In 1900, Victor Grignard discovered that an organomagnesium reagent (so called Grignard reagent) reacts with an electrophile, e.g. carbonyl compounds, such as ketones, aldehydes, and esters etc. The Grignard reagent is formed from the reaction between an alkylhalide (RX, X=Cl, Br) and metallic magnesium (Mg).
The insertion of the magnesium into the carbon-halogen bond generates an electropositive charge (δ+) on the carbon atom which makes it possible for the carbon to act as a nucleophile and attack the carbonyl center. Since the Grignard reagent is a strong base, the reaction is performed in anhydrous ether solvents.
1) Grignard, V. C. R. Acad. Sci. 1900, 130, 1322. Victor Grignard was awarded the Nobel Prize in Chemistry 1912 for the discovery of the Grignard reagent.