Stereoselective Synthesis of α-Aminophosphonic Acids Using the Betti Base as Chiral Auxiliary

Abstract

A new diastereoselective synthesis of α-aminophosphonates has been developed, based on the reaction of trialkyl phosphites with a chiral imines, derived from (R)- or (S)-1-(α-aminobenzyl)-2-naphthol, in the presence of trifluoroacetic acid. The major diastereomer of obtained aminophosphonates can be separated by crystallization from an appropriate solvent. The desired α-aminophosphonic acids can be obtained in enantiopure form by treating the corresponding diastereomers with HCl.