[2]Catenane Synthesis via Covalent Templating

Area of Science:

• Supramolecular Chemistry
• Organic Synthesis
• Materials Science

Background:

• Mechanically Interlocked Molecules (MiMs) are complex architectures with unique properties.
• Previous synthesis of MiMs often relied on supramolecular recognition sites, limiting design flexibility.
• Developing new templating strategies is crucial for accessing diverse MiM structures.

Purpose of the Study:

• To report a novel covalent templating strategy for synthesizing MiMs.
• To create MiMs that lack traditional supramolecular recognition sites.
• To demonstrate the formation of a [2]catenane using this method.

Main Methods:

• Utilized covalent templating with temporary benzylic linkages.
• Employed sequential macrocyclization reactions.
• Incorporated a central ketal linkage for controlled assembly.
• Cleaved temporary and linking bonds to yield the final product.

Main Results:

• Successfully synthesized mechanically interlocked molecules (MiMs) using covalent templating.
• Achieved perpendicular covalent connection of two linear strands.
• Formed a pseudo[1]rotaxane intermediate.
• Converted the intermediate to a [2]catenane via a second macrocyclization and cleavage steps.

Conclusions:

• Covalent templating is a viable strategy for synthesizing MiMs lacking supramolecular recognition sites.
• The developed method allows for controlled formation of complex interlocked architectures.
• This work expands the synthetic toolbox for creating novel mechanically interlocked molecules.