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.
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.