Selective Monofunctionalization Enabled by Reaction History-Dependent Communication in Catalytic Rotaxanes

Selective monofunctionalization of substrates with distant, yet equally-reactive functional groups is difficult to achieve, as it requires the second functional group to selectively modulate its reactivity once the first functional group has reacted. We now show that mechanically-interlocked catalytic rings can effectively regulate the reactivity of stoppering groups in rotaxanes over a distance of ~2 nm. Our mechanism of communication is enabled by a unique interlocked design, which effectively removes the catalytic rings from the substrates via fast dethreading, as soon as the first reaction has taken place. Our method not only led to a rare example of selective monofunctionalization, but also to a “molecular if function”. Overall, the results reported in this research article present a way to get distant functional groups to communicate with each other in a reaction-history-dependent manner to create linkers that can ultimately perform logical operations at the molecular level.