Copper-carbon bond

This simplified view can explain stability trends and differences between various organocopper(I) compounds, as well as the influence of bulky or coordinating substituents ortho to the copper-carbon bond on the stability of arylcopper compounds. This interpretation of the copper-carbon bond can also be applied to the binding of sp (alkyl e.g., CH2SiMe3), sp (C=C-R) [40], and other sp (vinyl) groups [41, 42]. 

The electron-withdrawing power of fluorine reduces the electron density at the copper-carbon bond and renders it less reactive. Therefore these complexes are more stable than their analogs containing hydrogen. 

Rearrangement processes of alkyltitanocene dichlorides that occur under electron impact have been investigated using deuterium labelling. A novel type of zirconium-mediated coupling reaction of alkynes with vinyl bromide to afford 2,3-disubstituted dienes has been reported (see Scheme 105), and an inter-intramolecular reaction sequence has been proposed for the observed formation of vinylcyclohexadienes and/or methylenecycloheptadienes from the copper-catalysed reaction of zirconacyclo-pentadienes with allylic dichlorides. The essential step in these processes appears to be transmetallation of the zirconium-carbon bond of the zirconacyclopentadiene to produce a more reactive copper-carbon bond. New phosphorus heterocycles, e.g. (417), have been constructed by the thermal rearrangement of a [l,4-bis(trimethylsilyl)->/ -cyclooctatetraene]- ,3,5-triphospha-7-hafhanorbomadiene complex (416). 

Another application of pure organocopper compounds is as starting materials for the synthesis of other organocopper compounds. Treatment of [CuCisHjCFj-3] with (CF3)sCBr, for example, affords CuC(CF3)3 throu a halogen/metal exchange reaction [73] (Eqn. 2 in Scheme 1.12). A further demonstration of the applicability of pure organocopper compounds is the insertion reaction of an isocyanide into a copper-carbon bond [74], (Eqn. 3 in Scheme 1.12). 

Reversible carbon dioxide fixation. This complex undergoes reversible insertion of CO2 into the copper—carbon bond at ambient temperatures and ordinary pressure (equation I). ... 

This process, which involves carbon-carbon bond formation, does not involve homolysis of the copper carbon bond followed by reactions analogous to Eqs. (26) or (27) (86). Whereas in highly acidic solutions (pH <1.5) Cu -CHjg q decomposes heterolytically, via reaction (17), yielding methane as the final product, the decomposition of Cu -CHat pH > 2.5 obeys a second order rate law (2k = 3.0 x 10 s ) (92), with the rate being independent of the concentrations of Cu +, Cu+q, (CH3)2S0, and CH3C02Na. Ethane is the final product of this reaction (86). Thus Cu -CHg q decomposes via a bimolecular or a heterolytic process depending on pH. 

Copper-Carbon Bonds in Mechanistic and Structural Probing of Proteins as well as in Situations where Copper Is a Catalytic or Receptor Site... 

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