Corey-House-Posner-Whitesides reaction
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The Corey-Posner-Whitesides-House reaction was developed by the co-operation of four organic chemists: E.J. Corey of Harvard University, G.H. Posner of the Johns Hopkins University, G.M. Whitesides of MIT and H.O. House of the Georgia Institute of Technology. E.J. Corey received the Nobel Prize for Chemistry in 1990 for his contributions to the science of synthesizing new organic compounds.
In general, the reaction uses lithium dialkylcuprates to couple two alkyl halides to create a larger alkane compound as per the following reaction:
- R-X + R'-X → R-R'
This reaction occurs in two steps. The alkyl halide is treated with lithium metal solvated in ether, which converts the alkyl halide into an alkyllithium compound, R-Li.
- R-X + 2Li → R-Li + Li-X
The second step requires the alkyllithium compound to be treated with cuprous iodide (CuI). This creates a lithium dialkylcuprate 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 dialkylcuprate is then treated with the second alkyl halide, which couples to the compound.
- R2CuLi + R'-X → R-R' + RCu + LiX
It is important to note that for this reaction to work successfully the alkyl halide must be a methyl halide, a primary alkyl halide or a secondary cycloalkyl halide. The relative simplicity of this reaction makes it a useful technique for synthesizing organic compounds.
