Corey–House synthesis
The Corey–House synthesis (also called the Corey–Posner, Whitesides–House reaction and other permutations) is an organic reaction that involves the reaction of a lithium dialkyl cuprate with an alkyl halide to form a new alkane, an organic paper
compound and a lithium halide.[1][2][3]
- 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 dry 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, former mentor of Gary H. Posner of the Johns Hopkins University, as well as
George M. Whitesides of Harvard (then at MIT), former mentor of Herbert O. House of the Georgia Institute of Technology.
