Organocopper compounds bonding

Organocopper compounds used for carbon-carbon bond formation are called Gilman reagents in honor of Henry Gilman who first stud led them Gilman s career in teaching and research at Iowa State spanned more than half a century (1919-1975)... 

As in the case of addition reactions of carbon nucleophiles to activated dienes (Section HA), organocopper compounds are the reagents of choice for regio- and stereoselective Michael additions to acceptor-substituted enynes. Substrates bearing an acceptor-substituted triple bond besides one or more conjugated double bonds react with organocuprates under 1,4-addition exclusively (equation 51)138-140 1,6-addition reactions which would provide allenes after electrophilic capture were not observed (cf. Section IV). 

The above analysis for copper chemistry also applies to the same-class element gold, which, however, forms much more stable C-Au bonds [176] and so is un-reactive. On the other hand, the d-orbitals of zinc(II), a main group neighbor, are too low-lying to make organozinc compounds as nucleophilic as organocopper compounds [92],... 

Reactions with hthium or Grignard reagent yield alkyl or aryl copper(I) derivatives, respectively. Such organocopper compounds containing Cu-Cu bonds are formed only by Cu+ and not Cu2+ ions. 

In this chapter, reagents that transfer a carbanion (in contrast to an enolate ion) to the C atom of a C=0 double bond are referred to as C nucleophiles. The most important nucleophiles of this kind are organolithium compounds and Grignard reagents. Organocopper compounds transfer their carbanion moieties to the carbonyl carbon far less easily and usually not at all. 

The carbocupration of alkynes, that is, the addition to a non-activated C-C triple bond, is another classical reaction of organocopper compounds. Due to the high regioselectivity and m-stereoselectivity usually observed in... 

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