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A novel copper(I)-mediated trifluoroacetylation of anilines with ethyl trifluoropyruvate as a trifluoroacetylating reagent has been developed. Although this protocol could provide good yields in most cases, the reaction exhibited the obvious electronic and steric effects of substituents. The trace amount of products was only obtained for the substrates with ortho-substituted or electron-deficient groups.

By means of alternating current-electrochemical synthesis novel Cu(I) π-complex of the composition [Cu4(dapt)2Cl4]∙0.38EtOH (dapt – (2Z)-3-allyl-2-(allylimino)-1,3-thiazolidin-4-one was obtained and studied by X-ray single crystal diffraction and IR-spectroscopy. π-Complex crystallizes in the trigonal centrosymmetric space group R‾3 and is built of dimeric tetranuclear [Cu4(dapt)2Cl4] fragments. Disordered solvent molecules are located in the voids of crystal structure. It was shown experimentally a high coherent laser induced second order effects like second harmonic generation. Principal role of the absorption due to 3dCu states is shown.

The copper(i)-promoted cross-coupling of 1,2-di(pyrimidin-2-yl) disulfides with aromatic amines and aliphatic amines to deliver C-N coupling products in moderate to good yields is reported in this paper. Central to this strategy is the conversion of disulfides into aryl- and alkyl amines by a copper-promoted chemoselective C-S bond cleavage.

Multicomponent ring-opening/Huisgen cycloaddition reactions combined with CO2 capture with a polyurea-encapsulated copper salt as a catalyst that in situ formed from simple CuCl and soluble polyurea during the reaction were carried out successfully for the synthesis of β-hydroxytriazoles under exceptionally mild conditions, in which the polyurea-encapsulated copper(I) chloride proved to be a robust and recyclable catalyst system with high yields as well as excellent chemoselectivity in this reaction.

A reaction between two equivalents of bulky thiourea, i.e., 1,3-bis(2,6-dimethylphenyl)thiourea (L) [L = (ArNH)2C = S; Ar = 2,6-Me2C6H3], and CuCl2 or CuCl in THF solvent afforded a bulky thiourea-stabilized copper(I) halide complex, LCu(Cl)L (1). Compound 1 was characterized by NMR spectroscopy, mass spectrometry and X-ray structural analysis. Further, we tested the catalytic activity of this well-defined compound 1 for azide–alkyne cycloaddition (AAC) reactions in solvent-free conditions. Compound 1 shows a high catalytic activity for the synthesis of 1,4-di- and 1,4,5-trisubstituted 1,2,3-triazoles in good to excellent yields from azides (aliphatic or aromatic) and alkynes (both terminal and disubstituted). Furthermore, three-component CuAAC reactions were successfully carried out to obtain both 1,4-di- and 1,4,5-trisubstituted 1,2,3-triazoles in good to excellent yields from an organic halide, sodium azide and alkyne (both terminal and disubstituted) in greener solvent water. More importantly, the catalyst can be reused efficiently up to ten consecutive cycles with negligible loss of catalytic activity.

Novel oxidative dimerization of silylallenes is described. Treatment of silylallenes with a catalytic amount of copper(I) chloride, a substoichiometric amount of N-hydroxyphthalamide, and a stoichiometric amount of a terminal oxidant diacetoxyiodobenzene afforded head-to-head dimers as the main products. Silyallenes containing a small ring afforded only dimers, whereas as the ring size increased 1,3-enynes became more favorable products. For silylallenes containing an acyclic substituent, dimer formation is a norm with exceptions where N-hydroxyphthalimide reacts at the propargylic center to generate the corresponding aminoxy ethers.

A new and effective catalytic system using [ N -benzyl DABCO] + [Cu 4 Cl 5 ] − was developed for the palladium-free Sonogashira cross-coupling reactions of phenylacetylene with a variety of aryl halides. In this homogeneous catalytic system, 1-benzyl-4-aza-1-azoniabicyclo[2.2.2]octane chloride, a quaternary ammonium salt containing a coordinating center, plays an important role and increases the efficiency of Cu(I) species during the reaction. A number of internal alkynes were produced in moderate to excellent yields, in short reaction times in DMF at 135 °C.

A simple and efficient copper(I) chloride- catalyzed aerobic oxidative coupling of glycine de- rivatives (glycine esters, glycine amides and short peptides) with indoles has been developed. The re- action is performed in the absence of any other ad- ditives under mild conditions and only requires simple copper salts as a catalyst and oxygen as a co- oxidant.

The copper(I) chloride catalyzed reaction of azides with alkynes in water at room temperature was promoted by the addition of a catalytic amount of 2-ethynylpyridine, affording the corresponding 1,4-disubstituted 1,2,3-triazoles in good yields after a specific reaction time. The catalytic system could be successfully applied to electron-rich, electron-poor, and sterically crowded substrates. A study of the additive effect of pyridine derivatives revealed that alkynyl and 2-pyridyl groups were essential for activating the copper catalyst.

B3LYP/6-31G(d), B3LYP/6-311++G(d,p), and CBS-QB3 calculations on the effect of CuCl on the azido/tetrazole isomerism have been performed. The cases of 2-azidopyridine and 2-azido-1H-imidazole have been selected as examples of heteroaromatic six- and five-membered rings. All minima and transition states have been characterized. © 2011 Elsevier Ltd. All rights reserved.

Direct transformation of five-membered zirconacycles to carbocyclic compounds is of great synthetic interest. The reaction of zirconacycles with electrophiles containing at least two reactive functional groups or an oxidant affords various carbocycles through cross coupling, addition, and/or oxidative coupling reactions. In this paper, we present our recent results on the zirconacycle-mediated formation of carbocycles, including: (1) 1,1-cycloaddition of oxalyl dichloride with zirconacycles; (2) benzoquinone-promoted coupling of zirconacyclopentadienes in the presence of CuCl; (3) cycloaddition of zirconacyclopentadienes to quinones; (4) cycloaddition of zirconacyclopentadiene with 2-bromoacrylate, 2-bromoacrylaldehyde and 3-bromofuran-2,5-dione in the presence of CuCl; (5) one-pot coupling of two alkynes and an alkene to form cyclohexene derivatives via zirconacyclopentadienes; and (6) dianionic cycloaddition of decatetraenes with esters or acyl chlorides to form nine-membered carbocycles.

The carbon-carbon bond-forming radical reactions using indium(I)chloride and copper(I) chloride proceeded effectively through asingle-electron transfer process in aqueous media.

Recyclable TEMPO-functionalized polyethylene glycol [PEG 6000 -(TEMPO) 2 ] in combination with cuprous chloride were developed for biomimetic oxidation of a series of benzylic, allylic, heterocyclic alcohols, and 2-phenylethanol into the corresponding aldehydes or ketones in high selectivity and in moderate to high conversion in compressed CO 2 , which enhanced the catalytic activity as well as improved the selectivity.

Copper(I) chloride was found to be a highly efficient reagent to promote the cleavage of acetylenic substituents from the camphor skeleton of compounds 1 containing two C–C triple bonds as well as from the compounds 6 and 7 containing one. This is a formal reversal of the formation of these compounds by the reaction of acetylides with keto and imino groups in compound 18 . The substituent R at the triple bond modifies the reactivity and regioselectivity. As intermediates in the process we identified complexes of the types [Cu(L) depr ] (where (L) depr denotes a deprotonated camphor-derived ligand (L)) and [CuCl(L)]. Quantum mechanical calculations support and rationalize the experimental results.

An efficient highly regio- and stereoselective copper(I) chloride-mediated carbometallation of differently substituted 2,3-allenols with primary or secondary alkyl or aromatic Grignard reagents followed by iodination to synthesize fully-substituted allylic alcohols has been developed. This protocol introduces the R 4 group from the Grignard reagent to the terminal position of the 2,3-allenols.

Addition of bridging diamine ligands to methanolic solutions of CuCl under a CO purge produces the polymeric complexes [(CuCl)2(CO)2(biL)] (biL = diazabicyclo[2.2.2]octane (DABCO), piperazine (Pip), N,N‘-dimethylpiperazine (DMP)). X-ray crystal structures of the three complexes reveal rhombic OC−Cu(μ-Cl)2Cu−CO bridged by biL. Unsaturated bridging ligands fail to produce carbonyl-bearing products.

In the presence of CuCl, zirconacyclopentanes reacted with two equivalents of a propargyl halide to give bisallenylation products in moderate to high yields. By controlling the amount of CuCl, stepwise allenylation was achieved and a variety of unsymmetrically substituted diallene derivatives were prepared as well.

Tertiary amines with three different substituents were straightforwardly obtained by the copper(I) chloride-catalyzed ­reaction of α-halogen substituted allylsilanes, electron-deficient olefins, and primary amines. This reaction was more effectively performed by the addition of chloroacetone to the reaction system.

The reaction of different aryl halides with aryl oxides catalyzed by CuCl in 1-butyl-3-methyl-imidazolium tetrafluoroborate [bmim][BF4] and 1-butyl-3-methyl-imidazolium hexafluorophosphate [bmim][PF6] ionic liquids to give diaryl ethers in 54–90% yields has been studied under mild reaction conditions.

WOS: 000355416200010, The present study on tetrazole compounds, which have a wide area of application, proposes a new, simple and highly effective method. A series of 5-substituted 1H-tetrazoles were synthesised in DMF via the [3 + 2] cycloaddition reaction, in which different aryl nitriles with sodium azide were used and copper( I) chloride served as a catalyst. Short reaction times, high yields and simple procedures rendered this method attractive and useful for the organic synthesis of 5-substituted 1H-tetrazoles. A further advantage was the use of an environmentally friendly catalyst. (C) 2015 Institute of Chemistry, Slovak Academy of Sciences, Dumlupinar University Research FundDumlupinar University [2014-62]; Dumlupinar University ILTEM research laboratoryDumlupinar University, This research was financed by the Dumlupinar University Research Fund (grant no. 2014-62) as well as by the Dumlupinar University ILTEM research laboratory. The authors wish to express their gratitude to Prof. Dr. Ali DISLI, Gazi University, Ankara, Turkey.

An efficient protocol for C-O and C-S bonds formation by the cross-coupling reaction of 1,2-di(pyrimidin-2-yl) disulfides with phenols/thiophenols promoted by copper(I) chloride was established. It was discovered that variously substituted di(hetero)aryl disulfides and phenols were well tolerated. This strategy is the conversion of disulfides into hetero-aryl ethers and thioethers by a copper-promoted chemoselective C-S bond cleavage of disulfides.

A large scale and commercially feasible synthesis of 5-chloroindole and its 3-substituted analogues has been described via a halogen - halogen exchange reaction from 5-bromoindole and its derivatives using cuprous chloride and dipolar aprotic solvent N-methyl-2-pyrrolidone in one pot with good yields.

A simple copper(I)-catalyzed process for the selective aerobic oxidative coupling of N-arylglycine esters and amides at C-3 of various indoles.

Reaction of N-heterocyclic-carbene (NHC)-stabilized disilicon (1) with CuCl gave a carbene-stabilized disilicon-copper(I) chloride complex (2). The nature of the structure and bonding in 2 has been investigated by crystallographic, spectroscopic, and computational methods. The dynamic complexation behavior of 2 was experimentally explored by variable-temperature NMR analysis.

The possibility of using copper(I) chloride as a doping salt to enhance the cationization of polystyrene in matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) was investigated. It was shown that copper(I) chloride possesses sufficient solubility in tetrahydrofuran. The parameters of the MALDI mass spectra of different polystyrene samples, such as the number-average (Mn) and mass-average (Mw) molecular mass values, obtained by copper(I) cationization were compared with those obtained by means of silver(I) cationization, and good agreement was found. It was also shown that application of copper(I) chloride as a doping salt, and dithranol as a matrix, ensured good MALDI mass spectra of the sample spots even after storage for 1 month. Copyright © 2001 John Wiley & Sons, Ltd.

Kieselghur-supported copper(I) chloride was found to be an efficient and convenient catalyst for the oxidative cleavage of oximes, phenylhydrazones, and p-nitrophenylhydrazones to the corresponding carbonyl compounds with molecular oxygen.

When the reaction of metallic silicon with methanol in the presence of a small amount of thiophene was carried out at 653 K, methyldimethoxysilane was formed together with trimethoxysilane and tetramethoxysilane, the selectivity for methyldimethoxysilane being 22%. Further adding a small amount of trioxane, trimer of formaldehyde, to the reaction system improved the selectivity for methyldimethoxysilane. This indicates that formaldehyde formed by the dehydrogenation of methanol takes part in methyldimethoxysilane formation. The reaction of silicon with ethanol also gave a 14% selectivity of ethyldiethoxysilane with a 43% silicon conversion.

Functionalized 2,3-dihydrobenzofuran can be synthesized in good yield via an intramolecular cyclization of an aryl chloride and a primary alcohol under the catalysis of copper(I) chloride salt.

A new copper(I)-mediated method for effecting intramolecular conjugate addition of alkenyl functions to α,β-unsaturated ketone systems is reported. Treatment of the substrates 14, 15, 19–21, 22 and 23 with 2.5 equiv. of CuCl in DMF at room temperature affords excellent yields of the corresponding bicyclic ketones 24, 25, 29–31, 32 and 33. On the other hand, treatment of substances 15–18 with CuCN in DMSO at 60°C provides good-to-excellent yields of the corresponding bicyclic products 25–28.

Lead tetraacetate oxidative ring-opening of a series of substituted catechols provides the corresponding substituted cis,cis-2,4-diene-1,6-dioates (1–10) in fair to good yields. A number of improvements on Wiessler's procedure for this reaction are reported. The analogous copper(I) chloride/pyridine/methanol ring-opening was found to be ineffective as a general synthetic method for this transformation.

The reaction of [Pt](CCPh) 2 ( 1 ) {[Pt]=(bipy)Pt; bipy=2,2′-bipyridyl} with [CuX] n ( 2a , X=Cl; 2b , X=Br) produces the heterodinuclear platinum(II)copper(I) complexes of structural type {[Pt](CCPh) 2 }CuX ( 3a , X=Cl; 3b , X=Br) in high yields. The result of the X-ray structure analysis of 1 and 3b is reported. Complexes 1 and 3b crystallize in the monoclinic space group P 2 1 / c with the following parameters: 1 : a =17.5714(1), b =15.1585(1), c =15.0105(1) A, β= 90.933(1)°, V =3997.61(4) A 3 and Z =8; 3b : a =9.5151(1), b =10.5178(2), c =22.0030(3) A, β= 102.120(1)°, V =2151.93(6) A 3 and Z =4. In 3b both PhCC ligands are σ-bonded to the platinum atom as well as η 2 -coordinated to the copper(I) center. The Pt(CCPh) 2 CuBr building block is distorted from planarity. The copper atom is by 0.784(4) A out of the Pt(CCPh) 2 plane.

Copper (I) chloride in combination with tributyltin hydride showed unique character as an initiator of certain radical reactions. Hydrostannation of α,β-unsaturated ketones with Bu3SnH was initiated by CuCl and the resulting tin enolates underwent subsequent aldol reaction with aldehydes under the influence of CuCl as a Lewis acid catalyst.

Homogeneous atom transfer radical polymerization of styrene initiated with 1-chloro-1-phenylethane/CuCl/2,2‘-bipyridine at 130 °C is easily achieved in the presence of a limited amount of dimethylf...

Allyltrimethylsilane reacted with polyhalogen compounds in the presence of copper species, such as copper(I) chloride, copper(II) chloride or metallic copper, to form polyhalo compounds containing an allyl group. Other allylsilane derivatives than allyltrimethylsilane were also subjected to a reaction with carbon tetrachloride. 3-Chloro- or 3-bromo-3-trimethylsilyl-1-propene gave 4,4,4-trichloro-1-trimethylsilyl-1-butene. Ethyl 1-trimethylsilylallyl carbonate afforded ethyl 4,4,4-trichloro-1-butenyl carbonate along with a hydrotrichloromethylation product. 2-Methyl-3-trimethylsilyl-1-propene yielded a product based on the addition of a trichloromethyl group followed by hydrogen-elimination from a 2-methyl group.

Cu(I)Cl decomposition of the phenyliodonium ylides derived from o-, m- and p-methoxyphenyl-3-ketopentanoic acid methyl esters affords the corresponding 5-, 6- and 7-methoxy-1-carbomethoxy-2-tetralones in preparative yields. The lower homologous phenyliodonium ylides derived from o-, m- and p-methoxyphenyl-3-ketobutyric acid methyl esters yield the analogous 1-carbomethoxy-2-indanone only in the meta-methoxyphenyl case, and the ortho- and para-methoxyphenyl substituted iodonium ylides yield dimeric products.

The copper(I) chloride catalyzed reaction of azides with alkynes in water at room temperature was promoted by the addition of a catalytic amount of 2-ethynylpyridine, affording the corresponding 1,4-disubstituted 1,2,3-triazoles in good yields after a specific reaction time. The catalytic system could be successfully applied to electron-rich, electron-poor, and sterically crowded substrates. A study of the additive effect of pyridine derivatives revealed that alkynyl and 2-pyridyl groups were essential for activating the copper catalyst.

Synthesis of 3-alkenyl-Δ 2 -cephems 3 was performed in regioselective manner by copper(I) chloride-promoted alkenylation of 3-trifluoromethylsulfonyloxy-Δ 3 -cephem 1 with alkenyltributyltins. Subsequent Diels-Alder reaction of the 3-vinyl-Δ 2 -cephem 3a with acrolein opened a new access to C(2) C(3) fused tricyclic cephalosporin 9 .

When copper(I) chloride was used as a catalyst in the reaction of silicon with phenol, a high selectivity for triphenoxysilane (HSi(OPh)3) (94%) was obtained, the other product being tetraphenoxysilane (Si(OPh)4). Addition of a small amount of propyl chloride to the feed for poisoning metallic copper enhanced the selectivity for HSi(OPh)3 without affecting the rate of silicon consumption. This result indicates that HSi(OPh)3 is an exclusive primary product and that Si(OPh)4 is formed by the secondary reaction between HSi(OPh)3 and phenol. The reaction mechanism involving surface silylene intermediate is proposed for the formation of HSi(OPh)3 as the sole primary product. The intermediacy of surface silylene was confirmed by adding ethylene in the silicon-phenol reaction to give rise to the trapped product ethyldiphenoxysilane, obtained in a 5.8% selectivity.

A novel copper(I)-mediated coupling of alkenyltrialkylstannane functions is reported. Thus, treatment of the functionalized stannanes 1–11 with 2.5 equivalents of CuCl in N,N-dimethylformamide (DMF) at room temperature provides good-to-excellent yields of the dienes 12–21 .

Superparamagnetic CuCl nanoparticles were prepared and identified as an effective heterogeneous catalyst for the tandem transformation of methylarenes and 1,3-dicarbonyl compounds into the corresponding enole esters by the use of tert-butyl hydroperoxide as an external oxidant. The catalyst can be removed from the reaction medium simply by use of an external magnet. As a consequence, various derivatives of enol esters were synthesized in moderate to good yields.

The reagent Na2Fe(CO)4 prepared in situ in THF by the reduction of Fe(CO)5 with sodium naphthalenide reacts with certain alkenes in the presence of CuCl to bring about isomerization of the alkenes. Thus the 1-alkenes (1-dodecene, 1-decene, safrole and allyl benzene) are isomerized to trans-2-alkenes, and β-pinene is isomerized to α-pinene. Reactions involving BrCH2CH2Br in place of CuCl give similar results.

Among different derivatives investigated, NHI is found to be the optimal catalyst component.

In the presence of copper(I) chloride, tert-butyl 1-hydroxy-2-methyl-6-trifluoromethyl-1H-indole-3-carboxylate acted as a catalyst for the chemoselective aerobic oxidation of allylic and benzylic alcohols. A variety of primary and secondary allylic and benzylic alcohols were oxidized into the corresponding α,β-unsaturated carbonyl compounds in good yields without affecting non-allylic alcohols.

Cu(I)Cl decomposition of the phenyliodonium ylides derived from o-, m- and p-methoxyphenyl-3-ketopentanoic acid methyl esters affords the corresponding 5-, 6- and 7-methoxy-1-carbomethoxy-2-tetralones in preparative yields. The lower homologous phenyliodonium ylides derived from o-, m- and p-methoxyphenyl-3-ketobutyric acid methyl esters yield the analogous 1-carbomethoxy-2-indanone only in the meta-methoxyphenyl case, and the ortho- and para-methoxyphenyl substituted iodonium ylides yield dimeric products.

Copper (I) chloride in combination with tributyltin hydride showed unique character as an initiator of certain radical reactions. Hydrostannation of α,β-unsaturated ketones with Bu3SnH was initiated by CuCl and the resulting tin enolates underwent subsequent aldol reaction with aldehydes under the influence of CuCl as a Lewis acid catalyst.