Synthesis and Shuttling Behavior of [2]Rotaxanes with a Pyrrole Moiety

Abstract

We synthesized [2]rotaxanes with a pyrrole moiety from a [2]rotaxane with a 1,3-diynyl moiety. The conversion of the 1,3-diynyl moiety of the axle component to the pyrrole moiety was accomplished by a Cu-mediated cycloaddition of anilines. The cycloaddition reaction was accelerated when the [2]rotaxane was used as the substrate. The effect of the structure of the pyrrole moiety on the rate of the shuttling was studied.

Properties and emerging applications of mechanically interlocked ligands

“…6). 21 The rate of the double hydroamination reaction was found to be significantly higher in the case of the interlocked structure than the non-interlocked axle with a range of Cu I sources, confirming that the reaction is significantly accelerated by the endotopically bound Cu I ion in rotaxane 16. By varying the size of the aniline nucleophile employed the authors were able to control the rate of macrocycle shuttling in the product.…”

Evaluation of the Steric Bulk of Substituents Utilizing the Shuttling Behavior of [2]Rotaxanes with N‐Arylpyrrole Moieties

“…Synthesis of [2]Rotaxane with Pyrrole Moiety 3a (A Representative Procedure, Procedure A): A reported procedure[9a] was generally followed to synthesize [2]rotaxane 3a . A mixture of [2]rotaxane 1 (51 mg, 0.020 mmol, 1.0 equiv.…”

“…[2]Rotaxane, which consists of an axle component and a ring component, is a mechanically interlocked compound and many applications have been reported to date . Recently we reported the synthesis of [2]rotaxanes with N ‐substituted pyrrole moiety . The shuttling of the ring component along the axle moiety was inhibited when a large substituent (R) was introduced to the pyrrole ring, and the kinetic parameters for the shuttling process were determined.…”

Chirality in rotaxanes and catenanes

“…The authors used the relationship between shuttling and racemisation to determine the activation parameters for the shuttling of the macrocycle over the pyrrole, something which they had been unable to do in a related achiral system as the process was too slow to monitor by 1 H NMR. 117 …”