Organocopper compounds functionalized

However, good yields of ketones can be obtained for an equivalent quantity of acid halide per group attached to copper. Suitable conditions exist for the coupling of dialkylcuprates with acid chlorides which contain other functional groups (233), such as carbonyl, carboxy, and cyano. The order of reactivity of these groups towards organocopper compounds is CHO > CO > COgR > CN. Benzoyl fluoride reacts very slowly with lithium dimethylcuprate. 

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). 

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... 

Grignard reagent or organocopper compounds. Therefore, the new approach is potentially applicable as a synthetic method for functionalized allenes. The exchange mechanism was also investigated by means of DFT calculations [55]. 

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

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