Figure 3
From: Photoredox C–H functionalization leads the site-selective phenylalanine bioconjugation

The scope of visible-light-induced strategy applied to polypeptides. (A) General reaction scheme. (B) MS/MS analysis of the fragmentation of RGDF(Pyr)S. (C) Substrate scope of polypeptides. All peptides are commercially available. * indicates site of pyrazole-tagged functionalization. (D) Two-step process for functionalizing the phenylalanine-contained tripeptide (Ac-FVN-OMe). The visible-light-induced bioconjugation of Ac-FVN-OMe with 4-ethynyl-1H-pyrazole and the further synthesis of the biotin tagged tripeptide Ac-F(Pyr-Biotin)VN-OMe by CuAAC reaction.