Palladium-Catalyzed Three-Component Cascade Carbonylation Reaction to Construct Benzofuran Derivatives

Area of Science:

• Organic Chemistry
• Catalysis
• Heterocyclic Chemistry

Background:

• Benzofurans are prevalent heterocyclic motifs found in numerous natural products and pharmaceuticals.
• Efficient synthetic methodologies for constructing the benzofuran core are of significant interest in medicinal and synthetic chemistry.

Purpose of the Study:

• To develop a novel, efficient, and versatile three-component reaction for the synthesis of benzofurans.
• To explore a palladium-catalyzed cascade process involving cyclization and carbonylation.

Main Methods:

• A novel three-component reaction involving iodoarene-tethered propargyl ethers, amines, and carbon monoxide (CO).
• Utilized palladium catalysis to facilitate a cascade sequence including oxidative addition, unsaturated bond migration, carbonyl insertion, and nucleophilic attack.
• Conducted the reaction under one atmosphere of CO.

Main Results:

• Successfully synthesized the benzofuran skeleton through a novel palladium-catalyzed cascade cyclization-carbonylation reaction.
• Demonstrated the compatibility of both aromatic and aliphatic amines in this transformation.
• The reaction proceeds efficiently under mild conditions (one atm CO).

Conclusions:

• A novel and efficient three-component cyclization-carbonylation reaction has been established for benzofuran synthesis.
• This method provides a facile route to substituted benzofurans using readily available starting materials.
• The developed methodology offers a valuable addition to the synthetic chemist's toolkit for constructing heterocyclic compounds.