31P NMR Based Method for Determining Enantiopurity of Chiral Phosphoric Acids and Its Application to the BINOL- and H8-BINOL-Based Chiral Phosphoric Acid Thermal Racemization Studies

Tay, Jia Hui; Nagorny, Pavel

doi:10.1055/s-0035-1560547

Cited by 5 publications

(3 citation statements)

References 6 publications

(8 reference statements)

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“…Based on the difficulties in performing the chiral discrimination of BINOL phosphoric acids 21 and derivatives, Nagorny and Tay have developed a simple and reliable protocol for determining the enantiopurity by 31 P-NMR spectroscopy [ 62 ]. The optical rotation measurements were not reliable for these compounds.…”

Section: 31 P-nmr Chiral Recognitionmentioning

confidence: 99%

Recent Advances in Multinuclear NMR Spectroscopy for Chiral Recognition of Organic Compounds

Silva

2017

Molecules

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Nuclear magnetic resonance (NMR) is a powerful tool for the elucidation of chemical structure and chiral recognition. In the last decade, the number of probes, media, and experiments to analyze chiral environments has rapidly increased. The evaluation of chiral molecules and systems has become a routine task in almost all NMR laboratories, allowing for the determination of molecular connectivities and the construction of spatial relationships. Among the features that improve the chiral recognition abilities by NMR is the application of different nuclei. The simplicity of the multinuclear NMR spectra relative to 1H, the minimal influence of the experimental conditions, and the larger shift dispersion make these nuclei especially suitable for NMR analysis. Herein, the recent advances in multinuclear (19F, 31P, 13C, and 77Se) NMR spectroscopy for chiral recognition of organic compounds are presented. The review describes new chiral derivatizing agents and chiral solvating agents used for stereodiscrimination and the assignment of the absolute configuration of small organic compounds.

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Section: 31 P-nmr Chiral Recognitionmentioning

confidence: 99%

Recent Advances in Multinuclear NMR Spectroscopy for Chiral Recognition of Organic Compounds

Silva

2017

Molecules

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“…For example, isotropic 31 P NMR chemical shifts, δP, could be used to estimate the π-accepting properties of carbenes in a series of carbine–phosphinidene adducts . The 31 P NMR spectroscopy also could be used to distinguish between nonequivalent isomers of organometallic complexes , and between enantiomers of chiral molecules. , Moreover, the sensitivity of δP to the noncovalent interactions was used to construct various scales of Brønsted and Lewis acidities . Most often, trialkylphosphines (R 3 P) and trialkylphosphine oxides (R 3 PO) are used as phosphorous probes.…”

Section: Introductionmentioning

confidence: 99%

Conformational Mobility and Proton Transfer in Hydrogen-Bonded Dimers and Trimers of Phosphinic and Phosphoric Acids

et al. 2019

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The monomers, H-bonded cyclic dimers, and trimers of five acids were studied by density functional theory calculations, such as hypophosphorous acid (H2POOH, 1), dimethylphosphinic acid (Me2POOH, 2), phenylphosphinic acid (PhHPOOH, 3), dimethylphosphoric acid ((MeO)2POOH, 4), and diphenylphosphoric acid ((PhO)2POOH, 5). Particular attention was paid to the conformational manifold existing due to the internal degrees of freedom: proton transfer (PT), puckering (“twist”) within the ring of H-bonds, and mobility of the substituents (namely, −Ph, −OMe, and −OPh rotations). For acid 3, the number of conformers is additionally increased because of the varying relative orientation of nonequivalent substituents in cyclic complexes. We show that 31P NMR chemical shifts (δP) are very sensitive to the details of the conformation, spanning ranges from ca. 1 ppm (for trimers of acids 1 and 2) to ca. 12 ppm (for trimers of 4). The energy barriers for the transitions between conformers are rather low (<6 kcal/mol for PTs, <2.5 kcal/mol for puckerings, and ca. <3 kcal/mol for rotations of substituents), such that the fast exchange regime in the NMR timescale and subsequent δP averaging are expected. Correlations are proposed linking the change of average δP with the H-bond energy, showing the slope of ca. 4 ppm per kcal/mol. The sensitivity of δP to the OPO angle and the OPOH dihedral angle and the geometries of both H-bonds formed by the POOH moiety are analyzed.

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“…Various chiral solvating agents, such as amides, amines, amino acids, hydroxamic acids, and macrocyclic compounds, have been utilized in 31 P NMR-based chiral analysis (Figure b). However, the application of this method for chiral analysis of phosphoric acids has been limited, with previous methods often showing poor peak resolution and being able to recognize only a single type of phosphoric acid. − To address this challenge, a new method was devised that leverages cationic octahedral Co(III) complexes for the chiral recognition of phosphoric acids (Figure c). This approach was demonstrated to be highly effective in resolving a variety of chiral phosphoric acids and even achieved an optical resolution of a phosphoric acid.…”

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confidence: 99%

Chiral Recognition and Resolution of Phosphoric Acids Using Octahedral Cobalt Complexes

et al. 2023

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Determining the chirality of phosphoric acids can be a challenging task. In this study, we present a novel approach for the chiral recognition of phosphates using cationic octahedral cobalt complexes. By utilizing 31P NMR spectroscopy, we are able to accurately measure the enantiopurities of chiral phosphoric acids after forming ion pairs with the cobalt complexes. We have successfully applied this method to a variety of chiral phosphoric acids derived from BINOL, H8-BINOL, SPINOL, VAPOL, and VANOL compounds, as well as ATP, and were able to efficiently resolve them in 31P{1H} NMR spectra. Furthermore, we were able to achieve an optical resolution of a phosphoric acid with an enantiomeric excess of greater than 99%.

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31P NMR Based Method for Determining Enantiopurity of Chiral Phosphoric Acids and Its Application to the BINOL- and H8-BINOL-Based Chiral Phosphoric Acid Thermal Racemization Studies

Cited by 5 publications

References 6 publications

Recent Advances in Multinuclear NMR Spectroscopy for Chiral Recognition of Organic Compounds

Recent Advances in Multinuclear NMR Spectroscopy for Chiral Recognition of Organic Compounds

Conformational Mobility and Proton Transfer in Hydrogen-Bonded Dimers and Trimers of Phosphinic and Phosphoric Acids

Chiral Recognition and Resolution of Phosphoric Acids Using Octahedral Cobalt Complexes

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