Chiral Separation of Organic Phosphonate Compounds on Polysaccharide-Based Chiral Stationary Phases

Four polysaccharide-based chiral stationary phases have been used to separate the enantiomers of fourteen O,O-dialkyl-1-benzyloxycarbonyl-aminoarylmethyl phosphonates. These polysaccharide-based chiral stationary phases are Chiralpak AD, Chiralpak AS, Chiralcel OG and Chiralcel OJ. The data obtained indicate that the chiral separation ability for these organophosphonate compounds are in the order Chiralpak AD > Chiralcel OG > Chiralcel OJ > Chiralpak AS. With Chiralpak AD, all of the studied compounds could be easily baseline separated. Those two polysaccharides possess different chiral discrimination mechanism due to of the difference of the conformational structures of amylose and cellulose. The chiral discrimination of derivatized amylose chiral stationary phases were based on the stereogenic fit of the analytes in the helical structures of amylose and the transient diastereomeric complex formation between the analyte and the amylose CSP through π–π interaction H-bond interactions and induced dipole interactions exerted by the substituents on the analyte molecules. The chiral discrimination, in case of derivatized cellulose chiral stationary phase is based on the stereogenic fit of the analytes in the grooves of cellulose followed by interactions mentioned above between the analytes and the cellulose CSP.