Organolithium reagents metal-halogen exchange

Scheme 7.2. Preparation of Organolithium Reagents by Halogen-Metal Exchange... 

Annulation of aryl halides with ortho side chains bearing a pendant electi ophilic moiety via treatment with an organolithium reagent, involving halogen-metal exchange and subsequent nucleophilic cyclization to form 4- to 7-membered rings. 

Organolithium reagents and aryl bromides and iodides tend to undergo metal-halogen exchange (Eq. 14.4) ... 

Among the extensive studies for the preparation of heteroaryl compounds, organometallic reagents are frequently used and mainly prepared from metal-halogen exchange reactions or the metathesis of the corresponding organolithium... 

Organolithium reagents and aryl bromides and iodides readily undergo metal-halogen exchange by nucleophilic attack of R on the halide (Eq. 14.4). This very rapid reaction is often carried out at very low temperature (—80°C) where other processes do not compete. 

Organolithium Reagents from Halogen-metal Exchange. 

Metal-halogen exchange is a second important method for preparation of organolithium reagents. This reaction proceeds in the direction of forming the more... 

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