Silaproline Helical Mimetics Selectively Form an All-trans PPII Helix

The polyproline II helix (PPII) is increasingly recognized as an important element in peptide and protein structures. The discovery of pertinent PPII peptidomimetics is of great interest to tune physical properties of the targeted structure. A series of silaproline oligomers from dimer to pentamer were synthesized. CD studies, NMR spectroscopy and molecular modeling revealed that the ribbon preferentially populates the polyproline type II secondary structure in both [D]chloroform and [D4]MeOH. The characteristics of this new lipophilic PPII‐like helix were determined. Helical track: The discovery of pertinent polyproline II (PPII) helix peptidomimetics is of great interest to tune physical properties of the targeted structure. A series of silaproline oligomers from dimer to pentamer (see figure) were synthesized and studied by CD and NMR spectroscopy and molecular modeling. The characteristics of this new lipophilic PPII‐like helix were determined.