Evaluation of a chiral stationary phase derived from a simple Diels-Alder reaction

The bicyclic, C(2)-symmetric dicarboxylic acid obtained from the cycloaddition of fumaric acid to anthracene can readily be prepared in enantiomerically pure form on a large scale. Conversion of either enantiomer of the diacid into its corresponding bis-allylamide yields a selector unit, used as a building block in the synthesis of a chiral stationary phase (CSP). The terminal C-C double bonds in the selector unit were used in a hydrosilylation reaction involving a multifunctional hydrosilane to effect polymerization, crosslinking, and immobilization to the vinyl-silica used as support. A study of the enantiomer-discriminating abilities of the new CSP was made. Large separation factors were obtained for a series of benzodiazepinones, which were studied in further detail by the use of different retention modifiers. To some extent, rationalization of retention data has been achieved in terms of competition for hydrogen bonding.