Iodides copper complexes

The complexation of anionic species by tetra-bridged phosphorylated cavitands concerns mainly the work of Puddephatt et al. who described the selective complexation of halides by the tetra-copper and tetra-silver complexes of 2 (see Scheme 17). The complexes are size selective hosts for halide anions and it was demonstrated that in the copper complex, iodide is preferred over chloride. Iodide is large enough to bridge the four copper atoms but chloride is too small and can coordinate only to three of them to form the [2-Cu4(yU-Cl)4(yU3-Cl)] complex so that in a mixed iodide-chloride complex, iodide is preferentially encapsulated inside the cavity. In the [2-Ag4(//-Cl)4(yU4-Cl)] silver complex, the larger size of the Ag(I) atom allowed the inner chloride atom to bind with the four silver atoms. The X-ray crystal structure of the complexes revealed that one Y halide ion is encapsulated in the center of the cavity and bound to 3 copper atoms in [2-Cu4(//-Cl)4(//3-Cl)] (Y=C1) [45] or to 4 copper atoms in [2-Cu4(/U-Cl)4(/U4-I)] (Y=I) and to 4 silver atoms in [2-Ag4(/i-Cl)4(/i4-Cl)] [47]. NMR studies in solution of the inclusion process showed that multiple coordination types take place in the supramolecular complexes. 

Addition of aqueous cyanide ion to a copper(II) solution gives a brown precipitate of copper(II) cyanide, soluble in excess cyanide to give the tetracyanocuprate(II) complex [Cu(CN)4] . However, copper(II) cyanide rapidly decomposes at room temperature, to give copper(I) cyanide and cyanogen(CN)2 (cf. the similar decomposition of copper(II) iodide, below) excess cyanide then gives the tetracyanocuprate(I) [Cu(CN)4] . 

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 ... 

Carboxylic acids, a-bromination of 55, 31 CARBOXYLIC ACID CHLORIDES, ketones from, 55, 122 CARBYLAMINE REACTION, 55, 96 Ceric ammonium nitrate [Ammonium hexa mtrocerate(IV)[, 55, 43 Chlorine, 55, 33, 35, 63 CHROMIUM TRIOXIDE-PYRIDINE COMPLEX, preparation in situ, 55, 84 Cinnamomtnle, a-phenyl- [2-Propeneni-tnle 2,3-diphenyl-], 55, 92 Copper(l) iodide, 55, 105, 123, 124 Copper thiophenoxide [Benzenethiol, copper(I) salt], 55, 123 CYCLIZATION, free radical, 55, 57 CYCLOBUTADIENE, 55, 43 Cyclobutadieneiron tricarbonyl [Iron, tn-carbonyl(r)4-l,3-cyclo-butadiene)-], 55,43... 

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... 

The reduction of a solution of a trialkylphosphine copper(I) iodide complex (CuIPR ) with preformed lithium naphthalide (LiNp) in THF or DME under argon was found to give a more reactive copper species, which will undergo oxidative addition with a variety of organic substrates at room... 

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)... 

The choice of catalyst is important, for instance the use of tetrakis(triphenylphos-phane)palladium(O) complex results in the quantitative cyclotrimerization of 3,3-dimethylcy-elopropene.17 In similar fashion 3,3-dimethoxycyclopropene cyciodimerizes to 3 (R = OMe, 74%) using bis(dibenzylideneacetone)paUadium(0) [Pd(dba)2] complex.18 The trisubstituted cyclopropene 4 is transformed to the head-to-head dimer 5 in the presence of copper(I) iodide.19... 

Silver iodide derivatives of trialkyl-phosphines and -arsines were prepared in 1937 for comparison with their copper(I) iodide analogues.201 The preparations involved shaking the ligands with silver iodide dissolved in concentrated aqueous KI. The products were found to be tetramers and of similar structure to the Cu1 complexes. The Pr As silver complex was isomorphous with [Cul-AsEt3]4. Molecular weight determinations in a range of organic solvents showed that partial dissociation occurred in solution. 

Vinylations and arylations of polystyrene-bound 2-bromofurans have been accomplished by treatment with stannanes [98] or boronic acids [99] in the presence of palladium complexes. Alternatively, 2-furylstannanes can be coupled with support-bound aryl iodides or bromides in the presence of palladium or copper complexes (Entries 5-7, Table 15.8). 

Phosphine-complexed cuprates, formed from copper(I) iodide, 1 mol equiv. of RtLi, and 2-5 mol equiv. of tri-n-butylphosphine, show good reactivity in conjugate addition reactions with enones (Table l).39 The hazards surrounding the use of excess Bun3P, and the availability of other methodologies lower the popularity of this method, but efficiency can be realized with this methodology. 

Tanaka reported the synthesis of (/ )-muscone (10) by an enantioselective conjugate addition of chiral alkoxydimethylcuprate, which was prepared from chiral ercdo-3-[(l-methylpyrrol-2-yl)methylamino]-l,7,7-trimethylbicyclo[2.2.1]heptan-2-ol (9), methyllithium, and copper iodide (Scheme 9.7) [16]. In this reaction, convex deviation from a linear correlation was observed when the chiral ligand had a higher enantiopurity. This positive NLE was probably induced by the formation of a reactive homochiral dinuclear copper complex to give (R)-muscone. Rossitter also observed asymmetric amplification in a copper-catalyzed conjugate addition of methyl-... 

Terminal alkynes can be alkenylated by alkenyl triflates (bromides, iodides) in the presence of catalytic amounts of a palladium(O) complex (or a precursor thereof) and usually an additional substoichiometric amount of copper(I) iodide (Cul), and they can be arylated by aryl triflates (bromides, iodides). These reactions are called Cacchi coupling reactions if triflate reagents are employed, and Sonogashira-Hagihara coupling reactions if halides are used. 

Cacchi- and Sonogashira-Hagihara couplings occur only if a primary, secondary, or tertiary amine is present, and it is best to have the amine present in large excess. Under these conditions the acetylene will at least form a small equilibrium concentration of the corresponding ammonium acetylide or copper complex thereof. The copper iodide serves to trap this species as a copper acetylide. The copper acetylide represents a substantially improved nucleophile in comparison to the free acetylene. Without the Cul addition, the acetylide content of the reaction mixture is so small that a reaction occurs only at higher temperatures. 

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