A Shapeshifting Roadmap for Polycyclic Skeletal Evolution.

Area of Science:

• Organic Chemistry
• Supramolecular Chemistry
• Materials Science

Background:

• Polycyclic ring systems are crucial 3D structural motifs in biologically active molecules and organic materials.
• Molecular shape and isomerism critically influence the function and properties of polycyclic compounds.
• Synthesizing specific isomers often requires developing distinct, complex synthetic routes.

Purpose of the Study:

• To develop a novel dynamic, 'shapeshifting' carbon cage system for controlled isomeric exploration.
• To establish a chemical blueprint for evolving a common skeletal ancestor into diverse isomeric ring systems.
• To investigate the role of through-space π-orbital interactions (homoconjugation) in driving isomerization.

Main Methods:

• Development of a new C9-chemotype exhibiting dynamic isomerization.
• Utilizing light and organic base as triggers for iterative chemical transformations.
• Employing computational and photophysical studies to analyze the isomer network and reaction mechanisms.

Main Results:

• A common skeletal ancestor was evolved into a complex network of valence isomers via homoconjugation.
• The system demonstrates controllable and continuous isomerization using only two chemical steps.
• Fundamental insights into the reactivity, mechanism, and homoconjugative interactions governing isomerization were gained.

Conclusions:

• This work presents a rare small molecule capable of controlled, continuous isomerization.
• The findings provide a foundation for the rational design of new dynamic, shapeshifting molecular systems.
• This approach offers a powerful tool for synthesizing diverse isomeric polycycles for drug discovery and materials science.