Nickel-catalyzed cross-coupling reaction of alkynyl bromides with Grignard reagents

We describe a convenient method for the synthesis of 1,2-disubstituted acetylenes via a cross-coupling reaction of (bromoethynyl)benzene with Grignard reagents. The reaction of (bromoethynyl)benzene (1 mmol) with Grignard reagent (1.3 mmol) mediated by NiCl2 (4 mol%) and (p-CH3Ph)3P (8 mol%) in THF could produce 1,2-disubstituted acetylenes in good yields at room temperature.

The NiCl2/(p-CH3Ph)3P complex was found to be a highly efficient catalyst for the synthesis of 1,2-disubstituted alkynes from (bromoethynyl)benzene and Grignard reagents. A catalytic cycle for the reaction was proposed.Figure optionsDownload as PowerPoint slide