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De los Santos ZA, Lynch CC, Wolf C. Dynamic Covalent Optical Chirality Sensing with a Sterically Encumbered Aminoborane. Chemistry 2022; 28:e202202028. [DOI: 10.1002/chem.202202028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Indexed: 11/07/2022]
Affiliation(s)
| | - Ciarán C. Lynch
- Department of Chemistry Georgetown University Washington DC 20057 USA
| | - Christian Wolf
- Department of Chemistry Georgetown University Washington DC 20057 USA
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2
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Thanzeel FY, Balaraman K, Wolf C. Quantitative Chirality and Concentration Sensing of Alcohols, Diols, Hydroxy Acids, Amines and Amino Alcohols using Chlorophosphite Sensors in a Relay Assay. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202005324] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- F. Yushra Thanzeel
- Department of Chemistry Georgetown University 37th and O Streets Washington DC 20057 USA
| | - Kaluvu Balaraman
- Department of Chemistry Georgetown University 37th and O Streets Washington DC 20057 USA
| | - Christian Wolf
- Department of Chemistry Georgetown University 37th and O Streets Washington DC 20057 USA
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3
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Thanzeel FY, Balaraman K, Wolf C. Quantitative Chirality and Concentration Sensing of Alcohols, Diols, Hydroxy Acids, Amines and Amino Alcohols using Chlorophosphite Sensors in a Relay Assay. Angew Chem Int Ed Engl 2020; 59:21382-21386. [PMID: 32762103 DOI: 10.1002/anie.202005324] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2020] [Revised: 08/03/2020] [Indexed: 11/08/2022]
Abstract
Analytical methods that allow simultaneous determination of the concentration and enantiomeric composition of small sample amounts and are also compatible with high-throughput multi-well plate technology have received increasing attention in recent years. We now introduce a new class of broadly useful small-molecule probes and a relay sensing strategy that together accomplish these tasks with five classes of compounds including the challenging group of mono-alcohols-a scope that stands out among previously reported UV, fluorescence, and CD assays. Several chlorophosphite probes and aniline indicators have been evaluated and used for on-the-fly CD/UV sensing following a continuous workflow. The wide application range of the readily available sensors is highlighted with almost 30 alcohols, diols, hydroxy acids, amines and amino alcohols, and the accuracy of the stereochemical analysis is showcased with samples covering a wide range of concentrations and enantiomeric ratios.
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Affiliation(s)
- F Yushra Thanzeel
- Department of Chemistry, Georgetown University, 37th and O Streets, Washington, DC, 20057, USA
| | - Kaluvu Balaraman
- Department of Chemistry, Georgetown University, 37th and O Streets, Washington, DC, 20057, USA
| | - Christian Wolf
- Department of Chemistry, Georgetown University, 37th and O Streets, Washington, DC, 20057, USA
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4
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Raval HB, Bedekar AV. Synthesis And Study of Fluorine Containing Kagan's Amides as Chiral Solvating Agents For Enantiodiscrimination of Acids by NMR Spectroscopy. ChemistrySelect 2020. [DOI: 10.1002/slct.202000779] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- Hiten B. Raval
- Department of Chemistry Faculty of Science, The MaharajaSayajirao University of Baroda Vadodara 390 002 India
| | - Ashutosh V. Bedekar
- Department of Chemistry Faculty of Science, The MaharajaSayajirao University of Baroda Vadodara 390 002 India
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5
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De los Santos ZA, MacAvaney S, Russell K, Wolf C. Tandem Use of Optical Sensing and Machine Learning for the Determination of Absolute Configuration, Enantiomeric and Diastereomeric Ratios, and Concentration of Chiral Samples. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201912904] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
| | - Sean MacAvaney
- Department of Computer Science Georgetown University Washington DC 20057 USA
| | - Katina Russell
- Department of Computer Science Georgetown University Washington DC 20057 USA
| | - Christian Wolf
- Department of Chemistry Georgetown University Washington DC 20057 USA
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6
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De Los Santos ZA, MacAvaney S, Russell K, Wolf C. Tandem Use of Optical Sensing and Machine Learning for the Determination of Absolute Configuration, Enantiomeric and Diastereomeric Ratios, and Concentration of Chiral Samples. Angew Chem Int Ed Engl 2019; 59:2440-2448. [PMID: 31714669 DOI: 10.1002/anie.201912904] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Revised: 11/04/2019] [Indexed: 12/17/2022]
Abstract
We have developed an optical method for accurate concentration, er, and dr analysis of amino alcohols based on a simple mix-and-measure workflow that is fully adaptable to multiwell plate technology and microscale analysis. The conversion of the four aminoindanol stereoisomers with salicylaldehyde to the corresponding Schiff base allows analysis of the dr based on a change in the UV maximum at 420 nm that is very different for the homo- and heterochiral diastereomers and of the concentration of the sample using a hypsochromic shift of another absorption band around 340 nm that is independent of the analyte stereochemistry. Subsequent in situ formation of CuII assemblies in the absence and presence of base enables quantification of the er values for each diastereomeric pair by CD analysis. Applying a linear programming method and a parameter sweep algorithm, we determined the concentration and relative amounts of each of the four stereoisomers in 20 samples of vastly different stereoisomeric compositions with an averaged absolute percent error of 1.7 %.
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Affiliation(s)
| | - Sean MacAvaney
- Department of Computer Science, Georgetown University, Washington, DC, 20057, USA
| | - Katina Russell
- Department of Computer Science, Georgetown University, Washington, DC, 20057, USA
| | - Christian Wolf
- Department of Chemistry, Georgetown University, Washington, DC, 20057, USA
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Thanzeel FY, Balaraman K, Wolf C. Streamlined Asymmetric Reaction Development: A Case Study with Isatins. Chemistry 2019; 25:11020-11025. [DOI: 10.1002/chem.201902688] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Revised: 07/08/2019] [Indexed: 12/31/2022]
Affiliation(s)
- F. Yushra Thanzeel
- Department of Chemistry Georgetown University 37th and O Streets Washington DC 20057 USA
| | - Kaluvu Balaraman
- Department of Chemistry Georgetown University 37th and O Streets Washington DC 20057 USA
| | - Christian Wolf
- Department of Chemistry Georgetown University 37th and O Streets Washington DC 20057 USA
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8
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Gördes D, Thurow K. High-Throughput Screening Application for the Determination of Enantiomeric Excess Using ESI-MS. ACTA ACUST UNITED AC 2016. [DOI: 10.1016/j.jala.2006.03.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Methods for the rapid determination of the enantiomeric excess (ee%) of organic substrates, especially for HTS, are often the “bottleneck” in a process. For this purpose, a new process of entirely automated sample preparation and the determination of ee% using electrospray ionization-mass spectrometry (ESI-MS) has been developed. Various substrates and new auxiliaries were explored to enhance the methodical scope. In combination with a very versatile liquid-handling system (HTS-PAL) and a comprehensive processing equipment, a multitude of standardized reaction vessels can be managed with the presented system. As an example of use, the ee% determination of I-phenylethanole via ESI-MS is compared to state-of-the-art GC analysis. In addition, a HTS suitable data processing network was constructed that allows postrun data manipulation and the automated data transfer to analysis and visualization templates with a maximum amount of automation.
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Affiliation(s)
| | - Kerstin Thurow
- Center for Life Science Automation - celisca, Rostock, Germany
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Iacobucci C, Reale S, De Angelis F. Elusive Reaction Intermediates in Solution Explored by ESI-MS: Reverse Periscope for Mechanistic Investigations. Angew Chem Int Ed Engl 2016; 55:2980-93. [DOI: 10.1002/anie.201507088] [Citation(s) in RCA: 91] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Revised: 09/18/2015] [Indexed: 01/02/2023]
Affiliation(s)
- Claudio Iacobucci
- Dipartimento di Scienze Fisiche e Chimiche; Università dell'Aquila; Via Vetoio, Coppito 67100 L'Aquila Italy
| | - Samantha Reale
- Dipartimento di Scienze Fisiche e Chimiche; Università dell'Aquila; Via Vetoio, Coppito 67100 L'Aquila Italy
| | - Francesco De Angelis
- Dipartimento di Scienze Fisiche e Chimiche; Università dell'Aquila; Via Vetoio, Coppito 67100 L'Aquila Italy
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Iacobucci C, Reale S, De Angelis F. Elektrospray-Massenspektrometrie: ein umgekehrtes Periskop zur Erforschung von Reaktionsmechanismen in Lösung. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201507088] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Claudio Iacobucci
- Dipartimento di Scienze Fisiche e Chimiche; Università dell'Aquila; Via Vetoio, Coppito 67100 L'Aquila Italien
| | - Samantha Reale
- Dipartimento di Scienze Fisiche e Chimiche; Università dell'Aquila; Via Vetoio, Coppito 67100 L'Aquila Italien
| | - Francesco De Angelis
- Dipartimento di Scienze Fisiche e Chimiche; Università dell'Aquila; Via Vetoio, Coppito 67100 L'Aquila Italien
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11
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Piovesana S, Samperi R, Laganà A, Bella M. Determination of Enantioselectivity and Enantiomeric Excess by Mass Spectrometry in the Absence of Chiral Chromatographic Separation: An Overview. Chemistry 2013; 19:11478-94. [DOI: 10.1002/chem.201300233] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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12
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Tao WA, Zhang D, Wang F, Thomas PD, Cooks RG. Kinetic Resolution of d,l-Amino Acids Based on Gas-Phase Dissociation of Copper(II) Complexes. Anal Chem 2012; 71:4427-9. [PMID: 21662869 DOI: 10.1021/ac990530h] [Citation(s) in RCA: 110] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Chiral recognition of d- and l-amino acids is achieved in the gas phase on the basis of the kinetics of competitive fragmentations of trimeric Cu(II)-bound complexes. The singly charged copper(II)-amino acid trimeric cluster ions [A(2)BCu(II) - H](+) dissociate to form [A(2)Cu(II) - H](+) and [ABCu(II) - H](+) upon collision-induced dissociation (CID) in a quadrupole ion trap. The abundance ratios of these fragments depend strongly on the stereochemistry of the ligands in the [A(2)BCu(II) - H](+) complex ion. The kinetic method was used to calculate relative Cu ion affinities (ΔCu(II)') for homo- and heterochiral copper(II)-bound dimeric cluster ions as the indicator of chiral discrimination. Six amino acids of four different types showed chiral distinctions which ranged from 0 to 6.5 kJ/mol in terms of values of ΔCu(II)' with abundance ratios, referenced to the other enantiomer, ranging from 1 to 9.2. Amino acids with aromatic substituents displayed the largest chiral distinction, which correlates well with reported chromatographic results. The methodology presented here provides a sensitive means to study enantiomers by mass spectrometry, and initial results show that it is applicable to measurement of enantiomeric excess.
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Affiliation(s)
- W A Tao
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907
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13
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Bui The Thuong M, Catala C, Colas C, Schaeffer C, Van Dorsselaer A, Mann A, Wagner A. Trimethoxyarene as a Highly Ionizable Tag for Reaction Analysis by Atmospheric Pressure Photoionization Mass Spectrometry (APPI/MS): Exploration of Heterocyclic Synthesis. European J Org Chem 2012. [DOI: 10.1002/ejoc.201100919] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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14
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Krasnov VP, Gruzdev DA, Levit GL. Nonenzymatic Acylative Kinetic Resolution of Racemic Amines and Related Compounds. European J Org Chem 2011. [DOI: 10.1002/ejoc.201101489] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Victor P. Krasnov
- Postovsky Institute of Organic Synthesis of RAS, 22/20, S. Kovalevskoy, Akademicheskaya St., 620990 Ekaterinburg, Russian Federation, Fax: +7‐343‐3741189
| | - Dmitry A. Gruzdev
- Postovsky Institute of Organic Synthesis of RAS, 22/20, S. Kovalevskoy, Akademicheskaya St., 620990 Ekaterinburg, Russian Federation, Fax: +7‐343‐3741189
| | - Galina L. Levit
- Postovsky Institute of Organic Synthesis of RAS, 22/20, S. Kovalevskoy, Akademicheskaya St., 620990 Ekaterinburg, Russian Federation, Fax: +7‐343‐3741189
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15
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Chen Y, Tang W, Mou J, Li Z. High-Throughput Method for Determining the Enantioselectivity of Enzyme-Catalyzed Hydroxylations Based on Mass Spectrometry. Angew Chem Int Ed Engl 2010; 49:5278-83. [DOI: 10.1002/anie.201001772] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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16
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Chen Y, Tang W, Mou J, Li Z. High-Throughput Method for Determining the Enantioselectivity of Enzyme-Catalyzed Hydroxylations Based on Mass Spectrometry. Angew Chem Int Ed Engl 2010. [DOI: 10.1002/ange.201001772] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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17
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Liu HL, Peng Q, Wu YD, Chen D, Hou XL, Sabat M, Pu L. Highly Enantioselective Recognition of Structurally Diverse α-Hydroxycarboxylic Acids using a Fluorescent Sensor. Angew Chem Int Ed Engl 2010. [DOI: 10.1002/ange.200904889] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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18
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Fleischer I, Pfaltz A. Enantioselective Michael Addition to α,β-Unsaturated Aldehydes: Combinatorial Catalyst Preparation and Screening, Reaction Optimization, and Mechanistic Studies. Chemistry 2010; 16:95-9. [DOI: 10.1002/chem.200902449] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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19
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Liu HL, Peng Q, Wu YD, Chen D, Hou XL, Sabat M, Pu L. Highly Enantioselective Recognition of Structurally Diverse α-Hydroxycarboxylic Acids using a Fluorescent Sensor. Angew Chem Int Ed Engl 2009; 49:602-6. [DOI: 10.1002/anie.200904889] [Citation(s) in RCA: 109] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Bustos-Jaimes I, Hummel W, Eggert T, Bogo E, Puls M, Weckbecker A, Jaeger KE. A High-Throughput Screening Method for Chiral Alcohols and its Application to Determine Enantioselectivity of Lipases and Esterases. ChemCatChem 2009. [DOI: 10.1002/cctc.200900190] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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21
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Vayá I, Bueno C, Jiménez M, Miranda M. Determination of Enantiomeric Compositions by Transient Absorption Spectroscopy using Proteins as Chiral Selectors. Chemistry 2008; 14:11284-7. [DOI: 10.1002/chem.200801657] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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22
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Müller CA, Pfaltz A. Mass spectrometric screening of chiral catalysts by monitoring the back reaction of quasienantiomeric products: palladium-catalyzed allylic substitution. Angew Chem Int Ed Engl 2008; 47:3363-6. [PMID: 18357605 DOI: 10.1002/anie.200705081] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Constanze A Müller
- Department of Chemistry, University of Basel, St. Johanns-Ring 19, 4056 Basel, Switzerland
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23
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Müller C, Pfaltz A. Mass Spectrometric Screening of Chiral Catalysts by Monitoring the Back Reaction of Quasienantiomeric Products: Palladium-Catalyzed Allylic Substitution. Angew Chem Int Ed Engl 2008. [DOI: 10.1002/ange.200705081] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Hamberg A, Lundgren S, Wingstrand E, Moberg C, Hult K. High-Throughput Synthesis and Analysis of Acylated Cyanohydrins. Chemistry 2007; 13:4334-41. [PMID: 17330315 DOI: 10.1002/chem.200601638] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The yields and optical purities of products obtained from chiral Lewis acid/Lewis base-catalysed additions of alpha-ketonitriles to prochiral aldehydes could be accurately determined by an enzymatic method. The amount of remaining aldehyde was determined after its reduction to an alcohol, whilst the two product enantiomers were analysed after subsequent hydrolysis first by the (S)-selective Candida antarctica lipase B and then by the unselective pig liver esterase. The method could be used for analysis of products obtained from a number of aromatic aldehydes and aliphatic ketonitriles. Microreactor technology was successfully combined with high-throughput analysis for efficient catalyst optimization.
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Affiliation(s)
- Anders Hamberg
- School of Biotechnology, Department of Biochemistry, AlbaNova University Center, SE 106 91 Stockholm, Sweden
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25
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Abstract
The Walden memorial at the Technical University in Riga is pictured in the frontispiece to mark the recent centennial of the Walden inversion. This is a rare public monument to key events from the first era of exploration in stereocontrolled synthesis, and may be the only such monument to use the language of organic chemistry expressed at the molecular level. The reaction of racemic substrates with chiral nucleophiles is one of many methods currently known to achieve kinetic resolution, a phenomenon that ranks as the oldest and most general approach for the synthesis of highly enantioenriched substances. The first nonenzymatic kinetic resolutions as well as the original forms of the Walden inversion were studied in the 1890s. All of these investigations were conducted within the first generation following the demonstration that carbon is tetrahedral, and provided abundant evidence that the principles and importance of enantiocontrolled syntheses were understood. However, a reliable, rapid technique to quantify results and guide the optimization process was still lacking. Many decades passed before this problem was solved by the advent of HPLC and GLPC assays on chiral supports, which stimulated explosive growth in the synthesis of nonracemic substances by kinetic resolution. The Walden monument is accessible to passers-by for hands-on inspection as well as for contemplation and learning. In a similar way, kinetic resolution is experimentally accessible and can be thought-provoking at several levels. We follow the story of kinetic resolution from the early discoveries through fascinating historical milestones and conceptual developments, and close with a focus on modern techniques that maximize efficiency.
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Affiliation(s)
- Edwin Vedejs
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109, USA.
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Vicennati P, Bensel N, Wagner A, Créminon C, Taran F. Sandwich Immunoassay as a High-Throughput Screening Method for Cross-Coupling Reactions. Angew Chem Int Ed Engl 2005. [DOI: 10.1002/ange.200501641] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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27
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Vicennati P, Bensel N, Wagner A, Créminon C, Taran F. Sandwich Immunoassay as a High-Throughput Screening Method for Cross-Coupling Reactions. Angew Chem Int Ed Engl 2005; 44:6863-6. [PMID: 16211640 DOI: 10.1002/anie.200501641] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Paola Vicennati
- Service de Marquage Moléculaire et de Chimie Bio-Organique, DSV/DBJC CEA Saclay, 91191 Gif sur Yvette Cedex, France
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Zhang Q, Curran DP. Quasienantiomers and Quasiracemates: New Tools for Identification, Analysis, Separation, and Synthesis of Enantiomers. Chemistry 2005; 11:4866-80. [PMID: 15915521 DOI: 10.1002/chem.200500076] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The old adage "never mix pure organic compounds" holds in spades for enantiomers. After going to all the trouble to make enantiopure molecules, who in their right mind would ever mix them to make a racemate? Quasienantiomers are almost enantiomers, but not quite. Yet unlike enantiomers, the interest is not so much in separating them but in mixing them to make quasiracemates. This backwards thinking opens new possibilities for identification, analysis, separation and synthesis of enantiomers. A short history is provided, the terms are defined and illustrated, and recent applications of quasienantiomers, quasiracemates and related species are reviewed.
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Affiliation(s)
- Qisheng Zhang
- Department of Chemistry, The Scripps Research Institute, La Jolla, CA 92037, USA
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29
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Vedejs E, Jure M. Effizienz in der nichtenzymatischen kinetischen Racematspaltung. Angew Chem Int Ed Engl 2005. [DOI: 10.1002/ange.200460842] [Citation(s) in RCA: 229] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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30
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Li ZB, Lin J, Pu L. A Cyclohexyl-1,2-diamine-Derived Bis(binaphthyl) Macrocycle: Enhanced Sensitivity and Enantioselectivity in the Fluorescent Recognition of Mandelic Acid. Angew Chem Int Ed Engl 2005; 44:1690-3. [PMID: 15688352 DOI: 10.1002/anie.200462471] [Citation(s) in RCA: 127] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Zi-Bo Li
- Department of Chemistry, University of Virginia, Charlottesville, VA 22904-4319, USA
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Li ZB, Lin J, Pu L. A Cyclohexyl-1,2-diamine-Derived Bis(binaphthyl) Macrocycle: Enhanced Sensitivity and Enantioselectivity in the Fluorescent Recognition of Mandelic Acid. Angew Chem Int Ed Engl 2005. [DOI: 10.1002/ange.200462471] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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32
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Affiliation(s)
- Manfred T Reetz
- Max-Planck-Institut für Kohlenforschung, Mülheim An Der Ruhr, Germany
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34
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Reetz M, Eipper A, Tielmann P, Mynott R. A Practical NMR-Based High-Throughput Assay for Screening Enantioselective Catalysts and Biocatalysts. Adv Synth Catal 2002. [DOI: 10.1002/1615-4169(200210)344:9<1008::aid-adsc1008>3.0.co;2-t] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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35
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Schrader W, Eipper A, Pugh DJ, Reetz MT. Second-generation MS-based high-throughput screening system for enantioselective catalysts and biocatalysts. CAN J CHEM 2002. [DOI: 10.1139/v02-069] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A high-throughput method is described, where the enantioselectivity of approximately 10 000 catalysts or biocatalysts can be determined per day. The method is based on electrospray mass spectrometric techniques using an eight-channel multiplexed (MUX) sprayer system connected to a time-of-flight mass spectrometer. The inlet of the ion source is controlled by a stepping rotor that is continuously moving from one sprayer to the next with a recording time of 100 ms for each channel and a delay time of 50 ms, thus allowing a spectrum to be obtained from each channel every 1.2 s. One cycle, where eight samples are being sprayed in parallel, requires around 70 s, which allows a 96-well microtiter plate to be screened in 14 min. Integration of two pseudo-enantiomers (S)-glycidyl phenyl ether and (R)-D5-glycidyl phenyl ether is necessary to quantify the enantiomeric excess (ee-value), where one enantiomer is isotopically labeled to allow easy identification of the mass spectrometric signals. Errors of ~2% for the ee-values indicate that in addition to the significant improvement in sample throughput this is also a precise method for high-throughput screening. This second-generation assay is useful for combinatorial enantioselective transition-metal catalysis and in the directed evolution of enantioselective enzymes.
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Abstract
Addition and substitution reactions with carbon nucleophiles are fundamental processes in organic synthesis, and the development of general catalytic asymmetric variants thereof is still a major challenge today. In contrast to enantioselective alkyl transfer reactions, the corresponding arylations have not yet reached a high level of maturity. The existing protocols are either of no general applicability or are limited in terms of selectivity. This article summarizes established routes for catalytic asymmetric aryl transfer together with the latest developments in this area. The scope and limitations of this reaction are discussed.
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Affiliation(s)
- Carsten Bolm
- Institut für Organische Chemie RWTH Aachen Prof.-Pirlet-Strasse 1, 52056 Aachen (Germany)
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Schalley CA. Molecular recognition and supramolecular chemistry in the gas phase. MASS SPECTROMETRY REVIEWS 2001; 20:253-309. [PMID: 11948654 DOI: 10.1002/mas.10009] [Citation(s) in RCA: 219] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Supramolecular chemistry, in particular, the fields of molecular recognition and self-assembly, profit much from the development of soft ionization techniques and advanced methods for mass analysis and gas-phase chemistry. Vice versa, weakly bonded architectures and host-guest complexes represent a veritable challenge for the mass spectrometrist, leading to further development of methods and techniques. This review describes the state-of-the-art in this field, and includes topics such as the effects of solvation on meta binding to crown ethers, chiral discrimination of guests by chiral hosts, the elucidation of the secondary structure of self assembled complexes, and the mechanistic pathways of self assembly or the fragmentations of supramolecular complexes in the gas phase.
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Affiliation(s)
- C A Schalley
- Kekulé-Institut für Organische Chemie und Biochemie der Universität, Gerhard-Domagk-Str. 1, D-53121 Bonn, Germany.
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Mikami K, Angelaud R, Ding K, Ishii A, Tanaka A, Sawada N, Kudo K, Senda M. Asymmetric activation of chiral alkoxyzinc catalysts by chiral nitrogen activators for dialkylzinc addition to aldehydes: super high-throughput screening of combinatorial libraries of chiral ligands and activators by HPLC-CD/UV and HPLC-OR/RIU systems. Chemistry 2001; 7:730-7. [PMID: 11261671 DOI: 10.1002/1521-3765(20010202)7:3<730::aid-chem730>3.0.co;2-1] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Asymmetric catalysts, prepared by chiral ligand exchange or chiral modification, can evolve further into highly activated catalysts through engineering with chiral activators. Two new methodologies for "super high-throughput screening" (SHTS) of chiral ligands and activators have been developed as a combination of HPLC-CD/UV (CD/ UV = circular dichroism/ultraviolet spectroscopy) or -OR/RIU (OR/RIU = optical rotation/refractive index unit) with a combinatorial chemistry (CC) factory. With these techniques, the % ee of the product is determined within minutes without separation of the enantiomeric products by using a nonchiral stationary phase. Therefore, those SHTS techniques combined with our 'asymmetric activation' concept can provide a powerful strategy for finding the best activated chiral catalyst.
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Affiliation(s)
- K Mikami
- Department of Chemical Technology, Faculty of Engineering, Tokyo Institute of Technology, Japan.
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Reetz M, Kühling K, Deege A, Hinrichs H, Belder D. Super-Hochdurchsatz-Screening von enantioselektiven Katalysatoren mittels parallelisierter Kapillarelektrophorese. Angew Chem Int Ed Engl 2000. [DOI: 10.1002/1521-3757(20001103)112:21<4049::aid-ange4049>3.0.co;2-n] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Reetz M, Kühling K, Deege A, Hinrichs H, Belder D. Super-High-Throughput Screening of Enantioselective Catalysts by Using Capillary Array Electrophoresis. Angew Chem Int Ed Engl 2000; 39:3891-3893. [DOI: 10.1002/1521-3773(20001103)39:21<3891::aid-anie3891>3.0.co;2-1] [Citation(s) in RCA: 171] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2000] [Indexed: 11/10/2022]
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Abstract
While nonracemic catalysts can generate nonracemic products with or without the nonlinear relationship in enantiomeric excesses between catalysts and products, racemic catalysts inherently give only a racemic mixture of chiral products. Asymmetric catalysts, either in nonracemic or racemic form, can be further evolved into highly activated catalysts with association of chiral activators. This asymmetric activation process is particularly useful in racemic catalysis through selective activation of one enantiomer of the racemic catalyst. Recently, a strategy whereby a racemic catalyst is selectively deactivated by a chiral additive has been reported to yield nonracemic products. However, reported herein is an alternative and conceptually opposite strategy in which a chiral activator selectively activates, rather than deactivates, one enantiomer of a racemic chiral catalyst. The advantage of this activation strategy over the deactivation counterpart is that the activated catalyst can produce a greater enantiomeric excess in the products-even with the use of a catalytic amount of activator relative to chiral catalyst-than that attained by the enantiomerically pure catalyst on its own. Therefore, asymmetric activation could provide a general and powerful strategy for not only the use of atropisomeric, racemic ligands but also chirally flexible and proatropisomeric ligands without enantiomeric resolution!
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Affiliation(s)
- K Mikami
- Department of Chemical Technology Tokyo Institute of Technology Meguro-ku, Tokyo 152-8552 (Japan)
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