Disclosed herein are accelerants for the formation of oxime-containing compounds from the reaction of a carbonyl-containing compound and a hydroxylamine-containing compound. The oxime-containing compound, the carbonyl-containing compound and the hydroxylamine-containing compound can each be a non-natural amino acid or a non-natural amino acid polypeptide. Also disclosed is the use of such accelerants to form oxime-containing compounds, the resulting oxime-containing compounds, and reaction mixtures containing such accelerants.