Copper-Catalyzed Selective N-Sulfenylation of Tryptophan-Containing Peptides

Site-selective modification of peptides is essential for biomedical research; herein, we develop a versatile strategy for the late-stage functionalization of peptides through copper-catalyzed N-sulfenylation of tryptophan residues. This method is quite compatible with a broad range of functional groups and enables the site-selective formation of a N-S bond at the nitrogen atom of tryptophan without the need for directing groups.