino esters and amides from dehydroalanine monomers, a process which was found to occur with up to 93:7 er under conditions milder than those previously reported for analogous reactions. Furthermore, the addition of the same sodium and potassium salts as applied in the case of thiostrepton leads to a nearly full reversal of the enantioselectivity of the reaction. As such, this study of site-selective catalysis in a complex molecular setting also delivered synergistic insights in the arena of enantioselective catalysis. In addition, these studies greatly expand the number of known thiostrepton analogues obtained by any method and reveal a high level of functional group tolerance for metal-catalyzed, site-selective modifications of highly complex natural products.
- Key, Hanna M.,Miller, Scott J.
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supporting information
p. 15460 - 15466
(2017/11/06)
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- Temperature-controlled bidirectional enantioselectivity in a dynamic catalyst for asymmetric hydrogenation
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Asymmetric catalysis using enantiomerically pure catalysts is one of the most widely used methods for the preparation of enantiomerically pure compounds. The separate synthesis of both enantiomerically pure compounds requires tedious and time-consuming pr
- Storch, Golo,Trapp, Oliver
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supporting information
p. 3580 - 3586
(2015/03/18)
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- Chiral diphosphites derived from (1R,2R)-trans-1,2-cyclohexanediol: A new class of ligands for asymmetric hydrogenations
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A series of novel chiral diphosphite ligands was easily prepared in a few steps from commercial (1R,2R)-trans-1,2-cyclohexanediol as the chiral source, and successfully employed in the Rh-catalyzed asymmetric hydrogenation of α,β-unsaturated carboxylic ac
- Pang, Zeng-Bo,Li, Hai-Feng,Tian, Mi,Wang, Lai-Lai
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p. 1389 - 1393
(2015/12/09)
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- Systematic methodology for the development of biocatalytic hydrogen-borrowing cascades: Application to the synthesis of chiral α-substituted carboxylic acids from α-substituted α,β-unsaturated aldehydes
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Ene-reductases (ERs) are flavin dependent enzymes that catalyze the asymmetric reduction of activated carbon-carbon double bonds. In particular, α,β-unsaturated carbonyl compounds (e.g. enals and enones) as well as nitroalkenes are rapidly reduced. Conversely, α,β-unsaturated esters are poorly accepted substrates whereas free carboxylic acids are not converted at all. The only exceptions are α,β-unsaturated diacids, diesters as well as esters bearing an electron-withdrawing group in α- or β-position. Here, we present an alternative approach that has a general applicability for directly obtaining diverse chiral α-substituted carboxylic acids. This approach combines two enzyme classes, namely ERs and aldehyde dehydrogenases (Ald-DHs), in a concurrent reductive-oxidative biocatalytic cascade. This strategy has several advantages as the starting material is an α-substituted α,β-unsaturated aldehyde, a class of compounds extremely reactive for the reduction of the alkene moiety. Furthermore no external hydride source from a sacrificial substrate (e.g. glucose, formate) is required since the hydride for the first reductive step is liberated in the second oxidative step. Such a process is defined as a hydrogen-borrowing cascade. This methodology has wide applicability as it was successfully applied to the synthesis of chiral substituted hydrocinnamic acids, aliphatic acids, heterocycles and even acetylated amino acids with elevated yield, chemo- and stereo-selectivity. A systematic methodology for optimizing the hydrogen-borrowing two-enzyme synthesis of α-chiral substituted carboxylic acids was developed. This systematic methodology has general applicability for the development of diverse hydrogen-borrowing processes that possess the highest atom efficiency and the lowest environmental impact. This journal is
- Knaus, Tanja,Mutti, Francesco G.,Humphreys, Luke D.,Turner, Nicholas J.,Scrutton, Nigel S.
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supporting information
p. 223 - 233
(2015/02/19)
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- RHODIUM CATALYST AND METHOD FOR MANUFACTURING OPTICALLY ACTIVE COMPOUND USING THE SAME
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PROBLEM TO BE SOLVED: To provide a new rhodium complex stable in the air, easy in handling and using an inexpensive optically active H-phosphinate HP(O)R(OR') as a ligand, and a method for asymmetrically hydrogenating olefins efficiently using the same. SOLUTION: The rhodium complex compound has a structure represented by the following general formula (I). (Where in the formula (I), R1 and R2 are carbon substituents which may be the same or different, and two olefins coordinated in Rh may combine with each other as shown by a dotted line to form a ring structure.) COPYRIGHT: (C)2015,JPOandINPIT
- -
-
Paragraph 0024; 0025; 0026
(2017/01/05)
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- Asymmetric chemoenzymatic synthesis of N-acetyl-α-amino esters based on lipase-catalyzed kinetic resolutions through interesterification reactions
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Several phenylalanine analogs have been synthesized through a four-step route starting from easily available ethyl acetamidocyanoacetate. In a first reaction, and making use of phase transfer catalysts, this compound reacted with several alkyl halides, being benzyltributylammonium chloride identified as the best one for the production of a series of quaternary amino acids in moderate to excellent yields (52-95%). Then, the corresponding N-acetyl-phenylalanine methyl and allyl ester derivatives were obtained through acidic hydrolysis, esterification, and N-acetylation. Rhizomucor miehei lipase was found as a versatile enzyme for the resolution of these amino esters, finding the best results through interesterification reactions with butyl butyrate in acetonitrile. A great influence in the stereoselectivity was found depending on the chemical structure of the compound, achieving for the non- or para-substituted in the phenyl ring excellent stereoselectivities, being moderate for the meta-nitro derivative, while the ortho-nitro amino ester did not react.
- Da Silva, Marcos Reinaldo,De Mattos, Marcos Carlos,De Oliveira, Maria Da Concei??o Ferreira,De Lemos, Telma Leda Gomes,Ricardo, Nágila Maria Pontes Silva,De Gonzalo, Gonzalo,Lavandera, Iván,Gotor-Fernández, Vicente,Gotor, Vicente
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p. 2264 - 2271
(2014/03/21)
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- Efficient asymmetric hydrogenation of α-acetamidocinnamates through a simple, readily available monodentate chiral H-phosphinate
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An air-stable, simple (RP)-mentylbenzylphosphinate, readily available in large quantities, can efficiently induce the rhodium-catalyzed asymmetric hydrogenation of α-acetamidocinnamates with high enantioselectivity (up to 99.6 % ee). Intramolecular hydrogen bonding plays an important role in this asymmetric induction.
- Wang, Xiang-Bo,Goto, Midori,Han, Li-Biao
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supporting information
p. 3631 - 3635
(2014/04/03)
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- Phosphane-phosphite chelators built on a α-cyclodextrin scaffold: Application in rh-catalysed asymmetric hydrogenation and hydroformylation
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Four hybrid phosphane-phosphite ligands were synthesised by regioselective A,B-functionalisation of a methylated α-cyclodextrin (α-CD) scaffold. In all these ligands the phosphite part comprises a 2,2′-bisaryloxyphosphanyloxy group. The ligands, which dis
- Jouffroy, Matthieu,Semeril, David,Armspach, Dominique,Matt, Dominique
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p. 6069 - 6077
(2013/09/24)
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- Practical enantioselective hydrogenation of α-aryl- and α-carboxyamidoethylenes by rhodium(I)-{1,2-bis[(o-tert-butoxyphenyl) (phenyl)phosphino]ethane}
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The rhodium(I)-{1,2-bis[(o-tert-butoxyphenyl)(phenyl)phosphino]ethane} [Rh(I)-(t-Bu-SMS-Phos)] catalyst system displayed prime efficiency in the hydrogenation of large series of aamidostyrenes and a-amidoacrylates. Up to >99.9% enantiomeric excesses coupl
- Mohar, Barbara,Stephan, Michel
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p. 594 - 600
(2013/05/09)
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- Chemoenzymatic synthesis of a mixed phosphine-phosphine oxide catalyst and its application to asymmetric allylation of aldehydes and hydrogenation of alkenes
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The chemoenzymatic synthesis of a Lewis basic phosphine-phosphine oxide organocatalyst from a cis-dihydrodiol metabolite of bromobenzene proceeds via a palladium-catalysed carbon-phosphorus bond coupling and a novel room temperature Arbuzov [2,3]-sigmatropic rearrangement of an allylic diphenylphosphinite. Allylation of aromatic aldehydes were catalysed by the Lewis basic organocatalyst giving homoallylic alcohols in up to 57% ee. This compound also functioned as a ligand for rhodium-catalysed asymmetric hydrogenation of acetamidoacrylate giving reduction products with ee values of up to 84%.
- Boyd, Derek R.,Bell, Mark,Dunne, Katherine S.,Kelly, Brian,Stevenson, Paul J.,Malone, John F.,Allen, Christopher C. R.
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experimental part
p. 1388 - 1395
(2012/03/27)
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- The use of a new carboranylamidophosphite ligand in the asymmetric Rh-catalyzed hydrogenation of α- And β-dehydroamino acid derivatives
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New chiral carboranylamidophosphite ligand was synthesized and tested in the Rh-catalyzed asymmetric hydrogenation of α- and β-dehydroamino acid derivatives (up to 93% ee). The catalytic performance is affected greatly by temperature and the nature of sol
- Lyubimov, Sergey E.,Rastorguev, Eugenie A.,Verbitskaya, Tatiana A.,Petrovskii, Pavel V.,Hey-Hawkins, Evamarie,Kalinin, Valery N.,Davankov, Vadim A.
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experimental part
p. 1258 - 1261
(2011/06/18)
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- Readily available and recoverable chiral ionic phosphite ligands for the highly enantioselective hydrogenation of functionalized olefins
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A series of novel ionic phosphite ligands bearing carbohydrate groups were conveniently synthesized and successfully applied in the asymmetric hydrogenation of enamides, α-dehydroamino acid esters, and dimethyl itaconate. High efficiency and excellent reu
- Zhao, Yingwei,Huang, Hanmin,Shao, Jianping,Xia, Chungu
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experimental part
p. 769 - 774
(2011/08/06)
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- The use of new carboranylphosphite ligands in the asymmetric Rh-catalyzed hydrogenation
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A series of new monodentate phosphite ligands based on carboranes have been synthesized and used for asymmetric Rh-catalyzed hydrogenation of prochiral olefins in CH2Cl2 with the result of up to 99.5% ee. High reactivities (100% conv
- Lyubimov, Sergey E.,Kuchurov, Ilya V.,Tyutyunov, Andrey A.,Petrovskii, Pavel V.,Kalinin, Valery N.,Zlotin, Sergei G.,Davankov, Vadim A.,Hey-Hawkins, Evamarie
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experimental part
p. 419 - 421
(2010/11/21)
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- Asymmetric hydrogenation with the use of chiral carborane amidophosphite derivatives in supercritical carbon dioxide and CH2Cl2
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New chiral carborane-containing amidophosphites containing the BINOL fragment (BINOL stands for 2,2′-dihydroxy-1,1′-binaphthyl) have been synthesized. The study of efficiency of these compounds as ligands in the Rh-catalyzed asymmetric hydrogenation of en
- Lyubimov,Ol'shevskaya,Petrovskii,Rastorguev,Verbitskaya,Kalinin,Davankov
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experimental part
p. 1836 - 1839
(2011/05/07)
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- Enantioselective hydrogenation of α-dehydroamino acid esters catalyzed by rhodium complexes with chiral bisaminophosphine ligands
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A highly efficient strategy for the synthesis of a series of chiral bisaminophosphine ligands was well established with several remarkable features. The synthetic utility of these ligands was explored for rhodium-catalyzed asymmetric hydrogenations of α-d
- Sun, Xianfeng,Li, Wei,Zhou, Le,Zhang, Xumu
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supporting information; experimental part
p. 1150 - 1154
(2010/06/20)
-
- Design and synthesis of a novel three-hindered quadrant bisphosphine ligand and its application in asymmetric hydrogenation
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A novel three hindered quadrant bisphosphine ligand has been synthesized. The ligand shows excellent enantioselectivities and reactivities for rhodium-catalyzed hydrogenations of various functionalized olefins.
- Huang, Kexuan,Zhang, Xiaowei,Emge, Thomas J.,Hou, Guohua,Cao, Bonan,Zhang, Xumu
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supporting information; experimental part
p. 8555 - 8557
(2011/01/03)
-
- Axial [6,6′-(2,4-pentadioxy)]-1,1′-biphenyl-2,2′-diamine (PD-BIPHAM): practical synthesis and applications in asymmetric hydrogenation
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A rapid, reliable, and atom-economical procedure for the novel axially biphenyl diamine, (R,R,Sax)-PD-BIPHAM 1, has been developed successfully by using highly efficient central-to-axial transformation strategy. The attractive feature of this m
- Wang, Chun-Jiang,Xu, Zhong-Ping,Wang, Xiang,Teng, Huai-Long
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experimental part
p. 3702 - 3706
(2010/07/05)
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- Modular synthesis of the ClickFerrophos ligand family and their use in rhodium- and ruthenium-catalyzed asymmetric hydrogenation
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A series of diphosphine ClickFerrophos ligands (CF), based on a triazoleferrocene backbone, was synthesized in a four-step sequence via click chemistry methodology. In addition to the four previously synthesized ligands CF1, CF4, CF7 and CF10, six novel C
- Oki, Hiroshi,Oura, Ichiro,Nakamura, Tatsuhito,Ogata, Kenichi,Fukuzawa, Shin-ichi
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experimental part
p. 2185 - 2191
(2010/03/03)
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- Supramolecular chiral dendritic monophosphites assembled by hydrogen bonding and their use in the Rh-catalyzed asymmetric hydrogenation
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A new type of supramolecular chiral dendritic monophosphite ligands has been prepared via a hydrogen-bonding assembly. The Rh complexes of these supramolecular ligands have been successfully applied in the asymmetric hydrogenation of enamides and dehydroa
- Li, Yong,He, Yan-Mei,Li, Zhi-Wei,Zhang, Feng,Fan, Qing-Hua
-
experimental part
p. 1890 - 1895
(2009/06/28)
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- Synthesis of atropisomeric 5,5′-linked biphenyl bisaminophosphine ligands and their applications in asymmetric catalysis
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Atropisomeric 5,5′-linked biphenyl bisaminophosphine ligands 2 has been synthesized. The axial chirality of this type of ligands can be retained by macro-ring strain produced from 5,5′-linkage of biphenyl even without 6,6′-substituents on biphenyls. The Rh complex of bisaminophosphine 2a as a catalyst is effectively working in the asymmetric hydrogenation of methyl (Z)-2-acetamido-3-arylacrylates, however, for hydrogenation of arylenamide, the low enantioselectivity was observed. When the ligands applied to Pd-catalyzed allylic alkylation, it is found that ligand 2b having a longer backbone linkage is a better ligand for enantioselection in the reaction.
- Zhang, Yong Jian,Wei, Hao,Zhang, Wanbin
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experimental part
p. 1281 - 1286
(2009/04/18)
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- A chiral bidentate phosphoramidite (Me-BIPAM) for Rh-catalyzed asymmetric hydrogenation of α-dehydroamino esters, enamides, and dimethyl itaconate
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High performance of Me-BIPAM for enantioselective hydrogenation of α-dehydroamino esters, enamides, and dimethyl itaconate was demonstrated. [Rh(Me-BIPAM)(diene)]X (diene = cod, nbd; X = BF4, PF6, SbF6) gave optically active β-aryl α-amino esters up to 99% ee, 1-arylethylamines up to 97% ee, methyl 2-acetylaminobutanoate with 90% ee, and dimethyl 2-methylsuccinate with 97% ee under 0.3-0.8 MPa dihydrogen with 0.1-1 mol % catalyst loading.
- Kurihara, Kazunori,Yamamoto, Yasunori,Miyaura, Norio
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experimental part
p. 3158 - 3160
(2009/08/09)
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- Supramolecular chiral phosphorous ligands based on a [2]pseudorotaxane complex for asymmetric hydrogenation
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A new type of supramolecular chiral phosphorus-based ligands was prepared from easily available monodentate ligands through complexation between dibenzylammonium salt and dibenzo[24]crown-8 macrocycle. Rhodium complexes with these supramolecular ligands w
- Li, Yong,Feng, Yu,He, Yan-Mei,Chen, Fei,Pan, Jie,Fan, Qing-Hua
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p. 2878 - 2881
(2008/09/21)
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- Novel atropisomeric aminophosphine ligands with a bridge across the 5,5′-position of biphenyl for Rh(I)-catalyzed asymmetric hydrogenation
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A new type of atropisomeric bisaminophosphine ligands 2 with a bridge across the 5,5′-position of biphenyl has been developed. The axial chirality of this type of ligands can be retained by macro-ring strain produced from 5,5′-linkage of biphenyl even wit
- Wei, Hao,Zhang, Yong Jian,Dai, Yijun,Zhang, Jiaming,Zhang, Wanbin
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p. 4106 - 4109
(2008/09/21)
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- Bidentates versus monodentates in asymmetric hydrogenation catalysis: Synergic effects on rate and allosteric effects on enantioselectivity
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C1-Symmetric phosphino/phosphonite ligands are prepared by the reactions of Ph2P(CH2)2P(NMe2) 2 with (S)-1,1′-bi-2-naphthol (to give LA) or (S)-10, 10′-bi-9-phenanthrol (to give LB). Racemic 10,10′-bi-9-phenanthrol is synthesized in three steps from phenanthrene in 44% overall yield. The complexes [PdCl2(LA,B)] (1a,b), [PtCl2(LA,B)] (2a,b), [Rh(cod)(LA,B)]BF 4 (3a,b) and [Rh(LA,B)2]BF4 (4a,b) are reported and the crystal structure of 1a has been determined. A 31P NMR study shows that M, a 1:1 mixture of the monodentates, PMePh2 and methyl monophosphonite L1a (based on (S)-1,1′-bi-2-naphthol), reacts with 1 equiv of [Rh(cod) 2]BF4 to give the heteroligand complex [Rh(cod)(PMePh 2)(L1a)]BF4 (5) and homoligand complexes [Rh(cod)(PMePh2)2]BF4 (6) and [Rh(cod)(L 1a)2]BF4 (7) in the ratio 2:1:1. The same mixture of 5-7 is obtained upon mixing the isolated homoligand complexes 6 and 7 although the equilibrium is only established rapidly in the presence of an excess of PMePh2. The predominant species 5 is a monodentate ligand complex analogue of the chelate 3a. When the mixture of 5-7 is exposed to 5 atm H2 for 1 h (the conditions used for catalyst preactivation in the asymmetric hydrogenation studies), the products are identified as the solvento species [Rh(PMePh2)(L1a)(S)2]BF4 (5′), [Rh(S)2(PMePh2)2]BF4 (6′) and [Rh(S)2(L1a)2]BF4 (7′) and are formed in the same 2:1:1 ratio. The reaction of M with 0.5 equiv of [Rh(cod)2]BF4 gives exclusively the heteroligand complex cis-[Rh(PMePh2)2(L1a) 2]BF4 (8), an analogue of 4a. The asymmetric hydrogenation of dehydroamino acid derivatives catalyzed by 3a,b is reported, and the enantioselectivities are compared with those obtained with (a) chelate catalysts derived from analogous diphosphonite ligands L2a and L2b, (b) catalysts based on methyl monophosphonites L1a and L 1b, and (c) catalysts derived from mixture M. For the cinnamate and acrylate substrates studied, the catalysts derived from the phosphino/ phosphonite bidentates LA,B generally give superior enantioselectivities to the analogous diphosphonites L2a and L 2b; these results are rationalized in terms of δ/λ- chelate conformations and allosteric effects of the substrates. The rate of hydrogenation of acrylate substrate A with heterochelate 3a is significantly faster than with the homochelate analogues [Rh(L2a)(COd)]BF 4 and [Rh(dppe)(cod)]BF4. A synergic effect on the rate is also observed with the monodentate analogues: the rate of hydrogenation with the mixture containing predominantly heteroligand complex 5 is faster than with the monophosphine complex 6 or monophosphonite complex 7. Thus the hydrogenation catalysis carried out with M and [Rh(cod)2]BF4 is controlled by the dominant and most efficient heteroligand complex 5. In this study, the heterodiphos chelate 3a is shown to be more efficient and gives the opposite sense of optical induction to the heteromonophos analogue 5.
- Norman, David W.,Carraz, Charles A.,Hyett, David J.,Pringle, Paul G.,Sweeney, Joseph B.,Orpen, A. Guy,Phetmung, Hirrahataya,Wingad, Richard L.
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p. 6840 - 6847
(2008/12/23)
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- Novel chiral phosphine-phosphoramidite ligands derived from 1-naphthylamine for highly efficient Rh-catalyzed asymmetric hydrogenation
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A new chiral phosphine-phosphoramidite ligand (S)-HY-Phos 1 has been prepared from 1-naphthylamine via a two-step transformation, and successfully applied in the Rh-catalyzed asymmetric hydrogenation of various functionalized olefins, including α-(acetamido)cinnamates, enamides and α-enol ester phosphonates, in which up to 98% ee, 99% ee and 99% ee were achieved, respectively.
- Yu, Sai-Bo,Huang, Jia-Di,Wang, Dao-Yong,Hu, Xiang-Ping,Deng, Jun,Duan, Zheng-Chao,Zheng, Zhuo
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p. 1862 - 1866
(2008/12/21)
-
- Modular phosphine-aminophosphine ligands based on chiral 1,2,3,4-tetrahydro-1-naphthylamine backbone: A new class of practical ligands for enantioselective hydrogenations
-
A series of new chiral phosphine-aminophosphine ligands [(R)-HW-Phos] has been prepared from (R)-1,2,3,4-tetrahydro-1-naphthylamine through a two-step procedure, and successfully applied in the rhodium-catalyzed asymmetric hydrogenation of various functionalized olefins such as α-enol ester phosphonates, α-enamido phosphonates, (Z)-β-(acylamino)acrylates and so on. Excellent enantioselectivities have been achieved in the hydrogenation of most substrates tested, demonstrating the high potential of these newly developed phosphine-aminophosphine ligands in asymmetric catalysis. The present research also discloses that these newly developed phosphine-aminophosphine ligands are more efficient than that derived from (S)-1-phenylethylamine, suggesting that the increased rigidity conferred by a cyclohexyl fragment in these phosphine-aminophosphine ligands has a positive effect in the asymmetric induction.
- Qiu, Min,Hu, Xiang-Ping,Huang, Jia-Di,Wang, Dao-Yong,Deng, Jun,Yu, Sai-Bo,Duan, Zheng-Chao,Zheng, Zhuo
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experimental part
p. 2683 - 2689
(2009/10/14)
-
- CHIRAL PHOSPHORUS COMPOUNDS
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The present invention provides P-chiral compounds of general formula (II) and (III): wherein at least one of R21, R25, R26 and R30 is independently selected from C1-4 alkyl, CF3, C1-4 alkoxy, phenyl and benzyloxy and the remaining substituents selected from R21, R25, R26 and R30 are hydrogen; at least one of R22, R24, R27 and R29 are independently selected from C1-4 alkyl, CF3, C1-4 alkoxy, phenyl and benzyloxy and the remaining substituents selected from R22, R24, R27 and R29 are hydrogen; and R23 and R28 are independently selected from hydrogen, C1-4 alkyl, CF3, C1-4 alkoxy, phenyl and benzyloxy; Formula (III): wherein at least one of R21, R25, R26 and R30 is independently selected from phenyl and benzyloxy and the remaining substituents selected from R21, R25, R26 and R30 are hydrogen; and R22, R23, R24, R27, R28 and R29 are independently selected from hydrogen, C1-4 alkyl, CF3, C1-4 alkoxy, phenyl and benzyloxy.wherein at least one of R21, R25, R26 and R30 is independently selected from phenyl and benzyloxy and the remaining substituents selected from R21, R25, R26 and R30 are hydrogen; and R22, R23, R24, R27, R28 and R29 are independently selected from hydrogen, C1-4 alkyl, CF3, C1-4 alkoxy, phenyl and benzyloxy.
- -
-
Page/Page column 37-39
(2008/12/04)
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- Axial 4,4′,6,6′-tetrakis-trifluoromethyl-biphenyl-2, 2′diamine (TF-BIPHAM): Resolution and applications in asymmetric hydrogenation
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(Equation Presented) The racemic TF-BIPHAM was resolved for the first time, and the effectiveness of the resolved diamine was demonstrated by highly enantioselective hydrogenation of α-aryl enamides and α-dehydroamino acid esters using readily accessible
- Wang, Chun-Jiang,Gao, Feng,Liang, Gang
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supporting information; experimental part
p. 4711 - 4714
(2009/05/31)
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- Chiral 1,2,3,4-tetrahydro-1-naphthylamine-derived phosphine-phosphoramidite ligand (THNAPhos): Application in highly enantioselective hydrogenations of functionalized C=C bonds
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We have recently reported a new chiral 1,2,3,4-tetrahydro-1-naphthylamine- derived phosphine-phosphoramidite ligand, (Rc,Ra)- THNAPhos, that is highly efficient in the rhodium-catalyzed asymmetrichydrog enation of a broad range of aenol ester phosphonates. To further demonstrate the utility of THNAPhos in asymmetric hydrogenation, in this paper, we describe its new application in the asymmetrichy drogenation of α-dehydroamino acid esters, enamides, dimethyl itaconate and α-enamido phosphonates. The results disclosed that the Rh/(Rc,Ra)-THNAPhos complex is highly effective for the enantioselective hydrogenation of these kinds of functionalized C=C olefins, affording the corresponding hydrogenation product in excellent enantioselectivities (normally over 99% ee).
- Qiu, Min,Hu, Xiang-Ping,Wang, Dao-Yong,Deng, Jun,Huang, Jia-Di,Yu, Sai-Bo,Duan, Zheng-Chao,Zheng, Zhuo
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scheme or table
p. 1413 - 1418
(2009/06/18)
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- Simply modified chiral diphosphine: Catalyst recycling via non-covalent absorption on carbon nanotubes
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A new type of recyclable chiral catalyst system was developed by absorption of pyrene-modified Pyrphos rhodium catalyst onto carbon nanotubes via π-π stacking interaction. This modified catalyst was successfully applied in the asymmetric hydrogenation of
- Xing, Liang,Xie, Jian-Hua,Chen, Yong-Sheng,Wang, Li-Xin,Zhoua, Qi-Lin
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scheme or table
p. 1013 - 1016
(2009/05/30)
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- A comparison of phosphaferrocene and phospharuthenocene ligands in Rh +-catalysed enamide hydrogenation reactions: Superior performance of the phospharuthenocene
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Enantiopure Cp*-substituted 3.4-dimethyl-5-phenylphosphametallocene- 2-methanols (M=Fe, Ru) have been prepared from the corresponding 2-carboxy-(-)-menthylphospholide anion and elaborated into 2-CH 2PPh2 phosphametallocenes (13: M =
- Carmichael, Duncan,Goldet, Gabrielle,Klankermayer, Juergen,Ricard, Louis,Seeboth, Nicolas,Stankevic, Marek
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p. 5492 - 5502
(2008/03/12)
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- Synthesis of chiral, monodentate aminophosphane and phosphoramidite ligands derived from amino acid esters: Application in Rh-catalysed asymmetric olefin hydrogenation reactions
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Six chiral monodentate ligands combining a 1,3-dioxa-2- phosphacycloheptadinaphthyl moiety [(R)- or (S)-binoP] either with a phenylalanine- or with an alanine-derived fragment were synthesised. The new phosphoramidites are all relatively air stable. Relat
- Eberhardt, Luc,Armspach, Dominique,Matt, Dominique,Toupet, Loic,Oswald, Benoit
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p. 4153 - 4161
(2008/03/14)
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- Efficient, rhodium-catalyzed hydrogenation of α-dehydroamino acid esters with chiral monodentate aminophosphanes bearing two binaphthyl groups
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All four stereoisomers of 4-{4,5-dihydro-3H-dinaphtho-[2,1-c:1′, 2′-e]azepin-4-yl)dinaphtho[2,1-d:1′,2′-f[1,3,2] dioxaphosphepine have been prepared from (R or S)-1,1′-binaphthyl-2, 2′-diyl chlorophosphite and the appropriate dinaphtho-azepine. When react
- Eberhardt, Luc,Armspach, Dominique,Matt, Dominique,Toupet, Loic,Oswald, Benoit
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p. 5395 - 5403
(2008/03/18)
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- Design and preparation of a chiral ligand based on a pseudorotaxane skeleton: Application to rhodium-catalyzed enantioselective hydrogenation of enamides
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We have prepared a novel pseudorotaxane molecule which works as a chiral bidentate ligand having a phosphine moiety in an axle and a phosphite moiety in a wheel as two coordination sites and applied it successfully to the rhodium-catalyzed enantioselectiv
- Hattori, Gaku,Hori, Tetsuharu,Miyake, Yoshihiro,Nishibayashi, Yoshiaki
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p. 12930 - 12931
(2008/04/11)
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- Efficient asymmetric hydrogenation of olefins with hydrazine-derived diphosphoramidites
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Enantiopure, BINOL-derived diphosphoramidites built upon an achiral hydrazine spacer are efficient ligands for the hydrogenation of 2-(acetylamino)-3-(aryl)-propenoic methyl esters. The activity and enantioselectivity of the hydrazine derivatives were sho
- Eberhardt, Luc,Armspach, Dominique,Matt, Dominique,Oswald, Benoit,Toupet, Loic
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p. 3340 - 3346
(2008/09/21)
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- New bidentate phosphorus ligands based on a norbornane backbone for rhodium-catalyzed asymmetric hydrogenation
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A new class of bidentate diphosphite and diphosphinite ligands has been developed from inexpensive norbornadiene. These ligands exhibited excellent enantioselectivities in the Rh(I)-catalyzed asymmetric hydrogenation of olefin derivatives (up to 99.9% ee)
- Cai, Chonglin,Deng, Fanguo,Sun, Wei,Xia, Chungu
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p. 3007 - 3010
(2008/03/12)
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- Highly enantioselective hydrogenation of α-dehydroamino esters and itaconates with triphosphorous bidentate ligands and the unprecedented solvent effect thereof
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(Chemical Equation Presented) An X-ray diffraction experiment revealed an interesting triphosphorous bidentate coordination in a Pd(II) complex of a phosphine-phosphoramidite ligand 1, which showed excellent enantioselectivity (up to 99.4% ee) in Rh-catalyzed hydrogenation of α-dehydroamino esters in acetone. A dramatic solvent effect was found in the hydrogenation of itaconates, which induces opposite chiralities of the product with the same catalytic system by the use of different solvents (e.g., 99.6% ee (R) in TFE vs 71.2% ee (S) in methyl ethyl ketone).
- Zhang, Weicheng,Zhang, Xumu
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p. 1020 - 1023
(2008/02/01)
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- High enantioselectivity is induced by a single monodentate phosphoramidite ligand in iridium-catalyzed asymmetric hydrogenation
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(Chemical Equation Presented) The Full Monty? Stripping a catalyst down to its bare essentials gives a neutral iridium complex containing only one monodentate phosphoramidite ligand that is an efficient catalyst for the enantioselective hydrogenation of α-dehydroamino acids (see picture).
- Giacomina, Francesca,Meetsma, Auke,Panella, Lavinia,Lefort, Laurent,De Vries, Andre H. M.,De Vries, Johannes G.
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p. 1497 - 1500
(2008/04/05)
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- The synthesis of spirobitetraline phosphoramidite ligands and their application in rhodium-catalyzed asymmetric hydrogenation
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A racemic 1,1′-spirobitetralin-8,8′-diol (SBITOL) was conveniently synthesized from 3-methoxybenzaldehyde in 26 % yield over 9 steps and resolved via its bis-(S)-camphorsulfonates. The corresponding chiral spirobitetraline monophosphoramidite ligands have
- Huo, Xiang-Hong,Xie, Jian-Hua,Wang, Qiu-Shi,Zhou, Qi-Lin
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p. 2477 - 2484
(2008/09/19)
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- Synthesis of a novel spiro bisphosphinite ligand and its application in Rh-catalyzed asymmetric hydrogenation
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A novel, chiral bisphosphinite ligand (R)-SpiroBIP has been synthesized. The rhodium complex of the ligand was found to be highly enantioselective in the asymmetric hydrogenation of α-dehydroamino acid derivatives.
- Guo, Zhenqiu,Guan, Xiaoyu,Chen, Zhiyong
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p. 468 - 473
(2007/10/03)
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- Unsymmetrical ferrocenylethylamine-derived monophosphoramidites: Highly efficient chiral ligands for Rh-catalyzed enantioselective hydrogenation of enamides and α-dehydroamino acid derivatives
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A new family of unsymmetrical ferrocenylethylamine-derived monophosphoramidites were synthesized and successfully applied in the Rh-catalyzed enantioselective hydrogenation of a range of enamides and α-dehydroamino acid esters, and ee values of up to 99.5% were obtained for both types of substrate. These results suggest that unsymmetrical amine-derived monophosphoramidites can also exhibit excellent enantioselectivity for a broad range of substrates, comparable to or higher than those of the most efficient symmetrical amine-derived monophosphoramidites reported thus far.
- Zeng, Qing-Heng,Hu, Xiang-Ping,Duan, Zheng-Chao,Liang, Xin-Miao,Zheng, Zhuo
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p. 393 - 396
(2007/10/03)
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- Practical by ligand design: A new class of monodentate phosphoramidite ligands for rhodium-catalyzed enantioselective hydrogenations
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A new class of low-cost and easy-to-prepare monodentate phosphoramidite ligands (Cydam-Phos) has been developed from readily accessible and cheap trans-1,2-diaminocyclohexane as starting material through a three-step transformation. This type of ligands exhibited excellent enantioseletivities and high activities in rhodium(I)-catalyzed asymmetric hydrogenations of dehydro-α-amino acid methyl esters 9 (ee: 96.2-99.8%) and acetylenamides 11 (91.8-98.8%). The remarkable substituent effects exhibited by the ligands on the enantioselective control of the catalysis are rationalized on the basis of molecular structure of the catalyst precursor.
- Zhao, Baoguo,Wang, Zheng,Ding, Kuiling
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p. 1049 - 1057
(2007/10/03)
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- Readily available phosphine-phosphoramidite ligands for highly efficient Rh-catalyzed enantioselective hydrogenations
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(Chemical Equation Presented) A new family of air- and moisture-stable phosphine-phosphoramidite ligands (PEAPhos) has been prepared from commercially available and inexpensive (S)-α-phenylethylamine through a two- or three-step transformation and success
- Huang, Jia-Di,Hu, Xiang-Ping,Duan, Zheng-Chao,Zeng, Qing-Hen,Yu, Sai-Bo,Deng, Jun,Wang, Dao-Yong,Zheng, Zhuo
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p. 4367 - 4370
(2007/10/03)
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- Dendritic MonoPhos: synthesis and application in Rh-catalyzed asymmetric hydrogenation
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A new class of dendritic monodentate phosphoramidite ligands were synthesized through substitution of the dimethylamino moiety in MonoPhos by the Frechet-type dendritic wedge and applied in the asymmetric hydrogenation of α-dehydroamino acid esters and di
- Tang, Wei-Jun,Huang, Yi-Yong,He, Yan-Mei,Fan, Qing-Hua
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p. 536 - 543
(2007/10/03)
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