Pd-Catalyzed picolinamide directed late-stage chalcogenation of tryp-tophan containing peptides

This report describes the Pd-catalyzed late-stage chalcogenation of tryptophan containing peptides with disulfides/diselenides in moderate to good yields. It comprises broad substrate scope, functional group diversity, late-stage mutation of drug mole-cules and various valuable synthetic transformations including room temperature easy removal of picolinamide auxiliary, which could be applicable to tune the structure and function of peptides.