Direct Lawsone O-Alkylation Employing Sulfonic Acid-Functionalized Chitosan as a Biodegradable Organocatalyst

Area of Science:

• Organic Chemistry
• Green Chemistry
• Catalysis

Background:

• Direct O-alkylation of lawsone is crucial for synthesizing various organic compounds.
• Existing methods may lack environmental friendliness, scalability, or cost-effectiveness.

Purpose of the Study:

• To develop a novel, environmentally friendly, and scalable protocol for direct lawsone O-alkylation.
• To utilize acid chitosan (CS-SO₃H) as a heterogeneous organocatalyst for this transformation.

Main Methods:

• Employed acid chitosan (CS-SO₃H) as a reusable heterogeneous organocatalyst.
• Investigated the direct O-alkylation of lawsone with a diverse range of alcohols.
• Assessed catalyst recycling and chemoselectivity of the reaction.

Main Results:

• Achieved efficient lawsone O-alkylation with a wide variety of alcohols.
• Demonstrated high functional group tolerance and excellent atomic economy.
• Confirmed the reusability of the acid chitosan catalyst and high chemoselectivity.

Conclusions:

• Presented the first report of a direct lawsone O-alkylation using acid chitosan.
• The developed protocol is environmentally friendly, cheap, scalable, and efficient.
• Highlights the potential of acid chitosan as a sustainable catalyst in organic synthesis.