- Solvent-induced chirality control in the enantioseparation of 1-phenylethylamine via diastereomeric salt formation
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Solvent-induced chirality control in the enantioseparation of 1-phenylethylamine 1 by N-(p-toluenesulfonyl)-(S)-phenylalanine 2 via diastereomeric salt formation was studied. (S)-·(S)-2 was preferentially crystallized as a less-soluble salt from aqueous a
- Kodama, Koichi,Kimura, Yuria,Shitara, Hiroaki,Yasutake, Mikio,Sakurai, Rumiko,Hirose, Takuji
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- Amplification of the enantiomeric excess of a compound in kinetic resolution by a racemic reagent
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The possibility of amplifying the small ee of a enantioimpure substance using a racemic reagent in kinetic resolution is discussed. A kinetic treatment of this problem along with some experimental proofs of the concept is presented. Simulation on kinetic resolution of small ee substrate by a racemic reagent showed an important enantioenrichment in the substrate ee, sometimes reaching close to absolute ee. Experiments of kinetic resolution of an amine of a small ee by a racemic acylating reagent gave a substantial amplification in ee of the amine. The possible transformation of an undetectable low ee in substrate to a detectable higher ee by using a suitable racemic reagent is also briefly discussed with help of calculations. The usefulness of asymmetric amplification by a racemic reagent is considered in the context of the biomolecular homochirality on earth.
- Satyanarayana, Tummanapalli,Kagan, Henri B.
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- Ph-tetrame-bithienine, the first member of the class of chiral heterophosphepines: Synthesis, electronic and steric properties, metal complexes and catalytic activity
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Unknown 1H-2,7-dihydro-1-phenylphosphepine, containing a 2,2,5,5-tetramethyl-3,3-bithiophene atropisomeric scaffold (Ph-tetraMe- Bithienine), and its oxide have been synthesized and structurally characterized by single-crystal X-ray diffraction analysis.
- Vaghi, Luca,Benincori, Tiziana,Cirilli, Roberto,Alberico, Elisabetta,Mussini, Patrizia Romana,Pierini, Marco,Pilati, Tullio,Rizzo, Simona,Sannicolo, Francesco
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- Chiroptical Asymmetric Reaction Screening via Multicomponent Self-Assembly
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Self-assembly of a stereodynamic phosphine ligand, Pd(II), and a chiral amine, amino alcohol, or amino acid generates characteristic UV and CD signals that can be used for quantitative stereochemical analysis of the bound substrate. A robust mix-and-measure chiroptical sensing protocol has been developed and used to determine the absolute configuration, ee, and yield of an amine produced by Ir-catalyzed asymmetric hydrogenation of an iminium salt. The analysis requires only 1 mg of the crude reaction mixture and minimizes cost, labor, time, and waste.
- De Los Santos, Zeus A.,Wolf, Christian
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- Unprecedented, fully recyclable, solid-supported reagent for the kinetic resolution of racemic amines through enantioselective N-acetylation
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The high-yielding synthesis and application of the first polymer supported reagent for the kinetic resolution (KR) of amines through enantioselective acetylation is described; this new supported chiral reagent allows the KR of primary amines with excellent selectivities at room temperature; moreover, this supported approach is highly efficient as the Merrifield-supported chiral scaffold can be quantitatively recovered and recycled. The Royal Society of Chemistry 2005.
- Arseniyadis, Stellios,Subhash, Pithani V.,Valleix, Alain,Wagner, Alain,Mioskowski, Charles
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- A new benchmark for the non-enzymatic enantioselective acylation of amines: Use of a planar-chiral derivative of 4-pyrrolidinopyridine as the acylating agent
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N-Acetylated Ph-PPY*, a new planar-chiral derivative of PPY, serves as an effective reagent for the enantioselective acylation of racemic amines, providing amides with very good stereoselectivity.
- Ie, Yutaka,Fu, Gregory C.
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- The application of monodentate secondary phosphine oxide ligands in rhodium- and iridium-catalyzed asymmetric hydrogenation
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Enantiopure secondary phosphine oxides have been tested as ligands in the rhodium- and iridium-catalyzed asymmetric hydrogenation of functionalized olefins. tert-Butylphosphinoyl benzene turned out to be a versatile ligand in the iridium-catalyzed hydroge
- Jiang, Xiao-Bin,Van Den Berg,Minnaard, Adriaan J.,Feringa, Ben L.,De Vries, Johannes G.
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- Rhodium-catalyzed asymmetric olefin hydrogenation by easily accessible aniline- and pyridine-derived chiral phosphites
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An aniline- and two pyridine-derived (R)-BINOL-based P,N-containing phosphite ligands have been synthesized via a one-pot procedure. Treatment of the aniline-derived ligand with 1 equiv of [Rh(COD)2]BF4 yielded a mixture of a P,N-che
- Vallianatou, Kalliopi A.,Frank, Dominik J.,Antonopoulou, Georgia,Georgakopoulos, Spyros,Siapi, Eleni,Zervou, Maria,Kostas, Ioannis D.
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- Asymmetric hydrogenation of enamides, α-enol and α-enamido ester phosphonates catalyzed by IndolPhos-Rh complexes
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(Chemical Equation Presented) The scope of the IndolPhos-Rh-catalyzed asymmetric hydrogenation of enamides, α-enol and α-enamido ester phosphonates, has been investigated. In addition, Taddol-based IndolPhos ligands are introduced. High activities and goo
- Wassenaar, Jeroen,Reek, Joost N. H.
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- Asymmetric Induction via Co-ordination to Cr(CO)3; Nucleophilic Attack on Acyclic Carbenium Ions
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Temporary complexation of (S)-(-)-1-phenylethanol by the Cr(CO)3 moiety allows the use of carbenium ions to bring about asymmetric transformations with a high degree of retention of configuration, even in open-chain compounds.
- Top, Siden,Jaouen, Gerard,McGlinchey, Michael J.
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- The asymmetric dialkylzinc addition to imines catalyzed by [2.2]paracyclophane-based N,O-ligands
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The first highly enantioselective dialkylzinc addition to imines in the presence of catalytic amounts of N,O-ligands is reported. N-formyl-α-(p-tolysulfonyl)benzylamines are the readily available starting materials easily obtained in a one-pot synthesis from benzaldehydes, formamide, and p-tolylsulfinic acid. Upon deprotonation, the sulfinate is eliminated to give the acyl imine. The acyl imines further react with alkylzinc reagents in the presence of catalytic amounts of [2.2]paracyclophane-based N,O-ligands L* yielding the alkylated N-(1-phenylpropyl)formamides with excellent yields and enantioselectivities. Copyright
- Dahment, Stefan,Braese, Stefan
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- Resolution of α-methylbenzylamine via diastereomeric salt formation using the naturally based reagent N-tosyl-(S)-phenylalanine together with a solvent switch technique
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The resolution of (RS)-α-methylbenzylamine 1 with the naturally based reagent N-tosyl-(S)-phenylalanine 2 via the diastereomeric salt formation method together with the solvent switch technique has been investigated. In various alcoholic solvents with a wide ε range, the less-soluble salt was (S)-1·(S)-2, while (R)-1·(S)-2 was obtained when dioxane was used as a resolving solvent system. The highest enantiomeric purities of (S)-1 and (R)-1 were obtained from 2-PrOH and dioxane/MeOH, respectively. The X-ray single-crystal analysis showed that both (S)-1·(S)-2 and (R)-1·(S)-2 crystals form a hydrogen-bonding network; however, (R)-1·(S)-2 contains dioxane molecules without incorporation in the hydrogen-bonding network. The drastic effect of dioxane on the present system is interpreted as space filling.
- Hirose, Takuji,Begum, Muksana,Sadequl Islam,Taniguchi, Kayoko,Yasutake, Mikio
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- Potential application of native lipases in the resolution of (RS)-phenylethylamine
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The performance of two native lipases (lipase from Aspergillus niger and Rhizoupus oligosporus) in the resolution of (RS)-phenylethylamine (1), varying the temperature, acyl donor type (ethyl acetate, vinyl acetate, iso-propenyl acetate and acetic anhydride) and organic medium, was studied. The effect of the nature of the anion using native A. niger lipase in n-heptane with a series of imidazolium-based ILs [BMIm][X], where X = BF4, PF6, SCN and Cl, was also evaluated. Using the lipase from A. niger, the R-2b amide was obtained with conversions from 6 to > 99percent and E-values from 2 to > 200, with n-heptane or n-hexane. This lipase showed better E-values in a two-phase system using n-heptane and [BMIm][PF6] or [BMIm][BF4] 9:1 (v/v), obtaining values of 9 and 7, respectively, when vinyl acetate was used as the acyl donor, compared to the use of pure n-heptane (E = 2). The series for the anions in terms of decreasing performance was as follows: PF 6->BF4-> SCN-> Cl-.
- Pilissa?o, Cristiane,De O. Carvalho, Patri?cia,Da G. Nascimento, Maria
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- Iridium-catalysed asymmetric hydrogenation of enamides in the presence of 3,3-substituted h8-phosphoramidites
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In situ generated iridium complexes containing bulky 3,3′-substituted H8-phosphoramidites as ligands catalyse the asymmetric hydrogenation of non-functionalised enamides in high yield and good to excellent selectivity.
- Erre, Giulia,Enthaler, Stephan,Junge, Kathrin,Addis, Daniele,Beller, Matthias
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- Synthesis and crystal structure of enantiomeric N-(dimethylfluorosilylmethyl) and N-(dimethylchlorosilylmethyl)-[N-( S) -1-phenylethyl ] acetamides
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Synthesis of the first optically active compounds containing asymmetric carbon and pentacoordinated silicon has been carried out. The enantiomeric (O-Si)-chelate N-(dimethylhalogenosilylmethyl) acetamides, MeC(O)N(CH(Ph)Me)CH2SiMe2X
- Baukov, Yuri I.,Ovchinnikov, Yuri E.,Shipov, Aleksandr G.,Kramarova, Evgeniya P.,Negrebetsky, Vadim V.,Struchkov, Yuri T.
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- Enantiomeric enrichments via the self-disproportionation of enantiomers (SDE) by achiral, gravity-driven column chromatography: A case study using N-(1-phenylethyl)acetamide for optimizing the enantiomerically pure yield and magnitude of the SDE
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This work explores the self-disproportionation of enantiomers (SDE) via achiral, gravity-driven column chromatography as typically used in laboratory settings for the purpose of enantiomeric enrichment using N-(1-phenylethyl)acetamide (PEA) as a case stud
- Wzorek, Alicja,Sato, Azusa,Drabowicz, J?zef,Soloshonok, Vadim A.,Klika, Karel D.
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- Chiral ferrocene-indole diphosphine ligand as well as preparation method and application thereof
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The invention relates to a chiral ferrocene-indole diphosphine ligand as well as a preparation method and application thereof. The specific preparation method comprises the following steps: dissolving an indole compound and a chiral ferrocene phosphine ac
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Paragraph 0069-0070
(2021/05/22)
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- Chiral ferrocene phosphine-indole aminophosphine ligand as well as preparation method and application thereof
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The invention discloses a chiral ferrocene phosphine-indole aminophosphine ligand as well as a preparation method and application thereof. The preparation method comprises the following steps: dissolving a chiral ferrocene phosphine-indole intermediate in
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Paragraph 0048-0049
(2021/05/22)
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- OPTICALLY ACTIVE BISPHOSPHINO METHANE AND PRODUCTION METHOD THEREFOR, AND TRANSITION METAL COMPLEX AND ASYMMETRIC CATALYST
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PROBLEM TO BE SOLVED: To provide a novel optically active bisphosphine methane that is useful as a ligand for an asymmetric catalyst, has excellent oxidation resistance in the air, and is easy to handle, and to provide a transition metal complex using, as
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Paragraph 0071-0073
(2021/02/10)
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- Enantioconvergent Cu-Catalyzed Radical C-N Coupling of Racemic Secondary Alkyl Halides to Access α-Chiral Primary Amines
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α-Chiral alkyl primary amines are virtually universal synthetic precursors for all other α-chiral N-containing compounds ubiquitous in biological, pharmaceutical, and material sciences. The enantioselective amination of common alkyl halides with ammonia is appealing for potential rapid access to α-chiral primary amines, but has hitherto remained rare due to the multifaceted difficulties in using ammonia and the underdeveloped C(sp3)-N coupling. Here we demonstrate sulfoximines as excellent ammonia surrogates for enantioconvergent radical C-N coupling with diverse racemic secondary alkyl halides (>60 examples) by copper catalysis under mild thermal conditions. The reaction efficiently provides highly enantioenrichedN-alkyl sulfoximines (up to 99% yield and >99% ee) featuring secondary benzyl, propargyl, α-carbonyl alkyl, and α-cyano alkyl stereocenters. In addition, we have converted the masked α-chiral primary amines thus obtained to various synthetic building blocks, ligands, and drugs possessing α-chiral N-functionalities, such as carbamate, carboxylamide, secondary and tertiary amine, and oxazoline, with commonly seen α-substitution patterns. These results shine light on the potential of enantioconvergent radical cross-coupling as a general chiral carbon-heteroatom formation strategy.
- Cheng, Jiang-Tao,Dong, Xiao-Yang,Gu, Qiang-Shuai,Li, Zhong-Liang,Liu, Juan,Liu, Xin-Yuan,Luan, Cheng,Wang, Fu-Li,Wang, Li-Lei,Yang, Ning-Yuan,Zhang, Yu-Feng
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supporting information
p. 15413 - 15419
(2021/09/30)
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- Metal coordination compound, intermediate, preparation method and applications thereof
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The invention discloses a metal coordination compound, an intermediate, a preparation method and applications thereof. According to the invention, the metal coordination compound represented by a formula I can be used as a catalyst for an asymmetric catalytic hydrogenation reaction to efficiently and catalytically synthesize a series of chiral beta-aryl amides with high optical purity (ee value ofmore than 99%) particularly to asymmetrically and catalytically hydrogenate a tetra-substituted alkenyl amide compound to synthesize a chiral amide with high optical purity (ee value of more than 60%), wherein the ligand bearing capacity (s/c) can reach 100000.
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Paragraph 0391-0397; 0424-0429
(2020/05/01)
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- New chiral ferrocene/indole-based diphosphine ligands for Rh-catalyzed asymmetric hydrogenation of functionalized olefins
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Convenient synthesis of a new family of chiral ferrocene/indole-based diphosphine ligands, (Rc,Rp)-IndoFerroPhos (L), from (Sc,Rp)-PPFA and 2-(diphenylphosphino)indole has been described. These new ligands exhibited high efficiency in the Rh-catalyzed asymmetric hydrogenation of functionalized olefins including α-dehydroamino acid esters, α-enamides and dimethyl itaconate, in which up to >99% yield and 98% ee were achieved.
- Abbas, Zaheer,Ali, Aijaz,Hu, Xiang-Ping,Hu, Xin-Hu,Xu, You-Wei
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supporting information
(2020/04/02)
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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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- Environmentally benign decarboxylative: N-, O-, and S-Acetylations and acylations
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An operationally simple and general method for acetylation and acylation of a wide variety of substrates (amines, alcohols, phenols, thiols, and hydrazones) has been reported. Meldrum's acid and its derivatives have been used as an air-stable, non-volatile, cost-effective, and easy to handle acetylating/acylating agent. Easily separable byproducts (CO2 and acetone) allowed the isolation of analytically pure acetylated products without the requirement of work-up and any chromatography. This journal is
- Ghosh, Santanu,Purkait, Anisha,Jana, Chandan K.
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supporting information
p. 8721 - 8727
(2020/12/30)
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- N-acetylation of amines in continuous-flow with acetonitrile—no need for hazardous and toxic carboxylic acid derivatives
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A continuous-flow acetylation reaction was developed, applying cheap and safe reagent, acetonitrile as acetylation agent and alumina as catalyst. The method developed utilizes milder reagent than those used conventionally. The reaction was tested on various aromatic and aliphatic amines with good conversion. The catalyst showed excellent reusability and a scale-up was also carried out. Furthermore, a drug substance (paracetamol) was also synthesized with good conversion and yield.
- Fül?p, Ferenc,Mándity, István M.,Orsy, Gy?rgy
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- Phosphite-thioether/selenoether Ligands from Carbohydrates: An Easily Accessible Ligand Library for the Asymmetric Hydrogenation of Functionalized and Unfunctionalized Olefins
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A large family of phosphite-thioether/selenoether ligands has been easily prepared from accessible L-(+)-tartaric acid and D-(+)-mannitol and applied in the M-catalyzed (M=Ir, Rh) asymmetric hydrogenation of a broad number of substrates (46 in total). Its highly modular architecture has been crucial to maximize the catalytic performance. Improving most of the reported approaches, this ligand family presents a broad substrate scope. By selecting the ligand parameters high enantioselectivities (ee's up to 99 %) have therefore been achieved in a broad range of both, functionalized and unfunctionalized substrates. Interestingly, both enantiomers of the hydrogenation products can be usually achieved by changing the ligand parameters.
- Margalef, Jèssica,Borràs, Carlota,Alegre, Sabina,Alberico, Elisabetta,Pàmies, Oscar,Diéguez, Montserrat
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p. 2142 - 2168
(2019/04/13)
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- BABIPhos Family of Biaryl Dihydrobenzooxaphosphole Ligands for Asymmetric Hydrogenation
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Novel bidentate phosphine ligands BABIPhos featuring a biaryl bis-dihydrobenzooxaphosphole core are presented. Their synthesis was achieved via Pd-catalyzed reductive homocoupling of dihydrobenzooxaphosphole aryl triflates. An efficient route toward various analogues was also established, giving access to phosphines with different electronic and steric properties. The newly obtained ligands demonstrated high efficiency and selectivity in Rh-catalyzed asymmetric hydrogenation of di- and trisubstituted enamides. This new class of ligands is complementary to previously described bidentate benzooxaphosphole ligands BIBOP.
- Li, Guisheng,Zatolochnaya, Olga V.,Wang, Xiao-Jun,Rodríguez, Sonia,Qu, Bo,Desrosiers, Jean-Nicolas,Mangunuru, Hari P. R.,Biswas, Soumik,Rivalti, Daniel,Karyakarte, Shuklendu D.,Sieber, Joshua D.,Grinberg, Nelu,Wu, Ling,Lee, Heewon,Haddad, Nizar,Fandrick, Daniel R.,Yee, Nathan K.,Song, Jinhua J.,Senanayake, Chris H.
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supporting information
p. 1725 - 1729
(2018/04/14)
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- Structural Investigations on Enantiopure P–OP Ligands: A High-Performing P–OP Ligand for Rhodium-Catalysed Hydrogenations
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A second generation of phosphine–phosphite (P–OP) ligands, incorporating a more sterically bulky phosphite group than previous P–OP ligand designs, gave very efficient catalysts for the Rh-catalysed asymmetric hydrogenation of a diverse array of substrate
- Fernández-Pérez, Héctor,Balakrishna, Bugga,Vidal-Ferran, Anton
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p. 1525 - 1532
(2018/04/20)
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- Modular 1,1′-Ferrocenediyl-cored P-Stereogenic Diphosphines: ′′JDayPhos′′ Series and its Use in Rhodium(I)-Catalyzed Hydrogenation
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A novel ferrocene-based P-stereogenic diphospine ligand series dubbed JDayPhos was developed, which rhodium(I) complexes of some of its members exhibited excellent enantioselectivity (up to >99% ee) and high activity in asymmetric hydrogenation of β-unsubstituted or -substituted itaconates and α-methylene-γ-oxo-carboxylates. (Figure presented.).
- Poklukar, Ga?per,Stephan, Michel,Mohar, Barbara
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supporting information
p. 2566 - 2570
(2018/05/16)
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- 1,1-Diacyloxy-1-phenylmethanes as versatile N-acylating agents for amines
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1,1-Diacyloxy-1-phenylmethanes and 1-pivaloxy-1-acyloxy-1-phenylmethanes have been used as bench stable N-acylating reagents for primary and secondary amines and anilines under solvent-free conditions to afford their corresponding amides in good yield.
- Chapman, Robert. S.L.,Tibbetts, Joshua. D.,Bull, Steven. D.
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p. 5330 - 5339
(2018/06/15)
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- Optimization of 2-alkoxyacetates as acylating agent for enzymatic kinetic resolution of chiral amines
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In this study, the activity of acetic acid esters modified with electron withdrawing 2-alkoxy-groups was investigated as acylating agent in kinetic resolution (KR) of racemic amines. A homologous series of the isopropyl esters of four 2-alkoxyacetic acids (2-methoxy-, 2-ethoxy-, 2-propoxy- and 2-butoxyacetic acids) were prepared and investigated for enantiomer selective N-acylation, catalyzed by lipase B from Candida antarctica, under batch and continuous-flow conditions. In the first set of experiments, isopropyl 2-propoxyacetate showed the highest effectivity with all of the four racemic amines [(±)-1-phenylethylamine, (±)-4-phenylbutan-2-amine, (±)-heptan-2-amine and (±)-1-methoxypropane-2-amine] in the set enabling excellent conversions (≥46%) and enantiomeric excess values (ee ≥ 99%) with each amines in continuous-flow mode KRs under the optimized reaction conditions. In a second set of experiments, KRs of five additional amines – being substituted derivatives of (±)-1-phenylethylamine – further demonstrated the usefulness of isopropyl 2-propoxyacetate – being the best acylating agent in the first set of KRs – in KRs leading to (R)-N-propoxyacetamides with high ee values (≥99.8%).
- Oláh, Márk,Kovács, Dániel,Katona, Gabriel,Hornyánszky, Gábor,Poppe, László
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p. 3663 - 3670
(2018/06/04)
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- Amine dehydrogenases: Efficient biocatalysts for the reductive amination of carbonyl compounds
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Amines constitute the major targets for the production of a plethora of chemical compounds that have applications in the pharmaceutical, agrochemical and bulk chemical industries. However, the asymmetric synthesis of α-chiral amines with elevated catalytic efficiency and atom economy is still a very challenging synthetic problem. Here, we investigated the biocatalytic reductive amination of carbonyl compounds employing a rising class of enzymes for amine synthesis: amine dehydrogenases (AmDHs). The three AmDHs from this study-operating in tandem with a formate dehydrogenase from Candida boidinii (Cb-FDH) for the recycling of the nicotinamide coenzyme-performed the efficient amination of a range of diverse aromatic and aliphatic ketones and aldehydes with up to quantitative conversion and elevated turnover numbers (TONs). Moreover, the reductive amination of prochiral ketones proceeded with perfect stereoselectivity, always affording the (R)-configured amines with more than 99% enantiomeric excess. The most suitable amine dehydrogenase, the optimised catalyst loading and the required reaction time were determined for each substrate. The biocatalytic reductive amination with this dual-enzyme system (AmDH-Cb-FDH) possesses elevated atom efficiency as it utilizes the ammonium formate buffer as the source of both nitrogen and reducing equivalents. Inorganic carbonate is the sole by-product.
- Knaus, Tanja,B?hmer, Wesley,Mutti, Francesco G.
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p. 453 - 463
(2017/08/14)
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- Asymmetric Allylic Alkylation and Hydrogenation with Transition Metal Complexes of Diphosphite Ligands Based on (1S,2S)-Trans-1,2-cyclohexanediol
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Abstract: The preparation of new palladium complexes in situ that were composed of a series of chiral diphosphite ligands, which were derived from (1S,2S)-trans-1,2-cyclohexanediol, have been described. It was found that (1S,2S)-bis[(S)-1,1′-binaphthyl-2,
- Pang, Zengbo,Tian, Mi,Li, Haifeng,Wang, Lailai
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p. 893 - 899
(2017/03/24)
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- Iron catalyzed diastereoselective hydrogenation of chiral imines
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Cyclopentadienone-based iron complexes were used for the first time to successfully catalyze the diastereoselective hydrogenation of enantiopure imines. Chiral amines, including valuable biologically active products, were obtained often as enantiomericall
- Brenna,Rossi,Cozzi,Benaglia
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supporting information
p. 5685 - 5688
(2017/07/22)
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- An unexpected copper-catalyzed carbonylative acetylation of amines
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A novel copper-catalyzed carbonylative acetylation of amines has been developed. With peroxide as the oxidant as well as the methyl source with a copper catalyst under CO pressure, good yields of N-acetyl amides could be obtained. Notably, this is the first example of carbonylative acetylation.
- Li, Yahui,Wang, Changsheng,Zhu, Fengxiang,Wang, Zechao,Fran?ois Soulé, Jean,Dixneuf, Pierre H.,Wu, Xiao-Feng
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supporting information
p. 142 - 144
(2016/12/27)
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- Stereoelectronic effects in the reaction of aromatic substrates catalysed by: Halomonas elongata transaminase and its mutants
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A transaminase from Halomonas elongata and four mutants generated by an in silico-based design were recombinantly produced in E. coli, purified and applied to the amination of mono-substituted aromatic carbonyl-derivatives. While benzaldehyde derivatives were excellent substrates, only NO2-acetophenones were transformed into the (S)-amine with a high enantioselectivity. The different behaviour of wild-type and mutated transaminases was assessed by in silico substrate binding mode studies.
- Contente, Martina Letizia,Planchestainer, Matteo,Molinari, Francesco,Paradisi, Francesca
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p. 9306 - 9311
(2016/10/13)
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- Transition metal complex, chiral alpha-amino tertiary borate and preparing methods thereof
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The invention discloses a transition metal complex, chiral alpha-amino tertiary borate and preparing methods thereof. The chiral alpha-amino tertiary borate preparing method comprises the step of mixing a compound II, a metal ligand complex and bis(pinaco
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- A split preparation of the optically pure S-1-benzoethylamine method
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The present invention relates to a method for resolution preparation of S-1-phenylethylamine in a dynamic kinetics manner. According to the method, 1-phenylethylamine is adopted as a raw material, Novozym435 is adopted as a resolution catalyst, S-1-phenethyl acetate is adopted as an acyl donor, raney nickel is adopted as a racemic catalyst, and hydrogen is introduced into an autoclave to carry out a reaction, wherein the 1-phenylethylamine is completely converted to obtain (S)-(1-phenylethyl)acetamide (ee value of 99%), the amide is purified and then acidolysis is performed to obtain a S-1-phenylethylamine salt, and the salt is subjected to alkalization, extraction, drying, concentration and other operations to obtain the S-1-phenylethylamine, wherein the product yield in each step can achieve more than 90%, and the ee values are more than 99%. The method of the present invention has characteristics of cheap and easily-available racemic catalyst, complete raw material use, good product yield, high optical purity and the like. In addition, great guidance and application values are provided in the S-1-phenylethylamine production preparation.
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Paragraph 0008; 0009
(2017/06/08)
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- Olefin hydrogenation with rigid mono-P-stereogenic diphosphines: A flexible rhodium ring to rule them all?
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The preparation of a rigid C1-symmetric P-stereogenic diphosphine series possessing a P-o-diphenylphosphinophenyl moiety and its use in RhI-catalyzed hydrogenation of benchmark olefins, is presented. This simplified ligand design, wh
- Rast, Slavko,Stephan, Michel,Mohar, Barbara
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p. 2214 - 2225
(2015/04/14)
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- Synthesis of phospholane-phosphoramidite ligands and their application in asymmetric catalysis
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A set of phospholane-phosphoramidite ligands, which possess four elements of chirality, has been synthesized through a modular diastereoselective process. The ligands were applied in the Rh-catalyzed asymmetric C =C hydrogenation of several functionalized olefins with enantioselectivities of up to 99 % ee and a turnover frequency of up to 12 000 h-1, in the Rh-catalyzed hydroformylation of vinyl arenes with enantioselectivities of up to 79 % ee, and in the Ir-catalyzed asymmetric C =N hydrogenation of different aryl imines with enantioselectivities of up to 79 % ee. New P,P′ hybrid ligands: A set of phospholane-phosphoramidites (quinaphoslane) with four elements of chirality are synthesized through a modular diastereoselective process and applied in the Rh-catalyzed hydrogenation of functionalized olefins with up to 99 % ee and a turnover frequency (TOF) of up to 12 000 h-1, in the Rh-catalyzed hydroformylation of vinyl arenes with regioselectivities of up to 99 % and up to 79 % ee, and in the Ir-catalyzed hydrogenation of imines with up to 79 % ee.
- Hammerer, Tim,Leitner, Walter,Franciò, Giancarlo
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p. 1583 - 1592
(2015/05/27)
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- Synthesis of chiral α-amino tertiary boronic esters by enantioselective hydroboration of α-arylenamides
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The rhodium-catalyzed asymmetric hydroboration of α-arylenamides with BI-DIME as the chiral ligand and (Bpin)2 as the reagent yields for the first time a series of α-amino tertiary boronic esters in good yields and excellent enantioselectivities (up to 99% ee).
- Hu, Naifu,Zhao, Guoqing,Zhang, Yuanyuan,Liu, Xiangqian,Li, Guangyu,Tang, Wenjun
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p. 6746 - 6749
(2015/06/16)
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- Supramolecularly Regulated Ligands for Asymmetric Hydroformylations and Hydrogenations
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Herein we report the use of polyether binders as regulation agents (RAs) to enhance the enantioselectivity of rhodium-catalyzed transformations. For reactions of diverse substrates mediated by rhodium complexes of the α,ω-bisphosphite-polyether ligands 1-5,a-d, the enantiomeric excess (ee) of hydroformylations was increased by up to 82 (substrate: vinyl benzoate, 96ee), and the ee value of hydrogenations was increased by up to 5 (substrate: N-(1-(naphthalene-1-yl)vinyl)acetamide, 78ee). The ligand design enabled the regulation of enantioselectivity by generation of an array of catalysts that simultaneously preserve the advantages of a privileged structure in asymmetric catalysis and offer geometrically close catalytic sites. The highest enantioselectivities in the hydroformylation of vinyl acetate with ligand 4b were achieved by using the Rb[B(3,5-(CF3)2C6H3)4] (RbBArF) as the RA. The enantioselective hydrogenation of the substrates 10 required the rhodium catalysts derived from bisphosphites 3a or 4a, either alone or in combination with different RAs (sodium, cesium, or (R,R)-bis(1-phenylethyl)ammonium salts). This design approach was supported by results from computational studies.
- Vidal-Ferran, Anton,Mon, Ignasi,Bauzá, Antonio,Frontera, Antonio,Rovira, Laura
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supporting information
p. 11417 - 11426
(2015/08/03)
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- A Single Lipase-Catalysed One-Pot Protocol Combining Aminolysis Resolution and Aza-Michael Addition: An Easy and Efficient Way to Synthesise β-Amino Acid Esters
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A novel one-pot protocol combining aza-Michael addition and aminolysis resolution was developed to obtain chiral β-amino acid esters with lipase B from Candida antarctica (CAL-B) as the only catalyst. This method is conducted under mild reaction conditions and is very easy to handle. After a series of detailed optimization studies, ten racemic aromatic or aliphatic amines were subjected to this one-pot procedure, and twelve chiral β-amino acid esters and ten chiral amides were successfully synthesised with excellent ee values in theoretical yields. Scaled-up procedures also worked without apparent reduction in reaction rate or enantioselectivity, which makes this method suitable for large-scale production of chiral β-amino acid esters. A one-pot protocol for simultaneous synthesis of chiral β-amino acid esters and amides was developed by combining single lipase B from Candida antarctica (CAL-B) catalysed aza-Michael addition and aminolysis resolution. This method requires mild reaction conditions and is very easy to handle. Chiral β-amino acid esters and chiral amides were obtained with excellent ee values and in theoretical yields.
- Xu, Fan,Wu, Qiongsi,Chen, Xiaoyang,Lin, Xianfu,Wu, Qi
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p. 5393 - 5401
(2015/08/24)
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- Chemoselective N-deacetylation under mild conditions
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A mild and efficient chemoselective N-deacetylation using the Schwartz reagent at room temperature in rapid time is described. The mild and neutral conditions enable orthogonal N-deacetylation in the presence of some of the common protecting groups (viz. Boc, Fmoc, Cbz, Ts). The deprotection conditions did not induce any epimerization at the chiral amino centre.
- Sultane, Prakash R.,Mete, Trimbak B.,Bhat, Ramakrishna G.
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supporting information
p. 261 - 264
(2014/01/06)
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- Transaminases applied to the synthesis of high added-value enantiopure amines
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Critical parameters affecting the stereoselective amination of (hetero)aromatic ketones using transaminases have been studied, such as temperature, pH, substrate concentration, cosolvent, and source and percentage of amino donor, to further optimize the production of enantiopure amines using both (S)- and (R)-selective biocatalysts from commercial suppliers. Interesting enantiopure amino building blocks have been obtained, overcoming some limitations of traditional chemical synthetic methods. Representative processes were scaled up, affording halogenated and heteroaromatic amines in enantiomerically pure form and good isolated yields.
- Paul, Caroline E.,Rodriguez-Mata, Maria,Busto, Eduardo,Lavandera, Ivan,Gotor-Fernandez, Vicente,Gotor, Vicente,Garcia-Cerrada, Susana,Mendiola, Javier,De Frutos, Oscar,Collado, Ivan
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supporting information
p. 788 - 792
(2014/07/08)
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- MaxPHOS ligand: PH/NH tautomerism and rhodium-catalyzed asymmetric hydrogenations
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MaxPHOS is an active and robust P-stereogenic ligand for asymmetric catalysis. The presence of an -NH- bridge between the two phosphine moieties allows the NH/PH tautomerism to take place. The neutral ligand, in which the NH form predominates, is an air-sensitive compound. However, protonation of MaxPHOS leads to the stable PH form of the ligand, in which the overall positive charge is distributed on both P centers. This protonation turns the MaxPHOS×HBF4 salt 3 into an air-stable compound both in the solid state and in solution. The salt 3 is also a convenient precursor for the preparation of rhodium(I) complexes by direct ligand exchange with the complex [Rh(acac)(cod)]. Finally, the corresponding rhodium(I)-MaxPHOS complex was tested in the asymmetric hydrogenation of a wide range of substrates. The complex proved to be a highly selective and robust system in these reactions.
- Cristobal-Lecina, Edgar,Etayo, Pablo,Doran, Sean,Reves, Marc,Martin-Gago, Pablo,Grabulosa, Arnald,Costantino, Andrea R.,Vidal-Ferran, Anton,Riera, Antoni,Verdaguer, Xavier
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p. 795 - 804
(2014/04/03)
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- Metallacrown ether catalysts containing phosphine-phosphite polyether ligands for Rh-catalyzed asymmetric hydrogenation - Enhancements in activity and enantioselectivity
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A new class of tunable metallacrown ether rhodium catalysts based on α,ω-(phosphine-phosphite) polyether ligands were prepared either by a template-induced method or by a nontemplate procedure. For the asymmetric hydrogenation of α-arylenamides with the a
- Song, Feng-Tao,Ouyang, Guang-Hui,Li, Yong,He, Yan-Mei,Fan, Qing-Hua
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supporting information
p. 6713 - 6719
(2016/02/18)
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- Enantiopure narrow bite-angle P-OP ligands: Synthesis and catalytic performance in asymmetric hydroformylations and hydrogenations
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Herein is reported the preparation of a set of narrow bite-angle P-OP ligands the backbone of which contains a stereogenic carbon atom. The synthesis was based on a Corey-Bakshi-Shibata (CBS)-catalyzed asymmetric reduction of phosphomides. The structure of the resulting 1,1-P-OP ligands, which was selectively tuned through adequate combination of the configuration of the stereogenic carbon atom, its substituent, and the phosphite fragment, proved crucial for providing a rigid environment around the metal center, as evidenced by X-ray crystallography. These new ligands enabled very good catalytic properties in the Rh-mediated enantioselective hydrogenation and hydroformylation of challenging and model substrates (up to 99 % ee). Whereas for asymmetric hydrogenation the optimal P-OP ligand depended on the substrate, for hydroformylation, a single ligand was the highest-performing one for almost all studied substrates: it contains an R-configured stereogenic carbon atom between the two phosphorus ligating groups, and an S-configured 3,3′-diphenyl-substituted biaryl unit. Ligand design: Narrow-bite-angle P-OP ligands incorporating a stereogenic carbon atom in their backbone have been synthesized by Corey-Bakshi-Shibata (CBS)-catalyzed asymmetric reduction of the corresponding intermediates followed by O-phosphorylation. Rhodium complexes of these ligands provided very good catalytic performance in hydroformylations and hydrogenations (see scheme).
- Fernández-Pérez, Héctor,Benet-Buchholz, Jordi,Vidal-Ferran, Anton
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p. 15375 - 15384
(2016/02/18)
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- Rh-catalyzed asymmetric hydrogenation using a furanoside monophosphite second-generation ligand library: Scope and limitations
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The ligand design of one of the most successful monophosphite ligand classes in Rh-catalyzed hydrogenation was expanded upon by introducing several substituents at the C-3 position of the furanoside backbone. A small but structurally important library of
- Alegre, Sabina,Alberico, Elisabetta,Pamies, Oscar,Dieguez, Montserrat
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p. 258 - 262
(2014/03/21)
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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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- Ethyl acetate as an acyl donor in the continuous flow kinetic resolution of (±)-1-phenylethylamine catalyzed by lipases
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The synthesis of chiral amines is still a challenge for organic synthesis since optically pure amines are of great importance for the pharmaceutical and agrochemical industries. Among all the methodologies developed until now, chemoenzymatic dynamic kinetic resolution has proven to be useful for the preparation of enantioenriched primary chiral amines. In our continuous efforts toward the development of a continuous flow process, herein we report our results on the continuous flow kinetic resolution of (±)-1- phenylethylamine leading to the desired products with high enantiomeric ratios (>200) and short residence times (40 minutes) using ethyl acetate as the acyl donor.
- De Miranda, Amanda S.,Miranda, Leandro S. M.,De Souza, Rodrigo O. M. A.
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supporting information
p. 3332 - 3336
(2013/06/05)
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- Rhodium-catalyzed enantioselective hydrogenation of oxime acetates
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Rh-catalyzed enantioselective hydrogenation of oxime acetates was first reported, which afforded a new approach for chiral amine synthesis.
- Huang, Kexuan,Li, Shengkun,Chang, Mingxin,Zhang, Xumu
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supporting information
p. 484 - 487
(2013/03/29)
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- Amination of ketones by employing two new (S)-selective ω-transaminases and the his-tagged ω-TA from Vibrio fluvialis
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Two recently identified (S)-selective ω-transaminases (ω-TAs) that originate from Paracoccus denitrificans (Strep-PD-ωTA, cloned with an N-terminal Strep-tag II) and Pseudomonas fluorescens (PF-ωTA) were employed for the asymmetric amination of selected prochiral ketones. The substrates tested were transformed into optically pure amines (>99 % ee) with high conversion (up to >99 %). The ω-TAs led to higher conversion in the absence of dimethyl sulfoxide as a cosolvent than in its presence (15 %, v/v). Additionally, it was shown that a His-tagged recombinant transaminase from Vibrio fluvialis (His-VF-ωTA, cloned with an N-terminal His 6-tag) showed for a single substrate, ethyl acetoacetate, significantly higher stereoselectivity for the amination compared to the corresponding commercial enzyme preparation (>99 vs. 50 %). The (S)-selective ω-transaminases (ω-TAs) from Paracoccus denitrificans and Pseudomonas fluorescens transformed various ketones into optically pure amines (>99 % ee). These enzymes extend the substrate spectrum of highly (S)-stereoselective ω-TAs. Copyright
- Mutti, Francesco G.,Fuchs, Christine S.,Pressnitz, Desiree,Turrini, Nikolaus G.,Sattler, Johann H.,Lerchner, Alexandra,Skerra, Arne,Kroutil, Wolfgang
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body text
p. 1003 - 1007
(2012/04/04)
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- Rhodium-catalyzed asymmetric hydrogenation of olefins with PhthalaPhos, a new class of chiral supramolecular ligands
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A library of 19 binol-derived chiral monophosphites that contain a phthalic acid diamide group (Phthala- Phos) has been designed and synthesized in four steps. These new ligands were screened in the rhodium-catalyzed enantioselective hydrogenation of prochiral dehydroamino esters and enamides. Several members of the library showed excellent enantioselectivity with methyl 2-acetamido acrylate (6 ligands gave >97% ee), methyl (Z)-2- acetamido cinnamate (6 ligands gave >94% ee), and N-(1-phenylvinyl)acetamide (9 ligands gave >95% ee), whilst only a few representatives afforded high enantioselectivities for challenging and industrially relevant substrates N-(3,4-dihydronaphthalen-1- yl)-acetamide (96% ee in one case) and methyl (E)-2-(acetamidomethyl)-3- phenylacrylate (99% ee in one case). In most cases, the new ligands were more active and more stereoselective than their structurally related monodentate phosphites (which are devoid of functional groups that are capable of hydrogen-bonding interactions). Control experiments and kinetic studies were carried out that allowed us to demonstrate that hydrogen-bonding interactions involving the diamide group of the PhthalaPhos ligands strongly contribute to their outstanding catalytic properties. Computational studies carried out on a rhodium precatalyst and on a conceivable intermediate in the hydrogenation catalytic cycle shed some light on the role played by hydrogen bonding, which is likely to act in a substrate-orientation effect.
- Pignataro, Luca,Boghi, Michele,Civera, Monica,Carboni, Stefano,Piarulli, Umberto,Gennari, Cesare
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supporting information; experimental part
p. 1383 - 1400
(2012/03/27)
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- Asymmetric Rh-catalyzed hydrogenation using a furanoside phosphite-phosphoroamidite and diphosphoroamidite ligand library
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A furanoside phosphite-phosphoroamidite and diphosphoroamidite ligand library L1-L5a-f was tested in the asymmetric Rh-catalyzed hydrogenation of α,β-unsaturated carboxylic acid derivatives and enamides. Enantioselectivity depended strongly on the ligand
- Coll, Mercedes,Pamies, Oscar,Dieguez, Montserrat
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experimental part
p. 3038 - 3045
(2012/04/10)
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- Synthesis of Binol-based diphosphinites bearing chiral phospholane units and their application in asymmetric catalysis
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New diphosphinite ligands based on atropoisomeric diol backbones and (R,R)-2,5-dimethylphospholane moieties have been prepared and fully characterised. For each ligand structure, both diastereomers have been synthesised. These ligands are available through a straightforward procedure in good yields. The solid state structures of two diastereomeric ligands are reported. These ligands have been applied to Rh-catalysed asymmetric hydrogenations and hydroformylations of CC bonds as well as in Ir-catalysed asymmetric hydrogenations of CN bonds. Turnover frequencies in the range of 10,000 h-1 and enantioselectivities of up to 98% ee have been achieved. The different chirality elements within the ligands led to marked cooperative effect in catalysis. Interestingly, there is no general privileged diastereomeric structure but rather a matched diastereomer for each application.
- Hammerer, Tim,Weisgerber, Laurent,Schenk, Stefan,Stelzer, Othmar,Englert, Ulli,Leitner, Walter,Franci, Giancarlo
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experimental part
p. 53 - 59
(2012/05/20)
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- Three-hindered quadrant phosphine ligands with an aromatic ring backbone for the rhodium-catalyzed asymmetric hydrogenation of functionalized alkenes
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The three-hindered quadrant phosphine ligands (R)-1-tert- butylmethylphosphino-2-(di-tert-butylphosphino)benzene ((R)-3H-BenzP*) and (R)-2-tert-butylmethylphosphino-3-(di-tert-butylphosphino)quinoxaline ((R)-3H-QuinoxP*) exhibited good to excellent enantioselectivities in the rhodium-catalyzed asymmetric hydrogenation of selected dehydroamino acid derivatives, enamides, and ethenephosphonates.
- Zhang, Zhenfeng,Tamura, Ken,Mayama, Daisuke,Sugiya, Masashi,Imamoto, Tsuneo
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experimental part
p. 4184 - 4188
(2012/06/18)
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- A library approach to the development of BenzaPhos: Highly efficient chiral supramolecular ligands for asymmetric hydrogenation
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A library of chiral supramolecular ligands, named BenzaPhos, of straightforward preparation (two steps from commercially or readily available starting materials) and modular structure, was designed and synthesized. The ligands were screened in the search for new rhodium catalysts for the enantioselective hydrogenation of several benchmark and industrially relevant substrates. Once a series of hits were identified, structural modifications were introduced on three of the best ligands and a small second-generation library was created. Members of the latter library showed outstanding levels of activity and enantioselectivity in the hydrogenation of challenging olefins, such as enamide S4 and β-dehydroamino ester S5 (>99 % ee: best value ever reported in both cases). A series of control experiments were undertaken to clarify the role of hydrogen bonding in determining the catalytic properties of the new ligands. The results of these experiments, together with those of computational studies carried out on four dihydride complexes involved in the catalytic hydrogenation of substrate S4, strongly suggest that a substrate orientation takes place in the catalytic cycle by formation of a hydrogen bond between the ligand amide oxygen atom and the substrate amide NH atom. As simple as selective: BenzaPhos ligands, benzamide-containing chiral monophosphites of modular structure and trivial synthesis, have been screened in the Rh-catalyzed hydrogenation of olefins (see scheme), giving excellent enantioselectivities with three benchmark and two industrially relevant substrates. Control experiments and computational studies suggest an important role of ligand-substrate hydrogen bonding in the stereodiscriminating step of the catalytic cycle. Copyright
- Pignataro, Luca,Bovio, Chiara,Civera, Monica,Piarulli, Umberto,Gennari, Cesare
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supporting information; experimental part
p. 10368 - 10381
(2012/10/08)
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- Nanomole-scale assignment of configuration for primary amines using a kinetic resolution strategy
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The absolute configurations of primary amines were assigned using a kinetic resolution strategy with Mioskowski's enantioselective 1-(R,R) and 2-(S,S) acylating agents. A simple mnemonic was developed to determine the configuration. A pseudoenantiomeric pair of reagents, 1-(R,R) and 2-(S,S)-d 3, was prepared and used to assay primary amines on a micromolar scale. The ESI-MS readout of the resulting acetamide products reproduced the selectivity factors from kinetic experiments. The method can be used on mixtures of amines and was validated with amine samples as small as 50 nmol.
- Miller, Shawn M.,Samame, Renzo A.,Rychnovsky, Scott D.
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supporting information
p. 20318 - 20321
(2013/02/23)
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- Self-disproportionation of enantiomers of non-racemic chiral amine derivatives through achiral chromatography
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Efficient self-disproportionation of enantiomers of several non-racemic chiral amines was achieved through conversion to N-acetamides and subsequent MPLC using an achiral column. The MPLC of these non-racemic N-acetamide derivatives gave the chart having a clear boundary between two fractions. Thus, in the less polar fraction, remarkable enantiomer enrichment was observed (>99%ee), while the ee of more polar fraction was considerably reduced. The magnitude of the enantiomer enrichments and depletions strongly depended on substituent on the amino group.
- Nakamura, Tsuyoshi,Tateishi, Kaori,Tsukagoshi, Shiori,Hashimoto, Saori,Watanabe, Shotaro,Soloshonok, Vadim A.,Ace?a, José Luis,Kitagawa, Osamu
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experimental part
p. 4013 - 4017
(2012/07/14)
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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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- Profiling the tuneable R-SMS-Phos structure in the rhodium(i)-catalyzed hydrogenation of olefins: The last stand?
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A diversified family of enantiopure P-stereogenic "R-SMS-Phos" {R-SMS-Phos = 1,2-bis[(o-RO-phenyl)(phenyl)phosphino]ethane} ligands wherein R = branched or heteroatom-substituted alkyl, aralkyl, silyl, acyl, sulfonyl, etc. was screened for the Rh(i)-catalyzed hydrogenation of a representative set of olefinic substrates. This systematic and detailed investigation revealed a marked beneficial impact on enantioselectivity and catalyst activity in comparison to Knowles' ultimate DiPAMP {DiPAMP = 1,2-bis[(o-anisyl)(phenyl) phosphino]ethane} design. Mutant ligands with highly enhanced properties possessing particular features wherein the DiPAMP structure is found embedded were identified. The Royal Society of Chemistry 2011.
- Stephan, Michel,?terk, Damjan,Zupan?i?, Borut,Mohar, Barbara
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supporting information; scheme or table
p. 5266 - 5271
(2011/09/20)
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