Attempts to remove the auxiliary units from rotaxane (S,Rco-mp,S,Rco-mp)-19 using the sequence described above for rotaxane 4b (reduction, Swern oxidation then AcOH) led to a complex mixture of products that included the corresponding non-interlocked bipyridine macrocycle, suggesting that the axle component is not stable to the reaction conditions. When the acetic acid salt of piperidine was used in place of AcOH to catalyse the cleavage of the auxiliary unit (Figure ), the reaction mixture slowly evolved to produce rotaxanes 20, presumably via hydrolysis of a piperidine enamine, without significant decomposition. Using this sequence, the other stereoisomeric samples of rotaxanes 20 (Figure ) were isolated in good stereopurity (96% de for the chiral diastereomers, 90% de for the meso diastereomer) and reasonable isolated yield.