The asymmetric addition of aromatic organometallic compounds to the carbonyl group(C-3)of isatins,catalyzed by transition metals,has emerged as a remarkably efficient method for the synthesis of chiral 3-hydroxyoxindo...The asymmetric addition of aromatic organometallic compounds to the carbonyl group(C-3)of isatins,catalyzed by transition metals,has emerged as a remarkably efficient method for the synthesis of chiral 3-hydroxyoxindoles.Here,an exceptionally enantioselective approach was developed for the first time to achieve a catalytic NHK reaction of isatins with aromatic halides(both aryl and heteroaryl).Utilizing chiral cobalt complexes as catalysts,and the presence of a diboron reagent B_(2)nep_(2)as both a reducing agent and determinant in enantiocontrol,has resulted in the triumphantly achieved synthesis of enantioenriched products.Compared to reported strategies,this approach exhibits remarkable compatibility with substrates bearing sensitive functional groups,such as halides and borate esters,while also eliminating the need for organometallic reagents as required in previous strategies.Through experimental investigations,the presence of aryl-cobalt species during the addition process was confirmed,rather than in-situ generation of an arylboron reagent.Furthermore,the successful attainment of the R absolute configuration through aryl addition was demonstrated.展开更多
A novel organocatalytic asymmetric approach to oxazoline derivatives that proceeds through Mannich/annulation reaction of N-acylimines with 3-chlorooxindoles is presented.This strategy provides an efficient and conven...A novel organocatalytic asymmetric approach to oxazoline derivatives that proceeds through Mannich/annulation reaction of N-acylimines with 3-chlorooxindoles is presented.This strategy provides an efficient and convenient method to access enantioenriched oxazolines such as valuable chiral S,Noxazoline ligand as well as Ferrox ligand in high yields with excellent enantio–and diastereroselectivity.Furthermore,the optically active oxazoline products can be converted to valuable 1,2-amino alcohols.More importantly,the synthetic utility of this transformation is demonstrated in the expeditious assembly of chiral Phox-type ligand,which shows excellent catalytic activities.展开更多
In this study,a novel linear polyimide chain(PTCDA-DCH)was used as an electrochemiluminescence(ECL)emitter,employing a chiral metal-organic framework(MOF)(Zn-Dcam-dabco)as the chiral selector and ferrocene(Fc)as a que...In this study,a novel linear polyimide chain(PTCDA-DCH)was used as an electrochemiluminescence(ECL)emitter,employing a chiral metal-organic framework(MOF)(Zn-Dcam-dabco)as the chiral selector and ferrocene(Fc)as a quencher to construct a chiral sensor for detecting histidine(His)enantiomers.Competitive interactions between Fc and His induce partial Fc desorption from the sensor surface,leading to ECL signal recovery.Differential Fc release due to the distinct binding affinities of Zn-Dcam-dabco for His enantiomers enabled precise chiral discrimination.Notably,the sensor achieved the quantitative detection of His enantiomers with an limits of detection(LOD)of 8μmol/L.Furthermore,the sensor demonstrated excellent recovery rates of 98.0%–104%for l-histidine(L-His)and 92.0%–95.9%for D-His in spiked milk samples,validating its reliability for real-sample analysis.This study provides a promising platform for ECL-based chiral recognition,bioanalysis,and the rapid assessment of amino acids in food products.展开更多
Axially chiral binaphthol have achieved great success in asymmetric catalysis.Compared toα-binaphthol,axially chiral aryl-β-naphthol are far less reported.Here,we report a method of asymmetric catalysis to construct...Axially chiral binaphthol have achieved great success in asymmetric catalysis.Compared toα-binaphthol,axially chiral aryl-β-naphthol are far less reported.Here,we report a method of asymmetric catalysis to constructβ-naphthol with up to 99%yield,95.5:4.5 enantiomeric ratio,using alkynyl esters as precursors and chiral phosphonic acid(CPA)/Lewis acid as catalysts.Key steps involve oxygen transfer and de novo arene formation to set up the chiral axis.Moreover,this methodology provides a versatile platform for structurally divergent synthesis of atroposelectiveβ-naphthol analogs,which are widely found in bioactive molecules and asymmetric catalysts.展开更多
Covalent organic cages(COCs)are three-dimensional organic molecules with permanent cavities,known for their ordered pore structures,excellent processability,and modular design.They have shown significant potential in ...Covalent organic cages(COCs)are three-dimensional organic molecules with permanent cavities,known for their ordered pore structures,excellent processability,and modular design.They have shown significant potential in applications such as gas adsorption,molecular separation,and catalysis.Introducing chiral elements into COCs results in chiral COCs with confined chiral cavities,which endows them with unique chiral functions and expands their application prospects.This review summarizes the research progress on chiral covalent organic cages,focusing on strategies for incorporating chiral elements,the structures and synthesis methods of representative chiral COCs,and advancements in their chiral functions.Additionally,we provide perspectives on future research directions.We hope this review will inspire further interest and creativity among researchers in the field of chiral molecular cages,leading to the development of materials with unique structures and functions.展开更多
G-quadruplex DNA(G4)can function as a kind of nucleic acid apoenzyme for constructing G4/hemin biocatalyst to mimic the catalytic function of hemoprotein.However,achieving stereoselective control with G4/hemin remains...G-quadruplex DNA(G4)can function as a kind of nucleic acid apoenzyme for constructing G4/hemin biocatalyst to mimic the catalytic function of hemoprotein.However,achieving stereoselective control with G4/hemin remains a persistent challenge.Here,we report that a PW17/hemin(PW17:5’-GGGTAGGGCGGGTTGGG-3’),adopting the 5’-5’stacked dimeric parallel G4 topology,can realize the enantioselective induction in intramolecular cyclopropanation of allyl diazoacetates with enantioselectivity up to 87%ee.Spectroscopic characterization and catalytic results demonstrate that the relatively open G-quartet of the 3’terminal in dimeric PW17 contributes a catalytic pocket for hemin accommodation and plays a pivotal role in enantioselective control.This finding expands the unique repertoire of heme enzyme using biological scaffolds from proteins to nucleic acids and resolves the long-standing challenge of stereochemical control in G4/hemin catalysis.展开更多
Rational tuning of chiral nanostructures of supramolecular assemblies as catalysts and investigating their chiral morphology-enantioselectivity dependence is rarely reported. Herein, we report a series of supramolecul...Rational tuning of chiral nanostructures of supramolecular assemblies as catalysts and investigating their chiral morphology-enantioselectivity dependence is rarely reported. Herein, we report a series of supramolecular M/P-helical nanoribbons(HNs) assembled from the chiral L/D-glutamate-based amphiphiles(L/D-Glu C16) and Cu(Ⅱ) ions, with their helical screw pitches adjusted from 217 nm to 104 nm through the facile regulation of their water/organic solvent assembly environment. They were then used as ideal models to reveal the chiral morphology-enantioselectivity relationship by catalyzing the asymmetric Diels-Alder reaction. Better enantioselectivity was achieved with more twist morphology. Experimental evidences of stronger chiral transfer effect from the supramolecular HNs with more twist to the aza-chalcone as reactant were obtained to understand such dependence. Our study demonstrates a new perspective for designing supramolecular catalysts with higher enantioselectivity.展开更多
A cobalt pincer complex bearing both P and C-stereogenic centers has been designed and synthesized,allowing for the development of the first cobalt-catalyzed asymmetric hydrogenation of quinoxalines under relatively m...A cobalt pincer complex bearing both P and C-stereogenic centers has been designed and synthesized,allowing for the development of the first cobalt-catalyzed asymmetric hydrogenation of quinoxalines under relatively mild conditions.Valuable chiral 1,2,3,4-tetrahydroquinoxalines could be obtained with high yields and excellent enantioselectivities(35 examples,up to>99%ee).展开更多
A comprehensive mechanistic study on the chiral phosphoric acid catalyzed an enantioselective asymmetric aza-pinacol rearrangement of 4-chloro-N-(2-(3'-hydroxy-1'-phenylspiro[cyclopentane-1,2'-indolin]-3&#...A comprehensive mechanistic study on the chiral phosphoric acid catalyzed an enantioselective asymmetric aza-pinacol rearrangement of 4-chloro-N-(2-(3'-hydroxy-1'-phenylspiro[cyclopentane-1,2'-indolin]-3'-yl)ethyl)(1a)is investigated at the M06-2X/6-311+G(d,p)level.Our computational results suggest that the whole catalytic cycle proceeds through dehydration of 1a,enantioselective aza-pinacol rearrangement,intramolecular cyclization and catalyst regeneration to deliver the fused indoline product.The aza-pinacol rearrangement is the key stereocontrolling step of the title reaction.The chiral catalyst controls the orientation of the transition states of the enantioselective step through two potential binding sites between the bifunctional chiral phosphate and the aza-ortho-xylylene intermediate.Moreover,theoretical studies identified that the multiple C—H…π,C—H…O,and C—H…N hydrogen bonds and N—H…O^(-)electrostatic interactions between the substrates and the arms as well as functional oxygen anion of the chiral catalyst(R)-4c play a crucial role in determining the stereochemical outcomes.And the strong N—H…O^(-)interaction in the major transition state was found to contribute to the high levels of enantioselectivity.Additionally,the predicted enantiomeric excess(ee)of 89%based on the 6.3 kJ·mol^(–1)energy difference between the enantioselective TS-2-major and TS-2-minor is in agreement with the experimental results of 90%.展开更多
A wide range of isoquinoline ring-modified Quinap oxides with different steric and electronic variations have been constructed through a palladium-catalyzed imidoylative cyclization of arylethenyl isocyanides with 2-d...A wide range of isoquinoline ring-modified Quinap oxides with different steric and electronic variations have been constructed through a palladium-catalyzed imidoylative cyclization of arylethenyl isocyanides with 2-diphenylphosphinyl-1-naphthyl bromides.The Pd-catalysis plays dual roles in the formation of both axial C–C bond and isoquinoline ring.This de novo synthetic strategy features good functional group tolerance,high yields and easy scale-up,providing Quinap derivatives with substitution patterns that could not be obtained using coupling reactions.Chiral ligands 7 and 12 can be readily prepared by transformation of the resulting Quinap oxide to their BINOL esters,and have been proven to be superb chiral ligands for the copper-catalyzed enantioselective A^(3)-coupling and alkynylation of quinoline reactions.In general,the enantioselectivies obtained using ligands 7 and 12 are excellent,and the ee values are higher than those using Quinap as ligand,even three times higher in some cases.Mechanism studies revealed that a monomeric copper(Ⅰ)complex bearing a single chiral ligand was formed and served as the catalytically active species.展开更多
Nineβ‐cyclodextrin derivatives containing an amino group were synthesized via nucleophilic sub‐stitution from mono（6‐O‐p‐tolylsulfonyl）‐β‐cyclodextrin and used in asymmetric biomimetic Mi‐chael addition re...Nineβ‐cyclodextrin derivatives containing an amino group were synthesized via nucleophilic sub‐stitution from mono（6‐O‐p‐tolylsulfonyl）‐β‐cyclodextrin and used in asymmetric biomimetic Mi‐chael addition reactions in water at room temperature. The mechanism responsible for the moder‐ate activity and enantioselectivity of the β‐cyclodextrin derivatives was explored using nuclear magnetic resonance spectroscopy, namely 2D 1H rotating‐frame overhauser effect spectroscopy （ROESY）, ultraviolet absorption spectroscopy, and quantum chemical calculations, which provide a useful technique for investigating the formation of inclusion complexes. The effects of the pH of the reaction medium, theβ‐cyclodextrin derivative dosage, the structure of the modifying amino group, and various substrates on the yield and enantioselectivity were investigated. The results indicated that these factors had an important effect on the enantiomeric excess （ee） in the reaction system. Experiments using a competitor for inclusion complex formation showed that a hydrophobic cavity is necessary for enantioselective Michael addition. A comparison of the reactions using 4‐nitro‐β‐nitrostyrene and 2‐nitro‐β‐nitrostyrene showed that steric hindrance improved the enan‐tioselectivity. This was verified by the optimized geometries obtained from quantum chemical cal‐culations. An ee of 71%was obtained in the asymmetric Michael addition of cyclohexanone and 2‐nitro‐β‐nitrostyrene, using （S）‐2‐aminomethylpyrrolidine‐modified β‐CD as the catalyst, in an aqueous buffer solution, i.e., CH3COONa‐HCl （pH 7.5）.展开更多
The chiral nature of biological systems enables their stereoselective interaction with chiral compounds. It has been well documented that the enantiomers ofa chiral drug may show differences in drug disposition especi...The chiral nature of biological systems enables their stereoselective interaction with chiral compounds. It has been well documented that the enantiomers ofa chiral drug may show differences in drug disposition especially in metabolic behavior. As a result, it is of vital importance to separate the enantiomers of a chiral drug in metabolic studies. This paper discusses enantioselective methods （include high-performance liquid chromatography, gas chromatography, capillary electrophoresis and high-performance liquid chromatography-mass spectrometry） that applied in chiral drug metabolism, using most recent examples where possible.展开更多
Effective enantioseparation of Naftopidil and its derivatives by HPLC was accomplished using several different polysaccharide-based chiral stationary phases（CSPs）.In normal-phase mode,the compounds were eluted on fo...Effective enantioseparation of Naftopidil and its derivatives by HPLC was accomplished using several different polysaccharide-based chiral stationary phases（CSPs）.In normal-phase mode,the compounds were eluted on four coated-and two immobilized-columns with the mixture of n-hexane,isopropanol and diethylamine（DEA）.Polysaccharide tris（3,5- dimethylphenyl carbamate） was shown to be the best enantiomer selector.In addition,the immobilized column packed with Chiralpak IA or IB was applied under polar-organic and reversed-phase conditions,both of which exhibited excellent enantioselectivity for Naftopidil and its derivatives.Furthermore,the underlying possible chiral recognition mechanisms were discussed.展开更多
Enantioselectivity of chiral pollutants is receiving growing concern due to the difference in toxicology and environment fate between enantiomers.In this study,enantiomers of insecticide beta-cypermethrin （beta-CP） ...Enantioselectivity of chiral pollutants is receiving growing concern due to the difference in toxicology and environment fate between enantiomers.In this study,enantiomers of insecticide beta-cypermethrin （beta-CP） were separated on selected chiral column by HPLC,and the toxicity of enantiomers was evaluated using the zebrafish embryo-larval assays.The enantiomers of beta-CP were baseline separated on Chiralcel OD and Chiralpak AD columns and detected by circular dichroism （CD） at 236 nm.Better separation could be achieved at lower temperature （e.g.,20°C） and with lower levels of polar modifiers.Pure enantiomers were obtained on Chiralcel OD.The CD spectra of enantiomers were recorded.By comparing the elution order with a previous similar study,the absolute configuration of beta-CP enantiomers was determined.The individual enantiomers were used in zebrafish embryo test,and the results showed that beta-CP enantioselectively induced yolk sac edema,pericardial edema and crooked body.The 1R-cis-αS and 1R-trans-αS enantiomers showed strong developmental toxicities at concentration of 0.1 mg/L,while the 1S-cis-αR and 1S-trans-αR induced no malformations at higher concentration （e.g.,0.3 mg/L）.The results suggest that the enantioselective toxicological effects of beta-CP should be considered when evaluating its ecotoxicological effects.展开更多
In a non-chiral environment, the enantiomers of a racemate possessed the identical physico-cbemical properties, but in the biological systems they possessed different activities. Considering that the involvement of ox...In a non-chiral environment, the enantiomers of a racemate possessed the identical physico-cbemical properties, but in the biological systems they possessed different activities. Considering that the involvement of oxidative damage has been implicated in the toxicities of various pesticides, this study investigated the possibility of enantioselective oxidative stress and cytotoxicity induction by acetofenate （AF） which contains an asymmetrical center on PC12 cells. The results of the cytotoxicity assay indicated that S-（＋）-AF presented more toxic effects than R-（-）-AF and （＋）-AF. It also demonstrated that S-（＋）-AF possessed the strongest effects in induction of reactive oxygen species （ROS） production, decrease in superoxide dismutase （SOD） and catalase （CAT） activities, and increase in malondialdehyde （MDA） level. These results suggested that AF and its enanfiomers could induce enantioselecfive cytotoxicity in PC12 cells mediated by oxidative stress. Therefore, the assessment in environmental safety and new chiral pesticide development should consider enantioselectivity.展开更多
Pseudomonas cepacia lipase （PSL） immobilized on the carboxyl-functionalized meso-cellular foams （HOOC-MCF） was used for the transesterification resolution of （R,S）-l-phenylethanol in organic solvent. The results...Pseudomonas cepacia lipase （PSL） immobilized on the carboxyl-functionalized meso-cellular foams （HOOC-MCF） was used for the transesterification resolution of （R,S）-l-phenylethanol in organic solvent. The results showed that the ee value of （S）-1- phenylethanol and （R）-1-phenylethyl acetate reached 99% with 50% conversion of 1-phenylethanol using toluene as solvent. Furthermore, it was found that PSL/HOOC-MCF exhibited high enantioselectivity in organic solvent with log P ≤ 2 such as toluene and hexane.展开更多
Aroma(volatile)compounds play important ecological functions in plants,and also contribute to the quality of plant-derived foods.Moreover,chiral aroma compounds affect their functions in plants and lead to different f...Aroma(volatile)compounds play important ecological functions in plants,and also contribute to the quality of plant-derived foods.Moreover,chiral aroma compounds affect their functions in plants and lead to different flavor quality properties.Formations of chiral aroma compounds are due to the presence of enzymes producing these compounds in plants,which are generally involved in the final biosynthetic step of the aroma compounds.Here,we review recent progress in research on the plant-derived enzymes producing chiral aroma compounds,and their changes in response to environmental factors.The chiral aroma enzymes that have been reported produce(R)-linalool,(S)-linalool,(R)-limonene,and(S)-limonene,etc.,and these enzymes are found in various plant species.We also discuss the origins of enantioselectivity in the plant-derived enzymes producing chiral aroma compounds and summarize the potential use of plants containing enzymes producing chiral aroma compounds for producing chiral flavors/fragrances.展开更多
With growing interests paid to the enantioselective analysis of chiral molecules, roles played by noble metal and semiconductor nanomaterials surface gradually. Given the unique physicochemical properties of noble met...With growing interests paid to the enantioselective analysis of chiral molecules, roles played by noble metal and semiconductor nanomaterials surface gradually. Given the unique physicochemical properties of noble metal and semiconductor nanomaterials, the enantioselective analyses are classified into three categories: fluorescence-based, colorimetry-based, and circular dichroism-based ones. In this paper, we review the existing progresses on enantioselective analysis, thanks to noble metal and semiconductor nanomaterials. Finally, the prospect of enantioselective analysis based on noble metal and semiconductor are discussed.展开更多
A novel preparation method was developed to form a surfactant-lipase complex for the resolution of 2-octanol in a solvent-free system. The E value was improved from 6.64 to 120.2. The lipase modified by the anion...A novel preparation method was developed to form a surfactant-lipase complex for the resolution of 2-octanol in a solvent-free system. The E value was improved from 6.64 to 120.2. The lipase modified by the anionic surfactant possessed a low solubility in the solvent-free system, which was beneficial to the recovery and the repeated usage of the lipase. The surfactant-lipase complex maintained a high enantioselectivity after five cycles of usage. The effect of water on both the activity and the enantioselectivity of the lipase has also been investigated; the direct addition of a salt hydrate pair of Na 4P 2O 7·H 2O and Na 4P 2O 7 can dramatically activate the modified enzyme.展开更多
基金the National Key R&D Program of China(No.2022YFA1503200)the National Natural Science Foundation of China(Nos.22025104,22171134,and 21972064)the Fundamental Research Funds for the Central Universities(No.020514380254)is greatly appreciated.
文摘The asymmetric addition of aromatic organometallic compounds to the carbonyl group(C-3)of isatins,catalyzed by transition metals,has emerged as a remarkably efficient method for the synthesis of chiral 3-hydroxyoxindoles.Here,an exceptionally enantioselective approach was developed for the first time to achieve a catalytic NHK reaction of isatins with aromatic halides(both aryl and heteroaryl).Utilizing chiral cobalt complexes as catalysts,and the presence of a diboron reagent B_(2)nep_(2)as both a reducing agent and determinant in enantiocontrol,has resulted in the triumphantly achieved synthesis of enantioenriched products.Compared to reported strategies,this approach exhibits remarkable compatibility with substrates bearing sensitive functional groups,such as halides and borate esters,while also eliminating the need for organometallic reagents as required in previous strategies.Through experimental investigations,the presence of aryl-cobalt species during the addition process was confirmed,rather than in-situ generation of an arylboron reagent.Furthermore,the successful attainment of the R absolute configuration through aryl addition was demonstrated.
基金Qingdao Marine Science and Technology Center(No.2022QNLM030003–2)the Fundamental Research Funds for the Central Universities,Taishan Scholar Program of Shandong Province(No.tsqn202103152)+2 种基金National Natural Science Foundation of China(No.22201270)Natural Science Foundation of Shandong Province(No.ZR2021QB033)the National Key Research and Development Program of China(No.2022YFC2804400)for financial support。
文摘A novel organocatalytic asymmetric approach to oxazoline derivatives that proceeds through Mannich/annulation reaction of N-acylimines with 3-chlorooxindoles is presented.This strategy provides an efficient and convenient method to access enantioenriched oxazolines such as valuable chiral S,Noxazoline ligand as well as Ferrox ligand in high yields with excellent enantio–and diastereroselectivity.Furthermore,the optically active oxazoline products can be converted to valuable 1,2-amino alcohols.More importantly,the synthetic utility of this transformation is demonstrated in the expeditious assembly of chiral Phox-type ligand,which shows excellent catalytic activities.
基金financially supported by the Natural Science Foundation of Shandong Province,China(Nos.ZR2020QB065 and ZR2021MB121)。
文摘In this study,a novel linear polyimide chain(PTCDA-DCH)was used as an electrochemiluminescence(ECL)emitter,employing a chiral metal-organic framework(MOF)(Zn-Dcam-dabco)as the chiral selector and ferrocene(Fc)as a quencher to construct a chiral sensor for detecting histidine(His)enantiomers.Competitive interactions between Fc and His induce partial Fc desorption from the sensor surface,leading to ECL signal recovery.Differential Fc release due to the distinct binding affinities of Zn-Dcam-dabco for His enantiomers enabled precise chiral discrimination.Notably,the sensor achieved the quantitative detection of His enantiomers with an limits of detection(LOD)of 8μmol/L.Furthermore,the sensor demonstrated excellent recovery rates of 98.0%–104%for l-histidine(L-His)and 92.0%–95.9%for D-His in spiked milk samples,validating its reliability for real-sample analysis.This study provides a promising platform for ECL-based chiral recognition,bioanalysis,and the rapid assessment of amino acids in food products.
基金financial support from the National Natural Science Foundation of China(Nos.22071062,22001077 and 22271096)Guangdong Science and Technology Department(Nos.2021A1515012331,2023A1515011001)+1 种基金the Fundamental Research Funds for the Central Universities(No.2022ZYGXZR016)South China University of Technology for start-up funds。
文摘Axially chiral binaphthol have achieved great success in asymmetric catalysis.Compared toα-binaphthol,axially chiral aryl-β-naphthol are far less reported.Here,we report a method of asymmetric catalysis to constructβ-naphthol with up to 99%yield,95.5:4.5 enantiomeric ratio,using alkynyl esters as precursors and chiral phosphonic acid(CPA)/Lewis acid as catalysts.Key steps involve oxygen transfer and de novo arene formation to set up the chiral axis.Moreover,this methodology provides a versatile platform for structurally divergent synthesis of atroposelectiveβ-naphthol analogs,which are widely found in bioactive molecules and asymmetric catalysts.
基金supported by the National Natural Science Foundation of China(Grant Nos.22271164 and U20A20259 and 22371147)the Fundamental Research Funds for the Central Universities,the NCC Fund(Grant No.NCC2020FH04)+1 种基金the Tianshan Innovation Team Plan of Xinjiang Uygur Autonomous Region(Grant No.2023D14002)Nankai University(NKU).
文摘Covalent organic cages(COCs)are three-dimensional organic molecules with permanent cavities,known for their ordered pore structures,excellent processability,and modular design.They have shown significant potential in applications such as gas adsorption,molecular separation,and catalysis.Introducing chiral elements into COCs results in chiral COCs with confined chiral cavities,which endows them with unique chiral functions and expands their application prospects.This review summarizes the research progress on chiral covalent organic cages,focusing on strategies for incorporating chiral elements,the structures and synthesis methods of representative chiral COCs,and advancements in their chiral functions.Additionally,we provide perspectives on future research directions.We hope this review will inspire further interest and creativity among researchers in the field of chiral molecular cages,leading to the development of materials with unique structures and functions.
文摘G-quadruplex DNA(G4)can function as a kind of nucleic acid apoenzyme for constructing G4/hemin biocatalyst to mimic the catalytic function of hemoprotein.However,achieving stereoselective control with G4/hemin remains a persistent challenge.Here,we report that a PW17/hemin(PW17:5’-GGGTAGGGCGGGTTGGG-3’),adopting the 5’-5’stacked dimeric parallel G4 topology,can realize the enantioselective induction in intramolecular cyclopropanation of allyl diazoacetates with enantioselectivity up to 87%ee.Spectroscopic characterization and catalytic results demonstrate that the relatively open G-quartet of the 3’terminal in dimeric PW17 contributes a catalytic pocket for hemin accommodation and plays a pivotal role in enantioselective control.This finding expands the unique repertoire of heme enzyme using biological scaffolds from proteins to nucleic acids and resolves the long-standing challenge of stereochemical control in G4/hemin catalysis.
基金support of this research by the National Natural Science Foundation of China(Nos.22202171,21922202,and 22272146)the Natural Science Foundation of Jiangsu Basic Research Program(No.BK20220559)+1 种基金the Natural Science Foundation of the Higher Education Institutions of Jiangsu Province(No.22KJD150009)the Jiangsu Specially-Appointed Professor Plan(Z.Xi)from the Jiangsu Education Department。
文摘Rational tuning of chiral nanostructures of supramolecular assemblies as catalysts and investigating their chiral morphology-enantioselectivity dependence is rarely reported. Herein, we report a series of supramolecular M/P-helical nanoribbons(HNs) assembled from the chiral L/D-glutamate-based amphiphiles(L/D-Glu C16) and Cu(Ⅱ) ions, with their helical screw pitches adjusted from 217 nm to 104 nm through the facile regulation of their water/organic solvent assembly environment. They were then used as ideal models to reveal the chiral morphology-enantioselectivity relationship by catalyzing the asymmetric Diels-Alder reaction. Better enantioselectivity was achieved with more twist morphology. Experimental evidences of stronger chiral transfer effect from the supramolecular HNs with more twist to the aza-chalcone as reactant were obtained to understand such dependence. Our study demonstrates a new perspective for designing supramolecular catalysts with higher enantioselectivity.
基金the financial support of the National Natural Science Foundation of China(No.21672133)the Opening Foundation of Key Laboratory of Applied Surface and Colloid Chemistry,Ministry of Education(No.GK202205011)the Fundamental Research Funds for the Central Universities(Nos.GK202307007 and GK202002003)。
文摘A cobalt pincer complex bearing both P and C-stereogenic centers has been designed and synthesized,allowing for the development of the first cobalt-catalyzed asymmetric hydrogenation of quinoxalines under relatively mild conditions.Valuable chiral 1,2,3,4-tetrahydroquinoxalines could be obtained with high yields and excellent enantioselectivities(35 examples,up to>99%ee).
基金financially supported by the National Natural Science Foundation of China(21873018,21573036,and21603028)the open project of the Jilin Province Key Laboratory of Organic Functional Molecular Design&Synthesis(130028655)the Northeast Normal University Research Frontier Exploration Program(XDFZ202501)
文摘A comprehensive mechanistic study on the chiral phosphoric acid catalyzed an enantioselective asymmetric aza-pinacol rearrangement of 4-chloro-N-(2-(3'-hydroxy-1'-phenylspiro[cyclopentane-1,2'-indolin]-3'-yl)ethyl)(1a)is investigated at the M06-2X/6-311+G(d,p)level.Our computational results suggest that the whole catalytic cycle proceeds through dehydration of 1a,enantioselective aza-pinacol rearrangement,intramolecular cyclization and catalyst regeneration to deliver the fused indoline product.The aza-pinacol rearrangement is the key stereocontrolling step of the title reaction.The chiral catalyst controls the orientation of the transition states of the enantioselective step through two potential binding sites between the bifunctional chiral phosphate and the aza-ortho-xylylene intermediate.Moreover,theoretical studies identified that the multiple C—H…π,C—H…O,and C—H…N hydrogen bonds and N—H…O^(-)electrostatic interactions between the substrates and the arms as well as functional oxygen anion of the chiral catalyst(R)-4c play a crucial role in determining the stereochemical outcomes.And the strong N—H…O^(-)interaction in the major transition state was found to contribute to the high levels of enantioselectivity.Additionally,the predicted enantiomeric excess(ee)of 89%based on the 6.3 kJ·mol^(–1)energy difference between the enantioselective TS-2-major and TS-2-minor is in agreement with the experimental results of 90%.
基金Financial support from the National Natural Science Foundation of China(No.22171168)Excellent Youth Foundation of Henan Scientific Committee(No.222300420012)Taishan Scholar Program of Shandong Province is gratefully acknowledged。
文摘A wide range of isoquinoline ring-modified Quinap oxides with different steric and electronic variations have been constructed through a palladium-catalyzed imidoylative cyclization of arylethenyl isocyanides with 2-diphenylphosphinyl-1-naphthyl bromides.The Pd-catalysis plays dual roles in the formation of both axial C–C bond and isoquinoline ring.This de novo synthetic strategy features good functional group tolerance,high yields and easy scale-up,providing Quinap derivatives with substitution patterns that could not be obtained using coupling reactions.Chiral ligands 7 and 12 can be readily prepared by transformation of the resulting Quinap oxide to their BINOL esters,and have been proven to be superb chiral ligands for the copper-catalyzed enantioselective A^(3)-coupling and alkynylation of quinoline reactions.In general,the enantioselectivies obtained using ligands 7 and 12 are excellent,and the ee values are higher than those using Quinap as ligand,even three times higher in some cases.Mechanism studies revealed that a monomeric copper(Ⅰ)complex bearing a single chiral ligand was formed and served as the catalytically active species.
基金supported by the National Natural Science Foundation of China (21425627,21376279)~~
文摘Nineβ‐cyclodextrin derivatives containing an amino group were synthesized via nucleophilic sub‐stitution from mono（6‐O‐p‐tolylsulfonyl）‐β‐cyclodextrin and used in asymmetric biomimetic Mi‐chael addition reactions in water at room temperature. The mechanism responsible for the moder‐ate activity and enantioselectivity of the β‐cyclodextrin derivatives was explored using nuclear magnetic resonance spectroscopy, namely 2D 1H rotating‐frame overhauser effect spectroscopy （ROESY）, ultraviolet absorption spectroscopy, and quantum chemical calculations, which provide a useful technique for investigating the formation of inclusion complexes. The effects of the pH of the reaction medium, theβ‐cyclodextrin derivative dosage, the structure of the modifying amino group, and various substrates on the yield and enantioselectivity were investigated. The results indicated that these factors had an important effect on the enantiomeric excess （ee） in the reaction system. Experiments using a competitor for inclusion complex formation showed that a hydrophobic cavity is necessary for enantioselective Michael addition. A comparison of the reactions using 4‐nitro‐β‐nitrostyrene and 2‐nitro‐β‐nitrostyrene showed that steric hindrance improved the enan‐tioselectivity. This was verified by the optimized geometries obtained from quantum chemical cal‐culations. An ee of 71%was obtained in the asymmetric Michael addition of cyclohexanone and 2‐nitro‐β‐nitrostyrene, using （S）‐2‐aminomethylpyrrolidine‐modified β‐CD as the catalyst, in an aqueous buffer solution, i.e., CH3COONa‐HCl （pH 7.5）.
基金National Natural Science Foundation of China(Grant No.30225047 and 30701038)
文摘The chiral nature of biological systems enables their stereoselective interaction with chiral compounds. It has been well documented that the enantiomers ofa chiral drug may show differences in drug disposition especially in metabolic behavior. As a result, it is of vital importance to separate the enantiomers of a chiral drug in metabolic studies. This paper discusses enantioselective methods （include high-performance liquid chromatography, gas chromatography, capillary electrophoresis and high-performance liquid chromatography-mass spectrometry） that applied in chiral drug metabolism, using most recent examples where possible.
基金Guangzhou mega Projects of Science Research in 2009(Grant No.2009A1-E011-7)
文摘Effective enantioseparation of Naftopidil and its derivatives by HPLC was accomplished using several different polysaccharide-based chiral stationary phases（CSPs）.In normal-phase mode,the compounds were eluted on four coated-and two immobilized-columns with the mixture of n-hexane,isopropanol and diethylamine（DEA）.Polysaccharide tris（3,5- dimethylphenyl carbamate） was shown to be the best enantiomer selector.In addition,the immobilized column packed with Chiralpak IA or IB was applied under polar-organic and reversed-phase conditions,both of which exhibited excellent enantioselectivity for Naftopidil and its derivatives.Furthermore,the underlying possible chiral recognition mechanisms were discussed.
基金supported by the National Natural Science Foundation of China (No. 20907042,20877071)the Zhejiang Provincial Natural Science Foundation ofChina (No. Y5090252)
文摘Enantioselectivity of chiral pollutants is receiving growing concern due to the difference in toxicology and environment fate between enantiomers.In this study,enantiomers of insecticide beta-cypermethrin （beta-CP） were separated on selected chiral column by HPLC,and the toxicity of enantiomers was evaluated using the zebrafish embryo-larval assays.The enantiomers of beta-CP were baseline separated on Chiralcel OD and Chiralpak AD columns and detected by circular dichroism （CD） at 236 nm.Better separation could be achieved at lower temperature （e.g.,20°C） and with lower levels of polar modifiers.Pure enantiomers were obtained on Chiralcel OD.The CD spectra of enantiomers were recorded.By comparing the elution order with a previous similar study,the absolute configuration of beta-CP enantiomers was determined.The individual enantiomers were used in zebrafish embryo test,and the results showed that beta-CP enantioselectively induced yolk sac edema,pericardial edema and crooked body.The 1R-cis-αS and 1R-trans-αS enantiomers showed strong developmental toxicities at concentration of 0.1 mg/L,while the 1S-cis-αR and 1S-trans-αR induced no malformations at higher concentration （e.g.,0.3 mg/L）.The results suggest that the enantioselective toxicological effects of beta-CP should be considered when evaluating its ecotoxicological effects.
基金supported by the National Basic Research Program(973) of China (No. 2009CB421603)the National Natural Science Foundations of China(No.20877071)the International Cooperation Project of Wenzhou City(No. H20090023)
文摘In a non-chiral environment, the enantiomers of a racemate possessed the identical physico-cbemical properties, but in the biological systems they possessed different activities. Considering that the involvement of oxidative damage has been implicated in the toxicities of various pesticides, this study investigated the possibility of enantioselective oxidative stress and cytotoxicity induction by acetofenate （AF） which contains an asymmetrical center on PC12 cells. The results of the cytotoxicity assay indicated that S-（＋）-AF presented more toxic effects than R-（-）-AF and （＋）-AF. It also demonstrated that S-（＋）-AF possessed the strongest effects in induction of reactive oxygen species （ROS） production, decrease in superoxide dismutase （SOD） and catalase （CAT） activities, and increase in malondialdehyde （MDA） level. These results suggested that AF and its enanfiomers could induce enantioselecfive cytotoxicity in PC12 cells mediated by oxidative stress. Therefore, the assessment in environmental safety and new chiral pesticide development should consider enantioselectivity.
基金financially supported by the National Natural Science Foundation of China(No.50662004)the State Key Program of Fundamental Research(No.2004CCA05900).
文摘Pseudomonas cepacia lipase （PSL） immobilized on the carboxyl-functionalized meso-cellular foams （HOOC-MCF） was used for the transesterification resolution of （R,S）-l-phenylethanol in organic solvent. The results showed that the ee value of （S）-1- phenylethanol and （R）-1-phenylethyl acetate reached 99% with 50% conversion of 1-phenylethanol using toluene as solvent. Furthermore, it was found that PSL/HOOC-MCF exhibited high enantioselectivity in organic solvent with log P ≤ 2 such as toluene and hexane.
基金supported by the financial supports from the Guangdong Basic and Applied Basic Research Foundation(2020A1515010539)the Medical Science and Technology Research Foundation of Guangdong Province,China(A2019046)+1 种基金Guangdong Province Higher Vocational Colleges&Schools Pearl River Scholar(50117G25002)the Key Project of Universities in Guangdong Province(2021ZDZX4066).
文摘Aroma(volatile)compounds play important ecological functions in plants,and also contribute to the quality of plant-derived foods.Moreover,chiral aroma compounds affect their functions in plants and lead to different flavor quality properties.Formations of chiral aroma compounds are due to the presence of enzymes producing these compounds in plants,which are generally involved in the final biosynthetic step of the aroma compounds.Here,we review recent progress in research on the plant-derived enzymes producing chiral aroma compounds,and their changes in response to environmental factors.The chiral aroma enzymes that have been reported produce(R)-linalool,(S)-linalool,(R)-limonene,and(S)-limonene,etc.,and these enzymes are found in various plant species.We also discuss the origins of enantioselectivity in the plant-derived enzymes producing chiral aroma compounds and summarize the potential use of plants containing enzymes producing chiral aroma compounds for producing chiral flavors/fragrances.
基金supported by the National Natural Science Foundation of China (Nos. 21605044 and 51872085)Joint NSFC-ISF Research (No. 21761142009)Hunan Provincial Natural Science Foundation of China (No. 2019JJ20003)
文摘With growing interests paid to the enantioselective analysis of chiral molecules, roles played by noble metal and semiconductor nanomaterials surface gradually. Given the unique physicochemical properties of noble metal and semiconductor nanomaterials, the enantioselective analyses are classified into three categories: fluorescence-based, colorimetry-based, and circular dichroism-based ones. In this paper, we review the existing progresses on enantioselective analysis, thanks to noble metal and semiconductor nanomaterials. Finally, the prospect of enantioselective analysis based on noble metal and semiconductor are discussed.
基金Supported by the National Natural Science Foundation of China( No.2 0 0 72 0 11and 2 0 2 72 0 17)
文摘A novel preparation method was developed to form a surfactant-lipase complex for the resolution of 2-octanol in a solvent-free system. The E value was improved from 6.64 to 120.2. The lipase modified by the anionic surfactant possessed a low solubility in the solvent-free system, which was beneficial to the recovery and the repeated usage of the lipase. The surfactant-lipase complex maintained a high enantioselectivity after five cycles of usage. The effect of water on both the activity and the enantioselectivity of the lipase has also been investigated; the direct addition of a salt hydrate pair of Na 4P 2O 7·H 2O and Na 4P 2O 7 can dramatically activate the modified enzyme.
