Chemoselective Peptide Ligation–Desulfurization at Aspartate

Asp-ecially useful: A synthetic β-mercapto aspartate residue facilitates the rapid ligation to a range of peptide thioesters. Following the ligation reaction (and without purification), chemoselective desulfurization of the β-mercapto moiety in the presence of unprotected cysteine residues afforded native peptide products.