An approach for simultaneous synthesis of cis-and trans-3-substituted proline-glutamic acid chimeras

Synthesis of cis- and trans-3-substituted proline-glutamic acid chimeras with suitable protection for peptide synthesis through Fmoc-strategy was accomplished in six steps from benzyl (2S)-4-oxo-1-(9-phenyl-9H-fluoren-9-yl)pyrrolidine-2-carboxylate, which had been synthesized from trans-4-hydroxyproline in three steps. This methodology involved generation of cis- and trans-3-alkylated proline moieties, and manipulation of functionality and protecting groups to obtain proline-chimera monomers in appropriate form for peptide synthesis.