Solid-State C-N Cross-Coupling Reactions with Carbazoles as Nitrogen Nucleophiles Using Mechanochemistry

Area of Science:

• Organic Chemistry
• Materials Science

Background:

• Palladium-catalyzed cross-coupling reactions are vital in organic synthesis.
• Conventional methods often require large volumes of organic solvents and struggle with poorly soluble or sterically hindered substrates.
• Developing greener and more efficient synthetic strategies is a key challenge.

Purpose of the Study:

• To develop a novel, solvent-free method for C-N cross-coupling.
• To synthesize N-arylcarbazole derivatives efficiently.
• To enable coupling of challenging, poorly soluble aryl halides.

Main Methods:

• Utilizing a palladium-catalyzed reaction.
• Employing a high-temperature ball-milling technique for solid-state synthesis.
• Reacting carbazoles with aryl halides under solvent-free conditions in air.

Main Results:

• Achieved simple, fast, and efficient synthesis of N-arylcarbazole derivatives.
• Obtained good to excellent yields for the target compounds.
• Successfully coupled poorly soluble aryl halides and large polyaromatic structures, which are unreactive under conventional conditions.

Conclusions:

• The developed solid-state coupling approach offers a greener and more versatile alternative to solution-based methods.
• High-temperature ball-milling provides an effective platform for challenging C-N cross-coupling reactions.
• This technique expands the scope of N-arylcarbazole synthesis, particularly for complex molecular architectures.