Mechanisms organocuprate conjugate addition

There are two major reactions of organocuprates, and both give products reminiscent of a carbon nucleophile (1) reaction with alkyl halides and (2) conjugate addition with a,p-unsaturated ketones. Conjugate addition to a, 3-unsaturated ketones is promoted when ether is used as a solvent.381 The substitution reaction is promoted by the use of THF or ether-HMPA as a solvent. l As mentioned earlier, the mechanism of these reactions probably involves a one-electron transfer, although other mechanistic proposals are in the literature,but the synthetic result is that expected of a carbon nucleophile. 85 The general reactivity of organocuprates with electrophiles follows the order ... 

When a stabilized enolate undergoes a 1,4-conjugate addition with an enone, it is called a Michael reaction. However, many related reactions with analogous mechanisms are also described as Michael additions. Any C=C double bond containing one or more EWGs is referred to as a Michael acceptor and soft nucleophiles that prefer 1,4-addition, including stabilized enolates and organocuprates, are described as Michael donors. ... 

Enones.—The synthetic utility of organocuprates has been reviewed. House has presented a correlation between the conjugate addition of lithium dimethylcopper to a -unsaturated carbonyl compounds and their polarographic reduction potentials such a correlation is compatible with the first step of the mechanism (Scheme 100) proposed for this reaction. In conjunction with empirical rules for the estimation (with an accuracy of 0.1 V) of the reduction potentials of such unsaturated compounds, this... 

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