Catenanes, rotaxanes and pretzelanes - template synthesis and chirality

Catenanes and Rotaxanes of the amide-type have been obtained in remarkable yields via supramolecular template syntheses. The amide-based structures ca n be designed by appropriate choice of building units. The regioselective s ynthesis of stable [2]catenane isomers allowed to draw conclusions about th eir formation. Tetralactams of type 1 act as a host for guests containg ami de-units (cf. key-lock intermediate 3). If the guest molecule is cyclisized a catenane is formed while reaction with voluminous stopper groups yield a rotaxane. Rotaxanes can also be synthesized by the 'slipping method' in wh ich wheel and axle are heated at about 300 degrees C for minutes. The forma tion of rotaxanes containing aliphatic chain axles showed that pi-pi-intera ctions are not necessary. Introduction of a sulfonamide unit allowed us to do chemistry with catenanes and rotaxanes (cf. 14, 15) and furthermore to s ynthesize topologically chiral spieces (15).