Synthesis of Nonnatural Helical Polypeptide via Asymmetric Polymerization and Reductive Cleavage of N–O Bond

Herein, we present a novel synthetic strategy, to amino-acid-free peptide synthesis based on postpolymerization conversion, for chiral nonnatural polypeptides. Optically active poly-N-alkoxyamides were prepared by our asymmetric polymerization as precursors of polypeptides, and the reductive cleavag...

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Bibliographic Details
Published inMacromolecules Vol. 50; no. 14; pp. 5301 - 5307
Main Authors Ishido, Yuki, Kanbayashi, Naoya, Okamura, Taka-aki, Onitsuka, Kiyotaka
Format Journal Article
LanguageEnglish
Published American Chemical Society 25.07.2017
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Summary:Herein, we present a novel synthetic strategy, to amino-acid-free peptide synthesis based on postpolymerization conversion, for chiral nonnatural polypeptides. Optically active poly-N-alkoxyamides were prepared by our asymmetric polymerization as precursors of polypeptides, and the reductive cleavage of N–O bonds using a SmI2–THF complex was carried out. The reaction proceeded smoothly with quantitative conversion to afford a nonnatural polypeptide. The resulting polypeptide adopted a one-handed stable helical structure in solution, which was established by circular dichroism (CD) and theoretical calculations using density functional theory (DFT). The simulated spectra by time-dependent (TD) DFT methods clearly indicated the validity of the proposed structure. The synthetic approach is a promising candidate for the synthesis of nonnatural polypeptides.
ISSN:0024-9297
1520-5835
DOI:10.1021/acs.macromol.7b01426