- Manganese catalyzed asymmetric transfer hydrogenation of ketones
-
The asymmetric transfer hydrogenation (ATH) of a wide range of ketones catalyzed by manganese complex as well as chiral PxNy-type ligand under mild conditions was investigated. Using 2-propanol as hydrogen source, various ketones could be enantioselectively hydrogenated by combining cheap, readily available [MnBr(CO)5] with chiral, 22-membered macrocyclic ligand (R,R,R',R')-CyP2N4 (L5) with 2 mol% of catalyst loading, affording highly valuable chiral alcohols with up to 95% ee.
- Zhang, Guang-Ya,Ruan, Sun-Hong,Li, Yan-Yun,Gao, Jing-Xing
-
supporting information
p. 1415 - 1418
(2020/11/20)
-
- Ruthenium-catalyzed hydrogenation of aromatic ketones using chiral diamine and monodentate achiral phosphine ligands
-
The Ru-catalyzed asymmetric hydrogenation of ketones with chiral diamine and monodentate achiral phosphine has been developed. A wide range of ketones were hydrogenated to afford the corresponding chiral secondary alcohols in good to excellent enantioselectivities (up to 98.1% ee). In addition, an appropriate mechanism for the asymmetric hydrogenation was proposed and verified by NMR spectroscopy.
- Wang, Mengna,Zhang, Ling,Sun, Hao,Chen, Qian,Jiang, Jian,Li, Linlin,Zhang, Lin,Li, Li,Li, Chun
-
-
- Cobalt-catalyzed asymmetric hydrogenation of ketones: A remarkable additive effect on enantioselectivity
-
A chiral cobalt pincer complex, when combined with an achiral electron-rich mono-phosphine ligand, catalyzes efficient asymmetric hydrogenation of a wide range of aryl ketones, affording chiral alcohols with high yields and moderate to excellent enantioselectivities (29 examples, up to 93% ee). Notably, the achiral mono-phosphine ligand shows a remarkable effect on the enantioselectivity of the reaction.
- Du, Tian,Wang, Biwen,Wang, Chao,Xiao, Jianliang,Tang, Weijun
-
supporting information
p. 1241 - 1244
(2020/10/02)
-
- Method for asymmetric functionalization of nickel-hydrogen catalytic olefin migration promoted by ligand relay strategy
-
The invention discloses a method for asymmetric functionalization of nickel-hydrogen catalytic olefin migration promoted by a ligand relay strategy. Under the action of a metal nickel salt, an achiral ligand, a chiral ligand, alkali, a hydrogen source, an additive and the like, olefin and various electrophilic reagents are dissolved in an organic solvent for reaction, and the chiral compound with excellent regioselectivity and enantioselectivity is obtained. According to the method, the chiral compound containing various functional groups can be efficiently synthesized, the product has high enantioselectivity, the raw materials are simple and easy to obtain, and operation is easy and convenient.
- -
-
Paragraph 0089-0091
(2021/06/12)
-
- A relay catalysis strategy for enantioselective nickel-catalyzed migratory hydroarylation forming chiral α-aryl alkylboronates
-
Ligand-controlled reactivity plays an important role in transition-metal catalysis, enabling a vast number of efficient transformations to be discovered and developed. However, a single ligand is generally used to promote all steps of the catalytic cycle (e.g., oxidative addition, reductive elimination), a requirement that makes ligand design challenging and limits its generality, especially in relay asymmetric transformations. We hypothesized that multiple ligands with a metal center might be used to sequentially promote multiple catalytic steps, thereby combining complementary catalytic reactivities through a simple combination of simple ligands. With this relay catalysis strategy (L/L?), we report here the first highly regio- and enantioselective remote hydroarylation process. By synergistic combination of a known chain-walking ligand and a simple asymmetric cross-coupling ligand with the nickel catalyst, enantioenriched α-aryl alkylboronates could be rapidly obtained as versatile synthetic intermediates through this formal asymmetric remote C(sp3)-H arylation process.
- Chen, Jian,Liang, Yong,Ma, Jiawei,Meng, Lingpu,Zhang, Yao,Zhu, Shaolin
-
supporting information
p. 3171 - 3188
(2021/11/16)
-
- Compartmentalization and Photoregulating Pathways for Incompatible Tandem Catalysis
-
This contribution describes an advanced compartmentalized micellar nanoreactor that possesses a reversible photoresponsive feature and its application toward photoregulating reaction pathways for incompatible tandem catalysis under aqueous conditions. The
- Qu, Peiyuan,Kuepfert, Michael,Hashmi, Maryam,Weck, Marcus
-
supporting information
p. 4705 - 4713
(2021/04/07)
-
- 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)
-
- An Enantioconvergent Benzylic Hydroxylation Using a Chiral Aryl Iodide in a Dual Activation Mode
-
The application of a triazole-substituted chiral iodoarene in a direct enantioselective hydroxylation of alkyl arenes is reported. This method allows the rapid synthesis of chiral benzyl alcohols in high yields and stereocontrol, despite its nontemplated nature. In a cascade activation consisting of an initial irradiation-induced radical C-H-bromination and a consecutive enantioconvergent hydroxylation, the iodoarene catalyst has a dual role. It initiates the radical bromination in its oxidized state through an in-situ-formed bromoiodane and in the second, Cu-catalyzed step, it acts as a chiral ligand. This work demonstrates the ability of a chiral aryl iodide catalyst acting both as an oxidant and as a chiral ligand in a highly enantioselective C-H-activating transformation. Furthermore, this concept presents an enantioconvergent hydroxylation with high selectivity using a synthetic catalyst.
- Abazid, Ayham H.,Clamor, Nils,Nachtsheim, Boris J.
-
p. 8042 - 8048
(2020/09/21)
-
- Chiral amino-pyridine-phosphine tridentate ligand, manganese complex, and preparation method and application thereof
-
The invention discloses a chiral amino-pyridine-phosphine tridentate ligand, a manganese complex, and a preparation method and application thereof. The chiral amino-pyridine-phosphine tridentate ligand is shown as a formula II, and the manganese complex of the chiral amino-pyridine-phosphine tridentate ligand can be used for efficiently catalyzing and hydrogenating ketone compounds to prepare chiral alcohol compounds in a high enantioselectivity mode. The chiral amino-pyridine-phosphine tridentate ligand and the manganese complex are simple in synthesis process, good in stability, high in catalytic activity and mild in reaction conditions.
- -
-
Paragraph 0597-0600; 0602
(2020/07/13)
-
- Manganese-Catalyzed Enantioselective Hydrogenation of Simple Ketones Using an Imidazole-Based Chiral PNN Tridentate Ligand
-
A series of Mn(I) catalysts containing imidazole-based chiral PNN tridentate ligands with controllable 'side arm' groups have been established, enabling the inexpensive base-promoted asymmetric hydrogenation of simple ketones with outstanding activities (up to 8200 TON) and good enantioselectivities (up to 88.5percent ee). This protocol features wide substrate scope and functional group tolerance, thereby providing easy access to a key intermediate of crizotinib.
- Chen, Jiachen,Hou, Huacui,Ling, Fei,Nian, Sanfei,Wu, Feifei,Xu, Min,Yi, Xiao,Zhong, Weihui
-
supporting information
p. 285 - 289
(2020/02/18)
-
- 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)
-
- Highly Focused Library-Based Engineering of Candida antarctica Lipase B with (S)-Selectivity Towards sec-Alcohols
-
Candida antarctica lipase B (CALB) is one of the most extensively used biocatalysts in both academia and industry and exhibits remarkable (R)-enantioselectivity for various chiral sec-alcohols. Considering the significance of tailor-made stereoselectivity in organic synthesis, a discovery of enantiocomplementary lipase mutants with high (R)- and (S)-selectivity is valuable and highly desired. Herein, we report a highly efficient directed evolution strategy, using only 4 representative amino acids, namely, alanine (A), leucine (L), lysine (K), tryptophan (W) at each mutated site to create an extremely small library of CALB variants requiring notably less screening. The obtained best mutant with three mutations W104V/A281L/A282K displayed highly reversed (S)-selectivity towards a series of sec-alcohol with E values up to 115 (conv. 50%, ee 94%). Compared with the previously reported (S)-selective CALB variant, W104A, a single mutation provided less selectivity, while the synergistic effects of three mutations in the best variant endow better (S)-selectivity and a broader substrate scope than the W104A variant. Structural analysis and molecular dynamics simulation unveiled the source of reversed enantioselectivity. (Figure presented.).
- Cen, Yixin,Li, Danyang,Xu, Jian,Wu, Qiongsi,Wu, Qi,Lin, Xianfu
-
supporting information
p. 126 - 134
(2018/12/05)
-
- Highly Enantioselective Transfer Hydrogenation of Prochiral Ketones Using Ru(II)-Chitosan Catalyst in Aqueous Media
-
Unprecedentedly high enantioselectivities are obtained in the transfer hydrogenation of prochiral ketones catalyzed by a Ru complex formed in situ with chitosan chiral ligand. This biocompatible, biodegradable chiral polymer obtained from the natural chitin afforded good, up to 86 % enantioselectivities, in the aqueous-phase transfer hydrogenation of acetophenone derivatives using HCOONa as hydrogen donor. Cyclic ketones were transformed in even higher, over 90 %, enantioselectivities, whereas further increase, up to 97 %, was obtained in the transfer hydrogenations of heterocyclic ketones. The chiral catalyst precursor prepared ex situ was examined by scanning electron microscopy, FT-mid- and -far-IR spectroscopy. The structure of the in situ formed catalyst was investigated by 1H NMR spectroscopy and using various chitosan derivatives. It was shown that a Ru pre-catalyst is formed by coordination of the biopolymer to the metal by amino groups. This precursor is transformed in water insoluble Ru-hydride complex following hydrogen donor addition. The practical value of the developed method was verified by preparing over twenty chiral alcohols in good yields and optical purities. The catalyst was applied for obtaining optically pure chiral alcohols at gram scale following a single crystallization.
- Sz?ll?si, Gy?rgy,Kolcsár, Vanessza Judit
-
p. 820 - 830
(2018/12/13)
-
- Enantioselective Hydrogenation of Ketones using Different Metal Complexes with a Chiral PNP Pincer Ligand
-
The synthesis of different metal pincer complexes coordinating to the chiral PNP ligand bis(2-((2R,5R)-2,5-dimethyl-phospholanoethyl))amine is described in detail. The characterized complexes with Mn, Fe, Re and Ru as metal centers showed good activities regarding the reduction of several prochiral ketones. Comparing these catalysts, the non-noble metal complexes produced best selectivities not only for aromatic substrates, but also for different kinds of aliphatic ones leading to enantioselectivities up to 99% ee. Theoretical investigations elucidated the mechanism and rationalized the selectivity. (Figure presented.).
- Garbe, Marcel,Wei, Zhihong,Tannert, Bianca,Spannenberg, Anke,Jiao, Haijun,Bachmann, Stephan,Scalone, Michelangelo,Junge, Kathrin,Beller, Matthias
-
supporting information
p. 1913 - 1920
(2019/03/13)
-
- Lutidine-Based Chiral Pincer Manganese Catalysts for Enantioselective Hydrogenation of Ketones
-
A series of MnI complexes containing lutidine-based chiral pincer ligands with modular and tunable structures has been developed. The complex shows unprecedentedly high activities (up to 9800 TON; TON=turnover number), broad substrate scope (81 examples), good functional-group tolerance, and excellent enantioselectivities (85–98 % ee) in the hydrogenation of various ketones. These aspects are rare in earth-abundant metal catalyzed hydrogenations. The utility of the protocol have been demonstrated in the asymmetric synthesis of a variety of key intermediates for chiral drugs. Preliminary mechanistic investigations indicate that an outer-sphere mode of substrate–catalyst interactions probably dominates the catalysis.
- Zhang, Linli,Tang, Yitian,Han, Zhaobin,Ding, Kuiling
-
supporting information
p. 4973 - 4977
(2019/03/17)
-
- Highly enantioselective reduction of ketones in air catalyzed by Rh-based macrocycles
-
The asymmetric transfer hydrogenation (ATH) of ketones catalyzed by Rh-based macrocycles proceeded smoothly in the presence of air with high catalytic activity and enantioselectivity. Even though the S/C ratio (substrate to catalyst molar ratio) was incre
- Zhang, Wen-Jing,Ruan, Sun-Hong,Shen, Wei-Yi,Wang, Zhe,An, Dong-Li,Li, Yan-Yun,Gao, Jing-Xing
-
p. 153 - 158
(2018/11/21)
-
- One-pot synthesis of chiral alcohols from alkynes by CF3SO3H/ruthenium tandem catalysis
-
A practical one-pot synthesis of chiral alcohols from readily available alkynes via tandem catalysis by the combination of CF3SO3H and a fluorinated chiral diamine Ru(ii) complex in aqueous CF3CH2OH is described. Very interestingly, the combination of fluorinated catalysts and solvent exhibits a positive fluorine effect on the reactivity and enantioselectivity. A range of chiral alcohols with wide functional group tolerance was obtained in high yield and excellent stereoselectivity under simple and mild conditions.
- Liu, Huan,Liu, Sensheng,Zhou, Haifeng,Liu, Qixing,Wang, Chunqin
-
p. 14829 - 14832
(2018/04/30)
-
- 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)
-
- Method for Catalytic Enantioselective Alkylation of Aldehydes Using Grignard Reagents as Alkyl Sources
-
Alkyltitanium reagents, generated in situ from Grignard reagents and ClTi(OiPr)3, can be employed without further manipulation in the enantioselective alkylation of aldehyde by the catalysis of a chiral titanium complex derived from DTBP-H8-BINOL. The reaction is performed with good stoichiometry [1.5 equiv each of Grignard reagents and ClTi(OiPr)3] at a low catalyst loading (2 mol %), affording a variety of chiral secondary alcohols in high enantioselectivity and yields and, hence, realizing an asymmetric version of the Grignard reaction in an indirect manner.
- Tanaka, Kento,Tomihama, Munehisa,Yamamoto, Koji,Matsubara, Naoki,Harada, Toshiro
-
p. 6127 - 6132
(2018/05/23)
-
- 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)
-
- Manganese(I)-Catalyzed Enantioselective Hydrogenation of Ketones Using a Defined Chiral PNP Pincer Ligand
-
A new chiral manganese PNP pincer complex is described. The asymmetric hydrogenation of several prochiral ketones with molecular hydrogen in the presence of this complex proceeds under mild conditions (30–40 °C, 4 h, 30 bar H2). Besides high catalytic activity for aromatic substrates, aliphatic ketones are hydrogenated with remarkable selectivity (e.r. up to 92:8). DFT calculations support an outer sphere hydrogenation mechanism as well as the experimentally determined stereochemistry.
- Garbe, Marcel,Junge, Kathrin,Walker, Svenja,Wei, Zhihong,Jiao, Haijun,Spannenberg, Anke,Bachmann, Stephan,Scalone, Michelangelo,Beller, Matthias
-
supporting information
p. 11237 - 11241
(2017/09/02)
-
- Ni-Catalyzed Enantioselective Conjunctive Coupling with C(sp3) Electrophiles: A Radical-Ionic Mechanistic Dichotomy
-
The catalytic enantioselective conjunctive coupling of C(sp3) electrophiles can be accomplished with Ni catalysis. The enantioselectivity of the reaction is dependent on reaction mechanism with many substrates able to engage in an asymmetric process with Pybox-Ni complexes, whereas other substrates provide racemic product mixtures. The link between substrate structure and selectivity is addressed.
- Lovinger, Gabriel J.,Morken, James P.
-
supporting information
p. 17293 - 17296
(2017/12/15)
-
- A Chiral Metal-Organic Material that Enables Enantiomeric Identification and Purification
-
We show that CMOM-3S, a previously unreported porous crystalline metal-organic material that exhibits intrinsic homochirality, serves as a general-purpose chiral crystalline sponge (CCS) and a chiral stationary phase (CSP) for gas chromatography (GC). The properties of CMOM-3S are enabled by nano-sized channels connected to adaptable molecular recognition sites that mimic enzyme-binding sites. Further, CMOM-3S is composed of inexpensive components, facile to prepare, and requires only trace amounts of analyte. When coupled with the thermal and hydrolytic stability of CMOM-3S, these features mean that a coated fused silica capillary column in which CMOM-3S serves as a CSP is both more versatile and more robust than three benchmark commercial columns. That the enantiomer with the longer GC retention time is consistently captured in CCS experiments enables CMOM-3S to serve as a powerful tool to enable both chiral purification and enantiomer identification.
- Zhang, Shi-Yuan,Yang, Cheng-Xiong,Shi, Wei,Yan, Xiu-Ping,Cheng, Peng,Wojtas, Lukasz,Zaworotko, Michael J.
-
supporting information
p. 281 - 289
(2017/09/05)
-
- Chiral N-heterocyclic carbene iridium catalyst for the enantioselective hydrosilane reduction of ketones
-
Enantioselective reduction of ketones with (EtO)2MeSiH catalyzed by an in-situ generated N-heterocyclic carbene (NHC) Ir complex at room temperature has been developed. A series of benzimidazolium salts were synthesized and screened in the asymmetric hydrosilylation reaction. As a result, propiophenone was efficiently reduced by the combined catalytic system of [IrCl(cod)]2 and NHC-Ag complex derived from N-(1-naphthalenylmethyl)-substituted benzimidazolium salt L12, affording the corresponding alcohol in 92% yield and with 92% ee. Moreover, the evaluation of an Ir catalyst precursor showed that cationic [Ir(cod)2]BF4 complex could be used. Furthermore, the introduction of a chiral hydroxyamide side arm into the benzimidazolium salt was critical for the successful design of the NHC ligand.
- Manabe, Yoshiki,Shinohara, Kanako,Nakamura, Hanako,Teramoto, Hiro,Sakaguchi, Satoshi
-
p. 138 - 145
(2016/06/15)
-
- Phosphine-free chiral iridium catalysts for asymmetric catalytic hydrogenation of simple ketones
-
Novel pyridylalkylamine and aminopyridinato ligand stabilized iridium complexes with no P ligand are introduced. These complexes have been investigated as catalysts for asymmetric hydrogenation of simple ketones, resulting in an active catalyst for bulky alkyl aryl ketones that is α-methylpropiophenone. The ligands were synthesized from inexpensive starting materials and their modular design allows for the introduction of a broad variety of substitution patterns. Additionally, better activity and selectivity was observed at 20 °C and 20 bar H2 pressure with a catalyst loading as low as 0.05 mol% iridium. These phosphorus free catalysts have always been a central issue in both academic and industrial research.
- Kumar, Prashant,Irrgang, Torsten,Kostakis, George E.,Kempe, Rhett
-
p. 39335 - 39342
(2016/05/24)
-
- Chiral-at-metal iridium complex for efficient enantioselective transfer hydrogenation of ketones
-
A bis-cyclometalated iridium(iii) complex with metal-centered chirality catalyzes the enantioselective transfer hydrogenation of ketones with high enantioselectivities at low catalyst loadings down to 0.002 mol%. Importantly, the rate of catalysis and enantioselectivity are markedly improved in the presence of a pyrazole co-ligand. The reaction is proposed to proceed via an iridium-hydride intermediate exploiting metal-ligand cooperativity (bifunctional catalysis).
- Tian, Cheng,Gong, Lei,Meggers, Eric
-
supporting information
p. 4207 - 4210
(2016/03/19)
-
- Iminophenyl Oxazolinylphenylamine for Enantioselective Cobalt-Catalyzed Hydrosilylation of Aryl Ketones
-
A new family of chiral iminophenyl oxazolinylphenylamines (IPOPA) was designed and synthesized through three steps from commercially available starting materials. An efficient cobalt-catalyzed asymmetric hydrosilylation of simple ketones with a low catalyst loading of CoCl2 and IPOPA was developed to afford chiral alcohols in good yields with high enantioselectivities.
- Chen, Xu,Lu, Zhan
-
supporting information
p. 4658 - 4661
(2016/09/28)
-
- Expanding substrate scope of lipase-catalyzed transesterification by the utilization of liquid carbon dioxide
-
Secondary alcohols having bulky substituents on both sides of the chiral center are often poor substrates for most lipases. Here we reported that substrate scopes of two of the most used lipases, Candida antarctica lipase B and Burkholderia cepacia lipase, were found to be expanded toward more bulky secondary alcohols such as 1-phenyl-1-dodecanol and 2-methyl-1-phenyl-1-propanol by simply using them in liquid carbon dioxide as a solvent. The effects of solvents, reaction pressure, and pre-treatment of the enzyme with liquid CO2on this acceleration phenomenon were also studied.
- Hoang, Hai Nam,Matsuda, Tomoko
-
p. 7229 - 7234
(2016/10/26)
-
- Third-Generation Amino Acid Furanoside-Based Ligands from d-Mannose for the Asymmetric Transfer Hydrogenation of Ketones: Catalysts with an Exceptionally Wide Substrate Scope
-
A modular ligand library of α-amino acid hydroxyamides and thioamides was prepared from 10 different N-tert-butyloxycarbonyl-protected α-amino acids and three different amino alcohols derived from 2,3-O-isopropylidene-α-d-mannofuranoside. The ligand library was evaluated in the half-sandwich ruthenium- and rhodium-catalyzed asymmetric transfer hydrogenation of a wide array of ketone substrates, including simple as well as sterically demanding aryl alkyl ketones, aryl fluoroalkyl ketones, heteroaromatic alkyl ketones, aliphatic, conjugated and propargylic ketones. Under the optimized reaction conditions, secondary alcohols were obtained in high yields and in enantioselectivities up to >99%. The choice of ligand/catalyst allowed for the generation of both enantiomers of the secondary alcohols, where the ruthenium-hydroxyamide and the rhodium-thioamide catalysts act complementarily towards each other. The catalytic systems were also evaluated in the tandem isomerization/asymmetric transfer hydrogenation of racemic allylic alcohols to yield enantiomerically enriched saturated secondary alcohols in up to 98% ee. Furthermore, the catalytic tandem α-alkylation/asymmetric transfer hydrogenation of acetophenones and 3-acetylpyridine with primary alcohols as alkylating and reducing agents was studied. Secondary alcohols containing an elongated alkyl chain were obtained in up to 92% ee. (Figure presented.).
- Margalef, Jèssica,Slagbrand, Tove,Tinnis, Fredrik,Adolfsson, Hans,Diéguez, Montserrat,Pàmies, Oscar
-
p. 4006 - 4018
(2016/12/30)
-
- HPLC enantioseparation on a homochiral MOF-silica composite as a novel chiral stationary phase
-
The last frontier in the development of chiral stationary phases for chromatographic enantioseparation involves homochiral metal-organic frameworks (MOFs). Using enantiopure (R)-2,2′-dihydroxy-1,1′-binaphthalene-6,6′-dicarboxylic acid as a starting material, we prepared three homochiral MOFs that were further used as chiral stationary phases for high-performance liquid chromatography to separate the enantiomers of various kinds of racemic sulfoxides, sec-alcohols, β-lactams, benzoins, flavanones and epoxides. The experimental results showed excellent performances for enantioseparation, and highlighted that enantioseparation on homochiral MOF columns is practical.
- Tanaka, Koichi,Muraoka, Toshihide,Otubo, Yasuhiro,Takahashi, Hiroki,Ohnishi, Atsushi
-
p. 21293 - 21301
(2016/03/08)
-
- Substrate specificity of an esterase from the archaeon Sulfolobus tokodaii bearing a GGG(A)X motif
-
A GGG(A)X-type esterase (Est0071) from an archaeon catalyzes asymmetric hydrolysis of prochiral bulky malonic diesters in good enantioselectivity. The selectivity of Est0071 was for the opposite enantiomer to that previously shown for pig liver esterase, and the resulting enantiomeric excess of the products was higher. Est0071 could also catalyze the hydrolysis of various acetates of secondary alcohols, and showed moderate enantioselectivity in these reactions.
- Wada, Reina,Ozaki, Masanaru,Kumon, Takashi,Ohta, Hiromichi,Miyamoto, Kenji
-
p. 188 - 190
(2015/11/09)
-
- Performance of Recombinant-Whole-Cell-Catalyzed Reductions in Deep-Eutectic-Solvent-Aqueous-Media Mixtures
-
Deep-eutectic solvents (DES) are cost-effective, nonhazardous solvents that may be used in biocatalysis as nonconventional media that enable biotransformations with industrially sound high substrate loadings. Based on promising prognoses, this paper explo
- Müller, Christoph R.,Lavandera, Iván,Gotor-Fernández, Vicente,Domínguezdemaría, Pablo
-
p. 2654 - 2659
(2015/09/15)
-
- Cobalt-catalyzed asymmetric hydroboration of aryl ketones with pinacolborane
-
The highly enantioselective cobalt-catalyzed hydroboration reaction of aryl ketones with HBpin was developed using iminopyridine oxazoline ligands. Halides, amines, ethers, sulfides, esters and amides are well tolerated under the mild reaction conditions, demonstrating its synthetic advantage. Substituted diaryl ketones could also be hydroborated with high enantioselectivity.
- Guo, Jun,Chen, Jianhui,Lu, Zhan
-
supporting information
p. 5725 - 5727
(2015/03/30)
-
- Identification of an ε-keto ester reductase for the efficient synthesis of an (R)-α-lipoic acid precursor
-
Abstract A novel reductase (CpAR2) with unusually high activity toward an ε-keto ester, ethyl 8-chloro-6-oxooctanoate, was isolated from Candida parapsilosis. The asymmetric reduction of ethyl 8-chloro-6-oxooctanoate using Escherichia coli cells coexpressing CpAR2 and glucose dehydrogenase genes gave ethyl (R)-8-chloro-6-hydroxyoctanoate, a key precursor for the synthesis of (R)-α-lipoic acid, in high space-time yield (530 gL-1d-1) and with excellent enantiomeric excess (>99%). This bioprocess was shown to be viable on a 10-L scale. This method provides a greener and more cost-effective method for the industrial production of (R)-α-lipoic acid.
- Zhang, Yu-Jun,Zhang, Wen-Xia,Zheng, Gao-Wei,Xu, Jian-He
-
supporting information
p. 1697 - 1702
(2015/06/02)
-
- Identification of key residues in Debaryomyces hansenii carbonyl reductase for highly productive preparation of (S)-aryl halohydrins
-
Key residues of Debaryomyces hansenii carbonyl reductase in the determination of the reducing activity towards aryl haloketones were identified through combinatorial mutation of conserved residues. This study provides a green and efficient biocatalyst for the synthesis of (S)-aryl halohydrins.
- Xu, Guo-Chao,Shang, Yue-Peng,Yu, Hui-Lei,Xu, Jian-He
-
supporting information
p. 15728 - 15731
(2015/11/02)
-
- Iron catalyzed asymmetric hydrogenation of ketones
-
Chiral molecules, such as alcohols, are vital for the manufacturing of fine chemicals, pharmaceuticals, agrochemicals, fragrances, and novel materials. These molecules need to be produced in high yield and high optical purity and preferentially catalytically. Among all the asymmetric catalytic reactions, asymmetric hydrogenation with H2 (AH) is the most widely used in the industry. With few exceptions, these AH processes use catalysts based on the three critical metals, rhodium, ruthenium, and iridium. Herein we describe a simple, industrially viable iron catalyst that allows for the AH of ketones, a process currently dominated by ruthenium and rhodium catalysts. By combining a chiral, 22-membered macrocyclic ligand with the cheap, readily available Fe 3(CO)12, a wide variety of ketones have been hydrogenated under 50 bar H2 at 45-65 C, affording highly valuable chiral alcohols with enantioselectivities approaching or surpassing those obtained with the noble metal catalysts. In contrast to AH by most noble metal catalysts, the iron-catalyzed hydrogenation appears to be heterogeneous.
- Li, Yanyun,Yu, Shenluan,Wu, Xiaofeng,Xiao, Jianliang,Shen, Weiyi,Dong, Zhenrong,Gao, Jingxing
-
supporting information
p. 4031 - 4039
(2014/04/03)
-
- Tandem α-Alkylation/Asymmetric Transfer Hydrogenation of Acetophenones with Primary Alcohols
-
Tandem α-alkylation/asymmetric transfer hydrogenation of acetophenones with primary alcohols, mediated by a single ruthenium catalyst, is described. Under optimized reaction conditions and with use of [Ru(p-cymene)Cl2]2 in combination with an amino acid hydroxyamide ligand, the chiral secondary alcohol products were isolated in moderate yields and in moderate to good enantiomeric excess (up to 89 % ee). One catalyst - one pot - two reactions. Acetophenones are initially alkylated with primary alcohols by the borrowing hydrogen methodology. The alkylation products are directly converted to enantiomerically enriched secondary alcohols.
- Kovalenko, Oleksandr O.,Lundberg, Helena,Hübner, Dennis,Adolfsson, Hans
-
supporting information
p. 6639 - 6642
(2016/02/19)
-
- Stereoselective benzylic hydroxylation of alkylbenzenes and epoxidation of styrene derivatives catalyzed by the peroxygenase of Agrocybe aegerita
-
Here we report on the stereoselective benzylic hydroxylation and C1-C2 epoxidation of alkylbenzenes and styrene derivatives, respectively, by a heme-thiolate peroxygenase (EC 1.11.2.1) from the fungus Agrocybe aegerita. Benzylic hydroxylation led exclusively to the (R)-1-phenylalkanols. For (R)-1-phenylethanol, (R)-1-phenylpropanol and (R)-1-tetralol, the ee reached >99%. For longer chain lengths, the enantiomeric excesses (ee) and total turnover numbers (TTN) decreased while the number of by-products, e.g. 1-phenylketones, increased. Epoxidation of straight chain and cyclic styrene derivatives gave a heterogeneous picture and resulted in moderate to excellent ee values and TTN: e.g., in the case of (1R,2S)-cis-β-methylstyrene oxide formation, an ee >99% and a TTN of 110000 was achieved. Hydroxylation and epoxidation were true peroxygenations, which was demonstrated by the incorporation of 18O from H218O2 into the products. The use of fed-batch devices and varying feeding strategies for the substrate and co-substrate turned out to be a suitable approach to optimize peroxygenase catalysis.
- Kluge, Martin,Ullrich, Rene,Scheibner, Katrin,Hofrichter, Martin
-
supporting information; experimental part
p. 440 - 446
(2012/04/10)
-
- Asymmetric transfer hydrogenation of ketones catalyzed by nickel complex with new PNO-type ligands
-
The new polydentate mixed-N, P, O chiral ligands have been synthesized by the condensation of bis(o-formylphenyl)-phenylphosphane and R-phenylglycinol in CHCl3, and fully characterized by IR, NMR and EIMS spectra. These ligands were employed with a simple Ni complex Ni(PPhs) 2Cl2 in situ as catalytic systems for asymmetric transfer hydrogenation of ketones, and the corresponding optical alcohols were obtained with up to 84% ee under mild conditions.
- Dong, Zhen Rong,Li, Yan Yun,Yu, Shen Luan,Sun, Guo Song,Gao, Jing Xing
-
scheme or table
p. 533 - 536
(2012/06/16)
-
- Synthesis of novel chiral tetraaza ligands and their application in enantioselective transfer hydrogenation of ketones
-
Novel chiral tetraaza ligands (R)-N, N′-bis[2-(piperidin-1-yl) benzylidene]propane-1, 2-diamine 6 and (S)-N-[2-(piperidin-1-yl)benzylidene]-3- {[2-(piperidin-1-yl)benzylidene]amino}-alanine sodium salt 7 have been synthesized and fully characterized by NM
- Yu, Shen Luan,Li, Yan Yun,Dong, Zhen Rong,Gao, Jing Xing
-
scheme or table
p. 395 - 398
(2012/06/18)
-
- A new chiral sulfinyl-NH-pyridine ligand for Ir-catalyzed asymmetric transfer hydrogenation reaction
-
A new flexible C1-symmetric tridentate ligand (S)-N-(2-(tert-butylsulfinyl)benzyl)-1-(pyridin-2-yl)methanamine sulfoxide (L1) was successfully prepared and utilized as a chiral ligand for Ir(I)-catalyzed ATH (asymmetric transfer hydrogenation) reactions. Without any cooperation of other chiral center, encouraging ee and conversion values have been achieved, which provide us a better understanding on these types of ligands and a new strategy to develop new high-efficiency chiral catalysts for asymmetric reaction.
- Tang, Lei,Wang, Qiwei,Wang, Juanjuan,Lin, Zechao,Wang, Xiaobei,Cun, Linfeng,Yuan, Weicheng,Zhu, Jin,Liao, Jian,Deng, Jingen
-
scheme or table
p. 3839 - 3842
(2012/08/14)
-
- Homogeneous enantioselective catalysis in a continuous-flow microreactor: Highly enantioselective borohydride reduction of Ketones catalyzed by optically active cobalt complexes
-
Highly enantioselective homogeneous catalysis under continuous-flow conditions was established for the cobalt-catalyzed borohydride reduction of tetralone derivatives. A microreactor allowed higher reaction temperature with the residence time of 12 min than the corresponding batch system to maintain enantioselectivity as well as reactivity. The present system was directly applied to gram-scale synthesis to afford the reduced product with 92% ee.
- Hayashi, Takuo,Kikuchi, Satoshi,Asano, Yukako,Endo, Yoshishige,Yamada, Tohru
-
experimental part
p. 1235 - 1240
(2012/09/21)
-
- Redesign of enzyme for improving catalytic activity and enantioselectivity toward poor substrates: Manipulation of the transition state
-
Secondary alcohols having bulky substituents on both sides of the hydroxy group are inherently poor substrates for most lipases. In view of this weakness, we redesigned a Burkholderia cepacia lipase to create a variant with improved enzymatic characteristics. The I287F/I290A double mutant showed a high conversion and a high E value (>200) for a poor substrate for which the wild-type enzyme showed a low conversion and a low E value (5). This enhancement of catalytic activity and enantioselectivity of the variant resulted from the cooperative action of two mutations: Phe287 contributed to both enhancement of the (R)-enantiomer reactivity and suppression of the (S)-enantiomer reactivity, while Ala290 created a space to facilitate the acylation of the (R)-enantiomer. The kinetic constants indicated that the mutations effectively altered the transition state. Substrate mapping analysis strongly suggested that the CH/π interaction partly enhanced the (R)-enantiomer reactivity, the estimated energy of the CH/π interaction being -0.4 kcal mol-1. The substrate scope of the I287F/I290A double mutant was broad. This biocatalyst was useful for the dynamic kinetic resolution of a variety of bulky secondary alcohols for which the wild-type enzyme shows little or no activity. The Royal Society of Chemistry 2012.
- Ema, Tadashi,Nakano, Yasuko,Yoshida, Daiki,Kamata, Shusuke,Sakai, Takashi
-
supporting information; experimental part
p. 6299 - 6308
(2012/09/05)
-
- A novel lipase enzyme panel exhibiting superior activity and selectivity over lipase B from Candida antarctica for the kinetic resolution of secondary alcohols
-
A novel, commercially available lipase enzyme panel performing kinetic bioresolutions of a number of secondary alcohols is reported. The secondary alcohols that have been chosen are known from the literature to be particularly challenging substrates to resolve. Following initial screening, four co-solvents were investigated for each lead enzyme in an effort to assess their tolerance to common organic solvents. The superiority of these novel enzymes over lipase B from Candida antarctica (CALB) has been demonstrated.
- O'Neill, Maeve,Beecher, Denis,Mangan, David,Rowan, Andrew S.,Monte, Agnieszka,Sroka, Stefan,Modregger, Jan,Hundle, Bhupinder,Moody, Thomas S.
-
experimental part
p. 583 - 586
(2012/08/13)
-
- Optical resolution of aromatic alcohols using silica nanoparticles grafted with helicene
-
Optically active silica nanoparticles, with a 70-nm diameter, grafted with (P)-1,12-dimethyl-8-methoxycarbonylbenzo[c]phenanthrene-5-carboxyamide were synthesized, and their use in the kinetic resolution of aromatic alcohols was examined. Up to 61% ee for (S)-2,2-dimethyl-1-phenyl-1-propanol was obtained by a preferential precipitation of aggregates formed with (P)-nanoparticles.
- Ichinose, Wataru,Miyagawa, Masamichi,An, Zengjian,Yamaguchi, Masahiko
-
supporting information; experimental part
p. 3123 - 3125
(2012/07/28)
-
- New chiral amino alcohol ligands derived from 1-phenylethylamine for efficient Ru-catalyzed asymmetric transfer hydrogenation
-
A series of chiral amino alcohols have been prepared from cheap and readily available (S)-1-phenylethylamine through a one-step transformation. The ability of these newly developed amino alcohols as chiral ligands was evaluated in the Ru-catalyzed asymmet
- Han, Mei-Ling,Hu, Xiang-Ping,Huang, Jia-Di,Chen, Li-Gong,Zheng, Zhuo
-
experimental part
p. 222 - 225
(2011/05/03)
-
- Asymmetric transfer hydrogenation of acetophenone derivatives with novel chiral phosphinite based η6-p-cymene/ruthenium(II) catalysts
-
Enantioselective reduction of prochiral ketones to optically active secondary alcohols is an important subject in synthetic organic chemistry because the resulting chiral alcohols are extremely useful, biologically active compounds. The new chiral ligands (2R)-2-[benzyl{(2-((diphenylphosphanyl)oxy) ethyl)}amino]butyldiphenylphosphinite, 1 and (2R)-2-[benzyl{(2- ((dicyclohexylphosphanyl)oxy)ethyl)}amino]butyldicyclohexylphosphinite, 2 and the corresponding ruthenium(II) complexes 3 and 4 have been prepared. The structures of these complexes have been elucidated by a combination of multinuclear NMR spectroscopy, IR spectroscopy and elemental analysis. 31P-{1H} NMR, DEPT, 1H-13C HETCOR or 1H-1H COSY correlation experiments were used to confirm the spectral assignments. These ruthenium(II)-phosphinite complexes have been used as catalysts for the asymmetric transfer hydrogenation of acetophenone derivatives. Under optimized conditions, aromatic ketones were reduced in good conversions and in moderate to good enantioselectivities (up to 85% ee).
- Aydemir, Murat,Meric, Nermin,Baysal, Akin,Turgut, Yilmaz,Kayan, Cezmi,?eker, Sevil,To?rul, Mahmut,Gümgüm, Bahattin
-
supporting information; experimental part
p. 1541 - 1546
(2011/06/17)
-
- Palladium-catalyzed asymmetric hydrogenation of simple ketones activated by Br?nsted acids
-
Homogeneous Pd(OCOCF3)2/(R)-C4-TunePhos has been successfully applied in the asymmetric hydrogenation of simple ketones activated by catalytic amount of Br?nsted acid with up to 88% ee.
- Zhou, Xiao-Yu,Wang, Duo-Sheng,Bao, Ming,Zhou, Yong-Gui
-
supporting information; experimental part
p. 2826 - 2829
(2011/06/21)
-
- A novel C3-symmetric prolinol-squaramide catalyst for the asymmetric reduction of ketones by borane
-
A novel C3-symmetric prolinol-squaramide has been developed for the asymmetric reduction of ketones by borane. By using only 5 mol % catalyst 1a for the reaction, high yields and excellent enantioselectivities (up to 95% yield, 93% ee) were obtained. Moreover, 1a can be easily recovered by simple precipitation and re-used for four cycles without losing the selectivity. Copyright
- Wu, Xiang-Fei,Min, Chang,Nyamzundui, Enkhtsetseg,Zhou, Hai-Bing,Dong, Chune
-
experimental part
p. 1640 - 1643
(2011/12/22)
-
- Highly enantioselective amido iridium catalysts for the hydrogenation of simple ketones
-
New family of cats: Tailormade amido iridium catalysts with simple structures and no P ligands show excellent enantioselectivities and activities in the asymmetric hydrogenation of simple ketones (see scheme; Cyellow, Ngreen, Oblue, Irred). These catalysts may thus be the key to ecologically and economically optimized value creation
- Irrgang, Torsten,Friedrich, Denise,Kempe, Rhett
-
supporting information; experimental part
p. 2183 - 2186
(2011/04/25)
-