Pleasingly, single crystal x-ray diffraction (SCXRD) analysis of a racemic sample of catenane 3b produced using rac-1b allowed the relative stereochemistry of the major diastereomer to be tentatively assigned as (S * ,Smt * ) and thus the major product of (S)-1b and macrocycle 2 is assigned as (S,Smt)-3b (Figure ). Although the solid-state structure of 3b supports the assumption, based on the high ppm chemical shift of Ha, that the bipyridine ring encircles the triazole moiety in the isolated samples of catenanes 3, over time changes were observed in their H NMR spectra that suggest this is a metastable co-conformation; isolated samples of catenanes 3 reversibly isomerize to new species in which Ha resonates at lower chemical shift (ESI section S11). This co-conformational isomerization also helps explain the challenges encountered in purifying the observed oligomeric species. Having demonstrated that a tyrosine-derived auxiliary can direct the stereoselective formation of a topologically chiral catenane, we turned to methods to remove the covalent stereogenic unit from catenane 3b. Attempts to ablate the covalent stereocenter in a model compound by radical decarboxylation met with failure due to scission of the triazole N 1 -C substituent bond (ESI section S9). Ultimately, we found that reduction of ester 3b to give alcohol catenane 5 followed by tandem Oppenauer-type oxidation / Rh I -mediated decarbonylation 26 gave rise to catenane 6 in reasonable isolated yield (32% over two steps). The major stereoisomer of 6 was assigned as (Smt)