Expedient synthesis of pseudo-Pro-containing peptides: Towards constrained peptidomimetics and foldamers

The reaction of sulfonyl peptides containing l- or d-configured Ser or Thr with bis(succinimidyl) carbonate in the presence of a catalytic amount of a base affords, in solution or in the solid phase, the corresponding peptides with one or two, consecutive or alternate oxazolidin-2-ones (Oxd). The Oxd ring can be regarded to as a pseudo-Pro with an exclusively trans conformation of the preceding peptide bond; homochiral Oxd-containing peptides adopt extended conformations, while the presence of a d-configured Oxd favours folded conformations. © The Royal Society of Chemistry 2012.