Recall from Section 9-7 how acetylide ions are alkylated by displacing unhindered alkyl...

Recall from Section 9-7 how acetylide ions are alkylated by displacing unhindered alkyl halides.

Like acetylide ions, Grignard and organolithium reagents are strong bases and strong nucleophiles. Fortunately, they do not displace halides as easily as acetylide ions do. If they did displace alkyl halides, it would be impossible to form the reagents from alkyl halides because whenever a molecule of reagent formed, it would react with a molecule of the halide starting material. All that would be formed is a coupling product. In fact, coupling is a side reaction that hurts the yield of many Grignard reactions.