Application of aromatic amide‐derived atropisomers as chiral solvating agents for discrimination of optically active mandelic acid derivatives in <sup>1</sup>H nuclear magnetic resonance spectroscopy

Zheng, Xiaotong; Tang, Tingfeng; Li, Li; Xu, Li‐Wen; Huang, Shaohua; Zhao, Yufen

doi:10.1002/mrc.5185

Cited by 6 publications

(6 citation statements)

References 30 publications

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“… DFT calculations of 1 H-, and 13 C- chemical shifts and J couplings can contribute significantly to the unequivocal resonance assignment, identification of cis / trans geometric isomers, and diastereomeric pairs of complex hydroperoxides and solvent effects [ 142 , 143 , 144 , 145 , 146 , 147 , 148 , 149 , 150 , 151 , 152 , 153 , 154 , 155 , 156 , 198 , 199 ]. Further, research is also required for the determination of chirality in solution [ 200 ]. Development of officially recognized NMR methodologies for LOOHs in fats and oils through collaboration of various NMR groups.…”

Section: Conclusion and Future Prospectsmentioning

confidence: 99%

Analytical and Structural Tools of Lipid Hydroperoxides: Present State and Future Perspectives

Kontogianni

Gerothanassis

2022

Molecules

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Mono- and polyunsaturated lipids are particularly susceptible to peroxidation, which results in the formation of lipid hydroperoxides (LOOHs) as primary nonradical-reaction products. LOOHs may undergo degradation to various products that have been implicated in vital biological reactions, and thus in the pathogenesis of various diseases. The structure elucidation and qualitative and quantitative analysis of lipid hydroperoxides are therefore of great importance. The objectives of the present review are to provide a critical analysis of various methods that have been widely applied, and more specifically on volumetric methods, applications of UV-visible, infrared, Raman/surface-enhanced Raman, fluorescence and chemiluminescence spectroscopies, chromatographic methods, hyphenated MS techniques, NMR and chromatographic methods, NMR spectroscopy in mixture analysis, structural investigations based on quantum chemical calculations of NMR parameters, applications in living cells, and metabolomics. Emphasis will be given to analytical and structural methods that can contribute significantly to the molecular basis of the chemical process involved in the formation of lipid hydroperoxides without the need for the isolation of the individual components. Furthermore, future developments in the field will be discussed.

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Section: Conclusion and Future Prospectsmentioning

confidence: 99%

Analytical and Structural Tools of Lipid Hydroperoxides: Present State and Future Perspectives

Kontogianni

Gerothanassis

2022

Molecules

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“…The role of salification processes in the mechanism of interaction between CSA I and enantiomeric substrates has been fully confirmed through the analysis of mixtures containing substrates 2-bromopropionate (28) and valine methyl ester hydrochloride (29) (Figure 2). Both substrates 28 and 29, devoid of free carboxylic functions, did not dissolve compound I.…”

Section: Interaction Mechanismmentioning

confidence: 83%

“…The remarkable significance of chiral carboxylic acids as constituents of numerous natural products and pharmaceutically relevant compounds has spurred the development of CSAs for NMR spectroscopy, primarily aimed at enantiodiscrimination within this compound class [4][5][6][7][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30].…”

Section: Introductionmentioning

confidence: 99%

A Squaramide-Based Organocatalyst as a Novel Versatile Chiral Solvating Agent for Carboxylic Acids

Spiaggia,

Uccello Barretta,

Iuliano

et al. 2024

Molecules

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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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“…Very recently, our group found that the four aromatic-amide-derived atropisomers 57 shown in Scheme could act as chiral solvating agents to recognize structurally diverse mandelic acid derivatives (12 examples) in 1 H NMR spectroscopy, where the stereogenic configurations of these atropisomers (hosts) have different effects on the stereoselective recognition of the mandelic acid derivatives used (guests) . For example, anti -( R , R s)- 57a displayed better recognition of most guests except for the electron-withdrawing mandelic acid derivatives.…”

Section: Merging Non-biaryl Atropisomers With Point Chiralitymentioning

confidence: 99%

Atropisomers with Axial and Point Chirality: Synthesis and Applications

et al. 2022

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Conspectus Enantiopure atropisomers have become increasingly important in asymmetric synthesis and catalysis, pharmaceutical science, and material science since the discovery of inherent features of axial chirality originating from rotational restriction. Despite the advances made in this field to date, it remains highly desirable to construct structurally diverse atropisomers with potentially useful functions. We propose superposition to match axial and point chirality as a potentially useful strategy to access structurally complex and diverse building blocks for organic synthesis and pharmaceutical science because merging atropisomeric backbones with one or more extra chiral elements can topologically broaden three-dimensional environments to create complex scaffolds with multiple tunable parameters. Over the past decade, we have successfully implemented a strategic design for the superposition of axial and point chirality to develop a series of enantiopure atropisomers and have utilized the synergistic functions of these molecules to enhance chirality transfer in various catalytic asymmetric transformations. In this Account, we present several novel atropisomers with superposed axial and point chirality developed in our laboratory. In our studies, this superposition strategy was used to design and synthesize both biaryl and non-biaryl atropisomers from commercially available chiral sources. Consequently, these atropisomers were used to demonstrate the importance of the synergetic functions of axial and point chirality in specific enantioselective reactions. For example, aromatic amide-derived atropisomers, simplified as Xing-Phos arrays, were broadly employed in Ag-catalyzed [3 + 2] cycloaddition by a series of reactions of aldiminoesters with activated alkenes and imines, as well as being used as chiral solvating agents for the discrimination of optically active mandelic acid derivatives. Considering the powerful potential of non-biaryl atropisomers for asymmetric catalysis, we also explored the transition-metal-catalyzed enantioselective construction of a novel backbone of non-biaryl atropisomers (Ar–alkene, Ar–N axis) bearing both axial and point chirality for the design and synthesis of chiral ligands and functional molecules. The studies presented herein are expected to stimulate further research efforts on the development of functional atropisomers by superposition of matching axial and point chirality. In addition to tunable electron and stereohindrance effects, the synergy between matching chiral elements of axial/point chirality and functional groups is proven to be a special function that cannot be ignored for promoting reactivity and chirality-transfer efficiency in enantioselective synthesis. Consequently, our novel types of scaffolds with superposed axial and point chirality that are capable of versatile coordination with various metal catalysts in asymmetric catalysis highlight the power of the superposition of matching axial and point chirality for the construction of synthetically useful atropi...

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Application of aromatic amide‐derived atropisomers as chiral solvating agents for discrimination of optically active mandelic acid derivatives in ¹H nuclear magnetic resonance spectroscopy

Cited by 6 publications

References 30 publications

Analytical and Structural Tools of Lipid Hydroperoxides: Present State and Future Perspectives

Analytical and Structural Tools of Lipid Hydroperoxides: Present State and Future Perspectives

A Squaramide-Based Organocatalyst as a Novel Versatile Chiral Solvating Agent for Carboxylic Acids

Atropisomers with Axial and Point Chirality: Synthesis and Applications

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Application of aromatic amide‐derived atropisomers as chiral solvating agents for discrimination of optically active mandelic acid derivatives in 1H nuclear magnetic resonance spectroscopy

Cited by 6 publications

References 30 publications

Analytical and Structural Tools of Lipid Hydroperoxides: Present State and Future Perspectives

Analytical and Structural Tools of Lipid Hydroperoxides: Present State and Future Perspectives

A Squaramide-Based Organocatalyst as a Novel Versatile Chiral Solvating Agent for Carboxylic Acids

Atropisomers with Axial and Point Chirality: Synthesis and Applications

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Product

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Application of aromatic amide‐derived atropisomers as chiral solvating agents for discrimination of optically active mandelic acid derivatives in ¹H nuclear magnetic resonance spectroscopy