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

Abstract

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 about 2 nm. Our mechanism of communication is enabled by a unique interlocked design, which effectively removes the catalytic rings from the substrates by 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 study presents a way to get distant functional groups to communicate with each other in a reaction‐history‐dependent manner by creating linkers that can ultimately perform logical operations at the molecular level.

Sequence Matters: Precise Synthesis of Hetero[3]rotaxane Isomers with Sequence-dependent Chemical Reactivity and Circularly Polarized Luminescence

“…In our design strategy, inspired by recent developments in post-synthetic modification of rotaxanes [35][36][37][38][39] , a wheel assembling approach is proposed for the efficient, precise, and diverse synthesis of both sequence isomers of hetero [3]rotaxanes. First, to shorten the synthetic routes and improve the synthetic efficiency, a [2]rotaxane with exchangeable stoppers is employed as the key precursor.…”

Supramolecular protection with a recyclable molecular container: an efficient strategy for the one-pot selective functionalization of polyfunctional substrates

“…The iteroselective monofunctionalization of a symmetrical diester was achieved in 74% yield through its dethreading from a mechanically-interlocked system after the first reaction. 9 In this context, the use of macrocyclic molecular containers as supramolecular protecting units emerges as a promising strategy. 10 The general concept relies on the protection of a functional group of a polyfunctional substrate through its binding in the cavity of a molecular receptor and the subsequent selective transformation of an accessible functional group (Fig.…”

Iterative Exponential Growth of Oxygen-Linked Aromatic Polymers Driven by Nucleophilic Aromatic Substitution Reactions

“…The backbones of conjugated and heteroatom-linked aromatic polymers tend to possess fewer conformational degrees of freedom than polymers with more flexible aliphatic or partially aliphatic backbones. This reduced amount of conformational freedom can help enhance the folding of aromatic polymers, to advance a variety of useful properties such as selective supramolecular recognition ( Goodman et al, 2007 ; Liu et al, 2015 ; Otte, 2016 ; Schneebeli et al, 2016 ; Adhikari et al, 2017 ; Xie et al, 2020 ), selective catalysis ( Rajappan et al, 2020 ; Sharafi et al, 2020 ), and self-assembly ( Cole et al, 2017 ; Greene et al, 2017 ; Bonduelle, 2018 ; Ong and Swager, 2018 ; Delawder et al, 2019 ; Zhao et al, 2019 ). However, while the precise chemical structures, lengths, and sequences of such macromolecules ( Dobscha et al, 2019 ; Gerthoffer et al, 2020 ; Zhao et al, 2020 ) dictate their folding, and with it their functionalities and physical properties ( Chen et al, 2015 ; Hanlon et al, 2017 ), it remains challenging to synthesize polyaromatic structures with precise lengths and/or sequences as unimolecular entities.…”