Methyllithium

This highly reactive compound, invariably used in solution with an ether as the solvent, is a reagent in organic synthesis as well as organometallic chemistry.

[3] Methyllithium is both strongly basic and highly nucleophilic due to the partial negative charge on carbon and is therefore particularly reactive towards electron acceptors and proton donors.

In contrast to n-BuLi, MeLi reacts only very slowly with THF at room temperature, and solutions in ether are indefinitely stable.

For example, ketones react to give tertiary alcohols in a two-step process: Nonmetal halides are converted to methyl compounds with methyllithium: Such reactions more commonly employ the Grignard reagents methylmagnesium halides, which are often equally effective, and less expensive or more easily prepared in situ.

In contrast the bulkier cluster (tertiary-butylLi)4, where intercluster interactions are precluded by steric effects, is volatile as well as soluble in alkanes.

Colour code: Li- purple C- black H- white The hexameric form features hexagonal prisms with Li and C atoms again at alternate corners.

Colour code: Li- purple C- black H- white The degree of aggregation, "n" for (MeLi)n, depends upon the solvent and the presence of additives (such as lithium bromide).

These clusters are considered "electron-deficient," that is, they do not follow the octet rule because the molecules lack sufficient electrons to form four 2-centered, 2-electron bonds around each carbon atom, in contrast to most organic compounds.

Skeletal formula of tetrameric methyllithium with all implicit hydrogens shown
Skeletal formula of tetrameric methyllithium with all implicit hydrogens shown
NFPA 704 four-colored diamond Health 3: Short exposure could cause serious temporary or residual injury. E.g. chlorine gas Flammability 3: Liquids and solids that can be ignited under almost all ambient temperature conditions. Flash point between 23 and 38 °C (73 and 100 °F). E.g. gasoline Instability 2: Undergoes violent chemical change at elevated temperatures and pressures, reacts violently with water, or may form explosive mixtures with water. E.g. white phosphorus Special hazard W: Reacts with water in an unusual or dangerous manner. E.g. sodium, sulfuric acid