Cu-Catalyzed Site-Selective C(sp2)-H Radical Trifluoromethylation of Tryptophan-Containing Peptides.

Site-selective functionalization of C-H bonds within a peptide framework poses a challenging task of paramount synthetic relevance. Herein, we report an operationally simple C(sp2)-H trifluoromethylation of tryptophan (Trp)-containing peptides. This fluorination technique is characterized by its chirality preservation, tolerance of functional groups, and scalability and exhibits chemoselectivity for Trp residues over other amino acid and heterocyclic units. As a result, it represents a sustainable tool toward the late-stage peptide modification and protein engineering.