The selective tagging of amino acids within a peptide framework while using atom-economical C-H counterparts poses an unmet challenge within peptide chemistry. Herein, we report a novel Pd-catalyzed late-stage C-H acylation of a collection of Tyr-containing peptides with alcohols. This water-compatible labeling technique is distinguished by its reliable scalability and features the use of ethanol as a renewable feedstock for the assembly of a variety of peptidomimetics.The authors are grateful to the Ministerio de Ciencia e Innovacion (RTI2018-093721-B-I00, MCI/AEI/FEDER, UE) and the Basque Government (IT1033-16) for financial support. The authors thank the technical and human support provided by the Central Service of Analysis-SGIker of UPV/EHU and European funding (ERDF and ESF). In~aki Urruzuno thanks UPV/EHU for the postdoctoral research grant (EspDoc2020
