nbutyylilitium

n-Butyllithium, often abbreviated as n-BuLi, is an organolithium compound with the chemical formula CH3CH2CH2CH2Li. It is a colorless liquid, though commercial samples are often yellowish due to impurities. It is a highly reactive pyrophoric substance, meaning it ignites spontaneously in air. As a result, it is typically handled under an inert atmosphere, such as nitrogen or argon.

n-Butyllithium is a strong base and a powerful nucleophile. Its primary use in organic synthesis is as a reagent for deprotonation, particularly of weakly acidic C-H bonds. This ability makes it invaluable for generating carbanions, which can then undergo further reactions such as alkylation or addition to carbonyl compounds. It is also used in the preparation of other organometallic reagents and in certain polymerization processes.

Commercially, n-butyllithium is usually supplied as solutions in hydrocarbon solvents like hexane, heptane, or cyclohexane, as it is unstable in its neat form. The concentration of these solutions is typically determined by titration. Due to its reactivity and hazardous nature, n-butyllithium requires careful handling and storage. It reacts violently with water, alcohols, and other protic solvents, producing flammable butane gas.