Neopentyllithium

Neopentyllithium is an organolithium reagent with the chemical formula C₅H₁₁Li. It is used in organic synthesis as a strong base and as a nucleophile for the formation of carbon-carbon bonds. Neopentyllithium is a member of the alkylithiums, which are compounds containing a direct bond between a carbon atom of an alkyl group and a lithium atom.

Properties

Neopentyllithium exists as a highly reactive, colorless solid at room temperature. It is extremely sensitive to moisture and air, requiring anhydrous conditions and inert atmosphere handling techniques, such as using a glovebox or Schlenk line. In solution, it tends to aggregate, forming higher-order structures that can influence its reactivity and selectivity.

Synthesis

Neopentyllithium can be synthesized by the reaction of neopentyl chloride (C₅H₁₁Cl) with lithium metal. This process typically involves the use of an inert solvent, such as diethyl ether or tetrahydrofuran (THF), under an inert atmosphere to prevent the reagent from reacting with moisture or oxygen.

2 Li + C5H11Cl → C5H11Li + LiCl

Applications

Neopentyllithium is primarily used in organic synthesis. Its strong basicity makes it suitable for deprotonating a wide range of acidic compounds, including ketones, aldehydes, and esters. As a nucleophile, it can be used in the addition to carbonyl compounds, the formation of carbon-carbon bonds, and the synthesis of various organic molecules.

Carbon-Carbon Bond Formation

One of the key applications of neopentyllithium is in the formation of carbon-carbon bonds. This can be achieved through reactions with electrophiles, such as alkyl halides, to form new alkylated products. The reactivity and selectivity of these reactions can be influenced by the choice of solvent and temperature.

Safety

Due to its high reactivity, especially towards water and air, neopentyllithium must be handled with extreme care. Precautions include the use of an inert atmosphere, such as nitrogen or argon, and the avoidance of any contact with moisture. Protective equipment, such as gloves and eye protection, is also essential when working with this reagent.

See Also

• Organolithium reagent
• Alkylithium
• Schlenk line
• Glovebox