Iron-Catalyzed Synthesis of 2-Arylbenzo[b]furans

Abstract

An iron-catalyzed procedure was employed to achieve both the Sonogashira cross-coupling and intramolecular o-arylation of o-iodophenols and aryl acetylenes/1-substituted-2-trimethylsilyl acetylenes. A variety of 2-arylbenzo[b]furans were synthesized in moderate to good yields under the catalysis of 5% FeCl₃ and 10% 1,10-phenanthroline.

GRAPHICAL ABSTRACT

Keywords:

• 2-Arylbenzo[b]furan
• intramolecular o-arylation
• iron-catalyzed
• one pot
• Sonogashira reaction
• synthesis

ACKNOWLEDGMENTS

This work was financially supported by the Natural Science Foundation of China (No. 21272169), the Specialized Research Fund for the Doctoral Program Foundation of Higher Education of China (No. 2060335036), and Natural Science Foundation of Zhejiang Province for founding (No. Y406049).

Notes

^a Reaction conditions: FeCl₃ (0.025 mmol), ligand (0.05 mmol), o-iodophenol (0.5 mmol), phenylacetylene (0.75 mmol), and base (2.0 mmol) in solvent (2.0 mL) under N₂.

^b Isolated yield.

^c Fe₂O₃ (0.025 mmol) was used.

^d No FeCl₃ was used.

^a Reaction conditions: FeCl₃ (0.025 mmol), 1,10-phenanthroline (0.05 mmol), o-iodophenols (0.5 mmol), phenylacetylene (0.75 mmol), and Cs₂CO₃ (2.0 mmol) in xylene (2.0 mL) under N₂.

^b Isolated yield.

^a Reaction conditions: FeCl₃ (0.025 mmol), 1,10-phenanthroline (0.05 mmol), o-iodophenols (0.5 mmol), 1-substituted-2-trimethylsilyl acetylene (0.75 mmol), and Cs₂CO₃ (2.0 mmol) in xylene (2.0 mL) under N₂.

^b Isolated yield.