a grignard reagent can also be involved in coupling reactions. for example, nonylmagnesium bromide reacts with methyl "p"-chlorobenzoate to give "p"-nonylbenzoic acid, in the presence of tris(acetylacetonato)iron(iii), often symbolized as fe(acac)3, after workup with naoh to hydrolyze the ester, shown as follows. without the fe(acac)3, the grignard reagent would attack the ester group over the aryl halide.