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Journal articles on the topic 'Chiral Enantiodiscrimination'

Author: Grafiati

Published: 6 September 2023

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1

Arnaboldi, Serena, Tiziana Benincori, Roberto Cirilli, Włodzimierz Kutner, Mirko Magni, Patrizia Romana Mussini, Krzysztof Noworyta, and Francesco Sannicolò. "Inherently chiral electrodes: the tool for chiral voltammetry." Chemical Science 6, no. 3 (2015): 1706–11. http://dx.doi.org/10.1039/c4sc03713h.

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2

Arnaboldi, Serena, Silvia Cauteruccio, Sara Grecchi, Tiziana Benincori, Massimo Marcaccio, Alessio Orbelli Biroli, Giovanna Longhi, Emanuela Licandro, and Patrizia Romana Mussini. "Thiahelicene-based inherently chiral films for enantioselective electroanalysis." Chemical Science 10, no. 5 (2019): 1539–48. http://dx.doi.org/10.1039/c8sc03337d.

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3

Pal, Indrani, Sachin Rama Chaudhari, and Nagarajarao Suryaprakash. "A versatile ternary ionic complex for chiral discrimination of molecules with diverse functionalities using 1H NMR." New J. Chem. 38, no. 10 (2014): 4908–12. http://dx.doi.org/10.1039/c4nj00417e.

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4

Ai, Bin, Hoang M. Luong, and Yiping Zhao. "Chiral nanohole arrays." Nanoscale 12, no. 4 (2020): 2479–91. http://dx.doi.org/10.1039/c9nr09722h.

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Ultra-thin chiral nanohole array films are fabricated by a simple and efficient shadow sphere lithography (SSL) method and achieve label-free enantiodiscrimination of biomolecules and drug molecules at the picogram level.

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5

Zhang, Xuebo, Jing Xu, Zhaofeng Sun, Guangling Bian, and Ling Song. "NMR analysis of the enantiomeric purity of chiral diols by a new chiral boron agent." RSC Advances 12, no. 8 (2022): 4692–96. http://dx.doi.org/10.1039/d2ra00428c.

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6

Berdagué, Philippe, Boris Gouilleux, Markus Noll, Stefan Immel, Michael Reggelin, and Philippe Lesot. "Study and quantification of the enantiodiscrimination power of four polymeric chiral LLCs using NAD 2D-NMR." Physical Chemistry Chemical Physics 24, no. 12 (2022): 7338–48. http://dx.doi.org/10.1039/d1cp04915a.

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7

Li, Gaowei, Jiangming Cao, Wen Zong, Xinxiang Lei, and Renxiang Tan. "Enantiodiscrimination of carboxylic acids using the diphenylprolinol NMR chiral solvating agents." Organic Chemistry Frontiers 3, no. 1 (2016): 96–102. http://dx.doi.org/10.1039/c5qo00264h.

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8

Lee, Wonjae, Eunjung Bang, Ji-Hye Yun, Man-Jeong Paik, and Weontae Lee. "Enantiodiscrimination Using a Chiral Crown Ether as a Chiral Solvating Agent Using NMR Spectroscopy." Natural Product Communications 14, no. 5 (May 1, 2019): 1934578X1984919. http://dx.doi.org/10.1177/1934578x19849191.

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For enantiomer separation of a variety of chiral compounds, a number of chiral selectors have been developed and applied. Among these chiral selectors are chiral crown ethers, a class of synthetic polyether molecules that bind protonated chiral primary amines with high selectivity. This article focuses on enantiodiscrimination using (18-crown-6)-2,3,11,12-tetracarboxylic acid as a crown ether-type chiral solvating agent for nuclear magnetic resonance spectroscopic method in several chirotechnologies.

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9

Huang, Huayin, Guangling Bian, Hua Zong, Yabai Wang, Shiwei Yang, Huifeng Yue, Ling Song, and Hongjun Fan. "Chiral Sensor for Enantiodiscrimination of Varied Acids." Organic Letters 18, no. 11 (May 18, 2016): 2524–27. http://dx.doi.org/10.1021/acs.orglett.6b00088.

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10

Ohmiya, Hirohisa, Masaya Sawamura, and Yuto Yasuda. "Copper-Catalyzed Enantioselective Coupling between Allylboronates and Phosphates Using a Phenol–Carbene Chiral Ligand: Asymmetric Synthesis of Chiral Branched 1,5-Dienes." Synthesis 50, no. 11 (March 20, 2018): 2235–46. http://dx.doi.org/10.1055/s-0036-1591548.

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Details of the Cu-catalyzed enantioselective allyl–allyl coupling reaction between allylboronates and (Z)-allylic phosphates using a new chiral N-heterocyclic carbene (NHC) ligand containing a phenolic hydroxy group are presented. The copper catalysis delivers enantioenriched chiral 1,5-dienes with a tertiary stereogenic center. Compatibility with various functional groups and the use of earth-abundant and relatively low-toxicity copper as a metal are attractive features of this protocol. The utility of the chiral phenol–NHC ligand for enantioselective copper catalysis with organoboron compounds is demonstrated and enantiodiscrimination models are discussed.

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11

Uccello-Barretta, Gloria, Federica Balzano, Jonathan Martinelli, Margherita-Giulia Berni, Claudio Villani, and Francesco Gasparrini. "NMR enantiodiscrimination by cyclic tetraamidic chiral solvating agents." Tetrahedron: Asymmetry 16, no. 22 (November 2005): 3746–51. http://dx.doi.org/10.1016/j.tetasy.2005.10.016.

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12

Balzano, Federica, Gloria Uccello-Barretta, Giuseppe Sicoli, Letizia Vanni, Alessandra Recchimurzo, and Federica Aiello. "Chiral Discrimination Mechanisms by Silylated-Acetylated Cyclodextrins: Superficial Interactions vs. Inclusion." International Journal of Molecular Sciences 23, no. 21 (October 29, 2022): 13169. http://dx.doi.org/10.3390/ijms232113169.

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Cyclodextrin derivatives constitute a powerful class of auxiliary agents for the discrimination of apolar chiral substrates. Both host–guest inclusion phenomena and interactions with the derivatizing groups located on the surface of the macrocycle could drive the enantiodiscrimination; thus, it is important to understand the role that these processes play in the rational design of new chiral selectors. The purpose of this study is to compare via nuclear magnetic resonance (NMR) spectroscopy the efficiency of silylated-acetylated α-, β-, and γ-cyclodextrins in the chiral discrimination of 1,1,1,3,3-pentafluoro-2-(fluoromethoxy)-3-methoxypropane (compound B) and methyl 2-chloropropionate (MCP). NMR DOSY (Diffusion Ordered SpectroscopY) experiments were conducted for the determination of the bound molar fractions and the association constants, whereas ROESY (Rotating-frame Overhauser Enhancement SpectroscopY) measurements provided information on the hosts’ conformation and on the interaction phenomena with the guests. Compound B, endowed with fluorinated moieties, is not deeply included due to attractive Si-F interactions occurring at the external surface of the cyclodextrins. Therefore, a low selectivity toward the size of cyclodextrin cavity is found. By contrast, enantiodiscrimination of MCP relies on the optimal fitting between the size of the guest and that of the cyclodextrin cavity.

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13

Bonetti, Giorgia, Serena Arnaboldi, Sara Grecchi, Giulio Appoloni, Elisabetta Massolo, Sergio Rossi, Rocco Martinazzo, Francesco Orsini, Patrizia R. Mussini, and Tiziana Benincori. "Effective Enantiodiscrimination in Electroanalysis Based on a New Inherently Chiral 1,1′-Binaphthyl Selector Directly Synthesizable in Enantiopure Form." Molecules 25, no. 9 (May 6, 2020): 2175. http://dx.doi.org/10.3390/molecules25092175.

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Enantioselective electroanalysis, which aims to discriminate the enantiomers of electroactive chiral probes in terms of potential difference, is a very attractive goal. To achieve this, its implementation is being studied for various "inherently chiral" selectors, either at the electrode surface or in the medium, yielding outstanding performance. In this context, the new inherently chiral monomer Naph2T4 is introduced, based on a biaromatic atropisomeric core, which is advantageously obtainable in enantiopure form without HPLC separation steps by a synthetic route hinging on enantiopure 2,2’-dibromo-1,1’-binaphthalenes. The antipodes of the new inherently chiral monomer can be easily electrooligomerized, yielding inherently chiral electrode surfaces that perform well in both cyclic voltammetry (CV) enantiodiscrimination tests with pharmaceutically interesting molecules and in magnetoelectrochemistry experiments.

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14

Fontana, Francesca, Benedetta Bertolotti, Sara Grecchi, Patrizia Romana Mussini, Laura Micheli, Roberto Cirilli, Matteo Tommasini, and Simona Rizzo. "2,12-Diaza[6]helicene: An Efficient Non-Conventional Stereogenic Scaffold for Enantioselective Electrochemical Interphases." Chemosensors 9, no. 8 (August 10, 2021): 216. http://dx.doi.org/10.3390/chemosensors9080216.

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The new configurationally stable, unsymmetrical 2,12-diaza[6]helicene was synthesized as a racemate and the enantiomers were separated in an enantiopure state by semi-preparative HPLC on chiral stationary phase. Under selected alkylation conditions it was possible to obtain both the enantiopure 2-N-mono- and di-N-ethyl quaternary iodides. Metathesis with bis(trifluoromethanesulfonyl)imide anion gave low-melting salts which were tested as inherently chiral additives to achiral ionic liquids for the electrochemical enantiodiscrimination of chiral organic probes in voltammetric experiments. Remarkable differences in the oxidation potentials of the enantiomers of two probes, a chiral ferrocenyl amine and an aminoacid, were achieved; the differences increase with increasing additive concentration and number of alkylated nitrogen atoms.

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15

Gospodarowicz, Krzysztof, Małgorzata Hołyńska, Marta Paluch, and Jerzy Lisowski. "Novel chiral hexaazamacrocycles for the enantiodiscrimination of carboxylic acids." Tetrahedron 68, no. 48 (December 2012): 9930–35. http://dx.doi.org/10.1016/j.tet.2012.09.093.

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16

Paladini, A., C. Calcagni, T. Di Palma, M. Speranza, A. Laganà, G. Fago, A. Filippi, M. Satta, and A. Giardini Guidoni. "Enantiodiscrimination of chiral α-aminophosphonic acids by mass spectrometry." Chirality 13, no. 10 (2001): 707–11. http://dx.doi.org/10.1002/chir.10022.

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17

Recchimurzo, Alessandra, Federica Balzano, Gloria Uccello Barretta, Luca Gherardi, Milo Malanga, and Federica Aiello. "Silylated-Acetylated Cyclodextrins as Chiral Sensors for the Enantiodiscrimination of Fluorinated Anesthetics." Molecules 28, no. 6 (March 20, 2023): 2804. http://dx.doi.org/10.3390/molecules28062804.

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Silylated-acetylated cyclodextrin (CD) derivatives have recently been investigated, via nuclear magnetic resonance (NMR) spectroscopy, as chiral sensors for substrates that are endowed and devoid of fluorine atoms, and the importance of Si-F interaction in the discrimination phenomena has been assessed. Here, the contributions of both superficial interactions and inclusion processes were further evaluated by extending the records to other chiral fluorinated substrates of interest for pharmaceutical applications. Non-equivalences were measured for both the 1H and 19F resonances in equimolar mixtures with the CDs; the promising results also supported the use of chiral sensors in sub-stoichiometric amounts. Finally, the occurrence of inclusion processes was evaluated by analyzing the intermolecular dipolar interactions by means of ROESY (Rotating-frame Overhauser Enhancement Spectroscopy) experiments. The study confirmed that the γCD derivative is the best chiral solvating agent for the fluorinated substrates investigated, likely due to the higher number of silyl moieties that can be involved in Si-F interactions. The contribution of inclusion processes to the enantiodiscrimination was also confirmed by comparison with the α- and β-analogues. Overall, the CD derivatives proved to be able to discriminate fluorinated substrates even when used in sub-stoichiometric amounts.

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18

Prata, José V., Alexandra I. Costa, Gennaro Pescitelli, and Hugo D. Pinto. "Chiroptical and emissive properties of a calix[4]arene-containing chiral poly(p-phenylene ethynylene) with enantioselective recognition ability." Polym. Chem. 5, no. 19 (2014): 5793–803. http://dx.doi.org/10.1039/c4py00729h.

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Through a combination of intrachain and interchain effects, supramolecular chirality is achieved in solution aggregates and thin films of P1. Enantiodiscrimination is observed between (R) and (S) amine antipodes.

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19

Cen, Mengjia, Jiawei Wang, Jianxun Liu, Huilin He, Ke Li, Wenfeng Cai, Tun Cao, and Yan Jun Liu. "Ultrathin Suspended Chiral Metasurfaces for Enantiodiscrimination (Adv. Mater. 37/2022)." Advanced Materials 34, no. 37 (September 2022): 2270263. http://dx.doi.org/10.1002/adma.202270263.

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20

Andreani, Romana, Cecilia Bombelli, Stefano Borocci, Juri Lah, Giovanna Mancini, Paolo Mencarelli, Gorazd Vesnaver, and Claudio Villani. "New biphenylic derivatives: synthesis, characterisation and enantiodiscrimination in chiral aggregates." Tetrahedron: Asymmetry 15, no. 6 (March 2004): 987–94. http://dx.doi.org/10.1016/j.tetasy.2004.01.038.

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21

Luo, Zengwei, Baohua Li, Xiantao Fang, Kai Hu, Xiaojun Wu, and Enqin Fu. "Novel chiral solvating agents derived from natural amino acid: enantiodiscrimination for chiral α-arylalkylamines." Tetrahedron Letters 48, no. 10 (March 2007): 1753–56. http://dx.doi.org/10.1016/j.tetlet.2007.01.036.

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22

Puglisi, Roberta, Francesco P. Ballistreri, Chiara M. A. Gangemi, Rosa Maria Toscano, Gaetano A. Tomaselli, Andrea Pappalardo, and Giuseppe Trusso Sfrazzetto. "Chiral Zn–salen complexes: a new class of fluorescent receptors for enantiodiscrimination of chiral amines." New Journal of Chemistry 41, no. 3 (2017): 911–15. http://dx.doi.org/10.1039/c6nj03592b.

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23

Noreen, Samar, Ameer Fawad Zahoor, Sajjad Ahmad, Irum Shahzadi, Ali Irfan, and Sadia Faiz. "Novel Chiral Ligands for Palladium-catalyzed Asymmetric Allylic Alkylation/ Asymmetric Tsuji-Trost Reaction: A Review." Current Organic Chemistry 23, no. 11 (August 29, 2019): 1168–213. http://dx.doi.org/10.2174/1385272823666190624145039.

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Background: Asymmetric catalysis holds a prestigious role in organic syntheses since a long time and chiral inductors such as ligands have been used to achieve the utmost desired results at this pitch. The asymmetric version of Tsuji-Trost allylation has played a crucial role in enantioselective synthesis. Various chiral ligands have been known for Pdcatalyzed Asymmetric Allylic Alkylation (AAA) reactions and exhibited excellent catalytic potential. The use of chiral ligands as asymmetric inductors has widened the scope of Tsuji-Trost allylic alkylation reactions. Conclusion: Therefore, in this review article, a variety of chiral inductors or ligands have been focused for palladium catalyzed asymmetric allylic alkylation (Tsuji-Trost allylation) and in this regard, recently reported literature (2013-2017) has been described. The use of ligands causes the induction of enantiodiscrimination to the allylated products, therefore, the syntheses of various kinds of ligands have been targeted by many research groups to employ in Pd-catalyzed AAA reactions.

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24

Lankhorst, Peter, Jozef van Rijn, and Alexander Duchateau. "One-Dimensional 13C NMR Is a Simple and Highly Quantitative Method for Enantiodiscrimination." Molecules 23, no. 7 (July 20, 2018): 1785. http://dx.doi.org/10.3390/molecules23071785.

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The discrimination of enantiomers of mandelonitrile by means of 1D 13C NMR and with the aid of the chiral solvating agent (S)-(+)-1-(9-anthryl)-2,2,2-trifluoroethanol (TFAE) is presented. 1H NMR fails for this specific compound because proton signals either overlap with the signals of the chiral solvating agent or do not show separation between the (S)-enantiomer and the (R)-enantiomer. The 13C NMR method is validated by preparing artificial mixtures of the (R)-enantiomer and the racemate, and it is shown that with only 4 mg of mandelonitrile a detection limit of the minor enantiomer of 0.5% is obtained, corresponding to an enantiomeric excess value of 99%. Furthermore, the method shows high linearity, and has a small relative standard deviation of only 0.3% for the minor enantiomer when the relative abundance of this enantiomer is 20%. Therefore, the 13C NMR method is highly suitable for quantitative enantiodiscrimination. It is discussed that 13C NMR is preferred over 1H NMR in many situations, not only in molecules with more than one chiral center, resulting in complex mixtures of many stereoisomers, but also in the case of molecules with overlapping multiplets in the 1H NMR spectrum, and in the case of molecules with many quaternary carbon atoms, and therefore less abundant protons.

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25

Reddy, U. Venkateswara, and N. Suryaprakash. "Scalable weak aligning medium for enantiodiscrimination of water soluble chiral molecules." Chemical Communications 47, no. 29 (2011): 8364. http://dx.doi.org/10.1039/c1cc12564h.

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26

Schefzick, Sabine, Wolfgang Lindner, Kenny B. Lipkowitz, and Mehran Jalaie. "Enantiodiscrimination by a quinine-based chiral stationary phase: A computational study." Chirality 12, no. 1 (2000): 7–15. http://dx.doi.org/10.1002/(sici)1520-636x(2000)12:1<7::aid-chir3>3.0.co;2-q.

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27

Grecchi, Sara, Serena Arnaboldi, Marcus Korb, Roberto Cirilli, Silvia Araneo, Vittoria Guglielmi, Giorgio Tomboni, et al. "Widening the Scope of “Inherently Chiral” Electrodes: Enantiodiscrimination of Chiral Electroactive Probes with Planar Stereogenicity." ChemElectroChem 7, no. 16 (July 13, 2020): 3429–38. http://dx.doi.org/10.1002/celc.202000657.

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28

Grecchi, Sara, Serena Arnaboldi, Marcus Korb, Roberto Cirilli, Silvia Araneo, Vittoria Guglielmi, Giorgio Tomboni, et al. "Widening the Scope of “Inherently Chiral” Electrodes: Enantiodiscrimination of Chiral Electroactive Probes with Planar Stereogenicity." ChemElectroChem 7, no. 16 (July 29, 2020): 3382. http://dx.doi.org/10.1002/celc.202000891.

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29

Talotta, Carmen, Gerardo Concilio, Paolo Della Sala, Carmine Gaeta, Christoph A. Schalley, and Placido Neri. "Study on the Influence of Chirality in the Threading of Calix[6]arene Hosts with Dialkylammonium Axles." Molecules 25, no. 22 (November 15, 2020): 5323. http://dx.doi.org/10.3390/molecules25225323.

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The influence of chirality in calixarene threading has been studied by exploiting the “superweak anion approach”. In particular, the formation of chiral pseudo[2]rotaxanes bearing a classical stereogenic center in their axle and/or wheel components has been considered. Two kind of pseudo[2]rotaxane stereoadducts, the “endo-chiral” and “exo-chiral” ones, having the stereogenic center of a cationic axle inside or outside, respectively, the calix-cavity of a chiral calixarene were preferentially formed with specifically designed chiral axles by a fine exploitation of the so-called “endo-alkyl rule” and a newly defined “endo-α-methyl-benzyl rule” (threading of a hexaalkoxycalix[6]arene with a directional (α-methyl-benzyl)benzylammonium axle occurs with an endo-α-methyl-benzyl preference). The obtained pseudorotaxanes were studied in solution by 1D and 2D NMR, and in the gas-phase by means of the enantiomer-labeled (EL) mass spectrometry method, by combining enantiopure hosts with pseudoracemates of one deuterated and one unlabeled chiral axle enantiomer. In both instances, there was not a clear enantiodiscrimination in the threading process with the studied host/guest systems. Possible rationales are given to explain the scarce reciprocal influence between the guest and host chiral centers.

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30

Li, Le, Xiaofei Ma, Yin Xiao, and Yong Wang. "Construction and Application of Graphene Oxide-Bovine Serum Albumin Modified Extended Gate Field Effect Transistor Chiral Sensor." Sensors 21, no. 11 (June 7, 2021): 3921. http://dx.doi.org/10.3390/s21113921.

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Chirality is an essential natural attribute of organisms. Chiral molecules exhibit differences in biochemical processes, pharmacodynamics, and toxicological properties, and their enantioselective recognition plays an important role in explaining life science processes and guiding drug design. Herein, we developed an ultra-sensitive enantiomer recognition platform based on an extended-gate metal-oxide semiconductor field-effect-transistor (Nafion–GO@BSA–EG-MOSFET) that achieved effective chiral resolution of ultra-sensitive Lysine (Lys) and α-Methylbenzylamine (α-Met) enantiodiscrimination at the femtomole level. Bovine serum albumin (BSA) was immobilized on the surface of graphene oxide (GO) through amide bond coupling to prepare the GO@BSA complex. GO@BSA was drop-cast on deposited Au surfaces with a Nafion solution to afford the extended-gate sensing unit. Effective recognition of chiral enantiomers of mandelic acid (MA), tartaric acid (TA), tryptophan (Trp), Lys and α-Met was realized. Moreover, the introduction of GO reduced non-specific adsorption, and the chiral resolution concentration of α-Met reached the level of picomole in a 5-fold diluted fetal bovine serum (FBS). Finally, the chiral recognition mechanism of the as-fabricated sensor was proposed.

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31

Martín-Rodríguez, María, Luis M. Castelló, Carmen Nájera, José M. Sansano, Olatz Larrañaga, Abel de Cózar, and Fernando P. Cossío. "Synthetic scope and DFT analysis of the chiral binap–gold(I) complex-catalyzed 1,3-dipolar cycloaddition of azlactones with alkenes." Beilstein Journal of Organic Chemistry 9 (November 11, 2013): 2422–33. http://dx.doi.org/10.3762/bjoc.9.280.

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The 1,3-dipolar cycloaddition between glycine-derived azlactones with maleimides is efficiently catalyzed by the dimeric chiral complex [(S a)-Binap·AuTFA]2. The alanine-derived oxazolone only reacts with tert-butyl acrylate giving anomalous regiochemistry, which is explained and supported by Natural Resonance Theory and Nucleus Independent Chemical Shifts calculations. The origin of the high enantiodiscrimination observed with maleimides and tert-butyl acrylate is analyzed using DFT computed at M06/Lanl2dz//ONIOM(b3lyp/Lanl2dz:UFF) level. Several applications of these cycloadducts in the synthesis of new proline derivatives with a 2,5-trans-arrangement and in the preparation of complex fused polycyclic molecules are described.

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32

Kotora, Martin. "Synthesis of axially chiral bipyridine N,N'-dioxides and enantioselective allylation of aldehydes." Pure and Applied Chemistry 82, no. 9 (June 7, 2010): 1813–26. http://dx.doi.org/10.1351/pac-con-09-10-01.

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N-oxides possessing the pyridine framework are strong Lewis bases that can activate the C–Si bond of allylhalosilanes to such an extent that they catalyze reactions with aldehydes. N-oxides embedded in chiral scaffolds are usually capable of highly selective chirality transfer to the derived products. Our goal was to develop a general synthetic method allowing the preparation of structurally varied N,N'-dioxides suitable for enantioselective organocatalysis. The underlying synthetic strategy was based on [2 + 2 + 2]-cyclotrimerization of suitably substituted diynes with nitriles catalyzed by Co-complexes to generate the desired bipyridines, their further oxidation and resolution of which furnished the corresponding chiral N,N'-dioxides. The prepared compounds were used in catalytic allylation of aromatic aldehydes to homoallyl alcohols with high enantioselectivity (up to 96 % ee). Enantioselectivity, enantiodiscrimination, and the reaction mechanism are controlled by the choice of solvent.

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33

Jávor, Bálint, Panna Vezse, Ádám Golcs, Péter Huszthy, and Tünde Tóth. "Enantiodiscriminating Lipophilic Liquid Membrane-Based Assay for High-Throughput Nanomolar Enantioenrichment of Chiral Building Blocks." Membranes 13, no. 1 (January 11, 2023): 94. http://dx.doi.org/10.3390/membranes13010094.

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The reported optical resolution method was designed to support high-throughput enantioseparation of molecular building blocks obtained by automated small-scale synthetic methods. Lipophilic esters of common resolving agents were prepared and used as liquid membranes on the indifferent polymer surface of a microtiter assay. Chiral model compounds were enriched in one of the enantiomers starting from the aqueous solutions of their racemic mixture. Enantiodiscrimination was provided by forming diastereomeric coordination complexes of lipophilic enantiopure esters with the enantiomers of the chiral building blocks inside the liquid membranes. This enantiomeric recognition resulted in a greater distribution ratio of the preferred isomer in the membrane phase, thus the process enables a simultaneous enantioenrichment of the solutions outside the membrane. This paper reports a novel microplate-integrated stereoselective membrane enrichment technique satisfying the need for automatable enantioseparation on a subpreparative scale.

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34

Erol Gunal, Sule, Senel Teke Tuncel, and Ilknur Dogan. "Enantiodiscrimination of carboxylic acids using single enantiomer thioureas as chiral solvating agents." Tetrahedron 76, no. 18 (May 2020): 131141. http://dx.doi.org/10.1016/j.tet.2020.131141.

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35

Deger, Wolfgang, Martin Gessner, Claus Guenther, Gabriele Singer, and Armin Mosandl. "Stereoisomeric flavor compounds. 18. Enantiodiscrimination of chiral flavor compounds by diastereomeric derivatization." Journal of Agricultural and Food Chemistry 36, no. 6 (November 1988): 1260–64. http://dx.doi.org/10.1021/jf00084a033.

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36

Barry, Nicolas P. E., Martina Austeri, Jérôme Lacour, and Bruno Therrien. "Highly Efficient NMR Enantiodiscrimination of Chiral Octanuclear Metalla-Boxes in Polar Solvent." Organometallics 28, no. 16 (August 24, 2009): 4894–97. http://dx.doi.org/10.1021/om900461s.

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37

Yang, Xuemei, Guitao Wang, Cheng Zhong, Xiaojun Wu, and Enqin Fu. "Novel NMR chiral solvating agents derived from (1R,2R)-diaminocyclohexane: synthesis and enantiodiscrimination for chiral carboxylic acids." Tetrahedron: Asymmetry 17, no. 6 (March 2006): 916–21. http://dx.doi.org/10.1016/j.tetasy.2006.03.011.

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38

Adhikari, Suraj, Kwang Joon Kim, and Wonjae Lee. "Enantiodiscrimination of Chiral Amines as Naphthaldimine Derivatives on Polysaccharide-derived Chiral Stationary Phases by Normal Phase HPLC." Yakhak Hoeji 63, no. 2 (April 30, 2019): 90–94. http://dx.doi.org/10.17480/psk.2019.63.2.90.

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39

Szabó, Zoltán-István, Francisc Boda, Béla Fiser, Máté Dobó, Levente Szőcs, and Gergő Tóth. "Chiral Separation of Oxazolidinone Analogs by Capillary Electrophoresis Using Anionic Cyclodextrins as Chiral Selectors: Emphasis on Enantiomer Migration Order." Molecules 28, no. 11 (June 2, 2023): 4530. http://dx.doi.org/10.3390/molecules28114530.

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Comparative chiral separations of enantiomeric pairs of four oxazolidinone and two related thio-derivatives were performed by capillary electrophoresis, using cyclodextrins (CDs) as chiral selectors. Since the selected analytes are neutral, the enantiodiscrimination capabilities of nine anionic CD derivatives were determined, in 50 mM phosphate buffer pH = 6. Unanimously, the most successful chiral selector was the single isomeric heptakis-(6-sulfo)-β-cyclodextrin (HS-β-CD), which resulted in the highest enantioresolution values out of the CDs applied for five of the six enantiomeric pairs. The enantiomer migration order (EMO) was the same for two enantiomeric pairs, irrespective of the CD applied. However, several examples of EMO reversals were obtained in the other cases. Interestingly, changing from randomly substituted, multi-component mixtures of sulfated-β-CD to the single isomeric chiral selector, enantiomer migration order reversal occurred for two enantiomeric pairs and similar observations were made when comparing heptakis-(2,3-di-O-methyl-6-O-sulfo)-β-CD, (HDMS-β-CD) with HS-β-CD. In several cases, cavity-size-dependent, and substituent-dependent EMO reversals were also observed. Minute differences in the structure of the analytes were also responsible for several cases of EMO reversal. The present study offers a complex overview of the chiral separation of structurally related oxazolidinones, and thio-analogs, highlighting the importance of the adequate choice of chiral selector in this group of compounds, where enantiomeric purity is of utmost importance.

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Peluso, Paola, Alessandro Dessì, Roberto Dallocchio, Barbara Sechi, Carlo Gatti, Bezhan Chankvetadze, Victor Mamane, et al. "Enantioseparation of 5,5′-Dibromo-2,2′-dichloro-3-selanyl-4,4′-bipyridines on Polysaccharide-Based Chiral Stationary Phases: Exploring Chalcogen Bonds in Liquid-Phase Chromatography." Molecules 26, no. 1 (January 4, 2021): 221. http://dx.doi.org/10.3390/molecules26010221.

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The chalcogen bond (ChB) is a noncovalent interaction based on electrophilic features of regions of electron charge density depletion (σ-holes) located on bound atoms of group VI. The σ-holes of sulfur and heavy chalcogen atoms (Se, Te) (donors) can interact through their positive electrostatic potential (V) with nucleophilic partners such as lone pairs, π-clouds, and anions (acceptors). In the last few years, promising applications of ChBs in catalysis, crystal engineering, molecular biology, and supramolecular chemistry have been reported. Recently, we explored the high-performance liquid chromatography (HPLC) enantioseparation of fluorinated 3-arylthio-4,4′-bipyridines containing sulfur atoms as ChB donors. Following this study, herein we describe the comparative enantioseparation of three 5,5′-dibromo-2,2′-dichloro-3-selanyl-4,4′-bipyridines on polysaccharide-based chiral stationary phases (CSPs) aiming to understand function and potentialities of selenium σ-holes in the enantiodiscrimination process. The impact of the chalcogen substituent on enantioseparation was explored by using sulfur and non-chalcogen derivatives as reference substances for comparison. Our investigation also focused on the function of the perfluorinated aromatic ring as a π-hole donor recognition site. Thermodynamic quantities associated with the enantioseparation were derived from van’t Hoff plots and local electron charge density of specific molecular regions of the interacting partners were inspected in terms of calculated V. On this basis, by correlating theoretical data and experimental results, the participation of ChBs and π-hole bonds in the enantiodiscrimination process was reasonably confirmed.

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Aroulanda, Christie, and Philippe Lesot. "Molecular enantiodiscrimination by NMR spectroscopy in chiral oriented systems: Concept, tools, and applications." Chirality 34, no. 2 (December 22, 2021): 182–244. http://dx.doi.org/10.1002/chir.23386.

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42

Tanaka, Koichi, Tomoharu Iwashita, Chihiro Sasaki, and Hiroki Takahashi. "Ring-expanded chiral rhombamine macrocycles for efficient NMR enantiodiscrimination of carboxylic acid derivatives." Tetrahedron: Asymmetry 25, no. 8 (April 2014): 602–9. http://dx.doi.org/10.1016/j.tetasy.2014.03.009.

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43

Berkecz, Róbert, Gábor Németi, Antal Péter, and István Ilisz. "Liquid Chromatographic Enantioseparations Utilizing Chiral Stationary Phases Based on Crown Ethers and Cyclofructans." Molecules 26, no. 15 (July 31, 2021): 4648. http://dx.doi.org/10.3390/molecules26154648.

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Natural compounds can exist in different forms, where molecules possessing chirality play an essential role in living organisms. Currently, one of the most important tasks of modern analytical chemistry is the enantioseparation of chiral compounds, in particular, the enantiomers of compounds having biological and/or pharmaceutical activity. Whether the task is to analyze environmental or food samples or to develop an assay for drug control, well-reproducible, highly sensitive, stereoselective, and robust methods are required. High-performance liquid chromatography best meets these conditions. Nevertheless, in many cases, gas chromatography, supercritical fluid chromatography, or capillary electrophoresis can also offer a suitable solution. Amino acids, proteins, cyclodextrins, derivatized polysaccharides, macrocyclic glycopeptides, and ion exchangers can serve as efficient selectors in liquid chromatography, and they are quite frequently applied and reviewed. Crown ethers and cyclofructans possessing similar structural characteristics and selectivity in the enantiodiscrimination of different amine compounds are discussed less frequently. This review collects information on enantioseparations achieved recently with the use of chiral stationary phases based on crown ethers or cyclofructans, focusing on liquid chromatographic applications.

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44

Hernández-Rodríguez, Marcos, and Eusebio Juaristi. "Structurally simple chiral thioureas as chiral solvating agents in the enantiodiscrimination of α-hydroxy and α-amino carboxylic acids." Tetrahedron 63, no. 32 (August 2007): 7673–78. http://dx.doi.org/10.1016/j.tet.2007.05.021.

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45

Chaudhari, Sachin Rama, and N. Suryaprakash. "Three-Component Chiral Derivatizing Protocols for NMR Spectroscopic Enantiodiscrimination of Hydroxy Acids and Primary Amines." Journal of Organic Chemistry 77, no. 1 (December 21, 2011): 648–51. http://dx.doi.org/10.1021/jo202334d.

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46

Peña, Carmen, Javier González-Sabín, Ignacio Alfonso, Francisca Rebolledo, and Vicente Gotor. "Cycloalkane-1,2-diamine derivatives as chiral solvating agents. Study of the structural variables controlling the NMR enantiodiscrimination of chiral carboxylic acids." Tetrahedron 64, no. 33 (August 2008): 7709–17. http://dx.doi.org/10.1016/j.tet.2008.06.031.

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47

Rivard, Michaël, Frédéric Guillen, Jean-Claude Fiaud, Christie Aroulanda, and Philippe Lesot. "Efficient enantiodiscrimination of chiral monophosphine oxides and boranes by phosphorus coupled 13C NMR spectroscopy in the presence of chiral ordering agents." Tetrahedron: Asymmetry 14, no. 9 (May 2003): 1141–52. http://dx.doi.org/10.1016/s0957-4166(03)00202-7.

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48

Fejős, Ida, Eszter Kalydi, Edit Luca Kukk, Mimimorena Seggio, Milo Malanga, and Szabolcs Béni. "Single Isomer N-Heterocyclic Cyclodextrin Derivatives as Chiral Selectors in Capillary Electrophoresis." Molecules 26, no. 17 (August 30, 2021): 5271. http://dx.doi.org/10.3390/molecules26175271.

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In order to better understand the chiral recognition mechanisms of positively charged cyclodextrin (CD) derivatives, the synthesis, the pKa determination by 1H nuclear magnetic resonance (NMR)-pH titration and a comparative chiral capillary electrophoretic (CE) study were performed with two series of mono-substituted cationic single isomer CDs. The first series of selectors were mono-(6-N-pyrrolidine-6-deoxy)-β-CD (PYR-β-CD), mono-(6-N-piperidine-6-deoxy)-β-CD (PIP-β-CD), mono-(6-N-morpholine-6-deoxy)-β-CD (MO-β-CD) and mono-(6-N-piperazine-6-deoxy)-β-CD (PIPA-β-CD), carrying a pH-adjustable moiety at the narrower rim of the cavity, while the second set represented by their quaternarized, permanently cationic counterparts: mono-(6-N-(N-methyl-pyrrolidine)-6-deoxy)-β-CD (MePYR-β-CD), mono-(6-N-(N-methyl-piperidine)-6-deoxy)-β-CD (MePIP-β-CD), mono-(6-N-(N-methyl-morpholine)-6-deoxy)-β-CD (MeMO-β-CD) and mono-(6-N-(4,4-N,N-dimethyl-piperazine)-β-CD (diMePIPA-β-CD). Based on pH-dependent and selector concentration-dependent comparative studies of these single isomer N-heterocyclic CDs presented herein, it can be concluded that all CDs could successfully be applied as chiral selectors for the enantiodiscrimination of several negatively charged and zwitterionic model racemates. The substituent-dependent enantiomer migration order reversal of dansylated-valine using PIP-β-CD contrary to PYP-β-CD, MO-β-CD and PIPA-β-CD was also studied by 1H- and 2D ROESY NMR experiments.

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49

Arnaboldi, Serena, Andrea Mezzetta, Sara Grecchi, Mariangela Longhi, Elisa Emanuele, Simona Rizzo, Fabiana Arduini, Laura Micheli, Lorenzo Guazzelli, and Patrizia Romana Mussini. "Natural-based chiral task-specific deep eutectic solvents: A novel, effective tool for enantiodiscrimination in electroanalysis." Electrochimica Acta 380 (June 2021): 138189. http://dx.doi.org/10.1016/j.electacta.2021.138189.

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50

Jain, Nilesh, Aditya N. Khanvilkar, Sibaprasad Sahoo, and Ashutosh V. Bedekar. "Modification of Kagan's amide for improved activity as Chiral Solvating Agent in enantiodiscrimination during NMR analysis." Tetrahedron 74, no. 1 (January 2018): 68–76. http://dx.doi.org/10.1016/j.tet.2017.11.036.

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