Enantiodifferentiation of polyethers by the dirhodium method. Part 2: Cyclotriveratrylenes and cryptophanes

Cycloveratrylenes and cryptophanes 1–12 are chiral compounds and were studied in their racemic form. Although most of them are non-polar oligocyclic ethers, their enantiomers can be easily differentiated by 1H and 13C NMR spectroscopy in the presence of an equimolar amount of Rh2[(R)-(+)-MTPA]4 (the standard protocol for the dirhodium method). Coordination mechanisms were studied. Various functionalities (sulfide, various ethers, olefin and phenol) were also sequenced according to their donor properties.