Singlet Oxygen-Induced Furan Oxidation for Site-Specific and Chemoselective Peptide Ligation.

A novel chemoselective ligation methodology has been developed for the facile construction of peptide-based fluorescent probes. Furan-containing peptides were activated by singlet oxygen and covalently engaged by nitrogen nucleophiles to yield stable conjugates. Singlet oxygen was compatible with sensitive amino acid residues within the peptides and a range of fluorophores, bearing different functionalities, were successfully incorporated, illustrating the broad scope of the developed strategy.