Optical Resolution of Some Mandelic Derivatives on a Chemically Bonded Cyclodextrin Stationary Phase

Preparation and use of a new type of cyclodextrin-bonded stationary phase are described. Resolution of racemic mandelates and their analogues has been achieved by using this phase. The chiral recognition has been explained in terms of a three-point attachment model. In addition to the inclusion of the aromatic ring of the sample into the cavity of cyclodextrin, enantioselective interaction occurs at two other points; hydrogen bonding of the two polar substituents on the asymmetric carbon atom with secondary hydroxyl groups on the rim of the wider opening face of the cyclodextrin molecule. The effect of the type and position of substituents and other factors responsible for the resolution is discussed.