Extreme Liquid Chromatographic Separation Effects in the Case of Diastereomeric Amides Containing Polar Substituents

Abstract

Routine separations of enantiomers may soon be common laboratory practice. On the basis of chromatographic data, four postulates were derived which serve as guidelines in the search for the structural feature of the amides (1)/(2) necessary for high separation factors α. The highest value of α = 5.77 has been found for (1)/(2), R1(CH2)2OH, A1CH2OH, R2=A2Ph; this is for separation on silica gel! Separations with α≳2 are possible on simple columns.