NMR analysis of the enantiomeric purity of chiral diols by a new chiral boron agent

Zhang, Xuebo; Xu, Jing; Sun, Zhaofeng; Bian, Guangling; Song, Ling

doi:10.1039/d2ra00428c

Cited by 4 publications

(2 citation statements)

References 29 publications

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“…The design of novel CSAs for the discrimination of enantiomers has been very crucial and imperative for prochiral analytes and has gained significant attraction. Various types of small organic molecular guests for chiral recognition of carboxylic acids, amino acids, alcohols, amines, and metabonomics applications have been developed and synthesized, including chiral thioureas, − amino alcohols, − chiral macrocyclic/crown ethers, − metal pincer complexes, − amide-derived atropisomers, etc. These CSAs with extensive hydrogen bonding sites have proven to be versatile shift reagents, allowing 1 H NMR based discrimination of a range of chiral compounds.…”

Section: Introductionmentioning

confidence: 99%

Enantiospecific Analysis of Carboxylic Acids Using Cinchona Alkaloid Dimers as Chiral Solvating Agents

Mo,

Wang,

Shen

et al. 2024

Anal. Chem.

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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) 2 PHAL, as a chiral solvating agent for discerning various mandelic acid derivatives through 1 H NMR spectroscopy. The addition of catalytic amounts of DMAP facilitated this process. Our experimental results demonstrate that dimeric (DHQ) 2 PHAL exhibits remarkable chiral discrimination properties regarding the diagnostic split protons of 1 H 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 31 P NMR spectroscopy. The quality of enantiodifferentiation has also been evaluated by means of the parameter "resolution (R s )". Significantly, this class of CSAs based on (alkaloid) 2 linker 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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Section: Introductionmentioning

confidence: 99%

Enantiospecific Analysis of Carboxylic Acids Using Cinchona Alkaloid Dimers as Chiral Solvating Agents

Mo,

Wang,

Shen

et al. 2024

Anal. Chem.

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“…In reported work, several chiral chain organic compounds have been often used as chiral substrates for the determination of the absolute configuration and evaluation of enantiomeric excess, including chiral amines, , alcohols, − amino alcohols, , carboxylic acids, , and amino acids or their derivatives . On the other hand, chiral cyclic organic compounds have been scarcely investigated as chiral substrates by means of 1 H NMR spectroscopy .…”

mentioning

confidence: 99%

Chiral Recognition of Chiral (Hetero)Cyclic Derivatives Probed by Tetraaza Macrocyclic Chiral Solvating Agents via ¹H NMR Spectroscopy

Wang,

Zhao,

Yang

et al. 2024

Anal. Chem.

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In the field of chiral recognition, chiral cyclic organic compounds, especially heterocyclic organic compounds, have attracted little attention and have been rarely studied as chiral substrates by means of 1 H NMR spectroscopy. In this paper, enantiomers of thiohydantoin derivatives, representing typical five-membered N,N-heterocycles, have been synthesized and utilized for assignment of absolute configuration and analysis of enantiomeric excess. All enantiomers have been successfully differentiated with the assistance of novel tetraaza macrocyclic chiral solvating agents (TAMCSAs) by 1 H NMR spectroscopy. Surprisingly, unprecedented nonequivalent chemical shift values (up to 2.052 ppm) of the NH proton of substrates have been observed, a new milestone in the evaluation of enantiomers. To better understand the intermolecular interactions between host and guest, Job plots and theoretical calculations of (S)-G1 and (R)-G1 with TAMCSA 1a were investigated and revealed significant geometric differentiation between the diastereomers. In order to evaluate practical applications of the present systems in analyzing optical purity of chiral substrates, enantiomeric excesses of a typical substrate (G1) with different optical compositions in the presence of a representative TAMCSA (1a) can be accurately calculated based on the integration of the NH proton's signal peaks. Importantly, this work provides a significant breakthrough in exploring and developing the chiral recognition of chiral heterocyclic organic compounds by 1 H NMR spectroscopy.

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Synthesis of Enantiomers of Chiral Ester Derivatives Containing an Amide Group and Their Chiral Recognition by ¹H NMR Spectroscopy

Zhao

Ren

et al. 2023

ChemistrySelect

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Enantiomers of chiral ester derivatives containing an amide group, and possessing one or two stereogenic centers were prepared from L-and D-α-amino acids, and glycine with (S)and (R)-mandelic acid for probing their chiral recognition as a new class of chiral guests by 1 H NMR spectroscopy, since chiral ester derivatives have been rarely used as chiral substrates for chiral recognition by 1 H NMR technology. The results indicated that these chiral ester derivatives have been successfully differentiated in the presence of tetraaza macrocyclic chiral solvating agents (TAMCSAs) 1 a-1 c. In order to better under-stand their chiral discriminating behavior, Job plots, association constants (K a ), and theoretical calculations of (S,S)-G1 and (R,R)-G1, as a representative example, were performed, respectively. In order to evaluate their practical application, the 1 H NMR spectra of G1 and G9 with various optical purities were measured (up to 98 % ee). In this work, a practical strategy has been effectively established for chiral recognition of chiral ester derivatives containing an amide group and possessing one or two chiral centers in the presence of tetraaza macrocyclic chiral solvating agents 1 a-1 c by means of 1 H NMR spectroscopy.

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NMR analysis of the enantiomeric purity of chiral diols by a new chiral boron agent

Abstract: A new boric agent with bridged structure, boric acid D, was first synthesized and used as an excellent chiral derivative agent for highly efficient enantiodiscrimination of various diols.

Cited by 4 publications

References 29 publications

Enantiospecific Analysis of Carboxylic Acids Using Cinchona Alkaloid Dimers as Chiral Solvating Agents

Enantiospecific Analysis of Carboxylic Acids Using Cinchona Alkaloid Dimers as Chiral Solvating Agents

Chiral Recognition of Chiral (Hetero)Cyclic Derivatives Probed by Tetraaza Macrocyclic Chiral Solvating Agents via ¹H NMR Spectroscopy

Synthesis of Enantiomers of Chiral Ester Derivatives Containing an Amide Group and Their Chiral Recognition by ¹H NMR Spectroscopy

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NMR analysis of the enantiomeric purity of chiral diols by a new chiral boron agent

Abstract: A new boric agent with bridged structure, boric acid D, was first synthesized and used as an excellent chiral derivative agent for highly efficient enantiodiscrimination of various diols.

Cited by 4 publications

References 29 publications

Enantiospecific Analysis of Carboxylic Acids Using Cinchona Alkaloid Dimers as Chiral Solvating Agents

Enantiospecific Analysis of Carboxylic Acids Using Cinchona Alkaloid Dimers as Chiral Solvating Agents

Chiral Recognition of Chiral (Hetero)Cyclic Derivatives Probed by Tetraaza Macrocyclic Chiral Solvating Agents via 1H NMR Spectroscopy

Synthesis of Enantiomers of Chiral Ester Derivatives Containing an Amide Group and Their Chiral Recognition by 1H NMR Spectroscopy

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Product

Resources

About

Chiral Recognition of Chiral (Hetero)Cyclic Derivatives Probed by Tetraaza Macrocyclic Chiral Solvating Agents via ¹H NMR Spectroscopy

Synthesis of Enantiomers of Chiral Ester Derivatives Containing an Amide Group and Their Chiral Recognition by ¹H NMR Spectroscopy