1900

Grignard Reaction

Philippe Antoine Barbier (1848–1922), François-Auguste-Victor Grignard (1871–1935)

Every organic chemist knows the Grignard reaction, which produces some of the most useful organometallic reagents in the toolbox. They are generally easy to prepare, stable on storage, and they react in handy and predictable ways. Uses are still being discovered for them, and the number of variations and modifications that have been found must be nearly beyond counting by now.

In 1900, French chemist François-Auguste-Victor Grignard was a twenty-nine-year-old doctoral student under the supervision of French chemist Philippe Antoine Barbier when he made the discovery that would earn them the 1912 Nobel Prize in Chemistry. Organometallic pioneer Barbier had suggested that Grignard investigate magnesium compounds, and this suggestion led directly to Grignard’s breakthrough: discovery of the preparation of magnesium alkyl halides (Grignard reagents).

Preparing Grignards usually requires just some magnesium metal, a solvent, and a starting compound with a carbon-bromine or carbon-chlorine bond. Many of these halide compounds will start to react with pieces of magnesium metal after only a bit of encouragement (a little heating, a speck of iodine, or some scratching of the metal surface to remove the oxide layer). Chemists learn quickly that if they start the reaction with heat, they’d better be prepared to cool it back down, because it can be vigorous after it gets going. Once prepared, the reagent acts largely as if there was a plain negative charge on the carbon that used to have the halide atom, and these species can react with a variety of partners to form new carbon-carbon bonds. Since those are the currency of organic synthesis, Grignards and other such reagents have been used constantly when assembling new molecular frameworks.

You can actually buy solutions of many common Grignard reagents, ready to be dispensed by syringe. An older generation of chemists, used to making their own as needed, rolled their eyes at such luxury, but these preparations are now widely used. The “handmade” Grignards are in no danger of disappearing from the world, though. Over a hundred years later, the reaction is going strong.

Victor Grignard, many years after his graduate school days, when he was a famous and honored professor in his own right.