Metalation (Alt. spelling: Metallation) is a chemical reaction that forms a bond to a metal. This reaction usually refers to the replacement of a halogen atom in an organic molecule with a metal atom, resulting in an organometallic compound. In the laboratory, metalation is commonly used to activate organic molecules during the formation of C—X bonds (where X is typically carbon, oxygen, or nitrogen), which are necessary for the synthesis of many organic molecules.
In synthesis, metallated reagents are typically involved in nucleophilic substitution, single-electron-transfer (SET), and redox chemistry with functional groups on other molecules (including but not limited to ketones, aldehydes and alkyl halides). Metallated molecules may also participate in acid-base chemistry, with one organometallic reagent deprotonating an organic molecule to create a new organometallic reagent.
The most common classes of metallated compounds are organolithium reagents and Grignard reagents. However, other organometallic compounds — such as organozinc compounds — also experience common use in both laboratory and industrial applications.