Gilman Reagent

Gilman Reagent is an organometallic reagent containing two alkyl or aryl group, copper and lithium. The general formula of Gilman reagents is R₂CuLi. Gilman reagent is more reactive, more nucleophilic and weaker base than that of Grignard reagent.
Gilman reagent provides a versatile method for coupling two alkyl fragments to give a larger alkane in a reaction called the Corey- House Reaction.

Preparation of Gilman Reagent

Preparation of Gilman reagent takes place in two steps. In the first step, alkyl halide is treated with lithium metal, and solvated in dry ether, which converts the alkyl halide into an alkyl lithium (R-Li) and in the second step, this alkyllithium (RLi) reacts with cuprous iodide (CuI) in THF at temperature -78 degrees Celsius. forms dialkyl cuprate iodide i.e. Gilman Reagent.
R-X + 2Li → R-Li + LiX
R-Li + CuI → R-Cu⁻-R Li⁺ + LiI

Applications of Gilman Reagent

Reaction with Alkyl halides

Gilman reagent reacts with alkyl halide except fluoride, one of the alkyl groups replaces the halide.


Epoxide reacts with Gilman reagent gives alcohols with inversion of configuration, at less substituted carbon atom of the epoxides as in SN₂ process.

Reaction with α, β unsaturated carbonyl compounds

With α, β unsaturated carbonyl compounds, Gilman reagent undergo 1,4 addition.

Reactions with Acid Chlorides

The reaction of a dialkyl cuprate and acid chloride is a preferred method to synthesize ketones.

Reactions with Aldehydes and Ketones

Organocuprates react with aldehydes to give alcohols in high yield. In the presence of chlorotrimethylsilane, the corresponding siliylenol ethers can be obtained. The reaction of ketones with organocuprates is very sluggish. However, the reaction takes place conveniently in the presence of chlorotrimethylsilane.

Examples of Gilman Reagent