Halogen/metal interconversion organolithium reagents

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

An important feature of the halogen/metal interconversion is that it is an equilibrium-controlled process, which is therefore shifted toward the most stable organolithium or organomagnesium reagent or, to put it in other words, toward the weakest base [18-20],... 

Metal-halogen interconversions are primarily used to prepare organolithium compounds from alkyl and aryl hahdes. Particular Grignard reagents can be prepared from this methodology. They often give better yields than reactions between halides and magnesium... 

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