Silver( <scp>i</scp> )-mediated oxazoline formation: a mild route to 2,4-oxazoles in peptides

We present a silver-promoted cyclization of peptide thioamides that enables site-specific insertion of oxazole and methyloxazole motifs through oxazoline intermediates. Demonstrated in di- and tetrapeptides, this mild, moisture-tolerant methodology delivers high-yield products, offering a robust and general strategy for constructing structurally diverse, conformationally constrained oxazole-containing peptidomimetics.