Alkanes [Gilman reagents]

Alkanes (Gilman reagent) Definition:


Alkyl halides (or tosylates) will react with Gilman reagents (organocuprates) to form alkanes in SN2 reaction.



Alkanes (Gilman reagent) Explained:


A Gilman reagent is a lithium and diorganocopper reagent compound, R2CuLi (R = alkyl or aryl). These reagents are excellent nucleophiles for SN2 reactions. Gilman reagents are useful because they react with alkyl halides to replace the halide group with an R group. Reactions such as this which form new carbon-carbon bonds are extremely useful in organic synthesis. In contrast, Grignard reagents do not work well for SN2 reactions because a lot of side reaction is observed, like deprotonation and reduction.



Gilman reagent reacts with alkyl halides via an SN2 mechanism which is not well understood. It appears that nucleophilic attack by the negatively charged copper atom leads to an intermediate which fragments to produce the alkane product.

This reaction is shown as electron pairs moving but this could be a radical reaction because the mechanism has not yet been established. This will surely predict the correct products.