Weak backbone CH⋯OC and side chain tBu⋯tBu London interactions help promote helix folding of achiral NtBu peptoids

The synthesis of all-cis amide (NtBu)-glycine oligomers up to 15 residues long by a blockwise coupling approach is reported. The structure and dynamical behavior of these peptoids have been studied by X-ray crystallography, NMR and molecular modeling. Analyses reveal that the folding of these oligomers is driven by weak CH⋯OC hydrogen bonding along the peptoid backbone and London interaction between tBu⋯tBu side-chains.