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Hydrogenation of adipic acid (AA) is a potential way to prepare 1,6‐hexanediol (HDOL). Herein, silica‐supported copper catalysts derived from copper phyllosilicates were synthesized, characterized, and tested in the hydrogenation of AA to HDOL. In a full conversion of AA, a high yield of HDOL (approximately 90 %) was obtained through the use of each Cu‐based catalyst. The turnover frequency calculated according to the consumption rate of AA was discovered to be dependent on the Cu+/(Cu0+Cu+) ratio and the reduction condition. Moreover, recycling tests showed that a catalyst derived from a copper phyllosilicate had better stability compared with Cu/SiO2 made through impregnation due to a stronger interaction between Cu and silica. The kinetic analyses based on the global rate expression and Langmuir−Hinshelwood−Hougen−Watson (LHHW) formalism of AA conversion were conducted. The possible competitive adsorption between AA and its derivatives, including hydroxycaproic acid and ϵ‐caprolactone, was thereby revealed. Deeply dipic about your copper catalysts: Silica‐supported copper catalysts derived from copper phyllosilicates are selective and stable in the hydrogenation of adipic acid to 1,6‐hexanediol [ABSTRACT FROM AUTHOR]

A direct synthetic route was developed to prepare mesoporous-silica-nanoparticle-supported copper catalysts featuring ordered mesostructures with extensive intraparticle voids, a high degree of silica condensation, and a high dispersion of copper species. After hydrogen reduction, the catalysts containing nanosized metallic copper showed superior and stable catalytic activity for the selective oxidation of propylene by dioxygen, with high conversion of both reactants and high yield and formation rate of acrolein. The best catalyst outperformed the state-of-the-art silica-supported copper catalysts, representing one of the most active acrolein-production catalysts. Results of in situ X-ray absorption spectroscopy, in situ diffuse reflectance infrared Fourier transform spectroscopy, and other characterizations suggested that the metallic copper transformed and mainly stayed in the 1+ oxidation state under reaction conditions and that factors including the small size of copper and the presence of silanol groups on the silica support were crucial for the catalytic performance of the catalysts. [ABSTRACT FROM AUTHOR]

Various strategies have been developed to improve the conversion for the Baeyer-Villiger oxidation. However, the catalytic effects of the Baeyer-Villiger oxidation for the mixed ketones are rarely reported, though it is also important for the natural and industrial separation processes. In this report, magnetite Cu modified Fe 3 O 4 supported mesoporous silica microspheres (Cu-Fe 3 O 4 @mSiO 2 ) have been successfully synthesized by two step direct hydrothermal method (DHT). Over 99% of cyclohexanone conversion was obtained with mild air oxidation and benzaldehyde as sacrificing agent over Cu-Fe 3 O 4 @mSiO 2 . The catalytic system also shows higher conversion rates for small molecular ketones in the mixed ketone reactants, which was attributed to the enhanced mass transfer effect and Fe-Cu composite active sites in the magnetite mesoporous silica microspheres. The catalyst could be recycled for four times with similar catalytic performance, which shows enhanced shape selectivity in aerobic Baeyer-Villiger oxidations for mixed cyclic ketones. [ABSTRACT FROM AUTHOR]

Metal-catalyzed cross-coupling reactions belong to the most important transformations in organic synthesis. Copper catalysis has received great attention owing to the low toxicity and low cost of copper. However, traditional Ullmann-type couplings suffer from limited substrate scopes and harsh reaction conditions. The introduction of several bidentate ligands, such as amino acids, diamines, 1,3-diketones, and oxalic diamides, over the past two decades has totally changed this situation as these ligands enable the copper-catalyzed coupling of aryl halides and nucleophiles at both low reaction temperatures and catalyst loadings. The reaction scope has also been greatly expanded, rendering this copper-based cross-coupling attractive for both academia and industry. In this Review, we have summarized the latest progress in the development of useful reaction conditions for the coupling of (hetero)aryl halides with different nucleophiles. Additionally, recent advances in copper-catalyzed coupling reactions with aryl boronates and the copper-based trifluoromethylation of aromatic electrophiles will be discussed. [ABSTRACT FROM AUTHOR]

Catalytic filter for DeNO x reaction composed of practical ceramic filter and catalytic active component enables simultaneous removal of dusts and NO x and therefore is of great potential for industrial application. To find out catalytically active components for DeNO x reaction and concurrently which can be grown on ceramic filter by an in-situ method, the Cu-based catalysts derived from LDHs precursor with different promoters (Co, Ni, Zn, Mg) were synthesized. The results of catalytic activity evaluation showed Zn is the most suitable promoter. Then, the effect of the Cu/Zn ratio on the catalytic performance was examined. It was found that the (Cu x Zn y ) 2 Al-MMO with an Cu/Zn ratio of 4 exhibited the maximum NO x conversion of 80% at 240 °C and a NH 3 /NO ratio of 0.8. The addition of Zn could weaken the catalytic oxidation of ammonia (NH 3 -SCO) and then improve turnover frequency (TOF) of NO x reduction per Cu atom. The characterizations of the TEM and H 2 -N 2 O titration to catalysts reveal that the addition of Zn helps the dispersity of CuO on the surface of the support. The H 2 -TPR results further demonstrates that the added Zn species facilitate the reducibility of CuO species at low temperature. At last, in-situ growth of Cu-Zn-Al-LDHs on a practical ceramic filter for DeNO x reaction was first successfully carried out and the resulted catalytic filter showed a reasonably high DeNO x activity and strong bonding strength between catalyst and filter. [ABSTRACT FROM AUTHOR]

The synthesis of azide functional microporous organic nanotube networks (N3-MONNs) via a Friedel-Crafts hyper-cross-linking reaction is reported. Subsequently, a general method for obtaining heterogeneous catalysts through a Cu-catalyzed alkyne-azide reaction is presented. The small-molecule catalysts such as 2,2,6,6,-tetramethylpiperidine-1-oyl and 4-(N,N-dimethylamino)pyridine can be anchored into the MONNs. Owing to the hierarchically porous structure and high surface area, these catalysts show high activity in selective oxidation of alcohols and acylation reaction, respectively. [ABSTRACT FROM AUTHOR]

Reported herein is an exceptional chemoselective ring-opening/C(sp3)−C(sp3) bond formation in the copper(I)-catalyzed reaction of cyclopropanols with diazo esters. The conventional O−H insertion product is essentially suppressed by judicious choice of reaction conditions. DFT calculations provide insights into the reaction mechanism and the rationale for this unusual chemoselectivity. [ABSTRACT FROM AUTHOR]

Concise syntheses of 9-methoxyellipticine, 3,4-dihydroellipticine (µ-alkaloid D), 1,2,3,4-tetrahydroellipticine, 2-methyl-1,2,3,4-tetrahydroellipticine, olivacine, 3,4-dihydroolivacine, (±)-guatambuine, and (±)-janetine were developed starting from hexatriene intermediates readily obtained by Pd-catalyzed tandem cyclization/cross-coupling reaction of indolylborates. The route enables the facile construction of pyrido[4,3- b]carbazoles by Cu-catalyzed 6π-electrocyclization and subsequent transformation of the pyridocarbazole intermediates into pyrido[4,3- b]carbazole alkaloids. [ABSTRACT FROM AUTHOR]

The scope of the copper-catalyzed coupling reactions between organoboron compounds and allylic phosphates is expanded significantly by employing triphenylphosphine as a ligand for copper, allowing the use of secondary alkylboron compounds. The reaction proceeds with complete γ- E-selectivity and preferential 1,3- syn stereoselectivity. The reaction of γ-silicon-substituted allylic phosphates affords enantioenriched α-stereogenic allylsilanes. [ABSTRACT FROM AUTHOR]

The first catalytic enantio- and diastereoselective synthesis of 1,2-hydroxyboronates is reported. Reactions are promoted by a readily available chiral monodentate phosphoramidite-copper complex in the presence of an alkyl 1,1-diboron reagent. Products contain two contiguous stereogenic centers and are obtained in up to 91% yield, >98:2 d.r., and 98:2 e.r. The reaction is tolerant of aryl and vinyl aldehydes, and the 1,2-hydroxyboronate products can be transformed into versatile derivatives. Mechanistic experiments indicate control of absolute stereochemistry of the α-boryl component. [ABSTRACT FROM AUTHOR]

Novel 2-iminochromene dimers were prepared in excellent yields (93-99%) and with high to excellent enantioselectivities (89-97% ee) by a simple and efficient method. The precursor 2-[(3-cyano-2H-chromen-2-ylidene)amino]acetates and both racemic and enantioselective 2-iminochromene dimers were disclosed and characterised for the first time. [ABSTRACT FROM AUTHOR]

The diastereo- and enantioselective reductive coupling of vinylazaarenes with N-Boc aldimines is described. The reactions proceed using chiral copper-bisphosphine complexes in the presence of TMDS as a hydride source to give reductive coupling products in moderate to high enantioselectivities. [ABSTRACT FROM AUTHOR]

Aerobic epoxidation of olefins at a mild reaction temperature has been carried out by using nanomorphology of [Cu3(BTC)2] (BTC=1,3,5-benzenetricarboxylate) as a high-performance catalyst through a simple synthetic strategy. An aromatic carboxylate ligand was employed to furnish a heterogeneous copper catalyst and also serves as the ligand for enhanced catalytic activities in the catalytic reaction. The utilization of a copper metal-organic framework catalyst was further extended to the aerobic oxidation of aromatic alcohols. The shape and size selectivity of the catalyst in olefin epoxidation and alcohol oxidation was investigated. Furthermore, the as-synthesized copper catalyst can be easily recovered and reused several times without leaching of active species or significant loss of activity. [ABSTRACT FROM AUTHOR]

Enantioselective construction of a C2-symmetric spirobi(1,2,3,4-tetrahydroquinoline) framework has been achieved through an intramolecular Cu-catalyzed C-N bond coupling of 1,3-propanediamide substrates possessing bromophenyl substituents. The use of N,N'-dimethyl-1,2-diphenylethylenediamine as the chiral ligand was found to be essential in this asymmetric catalysis. Optically pure compound was shortly obtained by a single recrystallization of the enantioenriched product, which was successfully derivatised to a new chiral diphosphine ligand. [ABSTRACT FROM AUTHOR]

An easy and versatile Cu-catalyzed propargylic substitution process is presented. Using easily prepared prochiral dichloro substrates, readily available Grignard reagents together with catalytic amount of copper salt and chiral ligand, we accessed a range of synthetically interesting trisubstituted chloroallenes. Substrate scope and nucleophile scope are broad, providing generally high enantioselectivity for the desired 1,3-substitution products. The enantioenriched chloroallenes could be further transformed into the corresponding trisubstituted allenes or terminal alkynes bearing all-carbon quaternary stereogenic centers, through the copper-catalyzed enantiospecific 1,1/1,3-substitutions. The two successive copper-catalyzed reactions could be eventually combined into a one-pot procedure and different desired allenes or alkynes were obtained respectively with high enantiomeric excesses. [ABSTRACT FROM AUTHOR]

The reactivity of homogeneous copper catalysts towards the selective CC bond cleavage of both phenolic and non-phenolic arylglycerol β-aryl ether lignin model compounds has been explored. Several copper precursors, nitrogen ligands, and solvents were evaluated in order to optimize the catalyst system. Using the optimized catalyst system, copper(I) trifluoromethanesulfonate [Cu(OTf)]/L/TEMPO (L=2,6-lutidine, TEMPO=2,2,6,6-tetramethyl-piperidin-1-yl-oxyl), aerobic oxidation of the non-phenolic β-O-4 lignin model compound proceeded with good selectivity for CαCβ bond cleavage, affording 3,5-dimethoxybenzaldehyde as the major product. Aerobic oxidation of the corresponding phenolic β-O-4 lignin model proceeded with different selectivity, affording 2,6-dimethoxybenzoquinone and α,β-unsaturated aldehyde products resulting from cleavage of the CαCaryl bond. At low catalyst concentrations, however, a change in selectivity was observed as oxidation of the benzylic secondary alcohol predominated with both substrates. [ABSTRACT FROM AUTHOR]

Novel PtCu alloy yolk-shell cubes were fabricated via the disproportionation and displacement reactions in Cu2O yolk-shell cubes, and they exhibit significantly improved catalytic activity and durability for methanol electrooxidation. [ABSTRACT FROM AUTHOR]

An efficient method for the synthesis of phosphoric fluoride via oxidative coupling between hydrophosphine oxide and NaF is reported. DDQ serves as the oxidizing reagent as well as the hydrogen acceptor. The process involves a Cu(II) catalysis and exhibits great functional group tolerance under mild reaction conditions. [ABSTRACT FROM AUTHOR]

Intramolecular propargylic amination of propargylic acetates bearing an amino group at the suitable position in the presence of chiral copperpybox complexes proceeds enantioselectively to give optically active 1-ethynyl-isoindolines (up to 98% ee). The method described in this communication provides a useful synthetic approach to the enantioselective preparation of nitrogen containing heterocyclic compounds with an ethynyl group at the a-position. [ABSTRACT FROM AUTHOR]

Copper-catalysis allows the direct oxygen-arylation of dialkyl phosphonates with diaryliodonium salts. This novel methodology proceeds with a wide range of phosphonates and phosphoramidates under mild conditions and gives straightforward access to valuable mixed alkyl aryl phosphonates in very good yields and near perfect selectivity. [ABSTRACT FROM AUTHOR]

Copper-catalyzed amidation of acids with formamides or acetamide for the selective synthesis of amides with the aid of 1,4-diazabicyclo[2.2.2]octane as the ligand and tert-butyl hydroperoxide as the oxidant is presented. This method is highly compatible with a wide range of acids, including alkyl acids, aryl acids, α,β-unsaturated acids, and amino acids. [ABSTRACT FROM AUTHOR]

Selective single arylsulfanylation reactions of aryl diiodides with aryl or hetaryl thiols to give a broad array of iodine-functionalized sulfides were developed. Further elaboration of the iodine-containing products to provide a variety of aryl and hetaryl sulfides through coupling reactions was also demonstrated. [ABSTRACT FROM AUTHOR]

The article discusses discusses the use of copper catalysts in the epoxidation of propylene into propylene oxide, focusing on the modulation of the steady-state selectivity of catalysts for this reaction using visible light. Photoexcitation of the localized surface plasmon resonance (LSPR) alters the oxidation state of copper nanoparticles by reducing the catalyst copper oxide shell. Other topics include ultrahigh-vacuum models of surface copper oxidation, ultraviolet spectra of copper catalysts, and the design of other photoswitchable metal nanoparticle catalysts.

A Cu(I)-phosphoramidite-based catalytic system that allows asymmetric allyl-allyl cross-coupling with high enantioselectivity is reported. This transformation tolerates a large variety of functionalized substrates. The versatility of this new reaction is illustrated in the catalytic asymmetric synthesis of the Martinelline alkaloids chromene derivative core. [ABSTRACT FROM AUTHOR]

A new Cu-catalyzed asymmetric [3 + 3] cycloaddition of propargyl esters with cyclic enamines is reported. With a combmatiori of Cu(OAc)2∙H2O and a chiral tridentate ferrocenyl-P,N,N ligand as the catalyst, perfect endo selectivities (endo/exo > 98/2) and excellent enantioselectivities (up to 98% ee) for endo cycloadducts were achieved under mild conditions. This method provides a simple and efficient approach for the synthesis of optically active bicyclo[n.3.1] frameworks. [ABSTRACT FROM AUTHOR]

Novel catalytic reductions of tertiary and secondary phosphine oxides to phosphines have been developed. Using tetramethyldisioxane (TMDS) as a mild reducing agent in the presence of copper complexes, PO bonds are selectively reduced in the presence of other reducible functional groups (FGs) such as ketones, esters, and oleuins. Based on this transformation, an efficient one pot reduction/phosphination domino sequence allows for the synthesis of a variety of functionalized aromatic and aliphatic phosphines in good yields. [ABSTRACT FROM AUTHOR]

A redox-reconfigurable catalyst derived from l-methionine and incorporating catalytic urea groups has been synthesized. This copper complex catalyzes the enantioselective addition of diethyl malonate to trans-β-nitrostyrene. Either enantiomer of the product can be predetermined by selection of the oxidation state of the copper ion. Enantiomeric excesses of up to 72% (S) and 70% (R) were obtained in acetonitrile. The ability of the catalyst to invert enantiomeric preference was reproduced with several different solvents and bases. Facile interconversion between the Cu2+ and Cu+ redox states allowed easy access to both active helical forms of the complex and, therefore, dial-in enantioselectivity. [ABSTRACT FROM AUTHOR]

Good to excellent reactivity and regiocontrol have been achieved in the CuI-catalyzed borylation of dialkyl internal alkynes with bis(pinacolato)diboron. The presence of a propargylic polar group (OH, OR, SAr, SO2Ar, or NHTs), in combination with PCy3 as ligand, allowed maximizing the reactivity and site-selectivity (β to the propargylic function). DFT calculations suggest a subtle orbitalic influence from the propargylic group, matched with ligand and substrate size effects, as key factors involved in the high β-selectivity. The vinylboronates allowed the stereoselective synthesis of trisubstituted olefins, while allylic substitution of the SO2Py group without affecting the boronate group provided access to formal hydroboration products of unbiased dialkylalkynes. [ABSTRACT FROM AUTHOR]

The article discusses methods of synthesis of sulfonyl-1,2,3-triazoles including the direct sulfonation with sulfonyl chlorides and the copper-catalyzed azide-alkyne cycloaddition (CuAAC) reaction of acetylenes with sulfonyl azides. It also presents that these reactions are precursors for the generation of N-sulfonylketenimines and azavinyl carbenes. It also discusses reactions of N-nucleophiles with ketenimines for synthesis of nitrogen, oxygen-heterocycles.

[Display omitted] • First report on enantioselective C H bond amination of β -Dicarbonyl group with PhNHOH. • Direct α -C H amination of β -Dicarbonyl compound without any post reaction manipulation. • Broad substrate scope with respect to nitrogen fragment donor, which is limited in previous reported amination methods. • Reaction is very easy to operate and carried out at room temperature. • Good to moderate enatioselectivity with Cu-Indabox complex. • Building of challenging C N bonds. We report a novel and efficient Cu-catalyzed direct asymmetric amination of tertiary β -carbonyl compounds using aryl hydroxylamine as electrophilic nitrogen donor. The process facilitates the convenient and direct synthesis of chiral α -amino carbonyl derivatives, without the need for any post-reaction manipulation. This method reveals an effective strategy for the synthesis of enantioenriched α -C H aminated derivatives which is hitherto challenging. The choice of the robust chiral indabox ligand was ascertained to be very crucial for the desired enantioselectivity in the contemporary transformation. The reaction mechanism is fully supported by ab initio electronic structure calculations. The reaction is facile, efficient and performs well at room temperature with an enantiomeric excess (ee) up to 93 %. [ABSTRACT FROM AUTHOR]

The title reaction proceeds under mild conditions and is suitable for a broad range of substrates providing optically active propargylic amines in high yields with high enantioselectivities. [ABSTRACT FROM AUTHOR]