Chemical Conversion of Cyclic α-Amino Acids to Cyclic α-Aminophosphonic Acids

Abstract

The oxidative decarboxylation of cyclic α-amino acids having urethane-type N-protecting groups with lead tetraacetate [Pb(OAc)₄] gave 2-hydroxy derivatives, which were transformed into the corresponding α-aminophosphonic acid esters by treatment of trialkyl phosphites in the presence of Lewis acids. Deprotection and ester cleavage of the products in the usual manner afforded cyclic α-aminophosphonic acids. The convenient chemical conversion of five- and six-membered cyclic α-amino acids to the corresponding cyclic α-aminophosphonic acids has been accomplished.