Epimerization Free Synthesis of O-Acyl Isodipeptides Employing COMU

O-Acyl isodipeptides are prepared by coupling Boc-Ser/Thr-OBzl with Fmoc-Xaa-OH employing COMU, well known third generation peptide coupling agent. The reaction proceeds with high yield and the chemical homogeneity of the synthesized molecules were established via chiral HPLC analyses. The O-acyl isodipeptide units play crucial role in the success of ‘click peptide’ protocol employed for assembling ‘difficult sequence’ peptides. Keywords: O-acyl isodipeptide, click peptide, difficult sequence, COMU, esterification