The application of CuAAC ‘click’ chemistry to catenane and rotaxane synthesis

Abstract

The copper(I)-catalysed azide-alkyne cycloaddition (the CuAAC 'click' reaction) is proving to be a powerful new tool for the construction of mechanically interlocked molecular-level architectures. The reaction is highly selective for the functional groups involved (terminal alkynes and azides) and the experimental conditions are mild and compatible with the weak and reversible intermolecular interactions generally used to template the assembly of interlocked structures. Since the CuAAC reaction was introduced as a means of making rotaxanes by an 'active template' mechanism in 2006, it has proven effective for the synthesis of numerous different types of rotaxanes, catenanes and molecular shuttles by passive as well as active template strategies. Mechanistic insights into the CuAAC reaction itself have been provided by unexpected results encountered during the preparation of rotaxanes. In this tutorial review we highlight the rapidly increasing utility and future potential of the CuAAC reaction in mechanically interlocked molecule synthesis.

Switchable Intermolecular Communication in a Four‐Fold Rotaxane

“…[3,4] Syntheses of rotaxanes have been well-established, and a large variety of fascinating examples of rotaxane-based molecular systems has been reported. [3][4][5] As a specific example of switchable rotaxanes, Stoddart, Credi and co-workers reported elevatorlike motion of a molecule with crown ethers along the strings on another molecule in a three-fold rotaxane, in which the relative position between the molecules was switchable by redox or acid-base reactions.[6] Sauvage and co-workers made a porphyrin dimer in a cyclic [4]rotaxane and showed its ability to act as switchable receptor.[7] Porphyrin, phthalocyanine, and their metal complexes have been applied to a broad range of functionalized molecular systems. Intermolecular electronic communication in their programmed arrays particularly has attracted a lot of interests in a wide range of fields, from photomaterials [8] to pigments, [9] molecular devices, [10] and catalysts.…”

Sequentially Palladium-Catalyzed Processes in One-Pot Syntheses of Heterocycles

“…Over the past decades, the Sonogashira alkynylation has turned out to be the most versatile catalytic synthesis of internal alkynes starting from (hetero)aryl or vinyl halides and terminal acetylenes [42,[57][58][59][60][61][62]. Most Sonogashira reactions are bimetallically catalyzed by palladium and copper complexes and, therefore, this unique catalyst system has also been shown to be suitable for CuAAC (Cu-catalyzed alkyne-azide cycloaddition) [63][64][65][66][67][68][69], eventually, in a sequential or consecutive fashion.…”

Synthesis and catalytic applications of C3-symmetric tris(triazolyl)methanol ligands and derivatives

“…13 Supramolecular chemistry has also benefitted from the diverse supramolecular interactions involving 1,2,3-triazoles. 14 In this context, click-derived triazoles have led to a wide range of supramolecular functional systems, 14,15 Threefold rotational symmetry, structural modularity and other key aspects of ligand design have played a crucial role in the development of new types of chelating tripodal ligands. 17 Due to the beneficial influence of molecular symmetry in catalytic reactions, the design and preparation of C 3 -symmetric ligands and of their metal complexes has found numerous successful applications in homogeneous catalysis.…”