Catenane pretzel-shaped

When macrocycle 65 is synthesized, the in/out isomer of [2]catenane 79 is also formed in 11% yield (Figure 29) [46]. A first attempt to methylate both sulfonamide groups by treatment of the DMF solution of 79 with iodomethane and potassium carbonate was successful. By bridging the two sulfonamide units with a bifunctional alkylating reagent, we were able to synthesize the first pretzel-shaped molecule [54]. Considerations of the X-ray structure analysis of amide-linked catenanes [16] and CPK models led to the diiodo compound 95 as a suitable brid-... 

Mechanically connected components of sulfonamide catenanes and rotaxanes can also be connected in an intramolecular manner by linking their sulfonamide moieties and producing the first pretzel-shaped compound 17 [48] and [ljrotaxane 18 [49], respectively. Interestingly, the [l]rotaxane can be bridged intramolecularly giving rise to a molecular 8 compound 19 [50],... 

Yamamoto, C., Okamoto, Y., Schmidt. T., Jager, R., Vogtle, F. Enantiomeric resolution of cycloenantiomeric rotaxane, topologically chiral catenane, and pretzel-shaped molecules observation of pronounced circular dichroism, J. Am. Chem. Soc. 119 (1997), 10547-10548. 

Figure 5.23 The synthesis of a pretzel-shaped molecule via the covalent linkage of the components of a [2 -catenane ...

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