Direct separation of carboxylic acid and amine enantiomers by high-performance liquid chromatography on reversed-phase silica gels coated with chiral copper(II) complexes

Excellent direct separation of various carboxylic acid and amine enentiomers was accomplished by HPLC on reversed-phase silica gels coated with copper(II) complexes of N,S-dioctyl- d -penicillamine and ( R , R )-tartaric acid mono-( R )-1-( α -naphthyl)ethylamide. The chiral recognition mechanism is discussed. These copper(II) complexes are promising as chiral stationary phases for the separation of a variety of racemic carboxylic acids and amines in which copper(II) complex formation can be assumed.