Grignard reagents do not typically react with organic halides, in contrast with their high reactivity with other main group halides.  In the presence of metal catalysts, however, Grignard reagents participate in C-C coupling reactions. For example, nonylmagnesium bromide reacts with methyl p-chlorobenzoate to give p-nonylbenzoic acid, in the presence of Tris(acetylacetonato)iron(III) (Fe(acac)), after workup with NaOH to hydrolyze the ester, shown as follows. Without the Fe(acac), the Grignard reagent would attack the ester group over the aryl halide.
For the coupling of aryl halides with aryl Grignard reagents, nickel chloride in tetrahydrofuran (THF) is also a good catalyst. Additionally, an effective catalyst for the couplings of alkyl halides is the Gilman catalyst lithium tetrachlorocuprate (), prepared by mixing lithium chloride (LiCl) and copper(II) chloride () in THF. The Kumada-Corriu coupling gives access to [substituted] styrenes.