論文

査読有り
2021年9月

Estimation of Enantiomeric Excess Based on Rapid Host–Guest Exchange

Chemosensors
  • Jan Labuta
  • ,
  • Shinsuke Ishihara
  • ,
  • Daniel T. Payne
  • ,
  • Kazuyoshi Takimoto
  • ,
  • Hisako Sato
  • ,
  • Lenka Hanyková
  • ,
  • Katsuhiko Ariga
  • ,
  • Jonathan P. Hill

9
9
開始ページ
259
終了ページ
259
記述言語
掲載種別
研究論文(学術雑誌)
DOI
10.3390/chemosensors9090259
出版者・発行元
MDPI AG

Chiral molecules possess enantiomers that have non-superimposable chemical structures but exhibit identical nuclear magnetic resonance (NMR) spectra. This feature prevents the use of NMR spectroscopic methods for the determination of enantiomeric excesses (ee) of chiral molecules, using simple mixtures of their enantiomers. Recently, however, it was reported that the addition of a symmetrical prochiral molecule (a reporter or host) into a solution of chiral analyte can lead to estimation of ee through interactions involving rapid exchange of the chiral analyte (guest) in the formed host–guest complex. This is due to the ee-dependent splitting of NMR resonances of the prochiral host molecule based on averaging the chemical shift non-equivalency caused by the presence of a chiral guest. The mechanism is not dependent on diastereomer formation, and 1:1 host–guest complexes can also show ee-dependent NMR peak splitting. Prochiral molecules capable of ee sensing using the NMR technique are now referred to as so-called prochiral solvating agents (pro-CSAs). pro-CSAs represent a family of reagents distinct from the commonly used NMR chiral derivatizing reagents (where chiral auxiliaries are used to derivatize enantiomers to diastereomers) or chiral solvating agents (where chiral auxiliaries interact in an asymmetric manner with analyte enantiomers). pro-CSA methods are unique since neither pro-CSA nor NMR contains chiral factors, making the technique neutral with respect to chirality. Here, we review our recent work on this matter involving several different nominally achiral receptor molecules whose unique guest binding properties and solution characteristics (especially with regard to NMR spectroscopy) allow for the estimation of ee in the corresponding chiral guests.

リンク情報
DOI
https://doi.org/10.3390/chemosensors9090259
URL
https://www.mdpi.com/2227-9040/9/9/259/pdf
ID情報
  • DOI : 10.3390/chemosensors9090259
  • eISSN : 2227-9040

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