OrganolithiumReagenzien

Organolithium reagents are a class of organometallic compounds containing a carbon-lithium bond. They are widely used in organic synthesis as strong bases and nucleophiles. The polarity of the carbon-lithium bond is significant, with the carbon atom bearing a partial negative charge and the lithium atom a partial positive charge. This polarity makes the carbon atom highly reactive towards electrophiles.

The preparation of organolithium reagents typically involves the reaction of an organohalide with an alkali metal, most commonly lithium metal, in an ethereal solvent like diethyl ether or tetrahydrofuran. Alternatively, they can be prepared by lithium-halogen exchange or by deprotonation of a hydrocarbon using a more reactive organolithium reagent.

Key applications of organolithium reagents include the formation of new carbon-carbon bonds through nucleophilic addition to carbonyl compounds, epoxides, and nitriles, as well as alkylation of amines and other heteroatoms. They are also employed in metal-halogen exchange reactions and as strong bases for deprotonation, enabling the generation of other reactive intermediates like enolates. Due to their high reactivity, organolithium reagents are sensitive to air and moisture and are typically handled under inert atmosphere conditions. Their pyrophoric nature necessitates careful handling and storage.