Grignard Reagents

Grignard Reagents

Grignard Reagents were discovered by a French chemist, Victor Grignard, who was awarded a Nobel prize in 1912. Grignard Reagents can be created by adding an organo-halide to a flask with a small amount of magnesium metal (Mg) with an ether solvent, making sure to keep the reaction completely inert and away from any moisture or water. The organo- halides that can be used to create Grignard reagents can range from alkyl, allyl, vinyl, aryl, and benzyl halides but are primarily created using alkyl and aryl halides. Grignard reagents act as very strong nucleophiles and can form new carbon-carbon bonds to primarily aldehydes and ketones.

1.) Formation of Grignard Reagents

The Alkyl halide formation of Grignard Reagents shows R-X as the electrophile and the organomagnesium as the nucleophile and are formed in the inert environment using either as the solvent to create the product.

Benzyl Halides are also a common organohalide used for creating Grignard Reagents, as shown below.

2.) Additions of Grignard Reagents

Grignard Reagents are very basic, acid-sensitive reagents that can be used to create carbon bonds or add alkyl groups to carbonyl compounds like aldehydes or ketones.

3.) Formation of Alcohols

The bond created between the carbon and magnesium is very polar, so the carbon being more electronegative causes the magnesium to have a partial positive charge.

4.) Addition of Phenols

Grignard Reagents are great in very regioselective reactions as a means of facillating the formation of specific compounds.

5.) Formation of Ketones

Reactions of grignard reagents with the use of carbon dioxide are great sources of carbonyles which can be used to attach larger alkyl groups or alcohols.