Synthesis of pseudopeptides with sulfoximines as chiral backbone modifying elements

The synthesis of pseudopeptides with a chiral alpha-sulfonimidoylcarboxy moiety in the backbone is described. Starting from readily available (Ss)-S-methyl S-phenyl sulfoximine and various cyclic and acyclic alpha-amino acids the desired products are obtained in good yields with peptide coupling methodology. Specific secondary structures caused by intramolecular hydrogen bonds may be adopted. Results of NMR studies to reveal conformational preferences will be discussed.