nbutyllithium

N-Butyllithium (n-BuLi) is an organolithium reagent widely used in organic synthesis as a strong base and nucleophile. It is typically supplied as a solution in hydrocarbon solvents such as hexanes or cyclohexane and appears as a colorless to pale yellow liquid. n-BuLi is highly reactive and pyrophoric, reacting with air and water; it is normally handled under inert atmosphere and with appropriate protective equipment.

Preparation and structure: n-BuLi is the linear C4H9Li organolithium compound. It is generally formed by metal-halogen exchange or lithium insertion into suitable butyl halides in hydrocarbon media. Its reactivity and selectivity depend on aggregation state and solvent, and it is usually stored and handled under strictly anoxic conditions.

Reactions and applications: As a base, n-BuLi can deprotonate hydrocarbons with relatively acidic C-H bonds to form carbanions and lithium salts, enabling formation of enolates and other reactive intermediates. As a nucleophile, it can alkylate electrophiles such as carbonyl compounds, imines, and epoxides, and it participates in halogen–metal exchange to generate other organolithium species in situ. It is also used as an initiator for anionic polymerization of dienes and styrenic monomers, and for metalation of arenes to give aryllithium intermediates.

Hazards and handling: It is highly reactive and can ignite on contact with air; contact with skin or eyes can cause severe burns. Handle under inert gas, in appropriate solvents, with suitable protective equipment and storage conditions. See safety data for detailed guidelines.