Fig. 6. (a) Transition state analogue TSA drives the distribution of the library towards the transient macrocycle which subsequently catalyses the degradation of TSA via the aza-Cope reaction and restores the equilibrium. The aza-Cope reaction and structures of the involved species are shown. (b) Change in composition of the dynamic disulfide network over the course of the aza-Cope rearrangement, showing the rapid conversion of catenanes 11 into tetramers 12 upon addition of the substrate (denoted by the black arrows). (c) Appearance of product 9 as a function of time in the presence and absence of a dynamic combinatorial library (DCL) made from a dithiol building block. Adapted from ref. 31 with permission from John Wiley and Sons.