Chiral Bambusurils


                                 Jan Sokolov, Vladimír Šindelář* ^


  Department of Chemistry and RECETOX, Faculty of Science, Masaryk University, Kamenice 5, 625 00
                                       Brno, Czech Republic.

                                  E-mail: sindelar@chemi.muni.cz


Bambusurils are a group of macrocyclic compounds that are composed of repeating glycoluril units
connected by a row of methylene bridges.^1 Bambusurils are potent anion receptors. They can bind
anions inside their cavity with high affinity in organic solvents as well as in aqueous media.^2,3
Most bambusurils are achiral compounds and achiral inorganic are mainly applied as guests for
complexation. This work focuses on synthesis of novel chiral bambusuril derivatives and
investigation of their supramolecular properties.^4,5 These compounds could serve as receptors for
discrimination of anions derived from chiral organic acids. The project starts with synthesis of
enantiomerically pure chiral glycoluril building blocks. These glycolurils were then subjected to
macrocyclization reactions with paraformaldehyde in the presence of an acid catalyst and an anionic
template yielding the desired chiral macrocycles. Supramolecular complexes of the macrocycles and
chiral carboxylate anions were studied by means of NMR. The complexation was slow on the NMR time
scale. Association constants of the complexes were determined from the concentrations of the free
and complexed form of the macrocycles that were calculated from integrals of corresponding NMR
signals. Enantioselective binding of chiral anions was observed.

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Figure 1. Structures of chiral bambusuril macrocycles.








References

^1 T. Lizal, and V. Sindelar, Isr. J. Chem. 2018, 58 (3-4), 326–333.

^2 V. Havel and V. Sindelar, ChemPlusChem 2015, 80 (11), 1601–1606.

^3 M. A. Yawer, V. Havel and V. Sindelar, Angew. Chem. Int. Ed. 2015, 54 (1), 276–279.

^4 J. Sokolov, and V. Šindelář, Chem. Eur. J. 2018, 24 (58), 15482–15485.

^5 J. Sokolov, A. Štefek and V. Šindelář, ChemPlusChem 2020, 85 (6), 1307–1314.