One-pot peptide ligation-desulfurization at glutamate.

An efficient methodology for ligation at glutamate (Glu) is described. A γ-thiol-Glu building block was accessed in only three steps from protected glutamic acid and could be incorporated at the N-terminus of peptides. The application of these peptides in one-pot ligation-desulfurization chemistry is demonstrated with a range of peptide thioesters, and the utility of this methodology is highlighted through the synthesis of the osteoporosis peptide drug teriparatide (Forteo).