Late‐Stage Peptide Diversification by Bioorthogonal Catalytic CH Arylation at 23 °C in H₂O

The step-economical late-stage diversification of tryptophan-containing peptides was accomplished through chemo- and site-selective palladium-catalyzed C-H arylation under exceedingly mild reaction conditions. Thus, the C-H functionalization occurred efficiently at 23 °C with a catalyst loading as low as 0.5 mol %, and/or in H2 O.