Structurally divergent dynamic combinatorial chemistry on racemic mixtures.

Area of Science:

• Supramolecular Chemistry
• Organic Synthesis
• Chemical Crystallography

Background:

• Structurally divergent reactions from racemic mixtures are rare in nature and typically require bulky chiral catalysts in organic solvents.
• Existing methods for generating molecular diversity often rely on non-racemic starting materials or complex catalytic systems.

Purpose of the Study:

• To develop a dynamic combinatorial approach for achieving structural divergence from racemic building blocks.
• To explore the formation of non-isomeric [2]catenanes through spontaneous, stereospecific assembly.

Main Methods:

• Employing a dynamic combinatorial library approach using racemic building blocks.
• Utilizing stereospecific electron-donor - electron-acceptor interactions between diastereomeric macrocycles.
• Characterizing the resulting pseudorotaxanes and [2]catenanes using advanced analytical techniques.

Main Results:

• Demonstrated the generation of structural divergence from racemic starting materials without chiral catalysts.
• Identified stereospecific interactions between macrocycles as the driving force for divergence.
• Observed the spontaneous formation of two distinct, non-isomeric [2]catenanes within the equilibrated library.

Conclusions:

• The described dynamic combinatorial strategy enables the creation of complex molecular architectures, including non-isomeric catenanes, from simple racemic precursors.
• This approach offers a new paradigm for generating molecular diversity in supramolecular chemistry.
• The findings highlight the potential of stereospecific interactions in driving spontaneous, divergent self-assembly processes.