The Grignard reaction is an organometallic chemical reaction in which alkyl, vinyl, or aryl-magnesium halides add to a carbonyl group in an aldehyde or ketone. This reaction is essential for the formation of carbon–carbon bonds. Grignard compound is a chemical compound with the generic formula R–Mg–X, where X is a halogen and R is an organic group, normally an alkyl or aryl.
Examples are: phenylmagnesium bromide (C. 6H. 5)–Mg–Br and methylmagnesium chloride H. 3C–Mg–Cl and .
Grignard Reagents are also utilised in the following reactions:
The addition of an excess of a Grignard reagent to an ester or lactone gives a tertiary alcohol in which two alkyl groups are the same, and the addition of a Grignard reagent to a nitrile produces an unsymmetrical ketone via a metalloimine intermediate.