Direct Chromatographic Separation of Racemates on the Basis of Isotopic Chirality

Abstract

Direct separation was achieved between two isomers which are enantiomeric to each other by virtue of the presence of hydrogen/deuterium isotopes. A racemic mixture of the R- and S-isomers of phenyl(phenyl-d(5))methanol was separated by high-performance liquid chromatography using cellulose tribenzoate-coated silica as a stationary phase and a 2-propanol/hexane (5/95) mixture as a mobile phase, and the absolute configuration of each separated isomer was identified. The cellulose derivative showed preferential retention of (R)-(-)-phenyl(phenyl-d(5))methanol compared to the (S)-(+)-isomer, with a separation factor of 1.0080 based on the preferential binding of a C(6)D(5) group over a C(6)H(5) group to the primary binding site.