Details

Autor(en) / Beteiligte

• Fanelli, Rossana
• Berta, Dénes
• Földes, Tamás
• Rosta, Edina
• Atkinson, Robert Andrew
• Hofmann, Hans-Jörg
• Shankland, Kenneth
• Cobb, Alexander J. A

Titel

Organocatalytic Access to a cis-Cyclopentyl-γ-amino Acid: An Intriguing Model of Selectivity and Formation of a Stable 10/12-Helix from the Corresponding γ/α-Peptide

Ist Teil von

• Journal of the American Chemical Society, 2020-01, Vol.142 (3), p.1382-1393

Ort / Verlag

United States: American Chemical Society

Erscheinungsjahr

2020

Link zum Volltext

Quelle

MEDLINE

Beschreibungen/Notizen

• In this study, we have developed a highly enantioselective organocatalytic route to the (1S,2R)-2-(aminomethyl)­cyclopentane-1-carboxylic acid monomer precursor, which has a cis-configuration between the C- and N-termini around the cyclopentane core. Kinetic measurements show that the product distribution changes over time due to epimerization of the C1 center. Computations suggest the cis-selectivity is a result of selective C–C bond formation, while subsequent steps appear to influence the selectivity at higher temperature. The resulting γ-amino acid residue was incorporated into a novel γ/α-peptide, which forms a well-ordered 10/12-helix with alternate H-bond directionality in spite of the smallest value of the ζ-angle yet observed for a helix of this type. This highly defined structure is also a result of the narrow range of potential ζ-angles in our monomer. In contrast, the larger range of potential ζ-values observed for the corresponding trans-system can be fulfilled by several competing helical structures.