C-Backbone branched peptides via reductive amination of cyanomethyleneamino pseudopeptides

The synthesis of branched peptides from cyanomethylenamino pseudopeptides, via catalytic hydrogenation in the presence of amino acid derivatives, is described. When the inserted amino acid was a glycine derivative, the resulting branched peptide lactamized in situ to 2-oxopiperazine derivatives. This new C-backbone peptide branching approach is compatible with the diversity of amino acid side chains.