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

Cyclodextrins were used as chiral selectors for the P-31 NMR determination of the enantiomeric excess of aminoalkanephosphonic and aminoalkanephosphinic acids. Most of these acids form inclusion complexes with alpha- and/or beta-cyclodextrin and upon increasing the cyclodextrin to aminophosphonic acid molar ratio IT NMR signals for (R)- and (S)-enantiomers separate. ROESY spectra allowed the determination of structures of the inclusion complexes. (C) 2003 Elsevier Science Ltd. All rights reserved.