New Method for the Synthesis of α-Amino Substituted Benzyl Phosphonic Acids and their Derivatives

Abstract

A new method for the synthesis of α-amino-substituted benzyl-phosphonic or phosphinic acid (5) was descrided. By reaction of phosphoramides (1) with substituted benzaldehydes (2) and phosphite (3) in the presence of BF₃, α-(N-phosphorylamino)-substituted benzylphosphonates or phosphinates (4) was obtained in moderate to good yield. This method distinguished itself by the simple manipulation and higher purity of the product resulted in both steps of the reaction sequences. Meanwhile, aminophosphonic esters are useful intermediated in the phosphorus peptide synthesis. The influence of variation in structure of 1, 2 and 3 on the yield of 5 was evaluated on the basis of sturcture-reactivity studies.