Copper iodide 723 CuBr

The Sandmeyer procedure for the synthesis of aryl halides from arylamines has been applied, with modification, to the conversion of 5- and 8-aminoquinolines to the iodo and bromo derivative. 8-Aminoquinoline is converted to 8-bromoquinoline in good yield on treatment with /-butyl nitrite in the presence of CuBr in acetonitrile at 60 °C <2003JOC5123> and 5-amino-6-nitroquinoline is converted to the 5-iodo derivative under equally mild conditions using potassium nitrite and copper iodide in DMSO at 60 °C <2005JOC2445>. 

There has been a great deal of study concerning the effect of solvents and other reaction conditions on the stability and reactivity of organocuprate species.8 These studies have found, for example, that (CH3)2S-CuBr, a readily prepared and purified complex of CuBr, is an especially reliable source of Cu(I) for cuprate preparation.9 Copper(I) cyanide and iodide are also generally effective and, in some cases, preferable.10... 

Copper 11 halides are formed with chlorine, bromine and iodine, the chloride and bromide by reduction of the coppertll) halides with copper powder, and the iodide by reduction of coppertll) sulfate. CuSOj solulion with potassium iodide. The fluoride appears never to have been made, despite reports to the contrary. All are insoluble in H20. CoppertUl fluoride, CuF may be made from CuO and hydrofluoric acid at 400°C. coppertll) chloride. CuCl by dissolving the oxide or carbonate in HCI, and coppertll) bromide. CuBr from copper and bromine water coppertll) iodide. Cub, is unstable at room temperature with respect to decomposition intu Cul and iodine. The chloride and bromide are water-soluble, and ionic. The fluoride is only slightly water-soluble. Anhydrous copper(U) chloride. Cud , is monoclinic and its structure contains infinite-chain molecules formed by CuCLi groups that share opposite edges. CuBr. has a similar structure. 

Alternative methods for obtaining these types of cuprates, R2CUX (where R = alkenyl or aryl), include treatment of RBr with lithium metal and copper(I) iodide under ultrasonication, reaction between a dialkylvinylborane and CuBr-Me2S or between a chlorodivinylborane and methylcopper. The latter... 

A large number of styrenic monomers have been investigated in metal-catalyzed radical polymerizations. Polymerization of styrene (M-19) can be controlled with copper,28,84,85 152 176 ruthenium,57 60 62 66 86,205 iron,71 75 rhodium,86 140 rhenium,141 and molybdenum catalysts.144 The polymerizations have actively been studied with the copper-based systems, among which precisely controlled molecular weights and very narrow MWDs (MJMn =1.1) were obtained in a homogeneous system consisting of 1-13 (X = Br), CuBr, and L-3 in the bulk at 130 °C.85 Similar well-controlled polymerizations are feasible with several ruthenium (Ru-5)60 and iron (Fe-2,72 Fe-3,73 and Fe-471) complexes in conjunction with a bromide or iodide initiator. Even a chloride initiator (1-25, X = Cl) can afford narrow MWDs (MJMn =1.1) when coupled... 

Copper(I) fluoride is not known CuCl, CuBr and Cul are white solids and are made by reduction of a Cu(II) salt in the presence of halide ions, e.g. CuBr forms when SO2 is bubbled through an aqueous solution of CUSO4 and KBr. Copper(I) chloride has a zinc blende structure (see Figure 5.18). The y-forms of CuBr and Cul adopt the zinc blende structure but convert to the jB-forms (wurtzite structure, Figure 5.20) at 660 and 690 K respectively. Values of iCsp(298K) for CuCl, CuBr and Cul are 1.72x10 , 6.27 X 10 and 1.27 x 10. Copper(I) iodide precipitates when any Cu(II) salt is added to KI solution (equation 21.102). 

Whereas interaction between 2-thienyllithium and 2-furyllithium and carbon disulfide in THF affords the corresponding dithioates RCSSLi as the predominant products, aryllithium compounds seem to attack mainly on sulfur with formation of arenethiolates and tarry products [9]. If during the addition of carbon disulfide copper bromide is present in the solution, however, the desired formation of Ar—CSSLi does take place and subsequent addition of methyl iodide affords the dithioesters in good yields. Good results are also obtained when using less than stoichiometric amounts of CuBr. We therefore presume that carbon disulfide reacts more easily with the arylcopper intermediate than with aryllithium copper is subsequently transmitted from the copper dithioate to aryllithium. 

Treatment of diazonium salts with cuprous, Cu(I), salts generates aryl halides. When 398 reacts with CuCl (cuprous chloride) or CuBr (cuprous bromide), the products are chlorobenzene or bromobenzene via what is probably a radical reaction.29l jhis conversion is known as the Sandmeyer reaction. 2 The use of copper powder rather than cuprous salts for this transformation is often called the Gattermann reaction. 93,292b,c Aryl iodides are also produced from diazonium salts by reaction with potassium iodide (KI) but the actual reactive species may be l3-.294,295 Treatment of aniline derivative 403 with sodium nitrite and HCl followed by treatment with KI, for example, gave a 89% yield of 404.Aryl nitriles are generated under Sandmeyer conditions using cuprous cyanide (CuCN), as in the conversion of 405 to benzonitrile derivative 407 via diazonium chloride, 406. 

In the presence of the phosphazene Et-P2 base as well as DBU the coupling of aryl iodides with arenethiols only requires catalytic amounts of copper(I) bromide (CuBr). Under these conditions, the reaction can be performed in refluxing toluene to give biaryl thioethers in excellent yields [40] (Scheme 5.22). 

The reaction is facilitated by the polar solvents, e.g. DMF [33], DMSO [33], or acetonitrile [32], and tetraalkylammonium fluorides as organic solvent-soluble sources of fluoride anion, which convert the aryldimethylsilicon chlorides to the respective fluorides. The latter smoothly undergo the transmetallation reaction from silicon to copper, what finally resulted in the formation of biaryls in high yields. Beside copper(I) iodide, other Cu(I) salts such as CuCl, CuBr and CuOTf have been employed, however, Cul works the most efficiently with ArSiMe2X [32], whereas copper(I) chloride and triflate are suitable in the reactions with ArSiEtF2, and ArSiFj... 

Accordingly, catalytic and stoichiometric amounts of cuprous salts were employed for Mizoroki-Heck-type reactions of various conjugated alkenes [ 19]. Intermolecular catalytic arylations of methyl acrylate (1, not shown) and styrene (2) were accomplished under ligand-free conditions using CuBr (3) or Cul (4) as catalyst in A-methyl-2-pyrrolidinone (NMP) as solvent various aryl iodides could be employed (Scheme 10.2). On the contrary, aryl bromides and chlorides, as well as aliphatic halides, were found to be unsuitable substrates. The reactions employing an alkenyl bromide, methylmethacrolein or methyl methacrylate required stoichiometric amounts of copper salts. 

Both intramolecular and intermolecular versions of palladium-free, copper-catalyzed, Stille reactions have been reported. In most of these cases, the Cu(I) is added as a salt in the absence of added ligand. In these cases, CuBr or Cul is typically used as the catalyst with CsF as an additive in DMF or NMP solvent at 60-90 Li and Zhang reported a reusable copper catalyst for the Stille reaction of aryl iodides, bromides, and even activated chlorides based on 10% of cubic Cu O nanoparticles with 20 mol % of P(o-tol), and the combination of KF 2H20 and Bu NBr at 125-130... 

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