Ring expansion and fused cyclization catalysis to construct indoloquinazolinones with functionalization.

Area of Science:

• Organic Chemistry
• Catalysis
• Synthetic Methodology

Background:

• Isatin and 2-alkynylaniline are common starting materials.
• Development of efficient synthetic routes for fused heterocyclic compounds is crucial.

Purpose of the Study:

• To develop a straightforward, moisture-insensitive, and regioselective catalytic reaction.
• To synthesize diverse 12-benzoyl/benzyl/alkyl indolo[1,2-c]quinazolin-6(5H)-ones.

Main Methods:

• Utilized a FeIII-CuII/p-TSA-CuI catalytic system.
• Employed isatin and 2-alkynylaniline as readily available precursors.
• The reaction involves C-C cleavage and ring expansion.

Main Results:

• Achieved regioselective synthesis of indolo[1,2-c]quinazolin-6(5H)-ones.
• Demonstrated a broad substrate scope and gram-scale producibility.
• The method exhibits high atom economy.

Conclusions:

• A novel and efficient catalytic system for synthesizing complex fused heterocycles.
• The developed method is practical, scalable, and environmentally conscious.