Halides, vinyl reaction with organolithium

Like magnesium, lithium reacts with alkyl halides, vinyl halides, and aryl halides to form organometallic compounds. Ether is not necessary for this reaction. Organolithium reagents are made and used in a wide variety of solvents, including alkanes. 

Organocuprates can react with all alkyl halides except tertiary alkyl halides. Because they can react with vinylic halides and aryl halides (an aryl hahde has a hydrogen attached to a benzene ring), they can be used to prepare compounds that cannot be prepared by Sn2 reactions with Grignard reagents or organolithium compounds. (Remember that vinylic and aryl halides cannot undergo nucleophilic attack Section 9.5). 

Lithium dialkylcuprate reagents (Gilman reagents) are formed by the reaction of two equivalents of an organolithium reagent with cuprous iodide. Reaction of the dialkylcuprate with an alkyl, aryl, or vinyl halide forms a new carbon-carbon bond. 

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