Cross-Coupling Reaction of Chloropyrazines with Acetylenes

Various chloropyrazines were subjected to cross-coupling reaction with acetylenes, such as phenylacetylene, 1-hexyne and propargyl alcohol, in the presence of palladium catalysts, to give the corresponding coupling products in good yields. It was found that tetrakis(triphenylphosphine)-palladium can catalyze the reaction of chloro-alkylpyrazines, and that a combination of bis-(triphenylphosphine)palladium dichloride and copper(I) iodide preferentially catalyzes the reaction of chloro-phenylpyrazines.