Lithium Diorganocopper Gilman Reagents

Organomagnesium and Organolithium Compounds 15-2 Lithium Diorganocopper (Gilman) Reagents 15.3 Carbenes and Carbenoids... 

Formation of Gilman Reagents (Section 15.2A) Lithium diorganocopper (Gilman) reagents are prepared by treating an organolithium compound with copper(I) iodide. 

Complete these reactions involving lithium diorganocopper (Gilman) reagents. 

Show how to convert 1-bromopentane to each of these compounds using a lithium diorganocopper (Gilman) reagent. Write an equation, showing structural formulas, for each s)mthesis. 

In Problem 15.8, you used a series of lithium diorganocopper (Gilman) reagents. Show how to prepare each Gilman reagent from an appropriate alkyl or vinylic halide. 

Acid chlorides react readily with lithium diorganocopper (Gilman) reagents (Section 15.2) to give ketones, as illustrated by the conversion of pentanoyl chloride to 2-hexanone. The reaction is carried out at -78°C in either diethyl ether or tetrahy-drofuran. Following hydrolysis in aqueous acid, the ketone is isolated in good yield. 

These alkyllithiums can combine with Cul to form lithium diorganocopper compounds (R2CuLi), which are known as Gilman reagents. 

Sec. 10.8) formation of lithium diorganocopper reagents (Gilman reagents) from... 

Cuprous iodide, Cul Reacts with organolithiums to yield lithium diorganocopper reagents (Gilman reagents Section 10.8). 

Lithium diorganocopper reagent (Gilman reagent), LiR2Cu Couples with alkyl halides to yield alkanes (Section 10.8). 

One of the most valuable reactions of alkyllithiums is their use in making lithium diorganocopper compounds, R2CuLi, called Gilman reagents. These reagents are easily prepared by reaction of an alkyllithium with cop-per(I) iodide, Cul, in ether solvent. 

AU l halides also react with lithium metal to form oi anolithium reagents, RLi. In the presence of Cul, these form diorganocoppers, or Gilman reagents (R CuLi). Gilman reagents react with alkyl halides to yield coupled hydrocarbon products. 

This example illustrates the coupling of a Gilman reagent, a nucleophile, with a vinylic halide, an electrophile. Vinylic halides are normally quite unreactive toward nucleophilic displacement. Thus, the lithium diorganocopper reaction shown here is unique. 

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