Chemical cyclization of tyrosine-containing peptides via in situ generated triazolinedione peptides.

Tyr-derived cyclic peptide natural products are formed by enzymatic manifolds that oxidatively cross-link embedded phenolic side chains of tyrosine (Tyr) and 4-hydroxyphenylglycine residues during their controlled production. Bioactive Tyr-derived cyclic peptides, such as the arylomycins and vancomycins, continue to motivate the development of enzymatic and chemical strategies for their de novo assembly and modification. However, chemical access to these structurally diverse natural cycles can be challenging and step intensive.