Titre | Aza-beta3-cyclopeptides: a new way of controlling nitrogen chirality. |
Publication Type | Journal Article |
Year of Publication | 2009 |
Authors | Mocquet, C, Salaün, A, Claudon, P, Le Grel, B, Potel, M, Guichard, G, Jamart-Grégoire, B, Le Grel, P |
Journal | J Am Chem Soc |
Volume | 131 |
Issue | 40 |
Pagination | 14521-5 |
Date Published | 2009 Oct 14 |
ISSN | 1520-5126 |
Mots-clés | Alanine, Aza Compounds, Models, Molecular, Nitrogen, Nuclear Magnetic Resonance, Biomolecular, Peptides, Cyclic, Phenylalanine, Protein Conformation, Stereoisomerism |
Abstract | Sixteen and 24 membered aza-beta(3)-peptidic macrocycles containing a alpha-hydrazinoacid or a beta(3)-aminoacid were synthesized. The conformation of these pseudopeptides was determined by using NH chemical shift analysis, NH extinction, VT-NMR experiments, and X-ray diffraction. The study shows that a stable conformation is retained between 223 and 413 K. The latter is characterized by an uninterrupted internal H-bond network and a syndiotactic arrangement of the asymmetric centers. It means that the presence of the optically pure residue acts as a conformational lock to select a single enantiomer through the cyclization by controlling the absolute configuration of all the nitrogen atoms. To our knowledge, this represents the first example of a dynamic enantioselection process involving several centers prone to pyramidal inversion. These results give a new impulsion to the control of nitrogen chirality, which remained limited to small cycles for 60 years. |
DOI | 10.1021/ja9058074 |
Alternate Journal | J. Am. Chem. Soc. |
PubMed ID | 19807190 |