A convenient synthesis of azido peptides by post-assembly diazo transfer on the solid phase applicable to large peptides

An efficient method for the conversion of solid phase bound peptide amines into azides by a diazo transfer using triflyl azide in the presence of divalent copper ions is described. α-Azido acids and azido peptides—up to 30 amino acids in length—are obtained in good yields and high purities after cleavage from the solid support.