Study of Enantioseparation of Selected Substituted Binaphthyls

8 1 INTRODUCTION Over the last two decades, high-performance liquid chromatography (HPLC) has become one of the most common techniques in chiral separations. HPLC has also been successfully employed for determination of the optical purity of newly synthesized organic compounds. Asymmetric synthesis is a direct way of synthesis of enantiomers that uses suitable optically pure ligands acting as catalysts. The chiral ligands in asymmetric reactions must have stable configurations (they must be resistant towards racemization) and a high optical purity is required. Binaphthyl derivatives have been extensively used to control many asymmetric processes and have demonstrated outstanding chiral discrimination properties, due to their unique properties derived from their rigidity and spatial arrangement. Most of 1,1'- binaphthyl molecules are C2 symmetric with two identical naphthyl units often substituted in the 2,2'-positions. Chirality of these compounds is caused by restricted rotation of atoms or groups of atoms around the single bond on the binaphthyl skeleton (axial chirality, atropisomerism). Increased hindrance to rotation at the pivotal 1,1'- bond makes these molecules potential candidates for enantioseparation [1]. The best representatives of the binaphthyl group are 2,2'-dihydroxy-1,1'-binaphthyl..