Highly Substituted Acephenanthrylenes and Their π-Extended Derivatives: Syntheses, Structural Analyses, and...

Area of Science:

• Organic Chemistry
• Materials Science
• Catalysis

Background:

• Polycyclic aromatic hydrocarbons (PAHs) are crucial in materials science and organic electronics.
• Traditional synthesis methods for complex PAHs often involve harsh conditions like pyrolysis.
• Developing efficient and versatile synthetic routes for substituted PAHs is an ongoing challenge.

Purpose of the Study:

• To develop a novel, facile synthetic protocol for substituted acephenanthrylenes (APs) and related PAHs.
• To achieve the first nonpyrolysis synthesis of dicyclopenta[cd,mn]pyrene.
• To demonstrate the versatility of the method for introducing substituents and extending the PAH backbone.

Main Methods:

• Palladium-catalyzed cycloaromatization of 2,3-diethynylbiphenyls.
• Utilizing substituted 2,3-diethynylbiphenyl precursors.
• Characterization of synthesized acephenanthrylenes, benzo[l]acephenanthrylene, and dicyclopenta[cd,mn]pyrene.

Main Results:

• Successfully synthesized a series of substituted acephenanthrylenes (APs), benzo[l]acephenanthrylene, and dicyclopenta[cd,mn]pyrene.
• Achieved the first nonpyrolysis synthesis of dicyclopenta[cd,mn]pyrene in high yield via a two-fold cycloaromatization.
• Demonstrated facile introduction of diverse substituents and efficient extension of the AP backbone.

Conclusions:

• The developed palladium-catalyzed cycloaromatization offers an efficient and versatile route to substituted PAHs.
• This method overcomes limitations of traditional synthesis, particularly for complex structures.
• The protocol facilitates the design and synthesis of novel PAH-based materials.