Enantiodifferentiation of aminophosphonic and aminophosphinic acids with α- and β-cyclodextrins

Abstract

Cyclodextrins were used as chiral selectors for the 31P NMR determination of the enantiomeric excess of aminoalkanephosphonic and aminoalkanephosphinic acids. Most of these acids form inclusion complexes with α- and/or β-cyclodextrin and upon increasing the cyclodextrin to aminophosphonic acid molar ratio 31P NMR signals for ( R)- and ( S)-enantiomers separate. ROESY spectra allowed the determination of structures of the inclusion complexes.