1445-91-6Relevant articles and documents
ENANTIOSELECTIVE CATALYTIC BORANE REDUCTIONS OF ACHIRAL KETONES: SYNTHESIS AND APPLICATION OF NEW CHIRAL β-AMINO ALCOHOLS FROM L-METHIONINE
Mehler, Thomas,Martens, Juergen
, p. 1983 - 1986 (1993)
The in situ formed chiral axazaborolidine catalysts from optically active β-amino alcohols 1-3 from L-methionine ethyl carboxylate 4 have been used successfully in the enantioselective catalytic homogenous borane reductions of various aromatic ketones.The corresponding optically active alcohols are obtained in high optical purity (up to 100percent ee).
Upcycling a plastic cup: One-pot synthesis of lactate containing metal organic frameworks from polylactic acid
Slater, Benjamin,Wong, So-On,Duckworth, Andrew,White, Andrew J. P.,Hill, Matthew R.,Ladewig, Bradley P.
, p. 7319 - 7322 (2019)
Waste PLA can be upcycled to metal organic frameworks of potential high value in a one-pot synthesis scheme, where PLA depolymerisation occurs in situ. Three homochiral lactate based frameworks were successfully synthesised and characterised from PLA as a feed source, including ZnBLD. The chiral separation ability of ZnBLD was maintained.
Enantioselective resolution of (±)-1-phenylethyl acetate by extracellular proteases from deep-sea bacterium Bacillus sp. DL-2
Dong, Lu,Xu, Yongkai,Zhang, Yun,Sun, Aijun,Hu, Yunfeng
, p. 466 - 478 (2019)
Chiral 1-phenylethanol and its ester derivative are important chiral chemicals in diverse industries and the preparation of those optically pure enantiomers is of great importance. One bacterium, Bacillus sp. DL-2, whose extracellular proteases could efficiently asymmetrically hydrolyse (±)-1-phenylethyl acetate, was isolated from the deep sea of the Western Pacific. After the immobilization of extracellular proteases and the optimization of enzymatic reactions, (R)-1-phenylethanol was prepared with the enantiomeric excess (e.e.) being 97% and the yield being 41%, respectively. The optimal resolution reaction condition for the preparation of (R)-1-phenylethanol using immobilized extracellular proteases was found to be 5-mM (±)-1-phenylethyl acetate, 360 mg/mL immobilized extracellular proteases, pH 6.5, and 20 °C for 2 h. (S)-1-phenylethyl acetate was generated through enzymatic kinetic resolution with the e.e. being as high as 99% and the yield being 71%, respectively. The optimal resolution reaction condition for the preparation of (S)-1-phenylethyl acetate was found to be 2.5-mM (±)-1-phenylethyl acetate, 440 mg/mL immobilized extracellular proteases, pH 7.5, and 35 °C for 10 h. Our report is the first report about the kinetic resolution of (±)-1-phenylethyl acetate using proteases and the enantio-preference of the proteases was found to be the same as those of most other esterases/lipases. Also notably, the optical purity of (S)-1-phenylethyl acetate generated through kinetic resolution using the proteases of Bacillus sp. DL-2 was the highest report so far. Proteases from deep-sea Bacillus sp. DL-2 are new contributions to the biocatalyst library for the preparation of valuable chiral alcohols and chiral esters through kinetic resolution.
Asymmetric Borane Reduction of Achiral Ketones Mediated by A Chiral Oxazaborolidine Derived from (-)-Ephedrine
Cho, Buyng Tae,Chun, Yu Sung
, p. 1539 - 1542 (1992)
Asymmetric borane reduction of achiral ketones in the presence of a chiral oxazaborolidine derived from (-)-ephedrine yielded the corresponding alcohols in optical yields of 41 - 83percent ee.
Ionic liquids incorporating camphorsulfonamide units for the Ti-promoted asymmetric diethylzinc addition to benzaldehyde
Gadenne, Beno?t,Hesemann, Peter,Moreau, Jo?l J.E.
, p. 8157 - 8160 (2004)
New hydrophobic ionic liquids containing camphorsulfonamide units were used as chiral auxiliaries in the titanium catalyzed asymmetric addition of diethylzinc to benzaldehyde. New hydrophobic ionic liquids containing chiral camphorsulfonamide units were used as chiral auxiliaries in the titanium catalyzed asymmetric diethylzinc addition to benzaldehyde. The ionic catalyst system shows catalytic properties similar to those of related nonionic counterparts in terms of activity and enantioselectivity. Interestingly, the ionic ligands can easily be recycled and re-used without loss of activity or selectivity.
Enantioselective catalytic borane reductions of achiral ketones: Synthesis and application of new rigid catalysts prepared from (R)-phenylglycine and (S)-phenylalanine
Dauelsberg,Martens
, p. 2091 - 2099 (1993)
Enantiocontrolled reduction of prochiral ketones with borane in the presence of homochiral amino alcohols 1-4 as enantioselective catalysts afforded the chiral corresponding secondary alcohols in moderate to high (55 to 88%) optical yields.
RATIONAL DESIGNING OF EFFICIENT CHIRAL REDUCING AGENTS. HIGHLY ENANTIOSELECTIVE REDUCTION OF AROMATIC KETONES BY BINAPHTHOL-MODIFIED LITHIUM ALUMINUM HYDRIDE REAGENTS.
Noyori,Tomino,Tanimoto,Nishizawa
, p. 6709 - 6716 (1984)
A new chiral hydride reagent, BINAL-H, has been devised by the modification of lithium aluminum hydride with equimolar amounts of (R)- or (S)-2,2 prime -dihydroxy-1,1 prime -binaphthyl and a simple alcohol. This reducing agent exhibits exceptionally high enantioface-differentiating ability in the reduction of prochiral alkyl phenyl ketones in tetrahydrofuran. The phenyl and alkyl groups attached to the carbonyl function are differentiated primarily by the difference in electronic properties rather than the relative bulkiness. A six-membered-ring transition-state model is proposed to account for the stereochemical consequences. This mechanism is consistent with the phenomena observed with other unsaturated carbonyl substrates.
Plants in organic synthesis: An alternative to baker's yeast
Bruni, Renato,Fantin, Giancarlo,Medici, Alessandro,Pedrini, Paola,Sacchetti, Gianni
, p. 3377 - 3379 (2002)
The reduction of acetophenone 1 and the hydrolysis of 1-acetoxy-2-methylcyclohexene 3 with various commercially available plants to the corresponding S-carbinol 2 and S-ketone 4 are described. The further incubation of 2-methylcyclohexanone 4 with some pl
Enantioselective catalytic reduction of ketones using C2-symmetric diamines as chiral ligands
Gamez,Fache,Mangeney,Lemaire
, p. 6897 - 6898 (1993)
The catalytic enantioselective reduction of various prochiral ketones is reported using C2-symmetric diamines as ligands. Up to 99% e.e. at 100% conversion are obtained.
Incorporation of Homochirality into a Zeolitic Imidazolate Framework Membrane for Efficient Chiral Separation
Chan, Jun Yong,Zhang, Huacheng,Nolvachai, Yada,Hu, Yaoxin,Zhu, Haijin,Forsyth, Maria,Gu, Qinfen,Hoke, David E.,Zhang, Xiwang,Marriot, Philip J.,Wang, Huanting
, p. 17130 - 17134 (2018)
Homochiral metal–organic frameworks (MOFs) have gained much attention because of their chiral properties and disposition for chiral separation. However, the fabrication of high-quality homochiral MOF membranes remains challenging because of the difficulty in controlling growth of MOF membranes with chiral functionalities. A homochiral zeolitic imidazolate framework-8 (ZIF-8) membrane is reported for efficient chiral separation. The membrane is synthesized by incorporating a natural amino acid, l-histidine (l-His), into the framework of ZIF-8. The homochiral l-His-ZIF-8 membrane exhibits a good selectivity for the R-enantiomer of 1-phenylethanol over the S-enantiomer, showing a high enantiomeric excess value up to 76 %.
Modification of chiral monodentate phosphine (MOP) ligands for palladium-catalyzed asymmetric hydrosilylation of styrenes
Hayashi, Tamio,Hirate, Seiji,Kitayama, Kenji,Tsuji, Hayato,Torii, Akira,Uozumi, Yasuhiro
, p. 1272 - 1273 (2000)
In the palladium-catalyzed asymmetric hydrosilylation of styrene with trichlorosilane, several chiral monophosphine ligands, (R)-2-diarylphosphino-1,1′-binaphthyls (2), were examined for their enantioselectivity. The highest enantioselectivity was observed in the reaction with (R)-2-bis[3,5-bis-(trifluoromethyl)phenyl]phosphino-1,1′-binaphthyl (2g) , which gave (S)-1-phenylethanol of 98% ee after oxidation of the hydrosilylation product.
Enantioselective reduction of acetophenone with 1,3,2-oxazaborolidines derived from ephedrine, pseudoephedrine, and phenylglycine
Berenguer,Garcia,Gonzalez,Vilarrasa
, p. 13 - 16 (1993)
The performance of several 1,3,2-oxazaborolidines as chiral catalysts in the reduction of acetophenone has been compared, to gain insight into the more relevant structural factors as far as yield and enantioselectivity are concerned. B-Alkyl-4,5,5-triphen
A general protein purification and immobilization method on controlled porosity glass: Biocatalytic applications
Engelmark Cassimjee,Kadow,Wikmark,Svedendahl Humble,Rothstein,Rothstein,B?ckvall
, p. 9134 - 9137 (2014)
A general combined purification and immobilization method to facilitate biocatalytic process development is presented. The support material, EziG, is based on controlled porosity glass (CPG) or polymer-coated versions thereof (HybCPG) and binds protein affinity tags. Biocatalytic reactions in aqueous and organic media with seven enzymes of biocatalytic interest are shown. This journal is the Partner Organisations 2014.
Quantitative analysis of the chiral amplification in the amino alcohol- promoted asymmetric alkylation of aldehydes with dialkylzincs
Kitamura, Masato,Suga, Seiji,Oka, Hiromasa,Noyori, Ryoji
, p. 9800 - 9809 (1998)
Asymmetric reaction of dimethylzinc and benzaldehyde in the presence of (2S)-3-exo-(dimethyl-amino)isoborneol [(2S)-DAIB] exhibits unusual nonlinear phenomena. The enantiomeric purity of the product is much higher than that of the chiral source, DAIB, while the rate of the enantioselective catalysis decreases considerably as the enantiomeric excess (ee) of DAIB is lowered. Such effects originate from the reversible homochiral and heterochiral interaction of the coexistent enantiomeric zinc amino alkoxide catalysts which are formed from dimethylzinc and (2S)- and (2R)-DAIB. The thermodynamics of the five-component equilibration between the two monomers and three dimers, when coupled with the kinetics of the alkylation, strongly affects the extent of enantioselectivity and the reaction rate of the alkylation reaction. The overall profile of the nonlinear effects has been clarified mathematically using experimentally available parameters, viz., the equilibrium constants of the dimer/monomer conversion and the association of the monomeric catalyst with the organozinc and aldehyde, the rate constant of alkyl transfer from the catalyst/dimethylzinc/aldehyde mixed complex, the ee of DAIB, and the concentrations of DAIB, dimethylzinc, and aldehyde. 3D graphics are presented for the correlation of the enantiomeric purity of the product with DAIB ee and the concentrations of dimethylzinc and aldehyde and for the relationship between the reaction rate, DAIB ee, and the concentrations of the organozinc and aldehyde. The computer simulation is in good agreement with the experimental results, confirming thai the nonlinear effects result from the competition of two enantiomorphic catalytic cycles involving the monomeric chiral zinc catalysts rather than the diastereomorphic catalytic cycles with dinuclear zinc catalysts. Furthermore, this study indicates that the degree of nonlinear effects in asymmetric catalysis could be affected not only by the catalyst ee but also by various reaction parameters, particularly the concentrations of the catalyst, reagent, and substrate as well as the extent of conversion.
Chiral α-branched mono phosphine auxiliaries, reversal of sense of asymmetric induction upon substitution
Kasak, Peter,Mereiter, Kurt,Widhalm, Michael
, p. 3416 - 3426 (2005)
A group of 10 (mono- or bis-) α-chiral mono phosphine ligands was synthesized from enantiopure phosphepine sulfide 3 by one or two subsequential highly diastereoselective α-deprotonation/alkylation steps, followed by desulfuration with Raney nickel. Their relative configuration was determined by X-ray crystal structure analysis. The new monophosphine ligands were tested in asymmetric hydrogenation, hydroboration, and Suzuki-Miyaura coupling showing asymmetric inductions up to 91% ee. In the case of hydrogenation, clear evidence was found that enantioselectivity is substantially controlled through α-C chirality rather than through biaryl chirality, which was demonstrated by a change of the sense of asymmetric induction upon change of substituents.
BINOL-linked 1,2,3-triazoles: An unexpected fluorescent sensor with anion-π interaction for iodide ions
Wang, Cai-Yun,Zou, Jin-Feng,Zheng, Zhan-Jiang,Huang, Wei-Sheng,Li, Li,Xu, Li-Wen
, p. 54256 - 54262 (2014)
A new family of cyclic and acyclic BINOL-derived triazoles has been prepared for the organocatalytic silylation and subsequent use of fluorescent sensors, in which this type of receptor can unexpectedly recognize I- with good selectivity. The spectral analysis, including UV and NMR titrations, demonstrated that the anion-π interaction of I- to the triazole ring was responsible for the formation of a weak charge-transfer complex. This journal is
Enzyme entrapped in polymer-modified nanopores: The effects of macromolecular crowding and surface hydrophobicity
Liu, Jia,Peng, Juan,Shen, Shuai,Jin, Qianru,Li, Can,Yang, Qihua
, p. 2711 - 2719 (2013)
Macromolecular crowding is an ubiquitous phenomenon in living cells that significantly affects the function of enzymes in vivo. However, this effect has not been paid much attention in the research of the immobilization of enzymes onto mesoporous silica. Herein, we report the combined effects of macromolecular crowding and surface hydrophobicity on the performance of an immobilized enzyme by accommodating lipase molecules into a series of mesoporous silicas with different amounts of inert poly(methacrylate) (PMA) covalently anchored inside the nanopores. The incorporation of the PMA polymer into the nanopores of mesoporous silica enables the fabrication of a crowded and hydrophobic microenvironment for the immobilized enzyme and the variation in polymer content facilitates an adjustment of the degree of crowding and surface properties of this environment. Based on this system, the catalytic features of immobilized lipase were investigated as a function of polymer content in nanopores and the results indicated that the catalytic efficiency, thermostability, and reusability of immobilized lipase could all be improved by taking advantage of the macromolecular crowding effect and surface hydrophobicity. These findings provide insight into the possible functions of the macromolecular crowding effect, which should be considered and integrated into the fabrication of suitable mesoporous silicas to improve enzyme immobilization.
BAKER'S YEAST REDUCTION OF α-HALOACETOPHENONES
Carvalho, Marcia de,Okamoto, Marina T.,Moran, Paulo Jose Samenho,Rodrigues, J. Augusto R.
, p. 2073 - 2080 (1991)
The fermenting baker's yeast reductions of α-haloacetophenones were carried out by three different procedures.While the α-fluoro-, α-chloro- and α-bromoacetophenones gave the correspondent (-)-halohydrins, the reduction of α-iodoacetophenone gave acetophenone and (-)-1-phenylethanol.
Plants-mediated reduction in the synthesis of homochiral secondary alcohols
Bruni, Renato,Fantin, Giancarlo,Maietti, Silvia,Medici, Alessandro,Pedrini, Paola,Sacchetti, Gianni
, p. 2287 - 2291 (2006)
The reduction of 5-hexen-2-one 1, 6-methyl-5-hepten-2-one 2, acetophenone 3, cis-bicyclo[3.2.0]hept-2-en-6-one 4 and 2-methylcyclohexanone 5 with various commercially available plants (i.e., Brassica oleracea botrytis, Cucurbita maxima, Cucurbita pepo, Cynara scolimus, Daucus carota, Foeniculum vulgare and Musa sapientum) is reported. In the reduction of ketones 1-3, both (S)- and (R)-enantiomers 6-8 were obtained in good yields and with appreciable enantiomeric excesses. With racemic ketones 4 and 5, both the diastereomeric endo/exo 9 and 10 and cis/trans 11 and 12 are produced with variable yields and enantiomeric excesses depending on the various plants used.
Highly enantioselective recombinant thermoalkalophilic lipases from Geobacillus and Bacillus sp
Hutchins, Lauren M.,Hunter, Luke,Ehya, Noosha,Gibbs, Moreland D.,Bergquist, Peter L.,Hutton, Craig A.
, p. 2975 - 2980 (2004)
Thermoalkalophilic lipases from Geobacillus and Bacillus strains have been cloned and characterised, several of which show excellent activity and enantioselectivity towards various substrates. The hydrolysis of methyl 2-methyldecanoate proceeds to give (R)-2-methyldecanoic acid in good yield and >99% enantiomeric excess (E>200). Crown Copyright
Immobilization and characterization of a new regioselective and enantioselective lipase obtained from a metagenomic library
Alnoch, Robson Carlos,Martini, Viviane Paula,Glogauer, Arnaldo,Costa, Allen Carolina Dos Santos,Piovan, Leandro,Muller-Santos, Marcelo,De Souza, Emanuel Maltempi,Pedrosa, Fábio De Oliveira,Mitchell, David Alexander,Krieger, Nadia
, (2015)
In previous work, a new lipase and its cognate foldase were identified and isolated from a metagenomic library constructed from soil samples contaminated with fat. This new lipase, called LipG9, is a true lipase that shows specific activities that are comparable to those of well-known industrially-used lipases with high activity against long-chain triglycerides. In the present work, LipG9 was co-expressed and co-immobilized with its foldase, on an inert hydrophobic support (Accurel MP1000). We studied the performance of this immobilized LipG9 (Im-LipG9) in organic media, in order to evaluate its potential for use in biocatalysis. Im-LipG9 showed good stability, maintaining a residual activity of more than 70% at 50°C after incubation in n-heptane (log P 4.0) for 8 h. It was also stable in polar organic solvents such as ethanol (log P -0.23) and acetone (log P -0.31), maintaining more than 80% of its original activity after 8 h incubation at 30°C. The synthesis of ethyl esters was tested with fatty acids of different chain lengths in n-heptane at 30°C. The best conversions (90% in 3 h) were obtained for medium and long chain saturated fatty acids (C8, C14 and C16), with the maximum specific activity, 29 U per gram of immobilized preparation, being obtained with palmitic acid (C16). Im-LipG9 was sn-1,3-specific. In the transesterification of the alcohol (R,S)-1-phenylethanol with vinyl acetate and the hydrolysis of the analogous ester, (R, S)-1-phenylethyl acetate, Im-LipG9 showed excellent enantioselectivity for the R-isomer of both substrates (E> 200), giving an enantiomeric excess (ee) of higher than 95% for the products at 49% conversion. The results obtained in this work provide the basis for the development of applications of LipG9 in biocatalysis.
Synthesis and application of arylmonophosphinoferrocene ligands: ultrafast asymmetric hydrosilylation of styrene.
Pedersen, Henriette Lodberg,Johannsen, Mogens
, p. 7982 - 7994 (2002)
A short and efficient synthetic route to a novel class of atropisomeric and planar chiral 2-aryl-1-diphenylphosphanylferrocene ligands is presented. The modular design of the ligands allows a synthetic approach in which both the aromatic moiety and the phosphino substituent can be varied easily. This permits fine-tuning of steric and electronic properties. The ligands have been tested in the asymmetric hydrosilylation of styrene where enantioselectivities up to 90% are obtained. Optimization of the palladium-to-ligand ratio resulted in hitherto unparalleled turnover frequencies (TOF) exceeding 180 000 h(-1). The absolute stereochemistry of the ligands was determined from an X-ray structure. 2D NMR experiments in combination with ab initio calculations were used to assign the conformation of the atropisomeric biarylic scaffold.
Homo- vs. heterometallic organoaluminum fencholates: Structures and selectivities
Soki, Francis,Neud?rfl, J?rg-Martin,Goldfuss, Bernd
, p. 2139 - 2146 (2008)
Homo (Al)- and heterometallic (Al, Li)-fencholates and TADDOLates (5-12) yield in methylations of benzaldehyde 1-phenylethanol with up to 90% ee. Surprisingly, the new BISFOL-based (Al, Li)-heterometallic fencholate (11) shows an strong increase and a change of the sense of enantioselectivity from 19% ee (S) to 62% ee (R) in comparison to its (Al)-homometallic fencholate (7). Despite of the presence of nucleophilic methylide groups, the O-BIFOL-based (Al, Li)-heterometallic fencholate (10) yields a stable complex with benzaldehyde, a lithium ion binds the carbonyl group.
Enantiocontrolled Reduction of Prochiral Aromatic Ketones with Borane using Diastereoisomeric Secondary Aminoalcohols as Chiral Catalysts
Tanaka, Kazuhiko,Matsui, Junichi,Suzuki, Hitomi
, p. 1311 - 1312 (1991)
Exo- and endo-2-hydroxy-3-(1-methyl-2-pyrrolyl)methylaminobornanes were found to be efficient catalysts for enantioselective borane reduction of prochiral aromatic ketones with predictable absolute stereochemistry.
Enantioselective sorption of alcohols in a homochiral metal-organic framework
Suh, Kyungwon,Yutkin, Maxim P.,Dybtsev, Danil N.,Fedin, Vladimir P.,Kim, Kimoon
, p. 513 - 515 (2012)
Single-crystal X-ray diffraction study reveals the host-guest interactions between a homochiral metal-organic framework and two enantiomers of a chiral alcohol providing the key driving force for the enantioselective sorption of alcohols in the framework.
Cinchona-Alkaloid-Derived NNP Ligand for Iridium-Catalyzed Asymmetric Hydrogenation of Ketones
Zhang, Lin,Zhang, Ling,Chen, Qian,Li, Linlin,Jiang, Jian,Sun, Hao,Zhao, Chong,Yang, Yuanyong,Li, Chun
supporting information, p. 415 - 419 (2022/01/12)
Most ligands applied for asymmetric hydrogenation are synthesized via multistep reactions with expensive chemical reagents. Herein, a series of novel and easily accessed cinchona-alkaloid-based NNP ligands have been developed in two steps. By combining [Ir(COD)Cl]2, 39 ketones including aromatic, heteroaryl, and alkyl ketones have been hydrogenated, all affording valuable chiral alcohols with 96.0-99.9% ee. A plausible reaction mechanism was discussed by NMR, HRMS, and DFT, and an activating model involving trihydride was verified.
Novel highly efficient absolute optical resolution method by serial combination of two asymmetric reactions from acetylene monomers having racemic substituents
Aoki, Toshiki,Kaneko, Takashi,Liu, Lijia,Suzuki, Junpei,Tang, Yanan,Teraguchi, Masahiro
supporting information, p. 450 - 461 (2022/01/15)
For general optical resolution, an optical resolution agent is necessary, and the best agent should be selected for each racemic compound. In this study, we will report that a novel optical resolution method by circularly polarized light (CPL) without any
Epoxide Hydrogenolysis Catalyzed by Ruthenium PNN and PNP Pincer Complexes
Borden, Olivia J.,Chianese, Anthony R.,Head, Marianna C.,Kelly, Sophie E.,Kirlin, Fallyn L.
supporting information, p. 1025 - 1033 (2022/04/25)
The metal-catalyzed hydrogenolysis of epoxides to give alcohols has advanced rapidly in the past several years, with some catalysts selectively giving linear (anti-Markovnikov) products and other catalysts providing branched (Markovnikov) products. The currently known branched-selective catalyst systems require catalyst loadings of 1% or higher and typically require a strong base additive. We report herein that PNN- and PNP-ruthenium pincer complexes containing N-H functional groups are highly active for branched-selective hydrogenolysis of epoxides. When isopropyl alcohol is used as the solvent, excellent yields of the branched alcohol products are obtained without strongly basic additives, using catalyst loadings as low as 0.03%. Epoxides with a directly attached secondary carbon give a very high (>99:1) selectivity for the branched products. Aryl-substituted epoxides give branched:linear ratios ranging from 2.7 to 19.0. For aryl epoxides, a PNP-Ru catalyst showed a greater preference for the branched product than a PNN-Ru catalyst, and substrates with electron-rich aryl substituents showed a lower preference for the branched product.
