title: Stereoselective synthesis of (Z)-alkene-containing proline dipeptide mimetics.
abstract: In peptides and proteins, the peptide bond between an amino acid and proline exists as an equilibrium mixture of the cis-imide and trans-imide due to the low energy barrier in their interconversion. This feature greatly influences the structure and function of the proline-containing peptides and proteins. Therefore, restricting the amide bond with an (E)- or (Z)-alkene should provide a promising method for elucidating the structure-activity relationships of the peptide and the proteins. In this report, the regio- and stereoselective synthesis of cis-alanylproline (Ala-Pro) type (Z)-alkene dipeptide mimetic is described. The key steps of this synthesis are to introduce a C3 unit onto a gamma-phosphoryloxy-alpha,beta-unsaturated-delta-lactam with an organocopper-mediated anti-S(N)2' reaction and subsequently construct a five-membered proline-like cyclic structure with an intramolecular Suzuki coupling reaction. Hydrolysis of the amide bond in the resulting bicyclic lactam yields the desired cis-Ala-Pro type (Z)-alkene dipeptide isostere. The presented synthetic methodology should be applicable to the general syntheses of other cis-aminoacylproline type (Z)-alkene dipeptide mimetics.
authors.affiliation: Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan.
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Sasaki
authors.forename: Ayumu
authors.initials: A
authors.lastname: Niida
authors.forename: Takashi
authors.initials: T
authors.lastname: Tsuji
authors.forename: Akira
authors.initials: A
authors.lastname: Shigenaga
authors.forename: Nobutaka
authors.initials: N
authors.lastname: Fujii
authors.forename: Akira
authors.initials: A
authors.lastname: Otaka
mesh_terms: D000475:Alkenes / Q000737:chemistry*; D020650:Combinatorial Chemistry Techniques; D004151:Dipeptides / Q000138:chemical synthesis* / Q000737:chemistry; D008968:Molecular Conformation; D011392:Proline / Q000031:analogs & derivatives* / Q000138:chemical synthesis* / Q000737:chemistry; D013237:Stereoisomerism
chemical_list: D000475:Alkenes; D004151:Dipeptides; D011392:Proline