Divergent aryne regulation for polycyclic aromatic hydrocarbons

Area of Science:

• Organic Chemistry
• Materials Science
• Supramolecular Chemistry

Background:

• Arynes are valuable synthons for π-extension and difunctionalization, crucial for constructing polycyclic aromatic hydrocarbons (PAHs).
• Challenges in aryne chemistry include thermodynamic stability and kinetic selectivity, particularly for heteroarynes due to distorted bond angles and shortened distances in the CC triple bond within aromatic systems.

Purpose of the Study:

• To achieve controllable aryne generation for nitrogen-doped polycyclic aromatic hydrocarbons (N-PAHs).
• To enhance thermodynamic stability and kinetic site-selectivity in aryne reactions.
• To establish a reliable method for regulating aryne generation and release.

Main Methods:

• Designed cyclic pyridine-benzene λ³-iodanes for aryne generation.
• Utilized p→π* interaction involving iodine for thermodynamic stability and kinetic selectivity.
• Employed a "pyridyne-benzyne" model for nucleophilic capture and [4+2]-cycloaddition.

Main Results:

• Achieved controllable generation of arynes for N-PAHs synthesis.
• Demonstrated preeminent ortho-selectivity in nucleophilic capture and cycloaddition reactions.
• Successfully assembled N-PAHs exhibiting adjustable Twisted Intramolecular Charge Transfer (TICT) and inverse Suppression of Proximity Effect (SOPE) phenomena.
• Established an empirical formula for aryne generation and release regulation.

Conclusions:

• Designed cyclic pyridine-benzene iodanes provide a stable and selective platform for aryne generation.
• The developed method enables the synthesis of N-PAHs with tunable electronic properties.
• This work offers a reliable strategy for constructing complex N-doped aromatic systems.