Nickel-catalyzed cross-coupling of primary alkyl halides with phenylethynyl- and trimethylsilyethynyllithium reagents

A highly efficient alkyl–alkynyl coupling system is described which is promoted by a well-defined and moisture-stable pincer complex [NiCl{C6H3-2,6-(OPPh2)2}] (1). Non-activated alkyl halides could be efficiently coupled with phenylethynyl- and trimethylsilylethynyllithium reagents at room temperature. Compared to the alkylation of primary alkyl halides with alkynyllithium reagents in literatures, this method requires milder conditions (room temperature) and proceeds quickly. This research will make these readily available alkynyllithium reagents much more useful for organic synthesis.

Graphical abstractAn alkyl–alkynyl coupling is promoted by a moisture-stable PCP-NiⅡ-Cl compound between phenylethynyl- and trimethylsilylethynyllithium reagents and alkyl halides at room temperature.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► A highly efficient alkyl–alkynyl cross-coupling system. ► Well-defined and moisture-stable pincer nickel complex as catalyst. ► Alkylation of alkyl halides with alkynyllithium reagents.