A novel α,α′-diaminoacetic acid derivative for the introduction of the α-oxo aldehyde functionality into peptides

A Fmoc-protected α,α′-diaminoacetic acid derivative acting as a masked glyoxylic acid equivalent was prepared in one step from glyoxylic acid and introduced into peptide chains after solid-phase peptide elongation. Deprotection and cleavage of the peptide from the solid support using trifluoroacetic acid was followed by unmasking of the glyoxylyl group in the presence of a base. This reagent allowed the synthesis of a glyoxylyl peptide using nonoxidizing conditions.