- Chiral-Anion-Mediated Asymmetric Heck-Matsuda Reaction of Acyclic Alkenyl Alcohols
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Acyclic internal alkenes are a class of challenging substrates in asymmetric Heck-type reactions due to difficulties related to both reactivity and selectivity control. Employing acyclic alkenyl alcohols, an asymmetric Heck-Matsuda reaction is developed through the strategy of chiral anion phase transfer. Various chiral ketones could be obtained in high levels of enantioselectivity. A catalytic amount of dimethyl sulfoxide (DMSO) as an additive is crucial for the reaction to suppress the palladium-hydride-mediated side reactions.
- Zhang, Tao,Li, Wen-Ao,Shen, Hong-Cheng,Chen, Shu-Sen,Han, Zhi-Yong
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supporting information
p. 1473 - 1477
(2021/03/08)
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- Asymmetric Umpolung Hydrogenation and Deuteration of Alkenes Catalyzed by Nickel
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Nickel-catalyzed asymmetric hydrogenation of several types of alkenes proceeds in high enantioselectivity, using acetic acid or water as the hydrogen source and indium powder as electron donor. The scope of alkenes herein include α,β-unsaturated esters, n
- Guo, Siyu,Wang, Xiuhua,Zhou, Jianrong Steve
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supporting information
p. 1204 - 1207
(2020/02/04)
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- In Situ Generated Gold Nanoparticles on Active Carbon as Reusable Highly Efficient Catalysts for a Csp3 ?Csp3 Stille Coupling
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Gold nanoparticle catalysts are important in many industrial production processes. Nevertheless, for traditional Csp2-Csp2 cross-coupling reactions they have been rarely used and Pd catalysts usually give a superior performance. Herein we report that in situ formed gold metal nanoparticles are highly active catalysts for the cross coupling of allylstannanes and activated alkylbromides to form Csp3-Csp3 bonds. Turnover numbers up to 29 000 could be achieved in the presence of active carbon as solid support, which allowed for convenient catalyst recovery and reuse. The present study is a rare case where a gold metal catalyst is superior to Pd catalysts in a cross-coupling reaction of an organic halide and an organometallic reagent.
- Holz, Julia,Pfeffer, Camilla,Zuo, Hualiang,Beierlein, Dennis,Richter, Gunther,Klemm, Elias,Peters, René
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supporting information
p. 10330 - 10334
(2019/06/27)
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- Chiral 1,3,2-Diazaphospholenes as Catalytic Molecular Hydrides for Enantioselective Conjugate Reductions
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Secondary 1,3,2-diazaphospholenes have a polarized P?H bond and are emerging as molecular hydrides. Herein, a class of chiral, conformationally restricted methoxy-1,3,2-diazaphospholene catalysts is reported. We demonstrate their catalytic potential in asymmetric 1,4-reductions of α,β-unsaturated carbonyl derivatives, including enones, acyl pyrroles, and amides, which proceeded in enantioselectivities of up to 95.5:4.5 e.r.
- Miaskiewicz, Solène,Reed, John H.,Donets, Pavel A.,Oliveira, Caio C.,Cramer, Nicolai
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p. 4039 - 4042
(2018/03/13)
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- Highly efficient synthesis of chiral aromatic ketones: Via Rh-catalyzed asymmetric hydrogenation of β,β-disubstituted enones
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A succinct and efficient protocol was developed for the synthesis of chiral aromatic ketones via asymmetric hydrogenation of β,β-disubstituted enones with rhodium catalysts based on chiral bisphosphine thiourea ligands. A series of substrates (17 examples) was smoothly catalyzed to afford the corresponding chiral aromatic ketones in high conversions (>99%) with excellent enantioselectivities (up to 96% ee).
- Zhang, Tao,Jiang, Jun,Yao, Lin,Geng, Huiling,Zhang, Xumu
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p. 9258 - 9261
(2017/08/22)
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- PHOSPHINE-OLEFIN LIGAND HAVING FACE ASYMMETRIC CYCLOPENTADIENYL-MANGANESE COMPLEX IN BASIC SKELETON
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PROBLEM TO BE SOLVED: To provide a face asymmetric ligand for a transition metal catalyst asymmetric reaction high in yield and optical purity to not only a cyclic enone compound, but also various enone compounds containing an aliphatic enone compound. SO
- -
-
Paragraph 0135
(2017/06/27)
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- Planar-chiral phosphine-olefin ligands exploiting a (Cyclopentadienyl)manganese(I) scaffold to achieve high robustness and high enantioselectivity
-
A series of 2-methyl-1,3-propenylene-bridged (η5-diarylphosphinocyclopentadienyl)(phosphine)manganese(I) di-carbonyl complexes 2 have been developed as a new class of phosphine-olefin ligands based on a planar-chiral transition-metal scaffold,
- Kamikawa, Ken,Tsen, Ya-Yi,Jian, Jia-Hong,Takahashi, Tamotsu,Ogasawara, Masamichi
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supporting information
p. 1545 - 1553
(2017/02/10)
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- Phosphine-olefin ligands based on a planar-chiral (π-Arene)chromium scaffold: Design, synthesis, and application in asymmetric catalysis
-
The NMR and X-ray crystallographic studies clarified that planar-chiral alkenylene-bridged (phosphino-π-arene)(phosphine)chromium complexes 3 were capable of coordinating to a rhodium(I) cation in a bidentate fashion at the (π-arene)-bound phosphorus atom
- Ogasawara, Masamichi,Tseng, Ya-Yi,Arae, Sachie,Morita, Tomotaka,Nakaya, Takeshi,Wu, Wei-Yi,Takahashi, Tamotsu,Kamikawa, Ken
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supporting information
p. 9377 - 9384
(2014/07/21)
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- Chiral porous organic frameworks for asymmetric heterogeneous catalysis and gas chromatographic separation
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Three chiral robust diene-based porous organic frameworks (POFs) are prepared. POF-1 is shown to be an efficient heterogeneous catalyst after metallation for asymmetric conjugation addition with up to 93% ee, and it can also function as a new chiral stationary phase for gas chromatographic separation of racemates. This journal is
- Dong, Jinqiao,Liu, Yan,Cui, Yong
-
supporting information
p. 14949 - 14952
(2015/01/08)
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- Effect of multinuclear copper/aluminum complexes in highly asymmetric conjugate addition of trimethylaluminum to acyclic enones
-
Al and friends: Asymmetric conjugate addition of Me3Al to β,β-disubstituted α,β-unsaturated ketones in the presence copper and L1 leads to a highly efficient construction of an all-carbon-substituted chiral quaternary center. This result is the first example of an asymmetric conjugate addition of Me3Al to acyclic enones to give a chiral quaternary carbon center with excellent yield and enantioselectivity under mild reaction conditions. Copyright
- Endo, Kohei,Hamada, Daisuke,Yakeishi, Sayuri,Shibata, Takanori
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supporting information
p. 606 - 610
(2013/02/23)
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- Tropanes as scaffolds for phosphorus-olefin ligands and their application in asymmetric catalysis
-
Tropane-derived phosphorus-olefin hybrid ligands bearing various combinations of P-units (chiral BINOL-derived units/achiral PPh 2-units) with a tropene skeleton (chiral/achiral) have been synthesized and used in Cu-catalysed conjugate 1,4-addi
- Vlahovic, Sandra,Schaedel, Nicole,Tussetschlaeger, Stefan,Laschat, Sabine
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supporting information
p. 1580 - 1590
(2013/04/23)
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- Regioselective reductions of β,β-disubstituted enones catalyzed by nonracemically ligated copper hydride
-
CuH-catalyzed 1,2-additions to β,β-disubstituted α,β-unsaturated ketones have been further explored. Asymmetric reductions of enones lacking an α-substituent can be achieved with CuH complexed by DTBM-SEGPHOS in Et2O at -25 °C leading to the ge
- Voigtritter, Karl R.,Isley, Nicholas A.,Moser, Ralph,Aue, Donald H.,Lipshutz, Bruce H.
-
experimental part
p. 3410 - 3416
(2012/06/15)
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- "Sulfolefin": Highly modular mixed S/Olefin ligands for enantioselective Rh-catalyzed 1,4-addition
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Reported is a single high yielding step approximation to mixed olefin/sulfinamide ligands enclosing a chiral sulfur atom as the sole chiral center. The synthetic design is validated by a rapid optimization of the substituent at the sulfinyl sulfur, and by
- Khiar, Noureddine,Salvador, Alvaro,Chelouan, Ahmed,Alcudia, Ana,Fernandez, Inmaculada
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supporting information; experimental part
p. 2366 - 2368
(2012/04/11)
-
- (S)-Phenylalanine-derived chiral phosphorus-olefin ligands in rhodium-catalyzed asymmetric 1,4-addition reactions
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Chiral phosphorus-olefins (S)-1, (S)-4, and (S)-5 have been designed and synthesized. These ligands were all synthesized from (S)-phenylalanine derivatives and act as phosphorus-olefin bidentate ligands to rhodium. The coordination face of the olefin can
- Narui, Rintaro,Hayashi, Sayuri,Otomo, Haruka,Shintani, Ryo,Hayashi, Tamio
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experimental part
p. 284 - 293
(2012/06/16)
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- Chiral proline-based P,O and P,N ligands for iridium-catalyzed asymmetric hydrogenation
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Two new classes of proline-based P,O and P,N ligands were prepared and applied in the iridium-catalyzed asymmetric hydrogenation of alkenes. Both types of ligands induced high enantioselectivities in the hydrogenation of trisubstituted C=C bonds. Iridium complexes derived from P,O ligands bearing sterically demanding amide or urea groups at the pyrrolidine N-atom proved to be especially efficient catalysts for the conjugate reduction of α,β-unsaturated esters and ketones, whereas analogous P,N ligands led to better results with dialkyl-phenyl-substituted alkenes and an allylic alcohol as substrates.
- Rageot, Denise,Pfaltz, Andreas
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p. 2176 - 2193
(2013/02/23)
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- Recent advances in iridium-catalyzed asymmetric hydrogenation: New catalysts, substrates and applications in total synthesis
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Iridium-catalyzed asymmetric hydrogenation has emerged as a highly efficient method for the synthesis of enantiomerically pure compounds. This account summarizes our recent efforts in this field. We have developed a new type of P,O-ligand that was success
- Ganic, Adnan,Rageot, Denise,Troendlin, Lars,Pfaltz, Andreas
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scheme or table
p. 187 - 191
(2012/09/21)
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- Proline-based P,O ligand/iridium complexes as highly selective catalysts: Asymmetric hydrogenation of trisubstituted alkenes
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P,O joins the mix: P,O ligands (L1) form efficient iridium catalysts for the asymmetric hydrogenation of olefins. The proline-derived ligands lead to high enantioselectivities with several classes of alkenes, most notably with α,β-unsaturated carboxylic e
- Rageot, Denise,Woodmansee, David H.,Pugin, Benoet,Pfaltz, Andreas
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supporting information; experimental part
p. 9598 - 9601
(2011/12/05)
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- Pd-catalyzed asymmetric hydrogenation of C=C bond of α,β- unsaturated ketones
-
Homogenous palladium-catalyzed asymmetric hydrogenation of C=C double bond of ,-unsaturated ketones has been -developed by using palladium(II) trifluoroacetate/(S)-7,7-bis-[di(4-methoxyphenyl]phosphino)-1,1-spirobiindane complex [Pd(OCOCF3)2-(S)-An-SDP] as the catalyst under ambient hydrogen pressure and room temperature with up to 89% ee. Georg Thieme Verlag Stuttgart · New York.
- Wang, Duo-Sheng,Wang, Da-Wei,Zhou, Yong-Gui
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p. 947 - 950
(2011/06/17)
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- Readily accessible chiral diene ligands for Rh-catalyzed enantioselective conjugate additions of boronic acids
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Enabled by the broad scope of the Pd-catalyzed asymmetric alkylation of meso- and d,l-divinylethylene carbonate, several chiral diene ligands were prepared in two steps from commercial materials. Subsequently, these ligands were evaluated in the Rh-catalyzed asymmetric conjugate addition of boronic acids to enones.
- Trost, Barry M.,Burns, Aaron C.,Tautz, Thomas
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supporting information; experimental part
p. 4566 - 4569
(2011/10/09)
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- Enders SAMP-hydrazone as traceless auxiliary in the asymmetric 1,4-addition of cuprates to enones
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Conjugate additions of Gilman cyanocuprates to (5)-N-amino-2- (methoxymethyl)pyrrolidine (SAMP)-hydrazones 4, 5 derived from cyclic and acyclic α,β-unsaturated ketones were investigated. A protocol utilizing copper(II) sulfate/ammonium chloride was evolved, which allowed cleavage of SAMP (S)-1 under the hydrolysis and work-up conditions, followed by recovery of the auxiliary with ethylenediaminetetraacetic acid (EDTA). The enantioselectivity of cuprate additions was dominated for cyclic SAMP-hydrazones 4 by the cuprate alkyl substituent and the ring size, in the case of acyclic arylidene SAMP-hydrazones 5, however, by the nature of the aryl substituent. Electron-donating substituents gave poor enantiomeric excesses, whereas electron-withdrawing groups provided excellent ee values of 98-99%. The configuration of the new stereocenter was determined to be (R). Moreover, a reaction sequence was developed which integrates a tandem 1,4-addition/ methylation and traceless hydrolytic cleavage of the auxiliary (S)-1 in a one-pot reaction, resulting in enantiomerically pure methyl ketones 11-13, each of them with > 99% ee.
- Sammet, Karsten,Gastl, Christoph,Baro, Angelika,Laschat, Sabine,Fischer, Peter,Fettig, Ina
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supporting information; experimental part
p. 2281 - 2290
(2010/12/29)
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- Hemilabile P-alkene ligands in chiral rhodium and copper complexes: Catalytic asymmetric 1,4 additions to enones. 2
-
Two equivalents of the chiral dibenz[b,f]azepine-derived P-alkene ligands 2-6 per metal afforded mononuclear Rh(I) and Cu(I) complexes that were used as catalysts for asymmetric conjugate addition reactions. Rh formed square-planar neutral (8-10) and cati
- Dorta, Romano,Drinkel, Emma,Briceno, Alexander,Dorta, Reto
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experimental part
p. 2503 - 2514
(2010/08/04)
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- Tert-butanesulfinylphosphines: Simple chiral ligands in rhodium-catalyzed asymmetric addition of arylboronic acids to electron-deficient olefins
-
An efficient rhodium complex catalyst system was developed by using a class of simple tert-butanesulfinylphosphines as bidentate ligands, which solely bear sulfur chirality and combine the advantages of both sulfoxide and phosphine ligands. Excellent activities (in 0.5 hour, up to 99% yield) and enantioselectivities (up to 98% ee) were displayed in Rh-catalyzed asymmetric 1,4-additions under mild conditions.
- Lang, Feng,Li, Dong,Chen, Junmin,Chen, Jun,Li, Liangchun,Cun, Linfeng,Zhu, Jin,Deng, Jingen,Liao, Jian
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supporting information; experimental part
p. 843 - 846
(2010/06/15)
-
- Novel olefin-phosphorus hybrid and diene ligands derived from carbohydrates
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Starting from readily available monosaccharides d-glucose and d-arabinose, a family of novel chiral diene and olefin-phosphinite hybrid ligands has been designed. These ligands were prepared by attaching phosphinite or allylic donor sites onto unsaturated carbohydrate scaffolds. In rhodium(I)-catalysed conjugate addition of boronic acids to enones, the olefin-phosphinite hybrids gave products in up to 99% ee and above, whereas the dienes only led to modest enantioselectivity. However, by shifting the allylic donor sites from position 4 of the pyranose to the anomeric centre, an unexpected reversal of the stereoinduction process was observed. Georg Thieme Verlag Stuttgart New York.
- Grugel, Holger,Minuth, Tobias,Boysen, Mike M. K.
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experimental part
p. 3248 - 3258
(2010/11/18)
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- Iron- and cobalt-catalyzed asymmetric hydrosilylation of ketones and enones with bis(oxazolinylphenyl)amine ligands
-
Chiral bis(oxazolinylphenyl)amines proved to be efficient auxiliary ligands for iron and cobalt catalysts with high activity for asymmetric hydrosilylation of ketones and asymmetric conjugate hydrosilylation of enones.
- Inagaki, Tomohiko,Phong, Le Thanh,Furuta, Akihiro,Ito, Jun-Ichi,Nishiyama, Hisao
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supporting information; scheme or table
p. 3090 - 3096
(2010/08/05)
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- Baeyer-Villiger monooxygenase-catalyzed kinetic resolution of racemic α-alkyl benzyl ketones: enzymatic synthesis of α-alkyl benzylketones and α-alkyl benzylesters
-
The application of three BVMOs for the enantioselective oxidation of 3-phenylbutan-2-ones with different substituents in the aromatic moiety is described. By choosing the appropriate biocatalyst and substrate combination, chiral ketones and esters can be obtained with excellent enantiopurities. This methodology could also be applied to the resolution of racemic α-alkyl benzylketones with longer alkyl chains as well as with two substituted α-substituted benzylacetones. A kinetic analysis revealed that the BVMOs studied effectively convert all tested compounds showing that the enzymes are tolerant towards the substrate structure while being highly enantioselective. These properties render BVMOs as valuable biocatalysts for the preparation of compounds with high interest in organic synthesis.
- Rodriguez, Cristina,Gonzalo, Gonzalo de,Torres Pazmino, Daniel E.,Fraaije, Marco W.,Gotor, Vicente
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experimental part
p. 1168 - 1173
(2009/10/02)
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- Novel, efficient alkene-phosphinite hybrid ligand based on D-glucose
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A commercially available 2,3-unsaturated pyranoside, derived from D-glucose, was converted Into a new type of olefin phosphorus chelate ligand in only three steps. Application In rhodium catalyzed conjugate additions of phenylboronic acid to enones led to
- Minuth, Tobias,Boysen, Mike M. K.
-
supporting information; experimental part
p. 4212 - 4215
(2009/12/31)
-
- Asymmetric 1,4-addition of organoboronic acids to α,β-unsaturated ketones and 1,2-addition to aldehydes catalyzed by a palladium complex with a ferrocene-based phosphine ligand
-
A combination of palladium with ferrocene-based phosphine ligand with a carbon-bromine bond was found to be a good catalyst for the 1,4-addition of arylboronic acids to α,β-unsaturated ketones and the 1,2-addition to aldehydes. Using Pd(dba)2 and (S,Rp)-[1-(2-bromoferrocenyl)ethyl]diphenylphosphine (S,Rp)-1, 3-phenylcyclohexanone was obtained from the reaction of 2-cyclohexen-1-one with phenylboronic acid in the presence of K2CO3 in toluene at room temperature after 3 h in 92% yield with 76% ee. In the 1,2-addition of 4-methylphenylboronic acid to benzaldehyde, 96% of (4-methylphenyl)phenylmethanol was afforded after 24 h, while the enantiomeric excess was only 6%.
- Suzuma, Yoshinori,Hayashi, Shoko,Yamamoto, Tetsuya,Oe, Yohei,Ohta, Tetsuo,Ito, Yoshihiko
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experimental part
p. 2751 - 2758
(2010/04/26)
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- ORGANIC SALTS AND METHOD FOR PRODUCING CHIRAL ORGANIC COMPOUNDS
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The invention relates to a method for producing chiral organic compounds by asymmetric catalysis, using ionic catalysts comprising a chiral catalyst anion. The claimed method is suitable for reactions which are carried out over cationic intermediate stages, such as iminium ions or acyl pyridinium ions. The invention enables the production of chiral compounds with high ee values, that until now could only be obtained by means of costly purification methods.
- -
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Page/Page column 7; 8
(2009/02/11)
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- α-Alkylation of carbonyl compounds by direct addition of alcohols to Enol acetates
-
A practical α-alkylation of ketones and aldehydes has been achieved by the direct addition of alcohols to enol acetates. The moderate Lewis acidity of InI3, CaBr3, and FeBr3 is a key factor in the catalytic cycle, and many different alcohols and enol acetates have been successfully used in this procedure.
- Nishimoto, Yoshihiro,Onishi, Yoshiharu,Yasuda, Makoto,Baba, Akio
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supporting information; experimental part
p. 9131 - 9134
(2010/03/01)
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- Highly chemo- And enantioselective hydrogenation of linear α,β-unsaturated ketones
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A study was conducted to report the synthesis of sulfoximine-derived P,N-ligands and their applications in indium-catalyzed asymmetric hydrogenation reactions. Investigations were conducted using linear β,β- disubstituted 1,3-diphenyl-2-butenone as model substrate and iridium, having a ketonic phenyl group and two alkyl substituents at the olefinic β-positions. Methyl ketone with β-methyl and β-phenyl substituent was also applied in the investigations.
- Lu, Sheng-Mei,Bolm, Carsten
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supporting information; experimental part
p. 7513 - 7516
(2009/09/06)
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- Rh-catalyzed enantioselective conjugate addition of arylboronic acids with a dynamic library of chiral tropos phosphorus ligands
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A library of 19 chiral tropos phosphorus ligands, based on a free-to-rotate (tropos) biphenol unit and a chiral P-bonded alcohol (11 phosphites, 1-P(O)2O to 11-P(O)2O) or secondary amine (8 phosphoramidites, 12-P(O)2N to 19-P(O)2N). were screened, individually and in combinations of two, in the rhodium-catalyzed asymmetric conjugate addition of arylboronic acids to enones and enoates. High enantioselectivities (up to 99% ee) and excellent yields were obtained in the addition to either cyclic or acyclic substrates. The flexible biphenolic P ligands outperformed the analogous rigid binaphtholic P ligands. Variable-temperature 31P NMR studies revealed that the biphenolic ligands are tropos even at low temperature. Only below 190 K was a coalescence observed: upon further cooling, two atropisomers were detected. The Rh homocomplexes ([Rh(La)2]+) were also studied: in general, a single doublet (P-Rh coupling) was observed in the case of the biphenolic phosphite ligands, over the temperature range 380-230 K, demonstrating their tropos nature in the rhodium complexes even at low temperatures. On the other hand, the phosphoramidites showed different behaviors depending on the structure of the ligand and on the nature of the rhodium source. The spectrum at 230 K of the mixture of [Rh(acac)(eth)2] (eth = C2H4) with phosphite 6-P(O)2O and phosphoramidite 19-P(O)2N (the most enantioselective ligand combination in the conjugate addition reaction) revealed the presence of four homocomplexes (total approximately 40%: [Rh(6-P(O)2}2], [Rh{(aR)-19-P(O)2N}2], [Rh((aS)-19-P(O)2N) 2], [Rh((aR)-19-P(O)2N}((aS)-19-P(O)2N}]) and one heterocomplex, [Rh{6-P(O)2O){(aR)-19-P(O)2NJ] (approximately 60%) In the heterocomplex, the biphenol-derived phosphite is free to rotate (tropos) while the biphenol-derived phosphoramidite shows a temperature-dependent tropos/atropos behavior (coalescence temperature = 310 K).
- Monti, Chiara,Gennari, Cesare,Piarulli, Umberto
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p. 1547 - 1558
(2008/02/03)
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- Chiral bicyclo[3.3.0]octa-2,5-dienes as steering ligands in substrate-dependent rhodium-catalyzed 1,4-addition of arylboronic acids to enones
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The synthesis of disubstituted chiral diene ligands (3aR,6aR)- and (3aS,6aS)-10 with a pentalene backbone from the corresponding bicyclo[3.3.0]octa1,4-diones 7 is described. The latter were accessible by enzymatic resolution of the racemic diol rac-5 and
- Heibig, Sarah,Sauer, Sven,Cramer, Nicolai,Laschat, Sabine,Baro, Angelika,Frey, Wolfgang
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p. 2331 - 2337
(2008/09/19)
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- Asymmetric conjugate reduction of α,β-unsaturated ketones and esters with chiral rhodium(2,6-bisoxazolinylphenyl) catalysts
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New asymmetric conjugate reduction of β,β-disubstituted α,β-unsaturated ketones and esters was accomplished with alkoxylhydrosilanes in the presence of chiral rhodium(2,6-bisoxazolinylphenyl) complexes in high yields and high enantioselectivity. (E)-4-Phenyl-3-penten-2- one and (E)-4-phenyl-4-isopropyl-3-penten-2-one were readily reduced at 60°C in 95% ee and 98 % ee, respectively, by 1 mol % of catalyst loading. (EtO) 2MeSiH proved to be the best hydrogen donor of choice. tert-Butyl (E)-β-methylcinnamate and β-isopropylcinnamate could also be reduced to the corresponding dihydrocinnamate derivatives up to 98% ee.
- Kanazawa, Yoshinori,Tsuchiya, Yasunori,Kobayashi, Kazuki,Shiomi, Takushi,Itoh, Jun-Ichi,Kikuchi, Makoto,Yamamoto, Yoshihiko,Nishiyama, Hisao
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- A new entry to Pd-H chemistry: Catalytic asymmetric conjugate reduction of enones with EtOH and a highly enantioselective synthesis of warfarin
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(Chemical Equation Presented) We report here the catalytic asymmetric conjugate reduction of enones using ethanol as a hydride source. The reaction was carried out in the presence of a chiral Pd complex at ambient temperature in ethanol, and the desired products were obtained in high chemical yield and high enantioselectivity. We applied this novel reaction to the catalytic asymmetric synthesis of warfarin (96% ee), and on the basis of d-labeling experiments, the reaction mechanism is proposed.
- Tsuchiya, Yasunori,Hamashima, Yoshitaka,Sodeoka, Mikiko
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p. 4851 - 4854
(2007/10/03)
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- Copper-in-charcoal (Cu/C): Heterogeneous, copper-catalyzed asymmetric hydrosilylations
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Asymmetric copper chemistry ... done heterogeneously? It's doable: Copper-incharcoal (Cu/C) is introduced as an easily prepared catalyst that is readily converted in situ into a nonracemically ligated form of copper hydride that effects asymmetric hydrosilylations. DTBM = 3,5-di-tert-butyl-4- methoxydiphenylphosphinyl. (Figure Presented)
- Lipshutz, Bruce H.,Frieman, Bryan A.,Tomaso Jr., Anthony E.
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p. 1259 - 1264
(2007/10/03)
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- Aminohydroxyphosphine ligand for the copper-catalyzed enantioselective conjugate addition of organozinc reagents
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An alanine-derived aminohydroxyphosphine ligand was developed for copper-catalyzed asymmetric conjugate addition of organozinc reagents to α,β-unsaturated carbonyl compounds. This new tridentate ligand induces consistently high enantioselectivity in react
- Hajra, Alakananda,Yoshikai, Naohiko,Nakamura, Eiichi
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p. 4153 - 4155
(2007/10/03)
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- Highly enantioselective transfer hydrogenation of α,β- unsaturated ketones
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We describe an efficient and highly enantioselective conjugate transfer hydrogenation of α,β-unsaturated ketones that is catalyzed by a salt made from tert-butyl valinate and a recently introduced powerful chiral phosphoric acid catalyst (TRIP). Copyright
- Martin, Nolwenn J. A.,List, Benjamin
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p. 13368 - 13369
(2007/10/03)
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- Asymmetric conjugate addition of copper reagents to α,β- unsaturated tert-butanesulfinyl imines
-
(Chemical Equation Presented) Addition of organocuprates to N-sulfinyl α,β-unsaturated imines proceeds in good yields and with good diastereoselectivities. α,β-Unsaturated sulfinyl ketimines and aldimines have both been shown to be suitable substrates for this reaction.
- McMahon, Jeffrey P.,Ellman, Jonathan A.
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p. 5393 - 5396
(2007/10/03)
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- Rhodium/diene-catalyzed asymmetric 1,4-addition of arylboronic acids to α,β-unsaturated Weinreb amides
-
Rhodium/chiral diene (S,S)-3b complex has been found to effectively catalyze the 1,4-addition of arylboronic acids to α,β-unsaturated Weinreb amides, furnishing useful β-chiral Weinreb amides in high enantioselectivity. The Royal Society of Chemistry 2005.
- Shintani, Ryo,Kimura, Takahiro,Hayashi, Tamio
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p. 3213 - 3214
(2007/10/03)
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- Thermally accelerated asymmetric hydrosilylations using ligated copper hydride
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Exposure of a variety of prochiral substrates to [(R)-(-)-DTBM-SEGPHOS]CuH + PMHS under microwave or conventionally heated conditions reduces reaction times for these hydrosilylations from hours to minutes without significant erosion in ee in most cases.
- Lipshutz, Bruce H.,Frieman, Bryan A.,Unger, John B.,Nihan, Danielle M.
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p. 606 - 614
(2007/10/03)
-
- Asymmetric conjugate addition of metal alkyl reagents catalyzed by copper complexes with BINPO: A hemilabile P,O-heterobidentate axially chiral ligand
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We herein report the use of a new class of P,O-bidentate arylphosphine ligand for the asymmetric copper catalyzed conjugate addition of dialkylzinc and trialkylaluminium with the enantiomeric excesses reaching 91% while (R)-muscone was obtained with 77% ee.
- Fuchs, Nicolas,D'Augustin, Magali,Humam, Munir,Alexakis, Alexandre,Taras, Rossana,Gladiali, Serafino
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p. 3143 - 3146
(2007/10/03)
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- Enantioselective Total Synthesis of Erogorgiaene: Applications of Asymmetric Cu-Catalyzed Conjugate Additions of Alkylzincs to Acyclic Enones
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The first enantioselective synthesis of erogorgiaene (1), an inhibitor of mycobacterium tuberculosis, is disclosed. The total synthesis highlights the utility of asymmetric conjugate additions (ACA) of alkylzincs to acyclic α,β-unsaturated ketones catalyzed by peptidic phosphine ligands and (CuOTf)2·C6H6. Moreover, several critical attributes of this catalytic C-C bond-forming reaction are illustrated in the context of the total synthesis; these include the significance of various structural features of the amino acid-based chiral ligands and the chiral ligand's effectiveness in reactions involving achiral and chiral substrates. In addition, the total synthesis showcases some of the special properties of nonphosphine Ru complex 3 as a highly effective catalyst for olefin cross-metathesis.
- Cesati III, Richard R.,De Armas, Judith,Hoveyda, Amir H.
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- Asymmetric Addition of Aryl Boron Reagents to Enones with Rhodium Dicyclophane Imidazolium Carbene Catalysis
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Chiral N-heterocyclic carbene ligands based on [2.2]paracyclophanes form complexes with rhodium. These catalysts can be used in the high-yielding and enantioselective asymmetric conjugate addition of arylboron compounds to cyclic and acyclic enones (see scheme).
- Ma, Yudao,Song, Chun,Ma, Changqing,Sun, Zhijun,Chai, Qiang,Andrus, Merritt B.
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p. 5871 - 5874
(2007/10/03)
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- Asymmetric 1,4-addition of organosiloxanes to α,β-unsaturated carbonyl compounds catalyzed by a chiral rhodium complex
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(Matrix presented) Highly enantioselective 1,4-addition of organosiloxanes to α,β-unsaturated carbonyl compounds was found to be catalyzed by a chiral rhodium complex generated from [Rh(cod)(MeCN)2]BF4 and (S)-BINAP. Both (E)- and (Z)-1-alkenyl groups as well as aryl groups can be introduced enantioselectively into the β-position of a variety of ketones, esters, and amides.
- Oi, Shuichi,Taira, Akio,Honma, Yoshio,Inoue, Yoshio
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- PalladiumdD-catalyzed exchange and isomerization reactions. 17. Exchange of chiral allyl alcohols with hydroxide, methoxide, and phenyl at high [Cl-]. Stereochemistry of the wacker reaction
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At high [Cl ] (> 2.0 M), PdCl42- catalyzes the exchange of chiral allylic alcohols with hydroxy, methoxy, and phenyl to give chiral allyl-substituted olefins. With unsymmetrical olefins, isomerization occurs along with exchange. The hydroxyl exchange occurs in aqueous solution while the other exchanges are carried out in methanol solution. At low [Cl-] (0.1 M) oxidation to the corresponding β-hydroxy-, methoxy-, and phenyl-substituted carbonyl compounds occurred. The absolute configurations of the oxidation and exchange products should be the same if the same mode of addition to the Pd(II)-β-complex is operative. The absolute configurations of the oxidation and exchange products for the phenylation reaction were the same, while for hydroxy and methoxy they were different. This result indicates methanol and water must have different stereochemistries of addition at high and low [Cl-]. Thus, previous studies showing anti hydroxypalladation at high [Cl-] are not valid indicators of the stereochemistry at low [Cl-]. If anti addition occurs at high [Cl-], the addition must be syn at low [Cl-].
- Hamed, Othman,Henry, Patrick M.,Thompson, Charles
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p. 7745 - 7750
(2007/10/03)
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- 1,1′-binaphthalene-2,2′-diol as a chiral auxiliary. Diastereoselective alkylation of binaphthyl esters, complex-induced proximity effects in enolate formation, and one-step synthesis of an optically active β-substituted ketone
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Diastereoselective alkylation of enolates derived from (S)-naphthyl phenylacetate 1 with LDA in THF gave the S,S-isomer as a major product. The diastereoselectivity increased as the bulkiness of the alkylating agent was increased. The low diastereomeric excess (~70%) of methylation was markedly raised to 92% by the use of n-BuLi as a base due to the complex-induced proximity effect (CIPE) in enolate formation. This highly diastereoselective methylation was used to synthesize the clinically important anti-inflammatory drugs (S)-naproxen (60) and (S)-suprofen (68). The stereochemistry of ketene trimethylsilyl acetals generated from several phenylacetates was investigated to understand the origin of the diastereoselectivity in this alkylation. Methyl phenylacetate (46) predominantly gave a (Z)-enolate by kinetic deprotonation, while the (E)-enolate was predominantly obtained from phenyl phenylacetate (47). An optically active ketone (88) was synthesized from binaphthyl ester 84 by a one-pot procedure involving the 1,4-addition, followed by the 1,2-addition, of organometallics. The CIPE again played a crucial role in the high enantiomeric excess in this case.
- Tanaka, Fujie,Node, Manabu,Tanaka, Kiyoshi,Mizuchi, Maki,Hosoi, Shinzo,Nakayama, Masayo,Taga, Tooru,Fuji, Kaoru
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p. 12159 - 12171
(2007/10/03)
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- Successive 1,4- and 1,2-additions of organometallic reagents to a chiral binaphthyl ester: One step synthesis of optically active ketones
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Organometallic reagents undergo a 1,4-addition onto the chiral binaphthyl ester of α,β-unsaturated carboxylic acid followed by the formal 1,2-addition to yield optically active ketones directly.
- Fuji,Tanaka,Mizuchi,Hosoi
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p. 7277 - 7280
(2007/10/02)
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- Chiral Homoenolate Equivalents, III Asymmetric Synthesis of 3-Substituted 3-Phenylketones via Metallated SMP-Allylamines
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The diastereomeric excess obtained in alkylation reactions of the chiral homoenolate equivalents 7 with prolinol ether as chiral auxiliary leading to the formation of 3-phenylketones 9 clearly depends on the temperature, the counter ion and the size of the alkyl iodide.But most important is the influence of the solvent used.By its variation even the course of induction may be controlled.Normally, the selectivity amounts to about 8:1 only.The best results (about 9:1) are obtained with lithium as counter ion and tert-butyl methyl ether as solvent.
- Ahlbrecht, Hubertus,Sommer, Horst
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p. 829 - 836
(2007/10/02)
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- Chelate Control in the Rhodium-catalysed Homogeneous Hydrogenation of Chiral Allylic and Homoallylic Alcohols
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Chelate bisphosphine rhodium complexes afford a high degree of stereoselection in the homogeneous hydrogenation of 3-phenylbut-3-en-2-ol and 4-phenylpent-4-en-2-ol, in opposite senses.
- Brown, John M.,Naik, Ramachandra G.
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p. 348 - 350
(2007/10/02)
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- ALKYLATION DES ESTERS ACETYLACETIQUES PAR DES ALCOOLS CHIRAUX, PAR DESHYDRATATION INTERMOLECULAIRE. CORRELATION ENTRE LES PURETES OPTIQUES DES PRODUITS FORMES.
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The formation of the C and O-alkylates involves inversion of configuration and the same weak racemization.
- Cabaret, Daniel,Maigrot, Nicole,Welvart, Zoltan
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p. 5279 - 5282
(2007/10/02)
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