Efficient Construction of Oligocholate Foldamers via “Click” Chemistry and Their Tolerance of Structural Heterogeneity
摘要:
The 1,3-dipolar cycloaddition between an alkynyl-terminated cholate trimer and an azido-functionalized cholate hexamer readily afforded the nonamer and dodecamer derivatives; whereas amide coupling employed in previous oligocholate synthesis failed beyond the octamer. Unlike typical oligocholate foldamers with exclusively head-to-tall arrangement of the repeat units, the newly synthesized "clicked" oligocholates contained head-to-head arrangement and flexible tethers in the sequence. Despite large structural perturbations, the clicked oligocholates folded similarly as the parent foldamers, demonstrating the robustness of the solvophobically driven folding mechanism.