Copper-Catalyzed Coupling of Aryl Halides with Terminal Alkynes in the Presence of KF/Al₂O₃

Abstract

A convenient catalyst system consisting of copper iodide, L-proline, and potassium fluoride/Al₂O₃ was effective for the coupling reaction of aryl iodides and bromides with terminal alkynes. In contrast to the conventional Sonogashira reactions, the new procedure is free of palladium and phosphines. Different functionalized aryl halides were coupled with terminal alkynes using this system in good to excellent yields.

Keywords:

• Aryl halides
• copper iodide
• coupling reaction
• KF/Al₂O₃
• Sonogashira reaction
• terminal alkynes

ACKNOWLEDGMENT

Financial support of this work from the Research Council of Mazandaran University is gratefully acknowledged.

Notes

^a Reaction conditions: Aryl iodide (1 mmol), alkyne (1.2 mmol), CuI (0.1 mmol), L-proline (0.3 mmol), KF/Al₂O₃ (5 mmol) in 5 mL of DMF, 110°C; or aryl bromide (1 mmol), alkyne (1.2 mmol), CuI (0.15 mmol), L-proline (0.45 mmol), KF/Al₂O₃ (5 mmol) in 5 mL of DMF, 110°C.

^b Isolated yield; products were characterized by ¹H NMR and mp.