Chiral additive induced self-disproportionation of enantiomers under MPLC conditions: Preparation of enantiomerically pure samples of 1-(aryl)ethylamines from racemates

Mixtures of enantiomerically pure (S)-N-formyl-1-phenylethyamine and various racemic N-formyl-1-arylethylamine derivatives, when submitted to achiral medium pressure liquid chromatography, afforded elution profiles in which the enantiomers of N-formyl-1-arylethylamines standout as separate peaks and can be isolated. In all of the investigated N-formyl-1-arylethylamine substrates, the virtually enantiomerically pure (S)-enantiomer eluted as a less polar fraction and subsequently, the (R)-enriched enantiomer mixtures were eluted in the more polar fractions.