Copper, organo compounds examples

All of the neutral (organo-)copper compounds just listed can be arylated by aryl iodides and/or -bromides Ar-Cu and R-C=C-Cu can also be alkynylated by alkynyl iodides and/or -bromides. Table 16.2 summarizes the whole spectrum of corresponding products. After having grasped the mechanism of these reactions by way of Figure 16.3, we will discuss their synthetic potential by means of the examples given in Figures 16.4-16.9. 

Although there are numerous examples of dimerizations of organo-metallic reagents by copper(II) salts, one particularly interesting example concerns 2,2 -dilithiobiphenyl 304). Wittig and Klar have proposed several transient copper(II) ate complexes and a stable copper(I) complex to account for the high yields of biphenylene and o-tetraphenyl-ene. Diarylcopper(II) compounds were supposedly isolated, and characterized by elemental analysis, from diarylmercury compounds and copper at 120°C 11, 197) an unlikely reaction. 

Organo-copper compounds are important for the C-C link. In the solid state such copper compounds can exist as linear polymers. An example is the cyanocuprat. 2,4,6-Tris[(4-pyridyl)-methylsulfanyl]-l,3,5-triazine with Ag forms a one-dimensional chain polymer with nanometer tubes 28a (M = Ag(I)) [83]. These tubes are connected via Ag-N and Ag-S bonds to form linear chains 28b (see Experiment 7-5, Section 7.7). Other comparable polymers are mentioned in [83]. 

The Cadiot-Chodkiewcz and Glaser reactions are the synthetic reaction with acetylene type compounds. As the acetylene compounds easily form stable organo-copper compounds, these acetylenecopper compounds react directly with halides to afford the acetylene derivatives. This synthetic reaction is called the Castro reaction [43]. For example, as shown in eq. (22.22), aryl compounds having functional groups such as OMe, NO2 and COOH are able to condense with copper acetylides... 

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