Alkyllithium

Alkyllithium compounds are organometallic compounds with the general formula R-Li, where R is an alkyl group and Li is lithium. They are widely used as strong bases and nucleophiles in organic synthesis. Due to the high polarity of the carbon-lithium bond, alkyllithium reagents exhibit significant carbanionic character. Common examples include n-butyllithium, sec-butyllithium, tert-butyllithium, and methyllithium.

These compounds are highly reactive and are often prepared in situ or purchased as solutions in hydrocarbon solvents such as hexane, heptane, or tetrahydrofuran. They are pyrophoric, meaning they can ignite spontaneously in air, and react vigorously with protic solvents like water and alcohols. Therefore, alkyllithium reagents must be handled under an inert atmosphere, typically nitrogen or argon, and with appropriate safety precautions.

Alkyllithiums are essential reagents for deprotonation reactions, forming new carbon-carbon bonds through nucleophilic attack on electrophiles, and for generating other organometallic species. Their strong basicity allows them to deprotonate even weakly acidic C-H bonds, facilitating a wide range of transformations. The choice of alkyllithium reagent depends on the desired reactivity and selectivity for a particular synthetic transformation.