Epimerisation-free peptide formation from carboxylic acid anhydrides and azido derivatives

Abstract

Conversion of C-terminal carboxy groups of N-protected α-amino acids to the corresponding 3,5-dinitrobenzoyl mixed anhydrides, followed by treatment with α-azido esters and trialkylphosphines, affords good yields of peptides, without appreciable formation of epimers even for reactions involving Phe–Val and Val–Val couplings and/or N-benzoyl α-amino acids.