Copper aryl iodides

Arylation or alkenylation of soft carbon nucleophiles such as malonate is carried out by using a copper catalyst, but it is not a smooth reaction. The reaction of malononitrile, cyanoacetate, and phenylsulfonylacetonitrile with aryl iodide is possible by using a Pd catalyst to give the coupling products. 

Copper-mediated coupling of the aryl iodide derived from l,3-bis(2-hydroxy-hexafluoroisopropyl)benzene with perfluorooctyl iodide gives the desired compound as a dimethyl sulfoxide (DMSO) complex [166] (equation 143) Even bromoarenes can be coupled [167] (equation 144)... 

Tnfluorometltylation of aryl, alkenyl, and alkyl halides can be accomplished by heating methyl fluorosulfonyldifluoroacetate and the appropriate halide precursor with copper(I) iodide at 60-80 °C in DMF [27 7] (equation 145). Similar trifluoromethylations of aryl, benzyl, and vinyl halides can be carried out with fluorosulfonyldifluoromethyl iodide and copper metal in DMF at 60-80 °C [2 75] (equation 146). 

The perfluoroacetylenic copper compounds undergo coupling reactions with aryl iodides and provide a useful synthetic route to the perfluoroalkyl aryl alkynes [147, 255] (equation 170) Coupling of these copper reagents with the 1-iodo-perfluoroalkynes gives the perfluorodiynes [747 255] (equation 171)... 

The analogous trifluoromethylseleno and pentafluorophenylseleno copper compounds are prepared via reaction of the corresponding diselenide with copper metal [265, 269] Coupling with aryl iodides gives the arylselenium denvative [265] (equation 185)... 

The original Sonogashira reaction uses copper(l) iodide as a co-catalyst, which converts the alkyne in situ into a copper acetylide. In a subsequent transmeta-lation reaction, the copper is replaced by the palladium complex. The reaction mechanism, with respect to the catalytic cycle, largely corresponds to the Heck reaction.Besides the usual aryl and vinyl halides, i.e. bromides and iodides, trifluoromethanesulfonates (triflates) may be employed. The Sonogashira reaction is well-suited for the synthesis of unsymmetrical bis-2xy ethynes, e.g. 23, which can be prepared as outlined in the following scheme, in a one-pot reaction by applying the so-called sila-Sonogashira reaction ... 

Aryl chlorides and bromides are prepared by reaction of an arenediazonium salt with the corresponding copper(I) halide, CuX, a process called the Sandmeyer reaction. Aryl iodides can be prepared by direct reaction with Nal without using a copper(T) salt. Yields generally fall between 60 and 80%. 

Aryl sulfones have been prepared from sulfinic acid salts, aryl iodides and Cul. Unactivated thiocyanation has been accomplished with charcoal supported copper(I) thiocyanate." ... 

Reaction between aryl iodides and copper acetylids... 

CHROMIUM TRIOXIDE-PYRIDINE COMPLEX, preparation in situ, 55, 84 Chrysene, 58,15, 16 fzans-Cinnamaldehyde, 57, 85 Cinnamaldehyde dimethylacetal, 57, 84 Cinnamyl alcohol, 56,105 58, 9 2-Cinnamylthio-2-thiazoline, 56, 82 Citric acid, 58,43 Citronellal, 58, 107, 112 Cleavage of methyl ethers with iodotri-methylsilane, 59, 35 Cobalt(II) acetylacetonate, 57, 13 Conjugate addition of aryl aldehydes, 59, 53 Copper (I) bromide, 58, 52, 54, 56 59,123 COPPER CATALYZED ARYLATION OF /3-DlCARBONYL COMPOUNDS, 58, 52 Copper (I) chloride, 57, 34 Copper (II) chloride, 56, 10 Copper(I) iodide, 55, 105, 123, 124 Copper(I) oxide, 59, 206 Copper(ll) oxide, 56, 10 Copper salts of carboxylic acids, 59, 127 Copper(l) thiophenoxide, 55, 123 59, 210 Copper(l) trifluoromethanesulfonate, 59, 202... 

More recently, a study with di- and mono-carbene Pd(II) complexes has demonstrated that the Sonogashira coupling of activated and non-activated aryl iodides can be carried out in an aqueous, aerobic medium and in the absence of amines. These results suggest that the moisture-sensitive copper-acetylide may not be present in this particular transformation, and that a Pd-acetyhde could be formed by deprotonation of the coordinated alkyne instead of transmetallation [130]. 

It has been found that a number of bidentate ligands greatly expand the scope of copper catalysis. Copper(I) iodide used in conjunction with a chelating diamine is a good catalyst for amidation of aryl bromides. Of several diamines that were examined, rra s-yV,yV -dimethylcyclohexane-l,2-diamine was among the best. These conditions are applicable to aryl bromides and iodides with either ERG or EWG substituents, as well as to relatively hindered halides. The nucleophiles that are reactive under these conditions include acyclic and cyclic amides.149... 

Copper(I) iodide with 1,10-phenanthroline catalyzes substitution of aryl iodides by alcohols. The reaction can be done either in excess alcohol or in toluene.152... 

The direct reaction of zinc metal with organic iodides dates back to the work of Frankland(67). Several modifications have been suggested since that time to increase the reactivity of the metal. The majority of these modifications have employed zinc-copper couples(68-72), sodium-zinc alloys(73), or zinc-silver couples(77). Some recent work has indicated that certain zinc-copper couples will react with alkyl bromides to give modest yields of dialkylzinc compounds(74,73). However, all attempts to react zinc with aryl iodides or bromides have met with failure. The primary use of zinc couples has been in the Simmons-Smith reaction. This reaction has been primarily used with diiodomethane as 1,1-dibromides or longer chain diiodides have proven to be too unneactive even with the most reactive zinc couples. 

Rh2(OAc)4-catalyzed decomposition of 2-diazocyclohexane-l,3-dione 380a or its 5,5-dimethyl derivate 380b in the presence of an aryl iodide leads to an iodonium ylide 381 355). The mild reaction conditions unique to the rhodium catalyst are essential to the successful isolation of the ylide which rearranges to 382 under the more forcing conditions required upon copper catalysis (copper bronze, Cu(acac)2, CuCl2) 355). 

The reaction of benzotriazoles with aryl halides catalyzed by a mixture of Pd(dppe)Cl2 (DPPE = bis-(diphenylphosphino)ethane) or Pd(dppf)Cl2, copper(I)iodide or copper(II)carboxylates, and a phase-transfer catalyst has been shown to proceed in good yield in DMF solvent.104 Both copper and palladium were required for these reactions to occur at the N-l position in high yields. Similar results for the coupling of amines with aryliodonium salts in aqueous solvent were observed.105... 

Bis(pyrazolyl)borate copper complex 47 has been employed as a catalyst in the homogeneous and heterogeneous styrene epoxidation reactions <00JCS(CC)1653>. Pyrazole palladacycles 48 have proven to be stable and efficient catalysts for Heck vinylations of aryl iodides <00JCS(CC)2053>. An asymmetric borane reduction of ketones catalyzed by N-hydroxyalkyl-/-menthopyrazoles has been reported <00JHC983>. 

The utility of a palladium catalyst in the synthesis of substituted aryl acetylenes is well established.(7,8,9,10) The end-capping agent I was produced by using a standard catalyst system, dichlorobls(triphenylphosphlne)palladlum (II)/copper (I) iodide/triphenylphosphlne mixture, which has been employed in previously developed ethynylation procedures.(10) The copper (I) iodide is believed to act as a cocatalyst, reducing the palladium (II) complex to the active palladium (0) catalyst. The scheme is shown in Figure 3 (diethylamine is the solvent).(11)... 

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