What is the mechanism of action of Grignard reagents?

Grignard reagents are highly reactive organomagnesium compounds that act primarily as strong nucleophiles. The mechanism of action involves the nucleophilic attack by the Grignard reagent on electrophilic centers, such as carbonyl carbons in aldehydes or ketones, or other functional groups that are electron-deficient.

In this process, the carbon atom of the Grignard reagent, which carries a partial negative charge due to the presence of the magnesium halide bond, approaches an electrophilic carbon. A bond is formed as the nucleophile donates its electron pair to the electrophile, resulting in the formation of a new carbon-carbon bond or a carbon-heteroatom bond. This characteristic makes Grignard reagents an important tool in synthesis for building complex organic molecules.

Understanding their function as nucleophiles is crucial in organic chemistry, particularly when considering reactions involved in the formation of alcohols from carbonyl compounds. The specificity and effectiveness of Grignard reagents in these types of reactions are what make them valuable in synthetic organic chemistry.