Synthesis and Solution Conformation of Homo-β-peptides Consisting of N-Mannofuranosyl-3-ulosonic acids

The synthesis and solution conformation of homo-oligomers of β-aminoacids, β-N-mannofuranosyl-3-ulosonic acids, have been studied by NMR, MD simulation, and circular dichroism. These oligomers feature a spirocyclic disubstitution and a N,O-acetal functionality at the β-carbon of the backbone, an unprecedented situation in the realm of β-peptides. Our study shows that tetramer 10 and hexamer 11 adopt a characteristic secondary structure. In the hexamer 11, NMR investigations coupled with MD simulations suggest the preference for a double C8 turn forming conformation.