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Analysis of the 13 C NMR Spectra of Molecules, Chiral by Isotopic Substitution, Dissolved in a Chiral Oriented Environment: Towards the Absolute Assignment of the pro‐ R /pro‐ S Character of Enantiotopic Ligands in Prochiral Molecules
Author(s) -
Lesot Philippe,
Lafon Olivier,
Courtieu Jacques,
Berdagué Philippe
Publication year - 2004
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200400065
Subject(s) - enantiomer , deuterium , molecule , absolute configuration , chemistry , kinetic isotope effect , asymmetric carbon , liquid crystal , carbon 13 , anisotropy , solvent , nmr spectra database , crystallography , spectral line , stereochemistry , organic chemistry , materials science , physics , alkyl , optoelectronics , quantum mechanics , astronomy
We examined and discuss the proton‐ and deuterium‐decoupled carbon‐13 1D spectrum of a molecule, chiral by virtue of the isotopic substitution, dissolved in a chiral oriented medium which simultaneously exhibits chiral discrimination, enantiomeric enrichment and isotope effect. Using the 1‐deutero‐(2′,3′,4′,5′,6′‐pentadeuterophenyl)phenylmethanol orientationally ordered in a chiral nematic liquid crystal as illustrative example, we point out three important features. First, we demonstrate that the absolute assignment of the pro‐ R /pro‐ S character may be derived from the absolute configuration of the isotopically chiral analogue. Second, we report evidence that isotopic effect on 13 C chemical shift anisotropy is negligible in a weakly orienting solvent. Third, we definitely establish that the molecular orientation of prochiral C s symmetry molecules and their parent compounds that are chiral by virtue of the isotopic substitution is the same.