Synthesis of β-amino acids using Boc-/Z-amino acid pentafluorophenyl esters

The pentafluorophenyl esters of Boc-/Z-amino acids are used for the preparation of the key intermediates α-aminoacyldiazomethanes during the homologation of α-amino acid to α-amino acid. Thus, all the Boc-/Z-amino acid diazoketones and the corresponding β-amino acids were obtained as crystalline solids in satisfactory yields. © 1999 Kluwer Academic Publishers