Post-Synthetic Macrocyclization of Rotaxane Building Blocks

Area of Science:

• Supramolecular Chemistry
• Organic Synthesis

Background:

• Cyclic interlocked molecules possess unique, restrained three-dimensional structures.
• Rotaxanes, a type of interlocked molecule, are potential precursors for post-synthetic modifications.
• Preserving the mechanical bond is crucial for maintaining the interlocked architecture during reactions.

Purpose of the Study:

• To review rare examples of macrocyclization via chemical linkage in rotaxanes.
• To highlight the underexploited potential of post-synthetic intramolecular cyclization for creating cyclic interlocked molecules.
• To explore reactions involving reactive sites on both the macrocycle and the axle of rotaxanes.

Main Methods:

• Literature review of existing examples of macrocyclization in rotaxanes.
• Analysis of reaction strategies that preserve the mechanical bond.
• Identification of chemical linkages between embedded reactive sites.

Main Results:

• Identified rare instances of macrocyclization through chemical connection within rotaxane systems.
• Demonstrated that modifications preserving the mechanical bond are key to successful cyclization.
• Highlighted the potential for linking reactive sites on macrocycles and axles.

Conclusions:

• Post-synthetic intramolecular cyclization is a viable, though underexploited, route to cyclic interlocked molecules.
• The mechanical bond's integrity is paramount for synthesizing these complex architectures.
• Further exploration of linking reactive sites within rotaxanes can yield novel molecular designs.