Internal Peptide Late‐Stage Diversification: Peptide‐Isosteric Triazoles for Primary and Secondary C(sp³)−H Activation

Secondary C(sp 3 )−H arylations were accomplished by palladium catalysis with triazoles as peptide bond isosteres. The unique power of this approach is highlighted by the possibility of achieving secondary C(sp 3 )−H functionalizations on terminal peptides as well as the unprecedented positional‐selective C(sp 3 )−H functionalization of internal peptide positions, setting the stage for modular peptide late‐stage diversification.