Enzymes in organic chemistry. Part 10: Chemo-enzymatic synthesis of L-phosphaserine and L-phosphaisoserine and enantioseparation of amino-hydroxyethylphosphonic acids by non-aqueous capillary electrophoresis with quinine carbamate as chiral ion pair agent

Diisopropyl 2-azido-1-acetoxyethylphosphonate (+/-)-7 was hydrolysed with h igh enantioselectivity by lipase SP 524 to give alpha-hydroxyphosphonate (S )-(-)-6 and ester (R)-(-)-7, which was saponified to give (R)-(+)-6. The tw o alpha-hydroxyphosphonates (R)- and (S)-6 were transformed into 1-phosphai soserine and L-phosphaserine, respectively. Their enantiomeric excesses wer e determined to be 97% by HPLC on an chiral stationary phase. A mixture of all four stereoisomeric amino-hydroxyethylphosphonic acids can be separated by non-aqueous capillary electrophoresis with quinine carbamate as the chi ral ion pair agent applying the partial filling technique. (C) 2000 Elsevie r Science Ltd. All rights reserved.