Syntheses with organolithium compounds

Many organolithium compounds may be prepared by the interaction of lithium with an alkyl chloride or bromide or with an aryl bromide in dry ethereal solution in a nitrogen atmosphere  

These compounds are soluble in ether, are comparatively stable, and exhibit many of the reactions of Grignard reagents but are more reactive. Because of their greater reactivity, organolithium compounds can often be used where Grignard reagents fail thus they add to the azomethine linkage in pyridines or 

Another example illustrating the greater reactivity of organolithium compounds is the preparation of the otherwise difficultly accessible esters of 2-pyridyI-scetic add by the following series of reactions from a-picoline  

Many organic halides do not react satisfactorily with lithium to form RLi cconpounds or with metallic magnesium to form Grignard reagents. The desired organolithium compound can often be prepared by a halogen-metal interconversion reaction  

Thus o-hydroxyphenyl-llthium cannot be obtained from o-bromophenol and lithium but, under proper conditions, o-bromophenol reacts with -butyl-lithium to give a good yield of the lithium salt of o-hydroxyphenyl-Uthium. An interesting application is to the preparation from w-bromochlorobenzene and -butyl-lithium of w-chlorobenzoic acid— an expensive chemical  

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G. Wittig Newer Prep. Methods Org. Chem. 1, Syntheses with organolithium compounds 21 < ... 

Summary Fluorosilylamines and -hydrazines react with organolithium compounds to yield stable lithium derivatives. Perfluoro (Si-N) four- and six-membered ring systems are obtained with SiF4. The synthesis and crystal structures of the compounds are discussed. 

One of the largest uses for lithium metal is in the synthesis of organolithium compounds which are of immense utility, generally resembling Grignard reagents, but more reactive.39 They are commonly made by direct interaction of Li with an alkyl or aryl chloride in ether, benzene, or alkanes ethers are slowly attacked, however, by LiR. 

This route is useful for the synthesis of organolithium compounds, but is often hindered with the more reactive and heavier alkali metals because of the tendency toward Wurtz coupling (equation 2). 

This method can often be used for synthesis of organolithium compounds that are difficultly accessible by other means e.g., o-dilithiobenzene is formed in good yield when o-phenylenemercury is shaken for 3 days with lithium pieces in anhydrous ether.51... 

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