Concise, aromatization-based approach to an elaborate C2-symmetric pyrenophane

Area of Science:

• Organic Chemistry
• Supramolecular Chemistry
• Crystal Engineering

Background:

• Pyrenophanes are macrocyclic compounds containing a pyrene unit.
• Inherently chiral molecules possess non-superimposable mirror images, crucial for various applications.
• Developing efficient synthetic routes to complex polycyclic aromatic hydrocarbons remains a challenge.

Purpose of the Study:

• To report a concise and efficient synthesis of an elaborate, inherently chiral [n](1,6)pyrenophane.
• To elucidate the crystal structure and resolution of the synthesized molecule.
• To explore novel synthetic methodologies for constructing complex pyrene-based systems.

Main Methods:

• A 5-step synthetic sequence.
• Utilizing a multicomponent reaction for key fragment assembly.
• Employing an unprecedented double-McMurry coupling followed by valence isomerization and dehydrogenation.
• Aromatization reactions for pyrene ring formation.
• X-ray crystallography for crystal structure determination and resolution.

Main Results:

• Successful synthesis of an elaborate, inherently chiral [n](1,6)pyrenophane in 5 steps.
• Detailed crystal structure and resolution of the target molecule were obtained.
• The synthesis highlights the efficacy of multicomponent reactions and the novel double-McMurry/valence isomerization/dehydrogenation sequence.
• Aromatization reactions were confirmed to be essential for the formation of the four pyrene rings.

Conclusions:

• A highly efficient and short synthetic route to a complex chiral pyrenophane has been established.
• The study provides valuable insights into the synthesis and structural characterization of novel polycyclic aromatic hydrocarbons.
• The developed methodology offers potential for accessing other elaborate chiral macrocyclic systems.