Synthesis and Functionalization of Decachlorobenzo[ghi]perylene

Area of Science:

• Organic Chemistry
• Materials Science
• Catalysis

Background:

• Polycyclic aromatic hydrocarbons (PAHs) halogenation is crucial for modifying their properties.
• Selective halogenation of complex polycyclic frameworks remains a significant synthetic challenge.
• Halogenated PAHs exhibit distinct electronic and physical characteristics compared to parent compounds.

Purpose of the Study:

• To develop a controlled method for multichlorination and annulation of [5]helicene.
• To synthesize decachlorobenzo[ghi]perylene efficiently.
• To explore downstream functionalization of the resulting chlorinated compound.

Main Methods:

• Utilizing a Carborane-SMe catalyst for directed halogenation.
• Employing controlled reaction conditions for multichlorination and annulation.
• Investigating the reactivity of remaining C-H bonds for further modification.

Main Results:

• Successful synthesis of decachlorobenzo[ghi]perylene from [5]helicene.
• Demonstration of controlled multichlorination and annulation.
• Identification of remaining C-H bonds suitable for direct lithiation and subsequent functionalization.

Conclusions:

• The Carborane-SMe catalyst enables efficient and selective edge-polyhalogenation of [5]helicene.
• Decachlorobenzo[ghi]perylene is accessible through this novel catalytic approach.
• The resulting chlorinated PAHs offer opportunities for diverse downstream chemical transformations.