Behaviour of allyl aryl sulfoxides in high-performance liquid chromatography on a chiral stationary phase

Several racemic allyl aryl sulfoxides were resolved by HPLC on a brush-type chiral stationary phase based on the 3,5-dinitrobenzoyl derivative of (R,R)-1,2-diaminocyclohexane. Peak deformations due to exchange phenomena (on-column enantiomerization) were observed at high column temperatures and low eluent flow-rates; under these conditions the extent of interconversion during chromatography was dependent on the kind of substitution of the aromatic ring of the analytes. Kinetic data for the racemization process in solution were also obtained after preparative HPLC separation of the individual enantiomers