metallated

Metallated is a term used in chemistry to describe a molecule or substructure that contains a metal atom as part of its framework or as a coordinated component. In organometallic chemistry, metallation typically refers to the conversion of a C–H bond into a C–M bond or the coordination of a metal to a heteroatom within an organic substrate. The result is a metallated or organometallic intermediate that is often highly reactive and can act as a nucleophile, a base, or a cross-coupling partner in subsequent transformations.

Common examples and methods include the metallation of arenes and heterocycles to form aryllithiums or other organometallic species. Direct metallation—often referred to as lithiation or magnesiation—uses strong metalating reagents such as organolithium or organomagnesium compounds. Directed metallation employs a functional directing group (such as an amide, sulfonamide, or ether) to guide metallation to a specific position on the ring, enabling regioselective functionalization. Metallation can also proceed via metal–halogen exchange or through transmetallation steps that transfer the metal to a reactive organic fragment.

Applications of metallated intermediates include the formation of carbon–carbon and carbon–heteroatom bonds, often through reactions with electrophiles (e.g., CO2, aldehydes, or halides) or in transition-metal-catalyzed cross-coupling processes such as Negishi or Kumada couplings. These species are valuable for assembling complex molecules in organic synthesis, medicinal chemistry, and materials science.

Safety and handling notes: metallated species are typically moisture- and air-sensitive and are prepared and used under inert atmosphere in dry solvents at low temperatures. Quenching and workup require careful control to prevent undesired side reactions.