- Discovery and Redesign of a Family VIII Carboxylesterase with High (S)-Selectivity toward Chiral sec-Alcohols
-
Highly enantioselective lipase has been widely utilized in the preparation of versatile enantiopure chiral sec-alcohols through kinetic or dynamic kinetic resolution. Lipase is intrinsically (R)-selective, and it is difficult to obtain (S)-selective lipase. Recent crystal structures of a family VIII carboxylesterase have revealed that the spatial array of its catalytic triad is the mirror image of that of lipase but with a catalytic triad that is distinct from lipase. We, therefore, hypothesized that the family VIII carboxylesterase may exhibit (S)-enantioselectivity toward sec-alcohols similar to (S)-selective serine protease, whose catalytic triad is also spatially arrayed as its mirror image. In this study, a homologous enzyme (carboxylesterase from Proteobacteria bacterium SG_bin9, PBE) of a known family VIII carboxylesterase (pdb code: 4IVK) was prepared, which showed not only moderate (S)-selectivity toward sec-alcohols such as 3-butyn-2-ol and 1-phenylethyl alcohol but also (R)-selectivity toward particular sec-alcohols among the substrates explored. Furthermore, the (S)-selectivity of PBE has been significantly improved by rational redesign based on molecular modeling. Molecular modeling identified a binding pocket composed of Ser381, Ala383, and Arg408 for the methyl substituent of (R)-1-phenylethyl acetate and suggested that larger residues may increase the enantioselectivity by interfering with the binding of the slow-reacting enantiomer. As predicted, substituting Ser381with larger residues (Phe, Tyr, and Trp) significantly improved the (S)-selectivity of PBE toward all sec-alcohols explored, even the substrates toward which the wild-type PBE exhibits (R)-selectivity. For instance, the enantioselectivity toward 3-butyn-2-ol and 1-phenylethyl alcohol was improved from E = 5.5 and 36.1 to E = 2001 and 882, respectively, by single mutagenesis (S381F).
- Park, Areum,Park, Seongsoon
-
p. 2397 - 2402
(2022/02/17)
-
- Exploration of highly electron-rich manganese complexes in enantioselective oxidation catalysis; A focus on enantioselective benzylic oxidation
-
The direct enantioselective hydroxylation of benzylic C-H bonds to form chiral benzylic alcohols represents a challenging transformation. Herein, we report on the exploration of new biologically inspired manganese and iron complexes bearing highly electron-rich aminopyridine ligands containing 4-pyrrolidinopyridine moieties ((S,S)-1, (R,R)-1, 2 and 5) in combination with chiral bis-pyrrolidine and N,N-cyclohexanediamine backbones in enantioselective oxidation catalysis with aqueous H2O2. The current manganese complexes outperform the analogous manganese complexes containing 4-dimethylaminopyridine moieties (3 and 4) in benzylic oxidation reactions in terms of alcohol yield while keeping similar ee values (~60% ee), which is attributed to the higher basicity of the 4-pyrrolidinopyridine group. A detailed investigation of different carboxylic acid additives in enantioselective benzylic oxidation provides new insights into how to rationally enhance enantioselectivities by means of proper tuning of the environment around the catalytic active site, and has resulted in the selection of Boc-l-Tert-leucine as the preferred additive. Using these optimized conditions, manganese complex 2 was shown to be effective in the enantioselective benzylic oxidation of a series of arylalkane substrates with up to 50% alcohol yield and 62% product ee. A final set of experiments also highlights the use of the new 4-pyrrolidinopyridine-based complexes in the asymmetric epoxidation of olefins (up to 98% epoxide yield and >99% ee).
- Klein Gebbink, Robertus J. M.,Li, Fanshi,Lutz, Martin,Masferrer-Rius, Eduard
-
p. 7751 - 7763
(2021/12/13)
-
- PQXdpap: Helical Poly(quinoxaline-2,3-diyl)s Bearing 4-(Dipropylamino)pyridin-3-yl Pendants as Chirality-Switchable Nucleophilic Catalysts for the Kinetic Resolution of Secondary Alcohols
-
Helically chiral poly(quinoxaline-2,3-diyl)s bearing 4-(dipropylamino)pyridin-3-yl pendants at the 5-position of the quinoxaline ring (PQXdpap) exhibited high catalytic activities and moderate to high selectivities (up to s = 87) in the acylative kinetic resolution of secondary alcohols. The solvent-dependent helical chirality switching of PQXdpap between pure toluene and a 1:1 mixture of toluene and 1,1,2-trichloroethane enabled the preparation of either compound of a pair of enantiomerically pure alcohols (>99% ee) from a single catalyst.
- Murakami, Ryo,Suginome, Michinori,Yamamoto, Takeshi
-
supporting information
p. 8711 - 8716
(2021/11/24)
-
- Rhizopus arrhizus mediated SAR studies in chemoselective biotransformation of haloketones at ambient temperature
-
We have demonstrated a green chemistry approach using the fungus Rhizopus arrhizus for the reductive dehalogenation and synthesis of chiral secondary carbinols and halohydrins of pharmaceutical importance in mild, inexpensive, and environmental friendly process at ambient temperature. In the present study, we have succeeded in unravelling the relationship between the position of the substituent group in the structure of substrate and bioreduction activity of the fungus Rhizopus arrhizus. The asymmetric reduction of the carbonyl group to corresponding chiral halohydrin takes place with good yield and excellent enantiomeric excess (≥92%) when the substituent halogen is on the aromatic nucleus. However, novel results concerning reductive dehalogenation are obtained when halogen is incorporated in the alkyl side chain. Thus, the fungus Rhizopus arrhizus has great potential to bring chemoenzymatic biotransformation of halo ketones. Various influential processing parameters such as microbe selection, temperature, pH, etc. were also investigated to optimize the growth of biocatalyst.
- Salokhe, Prabha R.,Salunkhe, Rajeshri S.
-
-
- Synthesis, characterization and catalytic performance in enantioselective reactions by mesoporous silica materials functionalized with chiral thiourea-amine ligand
-
Chiral heterogeneous catalysts have been synthesized by grafting of silyl derivatives of (1R, 2R)- or (1S, 2S)-1,2-diphenylethane-1,2-diamine on SBA-15 mesoporous support. The mesoporous material SBA-15 and so-prepared chiral heterogeneous catalysts were characterized by a combination of different techniques such as X-ray diffractometry (XRD), Fourier transform infrared (FT-IR), thermogravimetric analysis (TGA), field emission scanning electron microscopy (FESEM), and Brunauer–Emmett–Teller (BET) surface area. Results showed that (1R, 2R)- and (1S, 2S)-1,2-diphenylethane-1,2-diamine were successively immobilized on SBA-15 mesoporous support. Chiral heterogeneous catalysts and their homogenous counterparts were tested in enantioselective transfer hydrogenation of aromatic ketones and enantioselective Michael addition of acetylacetone to β-nitroolefin derivatives. The catalysts demonstrated notably high catalytic conversions (up to 99%) with moderate enantiomeric excess (up to 30% ee) for the heterogeneous enantioselective transfer hydrogenation. The catalytic performances for enantioselective Michael reaction showed excellent activities (up to 99%) with poor enantioselectivities. Particularly, the chiral heterogeneous catalysts could be readily recycled for Michael reaction and reused in three consecutive catalytic experiments with no loss of catalytic efficacies.
- G?k, Ya?ar,G?k, Halil Zeki
-
p. 853 - 874
(2020/11/10)
-
- Tridentate nitrogen phosphine ligand containing arylamine NH as well as preparation method and application thereof
-
The invention discloses a tridentate nitrogen phosphine ligand containing arylamine NH as well as a preparation method and application thereof, and belongs to the technical field of organic synthesis. The tridentate nitrogen phosphine ligand disclosed by the invention is the first case of tridentate nitrogen phosphine ligand containing not only a quinoline amine structure but also chiral ferrocene at present, a noble metal complex of the type of ligand shows good selectivity and extremely high catalytic activity in an asymmetric hydrogenation reaction, meanwhile, a cheap metal complex of the ligand can also show good selectivity and catalytic activity in the asymmetric hydrogenation reaction, and is very easy to modify in the aspects of electronic effect and space structure, so that the ligand has huge potential application value. A catalyst formed by the ligand and a transition metal complex can be used for catalyzing various reactions, can be used for synthesizing various drugs, and has important industrial application value.
- -
-
Paragraph 0095-0102; 0105-0109
(2021/06/26)
-
- Highly Active Cooperative Lewis Acid—Ammonium Salt Catalyst for the Enantioselective Hydroboration of Ketones
-
Enantiopure secondary alcohols are fundamental high-value synthetic building blocks. One of the most attractive ways to get access to this compound class is the catalytic hydroboration. We describe a new concept for this reaction type that allowed for exceptional catalytic turnover numbers (up to 15 400), which were increased by around 1.5–3 orders of magnitude compared to the most active catalysts previously reported. In our concept an aprotic ammonium halide moiety cooperates with an oxophilic Lewis acid within the same catalyst molecule. Control experiments reveal that both catalytic centers are essential for the observed activity. Kinetic, spectroscopic and computational studies show that the hydride transfer is rate limiting and proceeds via a concerted mechanism, in which hydride at Boron is continuously displaced by iodide, reminiscent to an SN2 reaction. The catalyst, which is accessible in high yields in few steps, was found to be stable during catalysis, readily recyclable and could be reused 10 times still efficiently working.
- Titze, Marvin,Heitk?mper, Juliane,Junge, Thorsten,K?stner, Johannes,Peters, René
-
supporting information
p. 5544 - 5553
(2021/02/05)
-
- Enantiocomplementary C–H Bond Hydroxylation Combining Photo-Catalysis and Whole-Cell Biocatalysis in a One-Pot Cascade Process
-
Enantiocomplementary hydroxylation of alkyl aromatics through a one-pot photo-biocatalytic cascade reaction is described. The photoredox process is implemented in aqueous phase with O2 as oxidant and the subsequent (R)- or (S)-selective bioreduction is performed by whole cell system without the addition of the expensive cofactor (NADPH). This mild, operationally simple protocol transforms a wide variety of readily available aromatic compounds into valuable chiral alcohols with high yield (up to 90 %) and stereoselectivity (up to 99 %), thereby displaying important potentials in organic synthesis.
- Peng, Yongzhen,Li, Danyang,Fan, Jiajie,Xu, Weihua,Xu, Jian,Yu, Huilei,Lin, Xianfu,Wu, Qi
-
p. 821 - 825
(2020/02/20)
-
- One-pot kinetic resolution-Mitsunobu reaction to access optically pure compounds, using silver salts in the substitution protocol
-
A practical method is developed to access chiral arylalkyl carbinols with a high yield from racemic alcohols. A one-pot enzyme mediated Kinetic Resolution followed by Mitsunobu esterification of the unreacted enantiomer of alcohol with metal acetate results in a nearly complete formation of chiral acetate. Substitution with AgOAc was found to be the most efficient, and the use of sub stoichiometric amounts of AgNO3 and excess of NaOAc affords comparable results; the protocol was further extended to introduce azide as a nucleophile.
- Raval, Hiten B.,Bedekar, Ashutosh V.
-
p. 21238 - 21243
(2020/12/31)
-
- Imine containing C2-Symmetric chiral half sandwich η6-p-cymene-Ru(II)- phosphinite complexes: Investigation of their catalytic activity in the asymmetric transfer hydrogenation of ketones
-
New chiral C2-symmetric bis(phosphinite) ligands containing imine group were synthesized from 1-({[(1R,2R)-2-{[(2-hydroxynaphthalen-1-yl)methylidene] amino}cyclohexyl]- imino}methyl)- naphthalen-2-ol and two equivalents of Ph2PCl, (i-Pr)2PCl or (Cy)2PCl, in high yields. Binuclear C2-symmetric half sandwich η6-p-cymene-Ru(II) complexes of the chiral phosphinite ligands were synthesized by treating of [Ru(η6-p-cymene)(μ-Cl)Cl]2 with the phosphinites in 1:1 M ratio in CH2Cl2. Their catalytic activities in asymmetric transfer hydrogenation (ATH) were investigated for the reaction of acetophenone derivatives with isopropyl alcohol. The corresponding optically active secondary alcohols were obtained in excellent levels of conversion (96–99%) and moderate enantioselectivity (up to 60% ee). Among three complexes investigated, complex 4 was the most efficient one.
- Saleh, Najmuldain Abdullah,Pa?a, Salih,Kayan, Cezmi,Meri?, Nermin,Sünkür, Murat,Aral, Tar?k,Aydemir, Murat,Baysal, Ak?n,Durap, Feyyaz
-
-
- SECONDARY ARYL ALCOHOL AND METHOD OF SYNTHESIZING THEREOF
-
The present invention relates to secondary aryl alcohol and a method for synthesizing the same and, specifically, to synthesizing secondary aryl alcohol having high optical selectivity through a hydrosilylation reaction using ketone containing an aryl group. In the method for synthesizing secondary aryl alcohol according to an embodiment of the present invention, secondary aryl alcohol is synthesized by making ketone react with hydrosilane under a chiral boron Lewis acid catalyst.COPYRIGHT KIPO 2020
- -
-
Paragraph 0032; 0062-0069
(2020/05/13)
-
- Palladium Complexes Bearing Chiral bis(NHC) Chelating Ligands on a Spiro Scaffold: Synthesis, Characterization, and Their Application in the Oxidative Kinetic Resolution of Secondary Alcohols
-
A series of chiral bis-N-heterocyclic carbene ligands H2[(S)-1a-d]X2 (X = Br, I) on a spiro scaffold and their palladium complexes (S)-2a-d and (S)-3a,b were prepared and applied in the enantioselective oxidative kinetic resolution of secondary alcohols. The corresponding alcohols can be obtained in high yields with moderate to excellent ee values.
- Zhang, Dao,Yu, Jueqin
-
p. 605 - 613
(2020/02/13)
-
- C1-Symmetric PNP Ligands for Manganese-Catalyzed Enantioselective Hydrogenation of Ketones: Reaction Scope and Enantioinduction Model
-
A family of ferrocene-based chiral PNP ligands is reported. These tridentate ligands were successfully applied in Mn-catalyzed asymmetric hydrogenation of ketones, giving high enantioselectivities (92%~99% ee for aryl alkyl ketones) as well as high efficiencies (TON up to 2000). In addition, dialkyl ketones could also be hydrogenated smoothly. Manganese intermediates that might be involved in the catalytic cycle were analyzed. DFT calculation was carried out to help understand the chiral induction model. The Mn/PNP catalyst could discriminate two groups with different steric properties by deformation of the phosphine moiety in the flexible 5-membered ring.
- Zeng, Liyao,Yang, Huaxin,Zhao, Menglong,Wen, Jialin,Tucker, James H. R.,Zhang, Xumu
-
p. 13794 - 13799
(2020/11/30)
-
- RETRACTED ARTICLE: The Manganese(I)-Catalyzed Asymmetric Transfer Hydrogenation of Ketones: Disclosing the Macrocylic Privilege
-
The bis(carbonyl) manganese(I) complex [Mn(CO)2(1)]Br (2) with a chiral (NH)2P2 macrocyclic ligand (1) catalyzes the asymmetric transfer hydrogenation of polar double bonds with 2-propanol as the hydrogen source. Ketones (43 substrates) are reduced to alcohols in high yields (up to >99 %) and with excellent enantioselectivities (90–99 % ee). A stereochemical model based on attractive CH–π interactions is proposed.
- Passera, Alessandro,Mezzetti, Antonio
-
supporting information
p. 187 - 191
(2019/12/11)
-
- Green synthesis of chiral aromatic alcohols with Lactobacillus kefiri P2 as a novel biocatalyst
-
Biocatalytic reduction is a very important field of research in synthetic organic chemistry. Herein, three different Lactic Acid Bacteria (LAB) strains were evaluated for their bioreduction potential using acetophenone as a model substrate. Among these strains, Lactobacillus kefiri P2 strain was determined as the best asymmetric reduction biocatalyst. Reaction optimization parameters such as reaction time, temperature, agitation speed and pH were systematically optimized using Lactobacillus kefiri P2 strain and model substrate acetophenone. Under these optimized reaction conditions, secondary chiral alcohols were obtained by bioreduction of various prochiral ketones with results up to 99% enantiomeric excess. In addition, the steric and electronic effects of substituents on enantioselectivity and conversion were evaluated. It has been shown that Lactobacillus kefiri P2 biocatalyst was an effective catalyst for asymmetric reduction. This method provides an environmentally friendly method for the synthesis of optically pure alcohols and an alternative approach to chemical catalysts.
- Bayda?, Yasemin,Dertli, Enes,?ahin, Engin
-
p. 1035 - 1045
(2020/03/03)
-
- Engineering an alcohol dehydrogenase with enhanced activity and stereoselectivity toward diaryl ketones: Reduction of steric hindrance and change of the stereocontrol element
-
Steric hindrance in the binding pocket of an alcohol dehydrogenase (ADH) has a great impact on its activity and stereoselectivity simultaneously. Due to the subtle structural difference between two bulky phenyl substituents, the asymmetric synthesis of diaryl alcohols by bioreduction of diaryl ketones is often hindered by the low activity and stereoselectivity of ADHs. To engineer an ADH with practical properties and to investigate the molecular mechanism behind the asymmetric biocatalysis of diaryl ketones, we engineered an ADH from Lactobacillus kefiri (LkADH) to asymmetrically catalyse the reduction of 4-chlorodiphenylketones (CPPK), which are not catalysed by the wild type (WT) enzyme. Mutants seq1-seq5 with gradually increased activity and stereoselectivity were obtained through iterative "shrinking mutagenesis." The final mutant seq5 (Y190P/I144V/L199V/E145C/M206F) demonstrated the highest activity and excellent stereoselectivity of >99% ee. Molecular simulation analyses revealed that mutations may enhance the activity by eliminating steric hindrance, inducing a more open binding loop and constructing more noncovalent interactions. The pro-R pose of CPPK with a halogen bond formed a pre-reaction conformation more easily than the pro-S pose, resulting in the high ee of (R)-CPPO in seq5. Moreover, different halogen bonds formed due to the different positions of chlorine substituents, resulting in opposite substrate binding orientation and stereoselectivity. Therefore, the stereoselectivity of seq5 was inverted toward ortho- rather than para-chlorine substituted ketones. These results indicate that the stereocontrol element of LkADH was changed to recognise diaryl ketones after steric hindrance was eliminated. This study provides novel insights into the role of steric hindrance and noncovalent bonds in the determination of the activity and stereoselectivity of enzymes, and presents an approach producing key intermediates of chiral drugs with practical potential.
- Chen, Rong,Huang, Jiankun,Meng, Xiangguo,Shao, Lei,Wu, Kai,Yang, Zhijun
-
p. 1650 - 1660
(2020/04/09)
-
- Control of enantioselectivity in the enzymatic reduction of halogenated acetophenone analogs by substituent positions and sizes
-
We utilized acetophenone reductase from Geotrichum candidum NBRC 4597 (GcAPRD), wild type and Trp288Ala mutant, to reduce halogenated acetophenone analogs to their corresponding (S)- and (R)-alcohols beneficial as pharmaceutical intermediates. Reduction by wild type resulted in excellent (S)-enantioselectivity for all of the substrates tested. Meanwhile, reduction by Trp288Ala resulted in high (R)-enantioselectivity for the reduction of 4′ substituted acetophenone and 2′-trifluoromethylacetophenone. In addition to that, we were able to control the enantioselectivity of Trp288Ala by the positions and sizes of the halogen substituents.
- Koesoema, Afifa Ayu,Standley, Daron M.,Ohshima, Shusuke,Tamura, Mayumi,Matsuda, Tomoko
-
supporting information
(2020/03/23)
-
- Enantiocomplementary decarboxylative hydroxylation combining photocatalysis and whole-cell biocatalysis in a one-pot cascade process
-
Designing a green, highly efficient and stereoselective catalytic system to generate valuable enantioenriched products is a long-standing goal in green chemistry. Here, we report a one-pot cascade combining photocatalysts with (R)- or (S)-selective ketoreductases for the decarboxylative carbonylation of carboxylic acids and the subsequent bioreduction to generate valuable chiral alcohols. Using this approach, various chiral alcohols with complementary (R)- or (S)-configurations were prepared with good yields (up to 93%) and excellent stereoselectivity (up to 99% ee). Such a photochemo-enzymatic one-pot whole-cell process combines the advantages of both photocatalysts and enzyme catalysts and provides a mild, green, metal-free and highly stereoselective alternative in asymmetric decarboxylative hydroxylation reactions.
- Xu, Jian,Arkin, Mamatjan,Peng, Yongzhen,Xu, Weihua,Yu, Huilei,Lin, Xianfu,Wu, Qi
-
p. 1907 - 1911
(2019/04/27)
-
- Combined Photoredox/Enzymatic C?H Benzylic Hydroxylations
-
Chemical transformations that install heteroatoms into C?H bonds are of significant interest because they streamline the construction of value-added small molecules. Direct C?H oxyfunctionalization, or the one step conversion of a C?H bond to a C?O bond, could be a highly enabling transformation due to the prevalence of the resulting enantioenriched alcohols in pharmaceuticals and natural products,. Here we report a single-flask photoredox/enzymatic process for direct C?H hydroxylation that proceeds with broad reactivity, chemoselectivity and enantioselectivity. This unified strategy advances general photoredox and enzymatic catalysis synergy and enables chemoenzymatic processes for powerful and selective oxidative transformations.
- Betori, Rick C.,May, Catherine M.,Scheidt, Karl A.
-
supporting information
p. 16490 - 16494
(2019/11/03)
-
- Iridium-catalyzed asymmetric hydrogenation method for the preparation of chiral alcohols
-
The present invention provides one kind of iridium-catalyzed asymmetric hydrogenation method for the preparation of chiral alcohols, the method specifically is: in the glove box filled with nitrogen, the [Ir (COD) Cl]2 With a chiral P, N, N ligand soluble in methanol, stir at room temperature 1 hour, [...] catalyst. Adding substrate alkone and alkali additive, is placed on the high-pressure in the reactor, for a certain reaction under the pressure of the hydrogenation reaction. Slowly release hydrogen, silica gel to remove the solvent and separate the product after the alcohol. The invention states iridium catalyzed alkone asymmetric hydrogenation for the preparation of chiral reaction has mild condition, easy to operate, and the product of the enantioselectivity and the like.
- -
-
Paragraph 0095-0100; 0103
(2019/06/07)
-
- Diphenylamine-amine-oxazoline ligand, synthesis method as well as metal complex and application thereof
-
The invention provides a diphenylamine-amine-oxazoline ligand which is a compound of formula (1) or an antipode or racemate of the compound of formula (1), wherein R1 and R2 are respectively and separately one of C1 to C10 hydrocarbon group, benzyl group, phenyl group or substituted phenyl group and heteroaryl group; and R3 is H or methyl. The invention also discloses a synthesis method as well asa metal complex and application thereof, which aims at providing a catalyst capable of realizing high synthesis yield by virtue of a simple synthesis route, and ensuring that the catalyst has very high catalytic activity in asymmetric hydrogenation and hydrogen transfer reactions of olefins and ketones.
- -
-
Paragraph 0122-0128; 0137; 0138
(2019/04/17)
-
- Deracemization of sec-alcohols through sequential application of C. Albicans and Ketoreductases
-
A biocatalytic cascade process was developed using immobilized cells of the wild type yeast Candida albicans CCT 0776 in calcium alginate beads and a commercially available ketoreductase. The aim was to promote deracemization by stereoinversion of (±)-1-arylethanols in high substrate concentration (above 100 mmol L-1) to prepare the (R)-enantiomers of the alcohols (90-99percent), with a high enantiomeric excess (83-99percent) after 2 to 19 h. The (R)-1-(3-methoxyphenyl)ethanol, with 70percent yield and 91percent ee, obtained after 5 h was used to prepare (S)-1-(3-methoxyphenyl)-ethylamine with 60percent yield and 91percent ee after two steps, a key intermediate in the synthesis of (S)-rivastigmine.
- Nasário, Fábio D.,Moran, Paulo J.S.,Rodrigues, José Augusto R.
-
p. 772 - 779
(2019/08/26)
-
- Chiral Frustrated Lewis Pairs Catalyzed Highly Enantioselective Hydrosilylations of Ketones
-
A highly enantioselective Piers-type hydrosilylation of simple ketones was successfully realized using a chiral frustrated Lewis pair of tri-tert-butylphosphine and chiral diene-derived borane as catalyst. A wide range of optically active secondary alcohols were furnished in 80%—99% yields with 81%—97% ee's under mild reaction conditions.
- Liu, Xiaoqin,Wang, Qiaotian,Han, Caifang,Feng, Xiangqing,Du, Haifeng
-
p. 663 - 666
(2019/05/21)
-
- Ir-catalyzed asymmetric hydrogenation of simple ketones with chiral ferrocenyl P,N,N-ligands
-
The Ir-catalyzed asymmetric hydrogenation of simple aromatic ketones with chiral ferrocenyl P,N,N-ligands has been developed. Under the optimized conditions, a wide range of ketones were hydrogenated to afford the corresponding chiral alcohols in good to excellent enantioselectivities (up to 98% ee).
- Qin, Chao,Hou, Chuan-Jin,Liu, Hongzhu,Liu, Yan-Jun,Huang, De-Zhi,Hu, Xiang-Ping
-
supporting information
p. 719 - 722
(2018/01/17)
-
- The open d-shell enforces the active space in 3d metal catalysis: Highly enantioselective chromium(ii) pincer catalysed hydrosilylation of ketones
-
Bis(oxazolinyldimethylmethyl)pyrrol (PdmBox) stereodirecting ligands provided the key to the chromium(ii)-catalysed highly enantioselective hydrosilylation of ketones. A rare square planar, chiral chromium(ii) alkyl complex was found to serve as a potent precatalyst for the reduction of a broad range of aryl alkyl and dialkyl ketone derivatives. The stereoelectronic preference of the open d4 shell of chromium(ii) firmly locks the molecular catalyst in a square planar geometry giving rise to two blocked quadrants of the coordination sphere. This earth-abundant base metal catalytic platform produces the corresponding chiral alcohols in excellent isolated yields with up to 98 %ee under mild reaction conditions (-40 °C to rt) and at low catalyst loadings (as low as 0.5 mol%).
- Schiwek, Christian H.,Vasilenko, Vladislav,Wadepohl, Hubert,Gade, Lutz H.
-
supporting information
p. 9139 - 9142
(2018/08/24)
-
- Immobilized and free cells of geotrichum candidum for asymmetric reduction of ketones: Stability and recyclability
-
Marine-derived fungus Geotrichum candidum AS 2.361 was previously reported by our group as an active strain for the enantioselective reduction of ketones. Although some other Geotrichum strains were also found from the terrestrial sources, information on their stability and reusability is scarce. Herein, the stabilities—in terms of pH tolerance, thermostability, and storage stability, and reusability—of G. candidum AS 2.361 were described for the asymmetric reduction of a series of aromatic ketones. Two differently immobilized cells (agar immobilization and calcium alginate immobilization) as well as free cells were prepared. For three substrates (1-(3-bromophenyl) ethan-1-one (1b), 1-(2-chlorophenyl) ethan-1-one (1d), and acetophenone (1g)) immobilized cells on agar showed a great improvement in the bioreduction activities compared to the free cells, increasing yields up to 97% with ee values of 99%. Cells immobilized on agar/calcium alginate could maintain more than 90% of the original activities within the assayed pH ranges of 3.5–11, while free cells were highly sensitive to alkaline and acidic conditions. Concerning thermostability, immobilized cells on agar kept 99% of their original activities after incubation at 60?C for 1 h, while almost no activity was detected for the free cells under the same condition. Immobilized cells were stable at 4?C for 80 days without any activity loss, while free cells started to decrease the activity after storage at 4?C for six days. The immobilized cells retained almost 99% activity after four reuse cycles, while free cells lost almost all the activities at on the third cycle.
- Liu, Hui,de Souza, Fayene Zeferino Ribeiro,Liu, Lan,Chen, Bi-Shuang
-
-
- Improved Enantioselectivity of Subtilisin Carlsberg towards Secondary Alcohols by Protein Engineering
-
Generally, the catalytic activity of subtilisin Carlsberg (SC) for transacylation reactions with secondary alcohols in organic solvent is low. Enzyme immobilization and protein engineering was performed to improve the enantioselectivity of SC towards secondary alcohols. Possible amino-acid residues for mutagenesis were found by combining available literature data with molecular modeling. SC variants were created by site-directed mutagenesis and were evaluated for a model transacylation reaction containing 1-phenylethanol in THF. Variants showing high E values (>100) were found. However, the conversions were still low. A second mutation was made, and both the E values and conversions were increased. Relative to that shown by the wild type, the most successful variant, G165L/M221F, showed increased conversion (up to 36 %), enantioselectivity (E values up to 400), substrate scope, and stability in THF.
- Dorau, Robin,G?rbe, Tamás,Svedendahl Humble, Maria
-
p. 338 - 346
(2017/12/26)
-
- Kinetic resolution of sterically hindered secondary alcohols catalyzed by aminophosphinite organocatalyst
-
Kinetic resolution of secondary alcohols by benzoylation using a phosphinite derivative of (1S,2R)-1-amino-2-indanol as the catalyst was investigated. The aminophosphinite catalyst is effective for the kinetic resolution of aryl cycloalkyl carbinols with a small number of examples for organocatalytic kinetic resolution to achieve resolution with s = up to 44. Although the benzoylation of phenylalkanols proceeded with a low selectivity, 1-arylalkanols bearing at least one substituent at the ortho position on the benzene ring or a branched alkyl group on the carbinol carbon were resolved with acceptable selectivity.
- Hara, Nanami,Fujisawa, Shu,Fujita, Mizuki,Miyazawa, Mikako,Ochiai, Kazuma,Katsuda, Satoshi,Fujimoto, Tetsuya
-
p. 296 - 302
(2017/12/11)
-
- Easy Access to Enantiopure (S)- and (R)-Aryl Alkyl Alcohols by a Combination of Gold(III)-Catalyzed Alkyne Hydration and Enzymatic Reduction
-
Chemoenzymatic one-pot processes based on the combination of metal catalysis and biocatalysis open up highly attractive perspectives regarding the production of enantiopure compounds. By combining a gold-catalyzed hydration reaction with an enzymatic reduction, we present a straightforward and atom-economical chemoenzymatic method for the synthesis of secondary alcohols with excellent optical purity. Efficient cofactor recycling exploits the solvent of the metal-catalyzed step as an auxiliary substrate for the enzymatic step.
- Schaaf, Patricia,Gojic, Vladimir,Bayer, Thomas,Rudroff, Florian,Schnürch, Michael,Mihovilovic, Marko D.
-
p. 920 - 924
(2018/02/23)
-
- A Ferrocene-Based NH-Free Phosphine-Oxazoline Ligand for Iridium-Catalyzed Asymmetric Hydrogenation of Ketones
-
A new type of ferrocene-based phosphine-oxazoline ligand has been prepared over a few simple steps. An iridium complex of this ligand is air stable and exhibits excellent performance for the asymmetric hydrogenation of simple ketones (up to 98% yield, up to 99% ee, and 20?000 S/C). Exo-α,β-unsaturated cyclic ketones could be regiospecifically hydrogenated to give chiral allylic alcohols with good results. This study indicates that P,N-ligands can also efficiently promote Ir-catalyzed asymmetric hydrogenation without NH-hydrogen-bonding assistance.
- Wang, Yanzhao,Yang, Guoqiang,Xie, Fang,Zhang, Wanbin
-
supporting information
p. 6135 - 6139
(2018/09/27)
-
- Synthesis of Enantiomerically Pure and Racemic Benzyl-Tethered Ru(II)/TsDPEN Complexes by Direct Arene Substitution: Further Complexes and Applications
-
The use of a direct arene-exchange method for the synthesis of benzyl-tethered arene/Ru/TsDPEN complexes for use in asymmetric transfer hydrogenation is reported. A series of complexes tethered through a three-carbon linear chain was also prepared. The arene-exchange approach significantly simplifies the synthetic approach to this class of catalyst and permits the ready formation of modified analogues. The approach also provides a route to racemic catalysts for use in general reductions with either hydrogen or transfer hydrogenation.
- Soni, Rina,Jolley, Katherine E.,Gosiewska, Silvia,Clarkson, Guy J.,Fang, Zhijia,Hall, Thomas H.,Treloar, Ben N.,Knighton, Richard C.,Wills, Martin
-
-
- Fine tuning the enantioselectivity and substrate specificity of alcohol dehydrogenase from Kluyveromyces polysporus by single residue at 237
-
Here, S237 was identified to be important in fine tuning the substrate specificity and enantioselectivity of alcohol dehydrogenase from Kluyveromyces polysporus (KpADH). In the reduction of a diaryl ketone, (4-chlorophenyl)-(pyridin-2-yl)-methanone (1a), the highest and lowest enantioselectivity of 96.1% and 27.0% e.e. (R) were obtained with S237A and S237C. Kinetic parameters analysis revealed that S237G, S237A, S237H and S237D displayed improved kcat/Km toward 1a. Various prochiral ketones, including acetophenone, 4-chloroacetophenone and ethyl 2-oxo-4-phenylbutyrate could be asymmetrically reduced by S237C, S237G and S237E with > 99% e.e. This study provides guidance for the application of KpADH in the preparation of chiral secondary alcohols.
- Wang, Yue,Dai, Wei,Liu, Yongmei,Zhang, Zhongwei,Zhou, Jieyu,Xu, Guochao,Ni, Ye
-
-
- Construction of a chiral macromolecular catalyst in hollow silica nanoreactors for efficient and recyclable asymmetric catalysis
-
The entrapment method is a fascinating pathway to convert homogeneous into heterogeneous catalysts. However, the types of entrapped catalysts and available supports are still limited because of the strict requirements of this method. Here, we reported a novel strategy for achieving efficient entrapment of a chiral homogeneous catalyst by forming macromolecular polymers in the cavity of hollow silica nanoreactors. Specifically, through in situ polymerization of the chiral ligand (1R,2R)-N1-(4-vinylbenzenesulfonyl)-1,2-diphenylethane-1,2-diamine (VBS-DPEN) with styrene followed by coordination of the metal precursor [Cp?RhCl2]2 (Cp? = pentamethylcyclopentadiene), a chiral solid catalyst with a confined macromolecular polymer was obtained. In the aqueous asymmetric transfer hydrogenation (ATH) of ketones, such a catalyst exhibited much better activity (TOF 991 vs. 724 h-1) and similar enantioselectivity (94% ee) compared with its homogeneous counterpart. This excellent activity can be attributed to the combination of the hollow mesoporous structure, unique hydrophobic@hydrophilic surface properties and semi-free state of the macromolecular catalyst. Moreover, the solid catalyst exhibits good recyclability, which is much better than the pure macromolecular polymer catalyst. Our studies not only provide an excellent heterogeneous asymmetric catalyst but also demonstrate that the pathway for confining macromolecules could be used as an efficient scaffold for the synthesis of entrapped catalysts.
- Jing, Lingyan,Zhang, Xiaoming,Guan, Ruqun,Yang, Hengquan
-
p. 2304 - 2311
(2018/05/23)
-
- A cationic cyclodextrin clicked bilayer chiral stationary phase for versatile chiral separation in HPLC
-
A cationic cyclodextrin (CD) clicked bilayer chiral stationary phase (CSP) was developed via click chemistry for chiral separations in multimode high-performance chromatography (HPLC). The versatility of this new CSP was evaluated using 17 model racemic pairs including aromatic alcohols, flavonoids and isoxazoline enantiomers in both reversed-phase (RP) and normal-phase (NP) HPLC. The CD functionality-enhanced chiral selectivity was elucidated in different elution modes. Higher chiral resolutions were shown in the RP-elution mode due to the inclusion complexation in comparison to the NP-elution mode. The highest chiral resolution of 4.40 was achieved for 4ClPh-OPr, with 12 racemic pairs baseline separated in RP-HPLC. The addition of organic modifiers in mobile phases plays an important role in optimizing the enantioselectivities of the cationic CD bilayer CSP in NP-HPLC.
- Zhou, Jie,Yang, Bo,Tang, Jian,Tang, Weihua
-
p. 3526 - 3533
(2018/03/06)
-
- Enzymatic chemical transformations of aldehydes, ketones, esters and alcohols using plant fragments as the only biocatalyst: Ximenia americana grains
-
The present study demonstrated the ability of Ximenia american as a biocatalyst in reduction, hydrolysis and esterification reactions. The reduction reactions of aldehydes and ketones, ester hydrolysis and esterification of alcohols were carried out with interesting results. Reduction of ketones afforded yields of 6–60% with ee in the range of 35–>99% and that of aldehydes in yields of 51–99%. On the other hand, ester hydrolysis afforded yields of 58–98% with ee in the range 34–87%, while esterification of alcohols in 18–99% yields. Experimental conditions for all reactions have been defined using standard substrates as indicated in results and discussion. Some of the products are the potential building blocks for the synthesis of molecules which are of pharmaceutical and agrochemical importance.
- da Silva, Romézio Alves Carvalho,de Mesquita, Bruna Marques,de Farias, Iolanda Frota,do Nascimento, Patrícia Georgiana Garcia,de Lemos, Telma Leda Gomes,Queiroz Monte, Francisco José
-
p. 187 - 194
(2018/01/05)
-
- Selective Activation of C?H Bonds in a Cascade Process Combining Photochemistry and Biocatalysis
-
Selective oxyfunctionalizations of inert C?H bonds can be achieved under mild conditions by using peroxygenases. This approach, however, suffers from the poor robustness of these enzymes in the presence of hydrogen peroxide as the stoichiometric oxidant. Herein, we demonstrate that inorganic photocatalysts such as gold–titanium dioxide efficiently provide H2O2 through the methanol-driven reductive activation of ambient oxygen in amounts that ensure that the enzyme remains highly active and stable. Using this approach, the stereoselective hydroxylation of ethylbenzene to (R)-1-phenylethanol was achieved with high enantioselectivity (>98 % ee) and excellent turnover numbers for the biocatalyst (>71 000).
- Zhang, Wuyuan,Burek, Bastien O.,Fernández-Fueyo, Elena,Alcalde, Miguel,Bloh, Jonathan Z.,Hollmann, Frank
-
p. 15451 - 15455
(2017/11/13)
-
- Manganese complex-catalyzed oxidation and oxidative kinetic resolution of secondary alcohols by hydrogen peroxide
-
The highly efficient catalytic oxidation and oxidative kinetic resolution (OKR) of secondary alcohols has been achieved using a synthetic manganese catalyst with low loading and hydrogen peroxide as an environmentally benign oxidant in the presence of a small amount of sulfuric acid as an additive. The product yields were high (up to 93%) for alcohol oxidation and the enantioselectivity was excellent (>90% ee) for the OKR of secondary alcohols. Mechanistic studies revealed that alcohol oxidation occurs via hydrogen atom (H-atom) abstraction from an α-CH bond of the alcohol substrate and a two-electron process by an electrophilic Mn-oxo species. Density functional theory calculations revealed the difference in reaction energy barriers for H-atom abstraction from the α-CH bonds of R- and S-enantiomers by a chiral high-valent manganese-oxo complex, supporting the experimental result from the OKR of secondary alcohols.
- Miao, Chengxia,Li, Xiao-Xi,Lee, Yong-Min,Xia, Chungu,Wang, Yong,Nam, Wonwoo,Sun, Wei
-
p. 7476 - 7482
(2017/10/30)
-
- Asymmetric Autoamplification in the Oxidative Kinetic Resolution of Secondary Benzylic Alcohols Catalyzed by Manganese Complexes
-
Herein, chiral Mn–aminopyridine complexes have been shown to catalyze the oxidation of alkylarenes to enantiomerically enriched 1-arylalkanols with hydrogen peroxide. The observed enantiomeric excess values result from the direct enantioselective benzylic C?H hydroxylation, accompanied by stereoconvergent oxidative kinetic resolution of the resulting alcohol. Testing several (S,S)-bipyrrolidine derived Mn complexes has revealed a novel catalyst (6) that exhibits the best kinetic resolution in the series (krel up to 8.8), along with sufficient reactivity and efficiency (>1000 catalytic turnovers). The mechanistic study of the Mn-mediated alcohol oxidation witnesses electrophilic active species (ρ=?1.2), with rate-limiting H abstraction (kH/kD=2.2), followed by oxygen rebound and dehydration of the resulting gem-diol to form the ketone. Intriguingly, while for the resolution of the relatively bulky 1,2-diphenylethanol, krel is virtually constant throughout the reaction, for less bulky alcohols, krel increases with increasing conversion, in line with the rising optical purity of the 1-arylalkanol. The latter participates in the oxidation as an auxiliary ligand, assisting the chiral recognition. This effect is related to the previously described asymmetric autocatalysis and asymmetric autoinduction, but is not identical with either of those, with the differences being discussed. To unambiguously identify this effect, the term asymmetric autoamplification (chiral autoamplification) is proposed.
- Talsi, Evgenii P.,Samsonenko, Denis G.,Bryliakov, Konstantin P.
-
p. 2599 - 2607
(2017/07/12)
-
- Iridium-Catalyzed Asymmetric Hydrogenation of Ketones with Accessible and Modular Ferrocene-Based Amino-phosphine Acid (f-Ampha) Ligands
-
A series of tridentate ferrocene-based amino-phosphine acid (f-Ampha) ligands have been successfully developed. The f-Ampha ligands are extremely air stable and exhibited excellent performance in the Ir-catalyzed asymmetric hydrogenation of ketones (full conversions, up to >99% ee, and 500?000 TON). DFT calculations were performed to elucidate the reaction mechanism and the importance of the COOH group. Control experiments also revealed that the COOH group played a key role in this reaction.
- Yu, Jianfei,Long, Jiao,Yang, Yuhong,Wu, Weilong,Xue, Peng,Chung, Lung Wa,Dong, Xiu-Qin,Zhang, Xumu
-
supporting information
p. 690 - 693
(2017/02/10)
-
- Highly Enantioselective Hydrosilylation of Ketones Catalyzed by a Chiral Oxazaborolidinium Ion
-
A highly enantioselective hydrosilylation of ketones was developed for the synthesis of a variety of chiral secondary alcohols. In the presence of a chiral oxazaborolidinium ion (COBI) catalyst, the reaction proceeded with good yields (up to 99%) with excellent enantioselectivities (up to 99% ee).
- Kang, Byung Chul,Shin, Sung Ho,Yun, Jaesook,Ryu, Do Hyun
-
supporting information
p. 6316 - 6319
(2017/12/08)
-
- Readily Accessible and Highly Efficient Ferrocene-Based Amino-Phosphine-Alcohol (f-Amphol) Ligands for Iridium-Catalyzed Asymmetric Hydrogenation of Simple Ketones
-
We have successfully developed a series of novel and modular ferrorence-based amino-phosphine-alcohol (f-Amphol) ligands, and applied them to iridium-catalyzed asymmetric hydrogenation of various simple ketones to afford the corresponding chiral alcohols with excellent enantioselectivities and conversions (98–99.9 % ee, >99 % conversion, turnover number up to 200 000). Control experiments and density functional theory (DFT) calculations have shown that the hydroxyl group of our f-Amphol ligands played a key role in this asymmetric hydrogenation.
- Yu, Jianfei,Duan, Meng,Wu, Weilong,Qi, Xiaotian,Xue, Peng,Lan, Yu,Dong, Xiu-Qin,Zhang, Xumu
-
supporting information
p. 970 - 975
(2017/02/05)
-
- Functionalities tuned enantioselectivity of phenylcarbamate cyclodextrin clicked chiral stationary phases in HPLC
-
The mixed chloro- and methyl- functionalities can greatly modulate the enantioselectivities of phenylcarbamate cyclodextrin (CD) clicked chiral stationary phases (CSPs). A comparison study is herein reported for per(4-chloro-3-methyl)phenylcarbamate and per(2-chloro-5-methyl)phenylcarbamate β-CD clicked CSPs (i.e., CCC4M3-CSP and CCC2M5-CSP). The enantioselectivity dependence on column temperature was studied in both normal-phase and reversed-phase mode high performance liquid chromatography (HPLC). The thermodynamic study revealed that the stronger intermolecular interactions can be formed between CCC4M3-CSP and chiral solutes to drive the chiral separation. The higher enantioselectivities of CCC4M3-CSP were further demonstrated with the enantioseparation of 17 model racemates in HPLC.
- Tang, Jian,Lin, Yuzhou,Yang, Bo,Zhou, Jie,Tang, Weihua
-
p. 566 - 573
(2017/08/26)
-
- Homologation Strategy for the Generation of 1-Chloroalkyl Radicals from Organoboranes
-
The generation of 1-bromo and 1-chloroalkyl radicals from organoboranes has been investigated. The direct approach involving the hydroboration of halogenated alkenes is impeded by partial dehalogenation taking place during the hydroboration process. An indirect method involving the generation of B-(1-chloroalkyl)catecholborane by homologation of B-alkylcatecholborane with dichloromethyllithium was developed. A reaction sequence involving a hydroboration reaction, a Matteson homologation, and a radical allylation process has been performed as a one-pot process that takes advantage of three different reactivities of organoboron species. Starting from styrene derivatives, it was possible to prepare B-(1-chloro-2-arylpropyl)catecholboranes that are excellent precursors to 1-chloro-2-arylpropyl radicals. A concise approach for the synthesis of an optically active α-methylene-γ-lactone from p-chlorostyrene has been developed on the basis of a two-step sequence involving an enantioselective hydroboration-homologation-cyclization reaction followed by a hydrolysis-lactonization process. (Chemical Equation Presented).
- Xu, Gong,Lüthy, Monique,Habegger, Jacqueline,Renaud, Philippe
-
p. 1506 - 1519
(2016/03/01)
-
- The design of second generation MOP-phosphonites: Efficient chiral hydrosilylation of functionalised styrenes
-
A series of enantiopure MOP-phosphonite ligands, with tailored steric profiles, have been synthesised and are proven to be very successful in high-yielding, regio- and enantioselective catalytic hydrosilylation reactions of substituted styrenes, affording important chiral secondary alcohols.
- Fleming, James T.,Ficks, Arne,Waddell, Paul G.,Harrington, Ross W.,Higham, Lee J.
-
supporting information
p. 1886 - 1890
(2016/02/09)
-
- Method for synthesizing chiral alcohol
-
The invention discloses a method for synthesizing chiral alcohol. The method comprises the following steps: adding alkyne, gold chloride [Au(L)Cl], a solvent methanol, and water into a reactor; carrying out reactions for 6 to 12 hours at a temperature of 110 DEG C, cooling to the room temperature; then adding sodium formate, water, and a transition metal rhodium catalyst Cp*RhCl[(R,R)-TsDPEN], carrying out reactions for 5 hours at a temperature of 30 to 40 DEG C, cooling to the room temperature, performing rotary evaporation to remove the solvent, and carrying out column separation to obtain the target compound. The provided method has the advantages that alkyne, which can be bought on the market or easily synthesized, is taken as the primary compound to synthesize chiral alcohol directly through cascade reactions, the intermediates do not need to be separated, the waste of time and solvent is avoided, and thus the provided method meets the requirements of green chemistry and has a wide development prospect.
- -
-
Paragraph 0050-0052
(2017/03/08)
-
- Catalytic Asymmetric Addition of Organolithium Reagents to Aldehydes
-
Herein we report an efficient catalytic system for the titanium-promoted enantioselective addition of organolithium reagents to aldehydes, based on chiral Ar-BINMOL ligands. Unprecedented yields and enantioselectivities are achieved in the alkylation reactions of aliphatic aldehydes. Remarkably, methyllithium can be added to a wide variety of aromatic and aliphatic aldehydes, providing versatile chiral methyl carbinol units in a simple one-pot procedure under mild conditions and in very short reaction times.
- Veguillas, Marcos,Solà, Ricard,Shaw, Luke,Maciá, Beatriz
-
p. 1788 - 1794
(2016/04/05)
-
- Enantioselective addition of organozinc reagents to carbonyl compounds catalyzed by a camphor derived chiral γ-amino thiol ligand
-
In this article, the design and synthesis of the chiral camphor derived γ-amino thiol ligand 17 and its application in catalytic enantioselective carbon-carbon forming reactions through the addition of organozinc reagents to carbonyl compounds is described. The catalytic activity and enantioselectivity of ligand 17 is demonstrated in the enantioselective addition of various organozinc reagents to aldehydes and ketoesters, offering the corresponding alcohols in high yields and enantioselectivities. The role of the mercapto group in the highly enantioselective 1,2-addition reaction of organozincs to aldehyde is also discussed.
- Wu, Hsyueh-Liang,Wu, Ping-Yu,Cheng, Ying-Ni,Uang, Biing-Jiun
-
p. 2656 - 2665
(2016/05/10)
-
- Chiral ferrocenyl tridentate ligands and its preparation method for catalytic asymmetric hydrogenation and the application of the catalyst in the reaction
-
The invention discloses a ferrocene tridentate ligand which has planar chirality and carbon chirality and is shown in a structure general formula (I). In the formula (I), R1 is aryl or C1-C6 alkyl, R2 is C1-C6 alkyl, n is equal to 1-4, or R2 does not exist. The ferrocene tridentate ligand is synthesized by adopting the steps of carrying out coupling and acetic anhydride esterifying with R12PCl after lithiating by sec-butyl lithium by using chiral Ugi's amine as a raw material, and finally generating nucleophilic substitution with aminomethyl pyridine or substituted aminomethyl pyridine. The chiral ferrocene tridentate ligand disclosed by the invention has high catalysis activity; and an Ir complex catalyst has excellent three-dimensional selectivity and high catalysis activity when being used in asymmetric hydrogenation of prochiral ketone.
- -
-
Paragraph 0049; 0050; 0051; 0052; 0053
(2017/01/26)
-
- Chiral tridentate nitrogen-phosphine-oxygen ligands and application of related ligands in asymmetric catalytic reactions
-
The invention relates to PNHO tridentate ligands and application of related ligands in asymmetric hydrogenation and similar reactions. The novel tridentate nitrogen-phosphine-oxygen ligands are first tridentate nitrogen-phosphine-oxygen ligands containing ferrocenyl planar chiral phosphine, and are successfully applied to high-efficiency high-selectivity asymmetric hydrogenation and other similar reactions of simple aromatic ketone, alpha-hydroxyketone and beta-ketone ester. Compared with other dominant tridentate ligands, the ligands provided by the invention have the advantages of simple synthesis route and low cost, can easily implement large-scale synthesis, are stable in air, and have high activity and high selectivity in asymmetric hydrogenation reactions of carbon-oxygen double bonds.
- -
-
Paragraph 0118; 0119; 0120; 0121
(2016/10/20)
-