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Enantiomer‐Differentiation Induced by an Enantiomeric Excess during Chromatography with Achiral Phases
Author(s) -
Tsai WenLiang,
Hermann Kurt,
Hug Erhard,
Rohde Bernhard,
Dreiding André S.
Publication year - 1985
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19850680818
Subject(s) - chemistry , enantiomer , enantiomeric excess , reagent , chromatography , column chromatography , organic chemistry , stereochemistry , enantioselective synthesis , catalysis
It is shown, in the case of the diketone 2 , that chromatography with achiral phases of a non‐racemic mixture of enantiomers can furnish fractions which differ in enantiomeric excess. Such chromatography may, therefore, be used to further enrich a sample in one enantiomer. By the same token, chromatography is not a generally safe method for the purification of the product of an enantio‐differentiating process, if the enantiomeric excess of a purified portion of that product is taken to be a measure of the efficiency of the process. The described effect represents an enantiomer differentiation induced solely by an alredy existing enantiomeric excess during chromatography. It thus belongs to a class of effects where the relative amounts of two enantiomers induce an observable difference between them. Such effects are called EE effects. The common principle underlying EE effects is explained by a simple symmetry argument. Since EE effects can also occur during reactions with achiral reagents, further transformations of an enantiomer‐enriched product may furnish false information on its enantiomeric excess.