Cu-catalyzed

Basic oxides of metals such as Co, Mn, Fe, and Cu catalyze the decomposition of chlorate by lowering the decomposition temperature. Consequendy, less fuel is needed and the reaction continues at a lower temperature. Cobalt metal, which forms the basic oxide in situ, lowers the decomposition of pure sodium chlorate from 478 to 280°C while serving as fuel (6,7). Composition of a cobalt-fueled system, compared with an iron-fueled system, is 90 wt % NaClO, 4 wt % Co, and 6 wt % glass fiber vs 86% NaClO, 4% Fe, 6% glass fiber, and 4% BaO. Initiation of the former is at 270°C, compared to 370°C for the iron-fueled candle. Cobalt hydroxide produces a more pronounced lowering of the decomposition temperature than the metal alone, although the water produced by decomposition of the hydroxide to form the oxide is thought to increase chlorine contaminate levels. Alkaline earths and transition-metal ferrates also have catalytic activity and improve chlorine retention (8). 

DARZENS - NENITZESCU Acylation Zn-Cu catalyzed Fnedel-Crafts type acylation of oleTms with acyl chlorides... 

LADEN8URG Pyadlne Benzyiation Cu catalyzed a- and y-benzyiation of pyndine. 

Formation of polyoyclics from a dazonlum salt. Intramolecular Cu catalyzed arylation of dazonlum salts (see Gombeig Bachmann). 

ROSENMUNO - B R A U N Aramatlc Cyanation Cu catalyzed nucleoptidic eubstitulion ol aromatic halogen by cyanide (see UHman-Goldberg)... 

Cu catalyzed arsonylation by substitution ol aromatic halides See also Bart-Schellet... 

ULLMANN GOLDBERG Aromatic substitution Cu catalyzed substitution of aromatic halides in the synthesis of disryls, diaiyl ethers, diaryl amines, phenols... 

It should be noted that these were the first examples of the Cu-catalyzed crosscoupling of arylhalides with terminal acetylenes. The authors (71IZV1764) carried out the acetylenic condensation with unreactive 4-iodo-l,3,5-trimethylpyrazole, a compound in which the halogen atom is not only found in a position more unfavorable for replacement, but is also further deactivated by the introduction of electron-donor methyl groups (Scheme 40). 

TABLE XL 3-Alkynylpyrazoles Prepared by Pd/Cu-Catalyzed Couplings between Acetylenes and Pyrazolylhalides [81IZV1342 86TH1 99JCS(P1) 3713]... 

TABLE XIII. Polyalkynylpyrazoles Prepared by Cu- or Pd/Cu-Catalyzed Coupling between Acetylenes and Pyrazolylhalides [71IZV1764 72IZV2524 86TH1 92IZV507]. 

A microwave-assisted Cu-catalyzed Sonogashira-type protocol on aryl iodide substrates without the involvement of a palladium catalyst has also been published (Scheme 54) [71]. Reactions were executed using Cut and CS2CO3 in NMP at 195 °C. The application seems to be fairly limited since there are indications that only (hetero)arylacetylenes are suitable coupHng partners for this protocol. In addition, aryl bromides react more sluggishly than aryl iodides. Moreover, even on aryl iodides the reaction times required are on the order of hours. 

A combined photochemical and biocatalytic approach provided access to bicyclo [4.2.0]octanes via a novel strategy. The Cu-catalyzed [2 + 2] photocydoaddition of... 

Scheme 31. Example of Cu-catalyzed asymmetric Michael addition...

Hoveyda and coworkers [142] developed the Cu-catalyzed allylic substitutions of phosphonate derivatives with pyridinyl peptide structures as efficient ligands. The structure of the ligands was chosen through synthesis, and analysis of libraries. Optimized compounds were used as ligands for the... 

Cu and Ag on Si(lll) surfaces. In the last example, we come back to surfaces. It is well known (44-46) that Cu catalyzes the formation of dimethyl-dichlorosilane from methylchloride and solid silicon, which is a crucial technological step in the synthesis of silicone polymers. Even today, the details of the catalytic mechanism are unclear. Cu appears to have unique properties for example, the congener Ag shows no catalytic activity. Thus, the investigation of the differences between Cu and Ag on Si surfaces can help in understanding the catalytic process. Furthermore, the bonding of noble metal atoms to Si surfaces is of great importance in the physics and chemistry of electronic devices. 

Addition of TCS 14 to Cu-catalyzed 1,4-additions of Grignard reagents of Li alkyls to a/yS-unsaturated carbonyl compounds has recently been repeatedly reviewed [42-44 a] and is thus not treated here. 

Butadynyl and butadynediyl complexes bearing the FeCp (CO)2 (Fp ) terminus were prepared by conventional methods(scheme 1). Butadynyl complexes, Fp -CsC-CsC-H, were readily obtained by the alkynylation of Fp -I with Li-C C-CsC-SiMea, followed by desilylation. The Cu-catalyzed metalation of complex 2 with M-X (M =Fp, Rp) gave the butadiyne complexes 3. 

The reaction was studied for all coinage metal nanoparticles. In the case of GMEs the rate follows zero-order kinetics with IT for all the coinage metal cases. The observed IT for the Cu catalyzed reaction was maximum but its rate of reduction was found to be minimum. Just the reverse was the case for Au and an intermediate value was obtained for the Ag catalyzed reaction (Figure 7). The adsorption of substrates is driven by chemical interaction between the particle surface and the substrates. Here phe-nolate ions get adsorbed onto the particle surface when present in the aqueous medium. This caused a blue shift of the plasmon band. A strong nucleophile such as NaBH4, because of its diffusive nature and high electron injection capability, transfers electrons to the substrate via metal particles. This helps to overcome the kinetic barrier of the reaction. 

A better diastereoselectivity with Cu-catalyzed cyclopropanation was discovered. 

For the installation of the pyrrolidinylethanol moiety 10 on the aryl group, we first tested Buchwald s Cu-catalyzed conditions with 10, aryl iodide 12, Cs2C03, Cul and 1,10-phenanthroline at 110°C in toluene to prepare the penultimate 49 [14a], The reaction was very slow, giving only 5-10% conversion even after 2 days. The reaction was faster at higher temperatures but two impurities 50 and 51 were observed (Scheme 5.14). To find the optimal conditions, xylene and diglyme were tested as solvents, lithium, potassium and cesium carbonates were screened as bases and 2,2 -bipyridy], TMEDA and l-(2-dimethylaminoethyl)-4-methylpiperazine were examined as ligands. The optimized protocol was identified as 10mol% of... 

Recently, a Pd/Cu-catalyzed three-component coupling reaction of aryl halides, norbomadiene, and alkynols was reported to generate 2,3-disubstituted norbomenes in high yields in the presence of aqueous NaOH and a phase-transfer catalyst in toluene at 100°C (Eq. 3.39).151... 

Scheme 31 Diastereoselective and enatioselective Cu-catalyzed reaction of keto-unsatur-ated esters...

Scheme 34 Cu-catalyzed asymmetric reaction of aryl methyl ketones and methyl acrylate...

Scheme 35 Cu-catalyzed asymmetric reaction of acrylates and allenic esters to ketones...

Polymer-supported catalysts often have lower activities than the soluble catalysts because of the intraparticle diffusion resistance. In this case the immobilization of the complexes on colloidal polymers can increase the catalytic activity. Catalysts bound to polymer latexes were used in oxidation reactions, such as the Cu-catalyzed oxidation of ascorbic acid,12 the Co-catalyzed oxidation of tetralin,13 and the CoPc-catalyzed oxidation of butylphenol14 and thiols.1516 Mn(III)-porphyrin bound to colloidal anion exchange resin was... 

Cu-catalyzed domino reactions have been used for the synthesis of carbocycles, as well as for heterocycles such as indoles, benzoxazoles, and quinoxalines. A very useful process is also the combination of the formation of allyl vinyl ethers, followed by a Claisen rearrangement. 

Glorius and colleagues [304] described a useful Cu -catalyzed preparation of 2-phenyl benzoxazoles 6/4-97 and related compounds from 1,2-dihaloaromatic substrates 6/4-95 and benzamide 6/4-96 (Scheme 6/4.23). 

Scheme 6/4.20. Combination of a Cu-catalyzed allylic substitution with a metathesis.

A Cu-catalyzed domino reaction has been developed by Cacchi and his group [305] for the synthesis of pyrrolo[2,3-b]quinoxalines 6/4-101 using a 2-bromo-3-tri-fluoroacetamido quinoxaline 6/4-98 and a tolane 6/4-99 containing electron-donating or -withdrawing groups as substrates, and with 6/4-100 as a proposed intermediate (Scheme 6/4.24). 

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