Copper 6-diketonates

Fig. 4a,b. Schematic diagram showing effect of lateral chains on the mesomorphism of copper -diketonate complexes... 

Copper catalysts for the formation of biaryl ethers have also been developed that contain diketonate ligands. Researchers at Merck Laboratories reported the coupling of aryl halides with phenols catalyzed by the combination of CuCl and 2,2,6,6-tetramethylhep-tane-3,5-dione (TMHD), which generates a copper diketonate catalyst (Equation 19.111). Catalysts containing related O-donor ligands have also been used. Two examples of reactions conducted with a polyol and with a phosphonic acid as ligand are shown in Equation 19.112 and Equation 19.113. ... 

The last example discussed concerns secondary acyclic amides, known to be poor nucleophilic partners rarely involved in coupling reactions with aryl halides. Recently a procedure (TaUlefer, Monnier et al.) has described a versatile catalytic system allowing their intermolecular N-arylation (Scheme 12) [165]. Overcoming this challenge using a simple copper/diketone (L27) system offers a general method for the preparation of acyclic tertiary amides. The structure-activity relationship studies of these important targets are thus facilitated by this method, which complements the known systems based on palladium. 

Copper is an attractive metallisation element because of its high conductivity. It has been added to Al in low concentrations (AlSi(l%)—Cu(0.5%)) to improve conductive priorities. Selective, low temperature copper CVD processing, using copper(I) P-diketonate compounds, has been carried out (23). 

P-diketones Hostaiex DK16, LIX54 Hoechst, Henkel copper extraction from ammoniacal solution... 

Copper(II) also forms stable complexes with O-donor ligands. In addition to the hexaaquo ion, the square planar /3-diketonates such as [Cu(acac)2l (which can be precipitated from aqueous solution and recrystallized from non-aqueous solvents) are well known, and tartrate complexes are used in Fehling s test (p. 1181). 

The mother liquor contains only 2-3 g. more of the diketone, which can be separated as the copper derivative by shaking an ethereal extract with a saturated aqueous solution of copper acetate,... 

In a similar reaction, lithium enoiates, RC(OLi)=CH2, were dimerized to 1,4-diketones, RCOCH2CH2COR, with CUCI2, FeCl3, or copper(II) triflate, in a nonprotic solvent." ... 

The reaction of crotonaldehyde and methyl vinyl ketone with thiophenol in the presence of anhydrous hydrogen chloride effects conjugate addition of thiophenol as well as acetal formation. The resulting j3-phenylthio thioacetals are converted to 1-phenylthio-and 2-phenylthio-1,3-butadiene, respectively, upon reaction with 2 equivalents of copper(I) trifluoromethanesulfonate (Table I). The copper(I)-induced heterolysis of carbon-sulfur bonds has also been used to effect pinacol-type rearrangements of bis(phenyl-thio)methyl carbinols. Thus the addition of bis(phenyl-thio)methyllithium to ketones and aldehydes followed by copper(I)-induced rearrangement results in a one-carbon ring expansion or chain-insertion transformation which gives a-phenylthio ketones. Monothioketals of 1,4-diketones are cyclized to 2,5-disubstituted furans by the action of copper(I) trifluoromethanesulfonate. ... 

Triphenylformazan behaves as a bidentate ligand forming 2 1 complexes (217) with divalent copper, nickel, and cobalt.377 Formazan metal complexes can be compared to complexes of azo dyes or beta diketones due to structural similarity.301,302 In general, formazan metal complexes have low stability toward acids. However, when electron-donating substituents are added to the aromatic ring, a considerable enhancement in stability is observed. Cationic complexes of type 218 are also known. The complexation of formazan with metal cation can be accompanied by oxidation to the tetrazolium salt and the formation of a complex... 

Organo copper and lithium enolates of cyclic ketones, lactones, and lactams or acyclic ketones are converted with acylimidazoles or imidazole-N-carboxylates into the corresponding / -diketones or / -ketoesters ... 

Silver(I) /3-diketonate derivatives have received significant attention due to the ease with which they can be converted to the elemental metal by thermal decomposition techniques such as metal organic chemical vapor deposition (MOCVD).59 The larger cationic radius of silver(I) with respect to copper(I) has caused problems in achieving both good volatility and adequate stability of silver(I) complexes for the use in CVD apparatus. These problems have been overcome with the new techniques such as super critical fluid transport CVD (SFTCVD), aerosol-assisted CVD (AACVD), and spray pyrolysis, where the requirements for volatile precursors are less stringent. 

The selectivity of the aldol addition can be rationalized in terms of a Zimmer -man-Traxler transition-state model with TS-2-50 having the lowest energy and leading to dr-values of >95 5 for 2-51 and 2-52 [18]. The chiral copper complex, responsible for the enantioselective 1,4-addition of the dialkyl zinc derivative in the first anionic transformation, seems to have no influence on the aldol addition. To facilitate the ee-determination of the domino Michael/aldol products and to show that 2-51 and 2-52 are l -epimers, the mixture of the two compounds was oxidized to the corresponding diketones 2-53. 

Copper chelates in which the ligands are rigid chiral p-diketonates of type 205 are responsible for the highest optical yields known in carbenoid cyclopropanation reactions 200). The cyclopropane 206 was even obtained enantiomerically pure from 2-diazodimedone and styrene in the presence of CuL (L = 205c). 

It has already been mentioned that prochirality of the olefin is not necessary for successful enantioselective cyclopropanation with an alkyl diazoacetate in the presence of catalysts 207. What happens if a prochiral olefin and a non-prochiral diazo compound are combined Only one result provides an answer to date The cyclopropane derived from styrene and dicyanodiazomethane shows only very low optical induction (4.6 % e.e. of the (25) enantiomer, catalyst 207a) 9S). Thus, it can be concluded that with the cobalt chelate catalysts 207, enantioface selectivity at the olefin is generally unimportant and that a prochiral diazo compound is needed for efficient optical induction. As the results with chiral copper 1,3-diketonates 205 and 2-diazodi-medone show, such a statement can not be generalized, of course. 

Kordosky, G. A. Virnig, M. J. Mattison, P. Beta-diketone copper extractants structure and stability. International Solvent Extraction Conference, Cape Town, South Africa, Mar. 17-21, 2002, 360-365. 

Symmetrical and unsymmetrical benzoins have been rapidly oxidized to benzils in high yields using solid reagent systems, copper(II) sulfate-alumina [105] or Oxone-wet alumina [105, 106] under the influence of microwaves (Scheme 6.32). Conventionally, the oxidative transformation of a-hydroxy ketones to 1,2-diketones is accomplished by reagents such as nitric acid, Fehling s solution, thallium(III) nitrate (TTN), ytterbium(III) nitrate, ammonium chlorochromate-alumina and dayfen. In addition to the extended reaction time, most of these processes suffer from drawbacks such as the use of corrosive acids and toxic metals that generate undesirable waste products. 

A different example of this general type involves the ds-dihydrazone complex (64). This complex is prepared by condensation of the corresponding dialdehyde with hydrazine in the presence of nickel or copper ion (Curtis, Einstein Willis, 1984). The two uncoordinated -NH2 groups react with a ketone or a diketone such that cyclization occurs in each case [2.8], In these systems, the pendant -NH2 groups are expected to be reactive since their non-coordination results in the respective nitrogen lone pairs being readily available for nucleophilic reaction. 

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