ASYMMETRIC-SYNTHESIS OF DIETHYL ALPHA-AMINO-ALPHA-ALKYL-PHOSPHONATES BY ALKYLATION OF THE CHIRAL SCHIFF-BASE DERIVED FROM (+)-KETOPINIC ACID AND DIETHYLAMINOMETHYL PHOSPHONATE

The alkylation of the chiral Schiff base derived from the condensation of (+)-ketopinic acid and diethyl aminomethylphosphonate followed by hydrolysis affords diethyl (S)-alpha-amino-alpha-alkyl phosphonates with high enantiomeric excesses when benzyl or allyl halides are used in the alkylation step. An improved procedure for the preparation of diethyl aminomethylphosphonate is also reported