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.