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Spiaggia F, Uccello Barretta G, Iuliano A, Baldassari C, Aiello F, Balzano F. A Squaramide-Based Organocatalyst as a Novel Versatile Chiral Solvating Agent for Carboxylic Acids. Molecules 2024; 29:2389. [PMID: 38792248 PMCID: PMC11123912 DOI: 10.3390/molecules29102389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2024] [Revised: 05/03/2024] [Accepted: 05/15/2024] [Indexed: 05/26/2024] Open
Abstract
A squaramide-based organocatalyst for asymmetric Michael reactions has been tested as a chiral solvating agent (CSA) for 26 carboxylic acids and camphorsulfonic acid, encompassing amino acid derivatives, mandelic acid, as well as some of its analogs, propionic acids like profens (ketoprofen and ibuprofen), butanoic acids and others. In many cases remarkably high enantiodifferentiations at 1H, 13C and 19F nuclei were observed. The interaction likely involves a proton transfer from the acidic substrates to the tertiary amine sites of the organocatalyst, thus allowing for pre-solubilization of the organocatalyst (when a chloroform solution of the substrate is employed) or the simultaneous solubilization of both the catalyst and the substrate. DOSY experiments were employed to evaluate whether the catalyst-substrate ionic adduct was a tight one or not. ROESY experiments were employed to investigate the role of the squaramide unit in the adduct formation. A mechanism of interaction was proposed in accordance with the literature data.
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Affiliation(s)
- Fabio Spiaggia
- Department of Chemistry and Industrial Chemistry, University of Pisa, Via G. Moruzzi 13, 56124 Pisa, Italy; (A.I.); (C.B.); (F.B.)
| | - Gloria Uccello Barretta
- Department of Chemistry and Industrial Chemistry, University of Pisa, Via G. Moruzzi 13, 56124 Pisa, Italy; (A.I.); (C.B.); (F.B.)
| | - Anna Iuliano
- Department of Chemistry and Industrial Chemistry, University of Pisa, Via G. Moruzzi 13, 56124 Pisa, Italy; (A.I.); (C.B.); (F.B.)
| | - Carlo Baldassari
- Department of Chemistry and Industrial Chemistry, University of Pisa, Via G. Moruzzi 13, 56124 Pisa, Italy; (A.I.); (C.B.); (F.B.)
| | - Federica Aiello
- National Research Council, Institute for Chemical and Physical Processes (CNR-IPCF), Via G. Moruzzi 1, 56124 Pisa, Italy;
| | - Federica Balzano
- Department of Chemistry and Industrial Chemistry, University of Pisa, Via G. Moruzzi 13, 56124 Pisa, Italy; (A.I.); (C.B.); (F.B.)
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Mo MY, Wang XJ, Shen RZ, Hu CY, Li XC, Li GW, Liu LT. Enantiospecific Analysis of Carboxylic Acids Using Cinchona Alkaloid Dimers as Chiral Solvating Agents. Anal Chem 2024; 96:7487-7496. [PMID: 38695134 DOI: 10.1021/acs.analchem.4c00053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/15/2024]
Abstract
Cinchona alkaloid derivatives as Brønsted base catalysts have attracted considerable attention in the field of asymmetric catalysis. However, their potential application as chiral solvating agents has not been described. In this research, we investigated the use of the Cinchona alkaloid dimer, namely, (DHQ)2PHAL, as a chiral solvating agent for discerning various mandelic acid derivatives through 1H NMR spectroscopy. The addition of catalytic amounts of DMAP facilitated this process. Our experimental results demonstrate that dimeric (DHQ)2PHAL exhibits remarkable chiral discrimination properties regarding the diagnostic split protons of 1H NMR signals (including 24 examples, up to 0.321 ppm). Furthermore, it serves as an excellent chiral discriminating agent and provides good resolution for racemic chiral phosphoric acid as determined by 31P NMR spectroscopy. The quality of enantiodifferentiation has also been evaluated by means of the parameter "resolution (Rs)". Significantly, this class of CSAs based on (alkaloid)2linker systems with an azaaromatic linker can be directly employed, which is commercially available in an enantiopure form at very low cost and exhibits promising potential in determining the enantiopurity of α-hydroxy acids by chemoselective and biocatalytic reactions.
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Affiliation(s)
- Ming-Yang Mo
- School of Chemistry, Zhengzhou University, Zhengzhou, 450001, China
- College of Chemistry and Chemical Engineering, Henan Engineering Research Center for Green Synthesis of Pharmaceuticals, Shangqiu Normal University, Shangqiu 476000, China
| | - Xiao-Juan Wang
- College of Chemistry and Chemical Engineering, Henan Engineering Research Center for Green Synthesis of Pharmaceuticals, Shangqiu Normal University, Shangqiu 476000, China
| | - Ren-Zeng Shen
- College of Chemistry and Chemical Engineering, Henan Engineering Research Center for Green Synthesis of Pharmaceuticals, Shangqiu Normal University, Shangqiu 476000, China
| | - Chang-Yan Hu
- College of Chemistry and Chemical Engineering, Henan Engineering Research Center for Green Synthesis of Pharmaceuticals, Shangqiu Normal University, Shangqiu 476000, China
| | - Xue-Chun Li
- College of Chemistry and Chemical Engineering, Henan Engineering Research Center for Green Synthesis of Pharmaceuticals, Shangqiu Normal University, Shangqiu 476000, China
| | - Gao-Wei Li
- School of Chemistry, Zhengzhou University, Zhengzhou, 450001, China
- College of Chemistry and Chemical Engineering, Henan Engineering Research Center for Green Synthesis of Pharmaceuticals, Shangqiu Normal University, Shangqiu 476000, China
| | - Lan-Tao Liu
- School of Chemistry, Zhengzhou University, Zhengzhou, 450001, China
- College of Chemistry and Chemical Engineering, Henan Engineering Research Center for Green Synthesis of Pharmaceuticals, Shangqiu Normal University, Shangqiu 476000, China
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Feuge N, Wilhelm R. Straightforward synthesis of chiral sulfonate-based ionic liquids from amino alcohols for chiral recognition. Chirality 2023; 35:993-1011. [PMID: 37497749 DOI: 10.1002/chir.23614] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Revised: 06/30/2023] [Accepted: 07/07/2023] [Indexed: 07/28/2023]
Abstract
New sulfonate-based chiral salts were prepared from amino alcohols and sodium hydroxymethanesulfonate, vinyl sulfonate, or sultone. The synthesis started with different amino acids from the chiral pool and gave the desired products in just four steps. After cation metathesis, the salts were explored as chiral solvating agents (CSAs) in NMR studies. The new chiral ionic liquids (CILs) were successfully able to interact with different chiral guest molecules and formed diastereomeric aggregates. In some cases, baseline separation was observed. The influence of the structural differences in the CIL as well as the structural requirements of the guest molecule is discussed.
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Affiliation(s)
- Niklas Feuge
- Institute of Organic Chemistry, Clausthal University of Technology, Clausthal-Zellerfeld, Germany
| | - René Wilhelm
- Institute of Organic Chemistry, Clausthal University of Technology, Clausthal-Zellerfeld, Germany
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Peluso P, Chankvetadze B. Recognition in the Domain of Molecular Chirality: From Noncovalent Interactions to Separation of Enantiomers. Chem Rev 2022; 122:13235-13400. [PMID: 35917234 DOI: 10.1021/acs.chemrev.1c00846] [Citation(s) in RCA: 57] [Impact Index Per Article: 28.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
It is not a coincidence that both chirality and noncovalent interactions are ubiquitous in nature and synthetic molecular systems. Noncovalent interactivity between chiral molecules underlies enantioselective recognition as a fundamental phenomenon regulating life and human activities. Thus, noncovalent interactions represent the narrative thread of a fascinating story which goes across several disciplines of medical, chemical, physical, biological, and other natural sciences. This review has been conceived with the awareness that a modern attitude toward molecular chirality and its consequences needs to be founded on multidisciplinary approaches to disclose the molecular basis of essential enantioselective phenomena in the domain of chemical, physical, and life sciences. With the primary aim of discussing this topic in an integrated way, a comprehensive pool of rational and systematic multidisciplinary information is provided, which concerns the fundamentals of chirality, a description of noncovalent interactions, and their implications in enantioselective processes occurring in different contexts. A specific focus is devoted to enantioselection in chromatography and electromigration techniques because of their unique feature as "multistep" processes. A second motivation for writing this review is to make a clear statement about the state of the art, the tools we have at our disposal, and what is still missing to fully understand the mechanisms underlying enantioselective recognition.
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Affiliation(s)
- Paola Peluso
- Istituto di Chimica Biomolecolare ICB, CNR, Sede secondaria di Sassari, Traversa La Crucca 3, Regione Baldinca, Li Punti, I-07100 Sassari, Italy
| | - Bezhan Chankvetadze
- Institute of Physical and Analytical Chemistry, School of Exact and Natural Sciences, Tbilisi State University, Chavchavadze Avenue 3, 0179 Tbilisi, Georgia
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Chiral tetraalkynylborate as a chiral solvating agent for N-chiral tetraalkylammonium salts. Tetrahedron 2022. [DOI: 10.1016/j.tet.2022.132783] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Zheng X, Tang T, Li L, Xu LW, Huang S, Zhao Y. Application of aromatic amide-derived atropisomers as chiral solvating agents for discrimination of optically active mandelic acid derivatives in 1 H nuclear magnetic resonance spectroscopy. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2022; 60:86-92. [PMID: 34106483 DOI: 10.1002/mrc.5185] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 06/03/2021] [Accepted: 06/04/2021] [Indexed: 06/12/2023]
Abstract
Non-biaryl atropisomers and their stereochemistry have attracted much attentions in the past years. However, application of the non-biaryl atropisomers as chiral solvating agents is yet to be explored. In this work, four aromatic amide-derived atropisomeric phosphine ligands (hosts) were used as chiral solvating agents to recognize various mandelic acid derivatives (guests) in 1 H nuclear magnetic resonance (NMR) spectroscopy. It is found that chiral center configurations of the four hosts have different effects on the enantiorecognition to the used guests. In addition, the host and guest interaction was further investigated by determination of the host-guest complex stoichiometry using the Job's method and density functional theory calculation, respectively. Moreover, chiral analysis accuracy of these hosts was evaluated through relationship between enantiomeric excess values of 4-chloromandelic acid provided by NMR and gravimetry, respectively.
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Affiliation(s)
- Xiaojing Zheng
- Institute of Drug Discovery Technology, Ningbo University, Ningbo, China
| | - Tingfeng Tang
- Institute of Drug Discovery Technology, Ningbo University, Ningbo, China
| | - Li Li
- Key Laboratory of Organosilicon Chemistry and Material Technology of Ministry of Education, Hangzhou Normal University, Hangzhou, China
| | - Li-Wen Xu
- Key Laboratory of Organosilicon Chemistry and Material Technology of Ministry of Education, Hangzhou Normal University, Hangzhou, China
| | - Shaohua Huang
- Institute of Drug Discovery Technology, Ningbo University, Ningbo, China
- Qian Xuesen Collaborative Research Center of Astrochemistry and Space Life Sciences, Ningbo University, Ningbo, China
| | - Yufen Zhao
- Institute of Drug Discovery Technology, Ningbo University, Ningbo, China
- Qian Xuesen Collaborative Research Center of Astrochemistry and Space Life Sciences, Ningbo University, Ningbo, China
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Li GW, Wang XJ, Cui DD, Zhang YF, Xu RY, Shi SH, Liu LT, Wang MC, Liu HM, Lei XX. Azaheterocyclic diphenylmethanol chiral solvating agents for the NMR chiral discrimination of alpha-substituted carboxylic acids. RSC Adv 2020; 10:34605-34611. [PMID: 35514411 PMCID: PMC9056771 DOI: 10.1039/d0ra06312f] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Accepted: 08/24/2020] [Indexed: 12/02/2022] Open
Abstract
A series of small-membered heterocycle probes, so-called azaheterocycle-containing diphenylmethanol chiral solvating agents (CSAs), have been developed for NMR enantiodiscrimination. These chiral sensors were readily synthesized were inexpensive and efficiently used for the chiral analysis of alpha-substituted carboxylic acids. The sensing method was operationally simple and the processing was straightforward. Notably, we propose (S)-aziridinyl diphenylmethanol as a promising CSA, which has excellent chiral discriminating properties and offers multiple detectable possibilities pertaining to the 1H NMR signals of diagnostic split protons (including 25 examples, up to 0.194 ppm, 77.6 Hz). Its ability to detect the molecular recognition of fluorinated carboxylic acids were further investigated, with a good level of discrimination via the 19F NMR spectroscopic analysis. In addition, an accurate enantiomeric excess (ee) analysis of the p-methoxyl-mandelic acid with different optical compositions have been calculated based on the integration of well-separated proton signals.
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Affiliation(s)
- Gao-Wei Li
- College of Chemistry and Chemical Engineering and Henan Engineering Laboratory of Green Synthesis for Pharmaceuticals, Shangqiu Normal University Shangqiu 476000 P. R. China
- School of Pharmaceutical Sciences, Zhengzhou University Zhengzhou 450001 P. R. China
| | - Xiao-Juan Wang
- College of Chemistry and Chemical Engineering and Henan Engineering Laboratory of Green Synthesis for Pharmaceuticals, Shangqiu Normal University Shangqiu 476000 P. R. China
| | - Dan-Dan Cui
- College of Chemistry and Chemical Engineering and Henan Engineering Laboratory of Green Synthesis for Pharmaceuticals, Shangqiu Normal University Shangqiu 476000 P. R. China
| | - Yu-Fei Zhang
- College of Chemistry and Chemical Engineering and Henan Engineering Laboratory of Green Synthesis for Pharmaceuticals, Shangqiu Normal University Shangqiu 476000 P. R. China
| | - Rong-Yao Xu
- College of Chemistry and Chemical Engineering and Henan Engineering Laboratory of Green Synthesis for Pharmaceuticals, Shangqiu Normal University Shangqiu 476000 P. R. China
| | - Shuai-Hua Shi
- College of Chemistry and Chemical Engineering and Henan Engineering Laboratory of Green Synthesis for Pharmaceuticals, Shangqiu Normal University Shangqiu 476000 P. R. China
| | - Lan-Tao Liu
- College of Chemistry and Chemical Engineering and Henan Engineering Laboratory of Green Synthesis for Pharmaceuticals, Shangqiu Normal University Shangqiu 476000 P. R. China
| | - Min-Can Wang
- School of Pharmaceutical Sciences, Zhengzhou University Zhengzhou 450001 P. R. China
| | - Hong-Min Liu
- School of Pharmaceutical Sciences, Zhengzhou University Zhengzhou 450001 P. R. China
| | - Xin-Xiang Lei
- School of Pharmaceutical Sciences, South-Central University for Nationalities Wuhan 430074 P. R. China
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