Corey–House synthesis

The Corey–Posner, Whitesides–House synthesis (also called the Corey–Posner, Whitesides–House reaction) is an organic reaction that involves the reaction of a lithium dialkyl cuprate with an alkyl halide to form a new alkane, an organocopper compound and a lithium halide.

R₂CuLi + R'-X → R-R' + RCu + LiX

Reaction mechanism

This reaction occurs in two steps. The alkyl halide is treated with lithium metal, and solvated in ether, which converts the alkyl halide into an alkyl lithium compound, R-Li. The starting R-X can be primary, secondary or tertiary alkyl halide:

R-X + 2Li → R-Li + Li-X

The second step requires the alkyl lithium compound to be treated with cuprous iodide (CuI). This creates a lithium dialkyl cuprate compound. These compounds were first synthesized by Henry Gilman of Iowa State University, and are usually called Gilman reagents in honor of his contributions:

2RLi + CuI → R₂CuLi + LiI

The lithium dialkyl cuprate is then treated with the second alkyl halide, which couples to the compound:

R₂CuLi + R'-X → R-R' + RCu + LiX

If second alkyl halide is not the same as the first, then cross-products are formed.

It is important to note that for this reaction to work successfully, the second alkyl halide must be a methyl halide, benzyl halide, primary alkyl halide or a secondary cyclo alkyl halide. The relative simplicity of this reaction makes it a useful technique for synthesizing organic compounds.

Background

This reaction was developed by the co-operation of four organic chemists: E.J. Corey of Harvard University, Gary H. Posner of the Johns Hopkins University, George M. Whitesides of Harvard, and Herbert O. House of the Georgia Institute of Technology.

See also

• Gilman reagent
• Wurtz reaction