1,4-addition functionalized organocopper compounds

Intensive studies have been devoted to a mechanistic rationale of the conjugate addition of organocopper compounds and give a rather complex picture [141, 135, 136]. A simplified mechanistic model starts from dimeric lithium cuprates 131, wherein oxygen is assumed to coordinate to lithium and the carbon-carbon double bond to copper. The chelated cuprate 133, but also the nonchelated species 132 might function as intermediates for the formation of... 

Scheme 2.11. Michael additions of functionalized organocopper reagents derived from Grignard compounds.

The facile iodination of organocopper compounds (79) is a useful reaction for the characterization of intermediate copper compounds which are formed by addition or insertion reactions 61, 223, 294, 304). Bromine has also been used 223, 294), but the yields may be low ( 15%) compared with iodolysis, because of bromine s ability to function as an oxidant 223). 

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