SEPARATION OF THE ENANTIOMERS OF ALPHA-HYDROXYBENZYLPHOSPHONATE ESTERS BY ENANTIOSELECTIVE HPLC AND DETERMINATION OF THEIR ABSOLUTE-CONFIGURATION BY CIRCULAR-DICHROISM

The enantiomers of 17 alpha-hydroxybenzylphosphonate diethylesters con taining para, or ortho substituents or other aromatic rings (1-naphthy l, 2-naphthyl, and 2-thienyl) have been successfully separated by HPLC on a Whelk-O 1 chiral stationary phase which is superior to other CSP s. The effect of the substituents, particularly halogens, on the enant ioselectivity was investigated and related to a chiral recognition mod el. The absolute configurations of 4-methyl and 2-methyl substituted a lpha-hydroxybenzylphosphonates were obtained by measurement of the cir cular dichroism spectra of the isolated enantiomers. (C) 1998 Wiley-Li ss, Inc.