Organometallic reagents organocopper compounds

Generally, organocopper compounds can be prepared by transmetallation between copper salts and organometallic reagents such as RLi, RMgX, and RZnX.53,53a,53b Copper alkynides can be obtained by reaction of terminal alkynes... 

Copper(II) chloride has often been employed in reactions with lithium and Grignard reagents to obtain organocopper(I) compounds. Two equivalents of the organometallic reagent are required, one of which is used to reduce Cu(II) to Cu(I). Unstable alkylcopper(II) compounds may be intermediates. The reaction is usually represented by the equation... 

Formation of metal-carbon bonds by addition of an organometallic reagent to an unsaturated compound or a diazonium compound is a little-used method in organocopper chemistry. Various alkylcopper reagents, (RCu + MgXg or LiX), add to acetylene or the alkynes, RC=CH, in a cis manner in ether or ether-pentane at low temperatures (223). A 7T-complex is a probable intermediate. The vinylcopper addition product obtained is dependent on the nature of the alkyne, being sensitive to electronic effects in the latter ... 

In this chapter, the substitution reactions of organometallic reagents with organic halides and related electrophiles are reviewed. - The major portion of the chapter is devoted to a discussion of organocopper compounds, which first transformed the alkylation of nonstabilized carbanions into a reaction of general synthetic utility. More recently, transition metals other than copper have also found widespread application in such coupling reactions, and developments in this area are outlined in Section 1.5.3. 

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