Synthesis of N‑Glyoxylyl Peptides Enabled by a Lossen Rearrangement-Induced Intramolecular Redox Reaction of N‑Terminal Glycyl Hydroxamic Acid

An oxidant-free approach to the synthesis of N-glyoxylyl peptides has been developed that utilizes the Lossen rearrangement of the N-terminal glycyl hydroxamic acid residue. The synthesis proceeds via an intramolecular redox mechanism to yield the glyoxylyl peptides, which are then subjected to various peptide cyclization procedures. The reaction scheme is suitable for oxidation-sensitive moieties including amino acids.