Regioselective template synthesis, X-ray structure, and chiroptical properties of a topologically chiral sulfonamide catenane

The synthesis of a topologically chiral in,out-bis-sulfonamide catenane and its "dimer" are reported. The structures of the amide wheel and of the cat enane were resolved by X-ray analysis. NMR-titration of the monosulfonamide -wheel yielded conclusive association constants supporting the proposed reg ioselective mechanism of the catenane formation. The enantioseparation of t he catenane via chiral HPLC was successful. The enantiomers show pronounced Cotton effects in the aromatic region of the CD-spectrum. Since the templa te synthesis was carried out leading to the in-oriented sulfonamide-wheel b locked with an N-methyl group at its reactive sulfonamide functionality, th e catenane represents the first monofunctional topologically chiral amide-b ased catenane. Reaction with 1,2-bis (2-iodoethoxy) ethane led to a bis-cat enane containing two topological units. The meso- and the RR/SS- isomers re present a new type of topological diastereomers. Chirality 12:76-83, 2000. (C) 2000 Wiley-Liss. Inc.