Simple chiral aza-crown ethers based on sucrose display high enantioselectivity in complexation of phenylethylammonium chlorides.

The synthesis of four fluorescent diastereoisomeric molecular cages containing cyclotriveratrylene and sucrose moieties connected via the naphthalene linkers is reported. These diastereoisomers were found to be selective and efficient receptors for acetylcholine and choline. Compound P-5a has a better affinity for choline over acetylcholine, while cage M-5a exhibits a higher association constant for acetylcholine over choline. The highest selectivity value was observed for compound M-5a (K_ACh/K_Ch = 3.1). Cages P-5a, P-5b, M-5a, and M-5b were fully characterized by the advanced NMR techniques, and ECD spectroscopy was supported by DFT calculations. The binding constants K_a of these receptors were determined by fluorescence titration experiments in acetonitrile.

Chiral macrocycles containing the sucrose skeleton were prepared by a ‘click chemistry’ route. The substrate for the Huisgen reaction was obtained from sucrose in eight steps. The 1,3-dipolar cycloaddition yielded the intramolecular as well as the C ₂-symmetric macrocycles. Optimization of the reaction conditions allowed the preparation of both types of adducts with high selectivity and in good yields.