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Determination of the enantiomeric composition of chiral delta‐2‐oxazolines‐1,3 by 1 H and 19 F NMR spectroscopy using chiral solvating agents
Author(s) -
Beaufour M.,
Merelli B.,
Menguy L.,
Cherton J.C.
Publication year - 2003
Publication title -
chirality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.43
H-Index - 77
eISSN - 1520-636X
pISSN - 0899-0042
DOI - 10.1002/chir.10225
Subject(s) - chemistry , diastereomer , enantiomer , oxazoline , solvation , stereochemistry , proton nmr , nuclear magnetic resonance spectroscopy , carbon 13 nmr , substrate (aquarium) , fluorine 19 nmr , computational chemistry , organic chemistry , solvent , catalysis , oceanography , geology
Studies of the perturbing effect of chiral solvating agents (CSAs) 5a and mostly of 5c upon the NMR spectra of chiral Δ 2 ‐oxazoline 1 demonstrated the ability of these fluoroalcohols to afford diastereomeric solvates from these solutes. Thus, for all tested Δ 2 ‐oxazolines 1Aa–d, 1Ba, and 1e there is at least one possibility to proceed to their enantiomeric discrimination either by 1 H or 19 F NMR using these CSAs (see Fig. 1). NMR results are discussed from substrate and CSA structure standpoints and a solvation model is proposed on the basis of the inequivalence senses generally observed. Then the method was applied to extracts of incubated locust tissues obtained by solid phase extraction (SPE) after a partial unmasking of the substrate 1. Chirality 15:382–390, 2003. © 2003 Wiley‐Liss, Inc.