Peptide‐Embedded Heterocycles by Mild Single and Multiple Aza‐Wittig Ring Closures

Abstract

Ring a ring o'azoles: The aza-Wittig cyclization of amino acids and peptides is extremely mild, selective, and versatile. The reaction of amino acid esters and amino acid thioester azides delivers peptidic 1,3-azolines and 1,3-azoles with unsurpassed functional-group tolerance. This method allows multiple ring closures and tolerates aqueous solvents.