Enantioselective Recognition of Functional Organic Molecules in Water by Biomimetic Macrocyclic Hosts

Enantioselective recognition of functional organic molecules in water is routine in nature but remains a formidable challenge for synthetic hosts. Here, we reported two pairs of chiral naphthotubes with chiral centers located in the neighborhood of the inward-directing amide groups. These naphthotubes, with a chiral twisted cavity, show highly enantioselective recognition in water to a wide scope of organic molecules (90 chiral guests). The highest enantioselectivity of 34 was achieved with neotame. Small differences between all of the noncovalent interactions shielded in the hydrophobic cavity were revealed to be responsible for the enantioselective recognition in water, which is different from the traditional views. Moreover, these hosts can differentiate the analogues of aspartame using fluorescence spectroscopy. These chiral naphthotubes have made unprecedented achievements in enantioselective recognition, providing the basis for their applications in chiral analysis and separations.