Synthesis of peptide di-aldehyde precursor for stepwise chemoselective ligations via oxime bonds

To synthezise a triple-function branched peptide in a modular way, we present a new strategy based on orthogonal generation of two aldehyde functions from an acetal and a 2-amino alcohol. Successive unmaskings of aldehyde functions of the stem peptide affords stepwise chemoselective ligations of two (aminooxy)acetyl peptides via oxime bonds.