Assignment of absolute configuration using chiral reagents and NMR spectroscopy

Three chiral α-(nonafluoro-tert-butoxy)carboxylic acids (R)-1, (RS)-2, (R)-3 were synthesized to examine their application as chiral solvating agents with amines. As a model compound, first (S)- and/or (RS)-α-phenylethylamine was used, and their diastereomeric salts were investigated by (1)H and (19)F NMR and ECD spectroscopy. The NMR spectroscopic studies were carried out at room temperature using the slightly polar CDCl3 and apolar C6D6 as solvents in 5 mM and 54 mM concentrations. The difference of the chemical shifts (Δδ) in the diastereomeric complexes is comparable with other, well-known chiral derivatizing and solvating agents (e.g., Mosher's acid, Pirkle's alcohol). Diastereomeric salts of racemic acids (RS)-1 and (RS)-2 with biologically active amines (1R,2S)-ephedrine and (S)-dapoxetine were also investigated by (19)F NMR spectroscopy.

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“…In NMR spectroscopy, three main protocols are used: chiral derivatization agents (CDA) [9,10], chiral lanthanide shift reagents (CLSR) [9][10][11] and chiral solvating agents (CSA) [9][10][11][12]. These methods rely on formation of diastereomeric complexes (between chiral resolving agent and analyte either through covalent or non-covalent coupling), which differ in the chemical shifts of some or all of their proton resonances.…”

Section: Introductionmentioning

confidence: 99%

Dynamic Processes in Prochiral Solvating Agents (pro-CSAs) Studied by NMR Spectroscopy

et al. 2014

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Several dynamic processes, including tautomerism and macrocyclic inversion, in 1H-NMR prochiral solvating agents (pro-CSAs) are investigated. Various features of pro-CSA, including modes of interaction for complex formation, stoichiometry, binding strength and temperature effects were compared for three representative pro-CSA molecules. Structural effects of conjugated tetrapyrrole pro-CSA on the mechanism of enantiomeric excess determination are also discussed. Detailed analysis of species (complexes) and dynamic processes occurring in solution and their 1H-NMR spectral manifestations at various temperatures is presented.

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Assignment of absolute configuration using chiral reagents and NMR spectroscopy

Abstract: An overview of chiral reagents that are used to assign the absolute configuration of particular classes of compounds using NMR spectroscopy is presented. The use of chiral derivatizing agents, chiral solvating agents, metal complexes, and liquid crystals is described.

Cited by 150 publications

References 238 publications

Integrated approaches to the configurational assignment of marine natural products

Integrated approaches to the configurational assignment of marine natural products

Chiral Recognition Studies of α-(Nonafluoro-tert-butoxy)carboxylic Acids by NMR Spectroscopy

Dynamic Processes in Prochiral Solvating Agents (pro-CSAs) Studied by NMR Spectroscopy

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