The stereoselective synthesis of aminooxy-containing proline analogues bearing Fmoc/Boc or Fmoc/Mtt protection that renders them suitable for incorporation into peptides using Fmoc protocols is reported. Acid-catalyzed unmasking at the completion of peptide synthesis yields free aminooxy-functionalities for oxime formation through reaction with libraries of aldehydes. This allows post solid-phase diversification strategies that may facilitate structure-activity relationship studies.
