C-H Olefination of Tryptophan Residues in Peptides: Control of Residue Selectivity and Peptide-Amino Acid Cross-linking.

There is high demand for new methods to modify peptides, for application in drug discovery and biomedicine. A C-H functionalization protocol for the olefination of tryptophan residues in peptides is described. The modification is successful for Trp residues at any position in the peptide, has broad scope in the styrene coupling partner, and offers opportunities for conjugating peptides with other biomolecules. For peptides containing both Trp and Phe, directing group manipulation enables full control of residue selectivity.