Efficient construction of oligocholate foldamers via "click" chemistry and their tolerance of structural heterogeneity.

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-tail 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.