Copper-Free Sonogashira Coupling of Aryl Chlorides with Pd/C

Significance

The Sonogashira coupling of aryl chlorides with terminal acetylenes under copper-free conditions in the presence of a palladium on charcoal catalyst were described. To a suspension of 10% Pd/C Selcat Q6 (5 mg, 0.005 mmol), XPhos (2.4 mg, 0.005 mmol) and K₂CO₃ (97 mg, 0.75 mmol) in dimethylacetaminde (0.25 mL) under argon were added an aryl chloride (0.5 mmol) and an alkyne (0.75 mmol). The reaction mixture was stirred at 110 ˚C to give the Sonogashira coupling product (29 examples: 72-99% yield).