| 초록 |
Cyclic polymers are fascinating macromolecules. Here, a facile and highly efficient strategy for the synthesis of cyclic (co)polypeptides is reported using N-heterocyclic carbenes-mediated ring-opening polymerization of α-amino acid N-carboxyanhydrides (NCA). The polymerization proceeds rapidly in a quasi-living manner, allowing access to cyclic polypeptides of well-defined chain length and narrow polydispersity, as evidenced by nuclear magnetic resonance spectrum and size exclusion chromatography analysis. Cyclic block copolypeptides are also accessible simply by controlling the order of addition of NCA monomers. The cyclic topology of the polypeptides was further verified by matrix-assisted laser desorption ionization-time of flight mass spectra and viscosity studies. This approach simplifies workup procedures and enables bulk-scale synthesis, which thereby opens avenues for practical implementation in the design of diverse polypeptide-based hybrid materials. |
