γ- and β‑Peptide Foldamers from Common Multifaceted Building Blocks: Synthesis and Structural Characterization

Structural characterization of 3,4-disubstituted γ-peptide and 2,3-disubstituted β-peptide foldamers derived from common multifaceted β-nitromethyl γ-amino acids and the chemical transformation of the β-nitromethyl group in γ-peptides into various functional derivatives are reported. The γ3,4-oligomers and α,γ-hybrid peptides showed characteristic C14-and C12-helical conformations in single crystals. Further, the new 2,3-disubstituted acyclic β-peptide showed the C6-helical conformation despite the poor geometry of H-bonds.