Template-Directed Quantitative One-Pot Synthesis of Homochiral Helical Receptors Enabling Enantioselective Binding

Template-directed synthesis and dynamic covalent chemistry were implemented to achieve quantitative one-pot syntheses of homochiral helical cavities inside aromatic foldamers. One-handed helical receptors P-1, M-1, P-2 and M-2 were assembled from their precursors in the presence of appropriate templates (d- and l-tartaric acid, and d- and l-sorbitol, respectively) via three sequential steps in one pot: imine-linked chain elongation, template-induced folding and [4+2] cycloaddition between helical turns. These helical receptors were proven to enantioselectively bind chiral guests used as the templates, and the differences between the association constants of enantiomeric guests were up to more than two orders of magnitude. The structures and binding modes of the receptors were fully characterized by single-crystal X-ray crystallography and ¹H NMR spectroscopy.