- Aerobic Oxidation of Alcohols to Carbonyl Compounds Catalyzed by N-Hydroxyphthalimide (NHPI) Combined with CoTPP-Zn2Al-LDH
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A catalytic system for the aerobic oxidation of alcohols by N-hydroxyphthalimide (NHPI) combined with cobalt porphyrin intercalated heterogeneous hybrid catalyst (CoTPP-Zn 2Al-LDH) has been developed. The results showed that this catalytic system can effectively catalyze the oxidation of alcohols to the corresponding carbonyl compounds. And the hybrid catalyst can be reused for five times with no appreciable reduction of activity. [Figure not available: see fulltext.]
- Zhou, Weiyou,Chen, Dongwei,Cui, Aijun,Qian, Junfeng,He, Mingyang,Chen, Qun
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- Metallopeptoids as efficient biomimetic catalysts
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Metallopeptoid catalysts incorporating phenanthroline-copper and TEMPO, and at least one non-catalytic group perform in the oxidation of various benzylic, allylic and aliphatic primary alcohols with a TON of up to 16 times higher than a mixture of the two catalytic groups or the peptoid dimer that is lacking the non-catalytic group.
- Prathap, Kaniraj Jeya,Maayan, Galia
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- Counterion effects in the preparation of aldehyde-bisulfite adducts
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The identification and development of an aldehyde-bisulfite adduct as an isolable starting material in the synthesis of the CETP inhibitor Evacetrapib are described. The physical properties of the sodium and potassium analogs are compared, and the extension of the scope of this study to include an investigation into the solid state properties of a range of sodium and potassium bisulfite adducts of commonly encountered aldehydes is discussed.
- Kissane, Marie G.,Frank, Scott A.,Rener, Gregory A.,Ley, Christopher P.,Alt, Charles A.,Stroud, Paul A.,Vaid, Radhe K.,Boini, Sathish K.,McKee, Laura A.,Vicenzi, Jeffrey T.,Stephenson, Gregory A.
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- [{RhCl(CO)2}2]-Derived MCM-41-Tethered Rhodium Complex Catalysts via Phosphine, Amine and Thiol Ligands for Cyclohexene Hydroformylation
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Functionalized silicate MCM-41-tethered rhodium complexes derived from [{RhCl(CO)2}2] have been studied by infrared spectroscopy (IR), X-ray diffraction (XRD) and N2 adsorption-desorption. [{RhCl(CO)2}2] reacts with aminated MCM-41 to result in a splitting of the chloride bridge. The same result is presumed with phosphinated MCM-41. Thiolated MCM-41 is presumed to displace the chloride in the bridge with thiol ligands. The tethering of rhodium complexes to MCM-41 leads to reduced pore sizes, pore volumes and BET surface areas without altering the structural ordering of MCM-41. The MCM-41-tethered catalysts show distinct activities and resistance to rhodium leaching in cyclohexene hydroformylation under equimolar CO and H2 at 28 bar and 100 °C, depending on the nature of complexation of the supported donor ligands with the rhodium centre. The aminated MCM-41-tethered catalyst displays good activity, selectivity and recycling for the formation of cyclohexane carboxaldehyde. The mesoporous structure of MCM-41 remains stable during the reaction.
- Huang, Lin,Kawi, Sibudjing
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- A new magnetic nanoparticle-supported Schiff base complex of manganese: An efficient and recyclable catalyst for selective oxidation of alcohols
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A new magnetic nanoparticle-supported Schiff base complex of manganese was prepared via the copper-catalyzed 'click' reaction of an aminosalicylidene manganese complex bearing terminal alkynyl with azide-functionalized shell-core magnetic nanoparticles. T
- Zhou, Qiangfei,Wan, Zijuan,Yuan, Xiaofeng,Luo, Jun
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- PTFE-Membrane Flow Reactor for Aerobic Oxidation Reactions and Its Application to Alcohol Oxidation
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A "tube-in-shell" membrane flow reactor has been developed for aerobic oxidation reactions that permits continuous delivery of O2 to a liquid-phase reaction along the entire length of the flow path. The reactor uses inexpensive O2-permeable PTFE ("Teflon") tubing that is compatible with elevated pressures and temperatures and avoids hazardous mixtures of organic vapor and oxygen. Several polymeric materials were tested, and PTFE exhibits a useful combination of low cost, chemical stability and gas diffusion properties. Reactor performance is demonstrated in the aerobic oxidation of several alcohols with homogeneous Cu/TEMPO and Cu/ABNO catalysts (TEMPO = 2,2,6,6-tetramethyl-1-piperidinyl-N-oxyl and ABNO = 9-azabicyclo[3.3.1]nonane N-oxyl). Kinetic studies demonstrate regimes where the overall rate is controlled by the kinetics of the reaction or the transport of oxygen through the tube wall. Near-quantitative product yields are achieved with residence times as low as 1 min. A parallel, multitube reactor enables higher throughput, while retaining good performance. Finally, the reactor is demonstrated with a heterogeneous Ru(OH)x/Al2O3 catalyst packed in the tubing.
- Greene, Jodie F.,Preger, Yuliya,Stahl, Shannon S.,Root, Thatcher W.
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- Mo2N nanobelts for dehydrogenation of aromatic alcohols
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Mo2N nanobelts about 60 nm wide and 0.5-7.2 μm long have been synthesized by reacting a belt-shaped α-MoO3 precursor with ammonia at 850 °C. The Mo2N nanobelts effectively and selectively catalyzed dehydrogenation of a variety of aromatic alcohols. The coordinatively unsaturated Mo sites on the surface of the Mo2N nanobelts might be the active species.
- Li, Zhongcheng,Chen, Chunhui,Zhan, Ensheng,Ta, Na,Shen, Wenjie
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- Kinetics and Mechanism of Hydration of Alkylketenes
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The hydration reactivities of CH2=C=O (1), t-Bu2C=C=O (5), Et2C=C=O (7), (CH2)4C=C=O (8), (CH2)5C=C=O (9), and t-BuCH=C=O (10) in H2O or H2O/CH3CN mixtures have been examined, including acid and base catalysis and solvent and structural isotope effects.These results provide the first systematic comparison of structural effects on the hydration of aliphatic ketenes, as well as the first measurements of base-induced hydration and pH-rate profiles for this process.The significant steric and electronic effects of the substituents observed lead to the interpretation that the acid-catalyzed reaction involves rate-limiting proton transfer to Cβ perpendicular to the ketene plane, while the H2O- and OH--induced reactions involve nucleophilic attack in the ketene plane.These results resolve the many conflicting previous reports and interpretations regarding ketene hydration.
- Allen, Annette D.,Tidwell, Thomas T.
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- HYDROFORMYLATION OF LESS REACTIVE OLEFINS WITH MODIFIED RHODIUM CATALYSTS
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The otherwise unreactive olefins (2-methyl-1-hexene, limonene, cyclohexene, methylene cyclohexane) are hydroformylated under mild conditions (90 deg C, 10 bar) in the presence of phosphite-modified rhodium catalysts.The high rates observed are attributed to the steric and electronic properties of these phosphite ligands and their ability to stabilize unsaturated rhodium species.Examples of these ligands are tris(o-t-butylphenyl) phosphite and tris(hexafluoroisopropyl) phosphite, which are, respectively, sterically demanding and strongly electron-withdrawing.
- Leeuwen, P. W. N. M. van,Roobeek, C. F.
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- SPECIFIC AND SELECTIVE REDUCTION OF AROMATIC NITROGEN HETEROCYCLES WITH THE BIS-PYRIDINE COMPLEXES OF BIS(1,4-DIHYDRO-1-PYRIDYL)ZINC AND BIS(1,4-DIHYDRO-1-PYRIDYL)MAGNESIUM
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Aromatic nitrogen heterocycles, e.g. quinoline, 2,2'-bipyridyl and 1,10-phenanthroline, are reduced in a uniquely specific and selective way by the bis-pyridine complexes of bis(1,4-dihydro-1-pyridyl)zinc and bis(1,4-dihydro-1-pyridyl)magnesium.The reactions occur by hydrogen transfer from the metal-bound 1,4-dihydropyridyl moieties to the substrates and yield zinc or magnesium salts of the 1,4-dihydroazaaromatic derivatives.Upon hydrolysis, the 1,4-dihydroazaaromatic compounds are liberated from the metal ions.The isolation and purification of several of the (novel) reduced compounds, e.g. 1,4-dihydroquinoline and 1,4-dihydro-1,10-phenanthroline, are described.
- Koning, A. J. De,Budzelaar, P. H. M.,Boersma, J.,Kerk, G. J. M. Van Der
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- Continuous-flow aerobic oxidation of primary alcohols with a copper(I)/TEMPO catalyst
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A scalable, continuous-flow process has been developed to implement a homogeneous CuI/TEMPO catalyst system for aerobic oxidation of primary alcohols to aldehydes. This catalyst system is compatible with a wide range of alcohols bearing diverse functional groups. A dilute oxygen source (9% O2 in N2) is used to avoid flammable oxygen/organic mixtures. Residence times in the heated reaction zone can be as low as 5 min with activated (e.g., benzylic) alcohols. The method has been demonstrated with nine different alcohols, including one up to 100 g scale. This flow-based catalytic method exhibits significant advantages for aerobic oxidation of alcohols, including substantially shorter residence times and broader substrate scope relative to a Pd-catalyzed method that we reported recently.
- Greene, Jodie F.,Hoover, Jessica M.,Mannel, David S.,Root, Thatcher W.,Stahl, Shannon S.
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- Picolinoyl functionalized MOF ligands for an air-promoted secondary alcohol oxidation with CuBr
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A novel Zr-derived metal-organic framework (MOF) ligand was designed and synthesized, and found to effect efficient Cu(i)-catalyzed oxidations of secondary alcohols. The UiO-66-NH-PC solid ligand was utilized as an efficient oxidation reaction ligand. Several secondary alcohols were selectively transformed to ketones in good yields, using air as the oxidant, and under mild reaction conditions. In order to broaden the applicability of the method, various primary alcohols and benzylic compounds were also tested in the oxidation reaction, and afforded the corresponding aldehydes and ketones in very high yields. Finally, the recyclability of the synthesized UiO-66-NH-PC ligand was confirmed by reusing the same batch of catalyst up to five times without observing any decrease in reactivity.
- Du, Xin,Luan, Yi,Yang, Fengxia,Ramella, Daniele,Shu, Xin
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- Copper/TEMPO-catalyzed aerobic alcohol oxidation: Mechanistic assessment of different catalyst systems
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Combinations of homogeneous Cu salts and 2,2,6,6-tetramethylpiperidine-N- oxyl (TEMPO) have emerged as practical and efficient catalysts for the aerobic oxidation of alcohols. Several closely related catalyst systems have been reported, which differ in the identity of the solvent, the presence of 2,2-bipyridine as a ligand, the identity of basic additives, and the oxidation state of the Cu source. These changes have a significant influence on the reaction rates, yields, and substrate scope. In this report, we probe the mechanistic basis for differences among four different Cu/TEMPO catalyst systems and elucidate the features that contribute to efficient oxidation of aliphatic alcohols.
- Hoover, Jessica M.,Ryland, Bradford L.,Stahl, Shannon S.
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- Immobilized bis-layered ionic liquids/peroxotungstates as an efficient catalyst for selective oxidation of alcohols in neat water
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An immobilized ionic liquids/peroxotungstates/SiO2 catalyst was prepared and characterized. The catalyst was proved to be very efficient for the selective oxidation of primary and secondary alcohols to their corresponding carbonyls with benign H2O2 as an oxidant in neat water. A 1.0 mol% (based on tungstate) dose of the catalyst was found to be sufficient for the oxidation. The catalyst is easily recovered after reaction via simple filtration, and was reused at least six times without a noticeable loss of the activity. A notable feature of this novel protocol is avoiding any organic co-solvent.
- Fan, Juan,Pu, Fan,Sun, Man,Liu, Zhong-Wen,Han, Xiao-Yan,Wei, Jun-Fa,Shi, Xian-Ying
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- UV light promoted 'Metal'/'Additive'-free oxidation of alcohols: Investigating the role of alcohols as electron donors
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UV light promoted selective oxidation of primary and secondary alcohols has been demonstrated under 'metal-free' and 'additive-free' conditions. Under the optimized conditions, a variety of aromatic, heteroaromatic, and alicyclic alcohols have been examined for their transformations to the corresponding carbonyl compounds. The mechanistic studies emphasize the important role of substrate (alcohol) and solvent (DMSO) in the generation of superoxide radical which is a vital intermediate for the transformation. This study also highlights the role of air as the oxidant in the oxidation process. Further, the practical application of the strategy has also been demonstrated for the oxidation of the alcoholic moiety in cholesterol.
- Walia, Preet Kamal,Sharma, Manik,Kumar, Manoj,Bhalla, Vandana
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- Immobilization of TEMPO derivatives in saponite and use of these novel hybrid materials as reusable catalysts
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The letter describes a novel approach for immobilization of 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) derivatives by cation-exchange reaction of TEMPO ammonium salts in a commercially available saponite. The organic-inorganic hybrid material is readily prepared and characterized by solid-state H NMR spectroscopy. The hybrid material can be used as recyclable catalyst for oxidation of various alcohols. High catalytic activity for up to 10 runs is obtained. Leaching of the nitroxide salt out of the saponite occurs to a small extent. However, original high activity of the hybrid material can be restored by simply reloading the hybrid material with nitroxide salt by cation exchange. Georg Thieme Verlag Stuttgart - New York.
- R?ben, Caren,Studer, Armido,Hemme, Wilhelm L.,Eckert, Hellmut
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- Nitrogen-Doped, Metal-Free Activated Carbon Catalysts for Aerobic Oxidation of Alcohols
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Various nitrogen-doped carbon materials were prepared via treatments of an activated carbon (AC) with ammonia and hydrogen peroxide, and their catalytic performance was tested for aerobic oxidation of several alcohols in ethanol. The amount and nature of doped nitrogen-species were examined by X-ray photoelectron spectroscopy to discuss the genesis of active species by nitrogen doping. The nitrogen-doped AC catalysts are active for the oxidation of such alcohols as benzyl alcohol, cinnamyl alcohol, and 5-(hydroxymethyl)-2-furaldehyde, and in some cases, they are even more selective to the oxidation of the hydroxyl group compared with conventional Pt/C and Ru/C catalysts, for which coupling products with the ethanol solvent are formed at low conversion levels. Graphite-type doped nitrogen species are significant for the formation of active sites on the surface of AC. The present results demonstrate the potential of nitrogen-doped AC materials as metal-free, carbon-based catalysts useable for organic synthetic reactions. (Chemical Equation Presented).
- Watanabe, Hiroyuki,Asano, Sayaka,Fujita, Shin-Ichiro,Yoshida, Hiroshi,Arai, Masahiko
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- Ruthenium/1,1′-bis(diphenylphosphino)ferrocene-catalysed Oppenauer oxidation of alcohols and lactonisation of α,ω-diols using methyl isobutyl ketone as oxidant
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A number of ruthenium catalysts, made in situ from [Ru(p-cymene)Cl2]2 and various monodentate and bidentate phosphorus ligands were screened in the double Oppenauer oxidation of 1,6-hexanediol to caprolactone using methyl isobutyl ketone as oxidant and potassium carbonate as base. The catalyst based on 1,1′-bis(diphenylphosphinyl)ferrocene gave this lactone in excellent yield. The same catalyst was evaluated for the oxidation of other diols to their lactones, of primary alcohols to the corresponding aldehydes and of secondary alcohols to the ketones under the same reaction conditions. The products were obtained in moderate to excellent yields.
- Nicklaus, Céline M.,Phua, Pim Huat,Buntara, Teddy,Noel, Sebastien,Heeres, Hero J.,De Vries, Johannes G.
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- Mechanism of copper(I)/TEMPO-catalyzed aerobic alcohol oxidation
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Homogeneous Cu/TEMPO catalyst systems (TEMPO = 2,2,6,6- tetramethylpiperidine-N-oxyl) have emerged as some of the most versatile and practical catalysts for aerobic alcohol oxidation. Recently, we disclosed a (bpy)CuI/TEMPO/NMI catalyst system
- Hoover, Jessica M.,Ryland, Bradford L.,Stahl, Shannon S.
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- Heterogeneous Ru/TiO2for hydroaminomethylation of olefins: multicomponent synthesis of amines
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Synthesizing aminesviathe hydroaminomethylation (HAM) reaction of olefins, a multicomponent reaction, has been regarded as one of the most attractive methods compared with the traditional methods considering the atom economy and environmental friendliness. However, the use of homogeneous catalysts, complex ligands containing diphosphine or nitrogen, and base or acid additives has severely hampered the utilization of these methods. Herein, an efficient heterogeneous Ru/TiO2-catalyzed HAM reaction of olefins is developed without any additives. Various amines, including secondary and tertiary amines, can be successfully obtained from olefins including aromatic and aliphatic olefins. Systematic studies demonstrate the lower electron density of Ruδ+and the higher number of acid sites of Ru/TiO2, leading to the high HAM reaction activity of olefins. Most importantly, nitrobenzene derivatives can also be transformed to the corresponding products over Ru/TiO2in excellent yields.
- An, Jinghua,Gao, Zhuyan,Wang, Yehong,Zhang, Zhixin,Zhang, Jian,Li, Lu,Tang, Bo,Wang, Feng
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supporting information
p. 2722 - 2728
(2021/04/21)
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- Atomically dispersed Rh on hydroxyapatite as an effective catalyst for tandem hydroaminomethylation of olefins
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Tandem hydroaminomethylation is an efficient and green route for one-pot synthesis of amines directly from olefins. Herein, heterogeneous hydroxyapatite (HAP) supported single-atom Rh catalyst was prepared and used for tandem hydroaminomethylation of olefins. Characterization techniques confirmed the atomic dispersion of Rh species on HAP. Up to 99% conversion of 1-hexene with high selectivity to the desired amines (93.2%) was obtained over 0.5Rh1/HAP catalyst. Mechanism study demonstrated that the first hydroformylation step during the tandem catalytic process was rate-determining. Compared with the Rh nanoparticles on other oxide supports (Mg3Al, MgO and Al2O3), the atomically dispersed Rh sites on HAP ensured the high hydroformylation activity, thereby guaranteed the outstanding catalytic performance for the total tandem process. Furthermore, various corresponding amines can be obtained with satisfactory yields over 0.5Rh1/HAP catalyst from a wide scope of olefins or amines substrates.
- Gun, Gong,Li, Liusha,Li, Xiao,Lin, Tiejun,Qin, Tingting,Zhong, Liangshu
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- An aerobic oxidation of alcohols into carbonyl synthons using bipyridyl-cinchona based palladium catalyst
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We have reported an aerobic oxidation of primary and secondary alcohols to respective aldehydes and ketones using a bipyridyl-cinchona alkaloid based palladium catalytic system (PdAc-5) using oxygen at moderate pressure. ThePdAc-5catalyst was analysed using SEM, EDAX, and XPS analysis. The above catalytic system is used in experiments for different oxidation systems which include different solvents, additives, and bases which are cheap, robust, non-toxic, and commercially available on the industrial bench. The obtained products are quite appreciable in both yield and selectivity (70-85%). In addition, numerous important studies, such as comparisons with various commercial catalysts, solvent systems, mixture of solvents, and catalyst mole%, were conducted usingPdAc-5. The synthetic strategy of oxidation of alcohol into carbonyl compounds was well established and all the products were analysed using1H NMR,13CNMR and GC-mass analyses.
- Cheedarala, Ravi Kumar,Chidambaram, Ramasamy R.,Siva, Ayyanar,Song, Jung Il
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p. 32942 - 32954
(2021/12/02)
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- DIBALH: From known fundamental to an unusual reaction; Chemoselective partial reduction of tertiary amides in the presence of esters
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This study presents a quick and reliable approach to the chemoselective partial reduction of tertiary amides to aldehydes in the presence of readily reducible ester groups using commercial DIBALH reagent. Moreover, the developed method was also extended to multi-functional molecules bearing ester moieties, which were successfully chemoselectively reduced to the corresponding aldehydes. This journal is
- An, Duk Keun,Heo, Yu Jin,Jaladi, Ashok Kumar,Kim, Hyun Tae
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p. 33809 - 33813
(2021/12/09)
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- Photoredox-Catalyzed Simultaneous Olefin Hydrogenation and Alcohol Oxidation over Crystalline Porous Polymeric Carbon Nitride
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Booming of photocatalytic water splitting technology (PWST) opens a new avenue for the sustainable synthesis of high-value-added hydrogenated and oxidized fine chemicals, in which the design of efficient semiconductors for the in-situ and synergistic utilization of photogenerated redox centers are key roles. Herein, a porous polymeric carbon nitride (PPCN) with a crystalline backbone was constructed for visible light-induced photocatalytic hydrogen generation by photoexcited electrons, followed by in-situ utilization for olefin hydrogenation. Simultaneously, various alcohols were selectively transformed to valuable aldehydes or ketones by photoexcited holes. The porosity of PPCN provided it with a large surface area and a short transfer path for photogenerated carriers from the bulk to the surface, and the crystalline structure facilitated photogenerated charge transfer and separation, thus enhancing the overall photocatalytic performance. High reactivity and selectivity, good functionality tolerance, and broad reaction scope were achieved by this concerted photocatalysis system. The results contribute to the development of highly efficient semiconductor photocatalysts and synergistic redox reaction systems based on PWST for high-value-added fine chemical production.
- Qiu, Chuntian,Sun, Yangyang,Xu, Yangsen,Zhang, Bing,Zhang, Xu,Yu, Lei,Su, Chenliang
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p. 3344 - 3350
(2021/07/26)
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- Method for reducing carboxylic acid compound into aldehyde
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The invention discloses a method for reducing a carboxylic acid compound into aldehyde. In a nitrogen atmosphere, in an organic solvent, a ligand/Cu catalyst, the carboxylic acid compound, an anhydride compound and hydrosilane are added by a one-pot method, a reaction is performed under the condition of the temperature of 20-120 DEG C for 2-20 h, after the reaction is completed, quenching and column chromatography separation are performed to obtain the product. The carboxylic acid compound can be successfully converted into aldehyde through one-pot reaction, especially unsaturated carboxylic acid can be reduced, and the reaction yield is generally relatively high. Compared with the prior art, the method has the outstanding advantages that the cheap copper salt is used as a catalyst, so that the experiment cost is greatly reduced. Meanwhile, the used method enlarges the application range of the reaction substrate, improves the compatibility of functional groups, and provides a new synthesis way for reducing the carboxylic acid compound into aldehyde.
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Paragraph 0060-0063
(2020/02/27)
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- A Strategy for Accessing Aldehydes via Palladium-Catalyzed C?O/C?N Bond Cleavage in the Presence of Hydrosilanes
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We report the catalytic reduction of both active esters and amides by selective C(acyl)?X (X=O, N) cleavage to access aldehyde functionality via a palladium-catalyzed strategy. Reactions are promoted by hydrosilanes as reducing reagents with good to excellent yields and with excellent chemoselectivity for C(acyl)?N and C(acyl)?O bond cleavage. Carboxylic acid C(acyl)?O bonds are activated by 2-chloro-4,6-dimethoxy-1,3,5-triazine (CDMT) to form triazine ester intermediates, which further react with hydrosilanes to yield aldehydes in one-pot two-step procedures. We demonstrate that C(acyl)?O cleavage/formylation offers higher yields and broader substrate scopes compared with C(acyl)?N cleavage under the same reaction conditions.
- He, Zhanyu,Liu, Tingting,Ru, Junxiang,Wang, Yulin,Wang, Zijia,Zeng, Zhuo
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p. 5794 - 5800
(2020/12/01)
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- Method for preparing aldehyde through hydroformylation of internal olefin
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The invention provides a method for preparing aldehyde through hydroformylation of internal olefin. The preparation method is characterized by comprising the following steps: adding a water-soluble rhodium compound, a water-soluble diphosphine ligand, an additive, deionized water and internal olefin into a reaction kettle equipped with a stirrer and a thermocouple; carrying out replacing 3-5 timesby using synthesis gas formed by mixing hydrogen and carbon monoxide according to a volume ratio of 1: 1; carrying out pressurizing to 1.0-5.0 MPa; conducting a reaction for 2-10 hours at a temperature of 60-120 DEG C; and conducting cooling, taking out a reaction product, and performing separating to obtain the product aldehyde.
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Paragraph 0045-0046
(2020/04/29)
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- Selective and solventless oxidation of organic sulfides and alcohols using new supported molybdenum (VI) complex in microwave and conventional methods
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A new dioxo-molybdenum (VI) complex supported on functionalized Merrifield resin (MR-Mo) has been synthesized and characterized by elemental, scanning electron mcroscopy, energy-dispersive X-ray analysis, TGA, Brunauer–Emmett–Teller method, powder-X-ray d
- Das, Siva Prasad,Boruah, Jeena Jyoti
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- Selective TEMPO-Oxidation of Alcohols to Aldehydes in Alternative Organic Solvents
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The TEMPO-catalyzed oxidation of alcohols to aldehydes has emerged to one of the most widely applied methodologies for such transformations. Advantages are the utilization of sodium hypochlorite, a component of household bleach, as an oxidation agent and the use of water as a co-solvent. However, a major drawback of this method is the often occurring strict limitation to use dichloromethane as an organic solvent in a biphasic reaction medium with water. Previous studies show that dichloromethane cannot easily be substituted because a decrease of selectivity or inhibition of the reaction is observed by using alternative organic solvents. Thus, up to now, only a few examples are known in which after a tedious optimization of the reaction dichloromethane could be replaced. In order to overcome the current limitations, we were interested in finding a TEMPO-oxidation method in alternative organic solvents, which is applicable for various alcohol oxidations. As a result, we found a method for N-oxyl radical-catalyzed oxidation using sodium hypochlorite as an oxidation agent in nitriles as an organic solvent component instead of dichloromethane. Besides the oxidation of aromatic primary alcohols also aliphatic primary alcohols, secondary alcohols as well as dialcohols were successfully converted when using this method, showing high selectivity towards the carbonyl compound and low amounts of the acid side-product.
- Hinzmann, Alessa,Stricker, Michael,Busch, Jasmin,Glinski, Sylvia,Oike, Keiko,Gr?ger, Harald
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p. 2399 - 2408
(2020/04/29)
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- Phosphine ligand, preparation method and application thereof
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The invention provides a preparation method of a phosphine ligand and application of the phosphine ligand in catalyzing olefin hydroformylation reaction. A structural formula of the phosphine ligand is shown as the specification, wherein R, R1, R2 and R3 are selected from C1-C40 alkyl, alkenyl, alkynyl, and phenyl, substituted phenyl, naphthyl, anthryl, phenanthryl or other aromatic ring and aromatic heterocyclic substituents with higher carbon number. The preparation method of the phosphine ligand comprises the following step: carrying out one-step reaction on an isochroman salt and trisilylphosphine under the promotion of villiaumite. The phosphine ligand has strong stability and coordination ability, and can be well coordinated with cobalt, rhodium and other metals, the obtained complex can be used for hydroformylation reaction of terminal olefin, internal olefin, trisubstituted olefin and tetrasubstituted olefin, the catalyst dosage is small, the reaction conditions are mild, andthe yield and selectivity of aldehyde products are very high.
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Paragraph 0072-0074
(2020/07/13)
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- The formyloxyl radical: Electrophilicity, C-H bond activation and anti-Markovnikov selectivity in the oxidation of aliphatic alkenes
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In the past the formyloxyl radical, HC(O)O, had only been rarely experimentally observed, and those studies were theoretical-spectroscopic in the context of electronic structure. The absence of a convenient method for the preparation of the formyloxyl radical has precluded investigations into its reactivity towards organic substrates. Very recently, we discovered that HC(O)O is formed in the anodic electrochemical oxidation of formic acid/lithium formate. Using a [CoIIIW12O40]5- polyanion catalyst, this led to the formation of phenyl formate from benzene. Here, we present our studies into the reactivity of electrochemically in situ generated HC(O)O with organic substrates. Reactions with benzene and a selection of substituted derivatives showed that HC(O)O is mildly electrophilic according to both experimentally and computationally derived Hammett linear free energy relationships. The reactions of HC(O)O with terminal alkenes significantly favor anti-Markovnikov oxidations yielding the corresponding aldehyde as the major product as well as further oxidation products. Analysis of plausible reaction pathways using 1-hexene as a representative substrate favored the likelihood of hydrogen abstraction from the allylic C-H bond forming a hexallyl radical followed by strongly preferred further attack of a second HC(O)O radical at the C1 position. Further oxidation products are surmised to be mostly a result of two consecutive addition reactions of HC(O)O to the CC double bond. An outer-sphere electron transfer between the formyloxyl radical donor and the [CoIIIW12O40]5- polyanion acceptor forming a donor-acceptor [D+-A-] complex is proposed to induce the observed anti-Markovnikov selectivity. Finally, the overall reactivity of HC(O)O towards hydrogen abstraction was evaluated using additional substrates. Alkanes were only slightly reactive, while the reactions of alkylarenes showed that aromatic substitution on the ring competes with C-H bond activation at the benzylic position. C-H bonds with bond dissociation energies (BDE) ≤ 85 kcal mol-1 are easily attacked by HC(O)O and reactivity appears to be significant for C-H bonds with a BDE of up to 90 kcal mol-1. In summary, this research identifies the reactivity of HC(O)O towards radical electrophilic substitution of arenes, anti-Markovnikov type oxidation of terminal alkenes, and indirectly defines the activity of HC(O)O towards C-H bond activation.
- Iron, Mark A.,Khenkin, Alexander M.,Neumann, Ronny,Somekh, Miriam
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p. 11584 - 11591
(2020/11/23)
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- Boosting the hydrolytic stability of phosphite ligand in hydroformylation by the construction of superhydrophobic porous framework
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The development of a catalyst that delivers high activities and selectivities with excellent durability is of great importance. Numerous efficient catalysts suffer from the inherent hydrolysis liabilities, plaguing their practical applications. Herein, we show that this challenge can be tackled by constructing them into superhydrophobic porous frameworks, as exemplified by a water-sensitive phosphite ligand, tris(2-tert-butylphenyl) phosphite. The efficiency and long-term stability of the developed system are remarkably high in the hydroformylation of internal olefins after metalation with Rh species, superior to the corresponding homogeneous analogues. The significantly boosted hydrolytic stability allows for catalytic transformations using water as a green solvent, which not only facilitates the isolation of the products, but also furnishes the aldehydes with higher regioselectivities for the desired linear form in comparison with that operated under benchmark conditions using toluene as a reaction medium. Given these promising results, we anticipate the strategy advanced herein will form the basis for constructive perspectives in the enhancement of the water resistance of catalysts and the development of high performance hydroformylation catalysts.
- Tang, Yongquan,Dong, Ke,Wang, Sai,Sun, Qi,Meng, Xiangju,Xiao, Feng-Shou
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- Supported Cobalt Nanoparticles for Hydroformylation Reactions
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Hydroformylation of olefins has been studied in the presence of specific heterogeneous cobalt nanoparticles. The catalytic materials were prepared by pyrolysis of preformed cobalt complexes deposited onto different inorganic supports. Atomic absorption spectroscopy (AAS) measurements indicated a correlation of catalyst activity and cobalt leaching as well as a strong influence of the heterogeneous support on the productivity. These new, low-cost, easy-to-handle catalysts can substitute more toxic, unstable and volatile cobalt carbonyl complexes for hydroformylations on a laboratory scale.
- Hertrich, Maximilian Franz,Scharnagl, Florian Korbinian,Pews-Davtyan, Anahit,Kreyenschulte, Carsten Robert,Lund, Henrik,Bartling, Stephan,Jackstell, Ralf,Beller, Matthias
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supporting information
p. 5534 - 5538
(2019/03/26)
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- Synthesis of an Azaphosphatriptycene and Its Rhodium Carbonyl Complex
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A 10-aza-9-phosphatriptycene is accessible on a gram scale, in three laboratory steps from commercially available precursors. Infrared spectroscopy of a rhodium(I) carbonyl complex bearing this ligand reflects the weak σ-donor/strong π-acceptor character of the phosphine; the solid-state structure reveals moderate steric demand. This ligand supports highly active catalysts for the hydroformylation of cyclic alkenes.
- Cao, Yu,Napoline, Jonathan W.,Bacsa, John,Pollet, Pamela,Soper, Jake D.,Sadighi, Joseph P.
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p. 1868 - 1871
(2019/05/16)
-
- Efficient selective oxidation of alcohols to aldehydes catalyzed by a morpholinone nitroxide
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Efficient chemoselective oxidation of primary alcohols to the corresponding aldehydes is described. The transformation is promoted by a catalytic morpholinone nitroxide radical catalyst which can be easily synthesized. A broad range of substrates includin
- Dong, Zhenhua,Gao, Pengwei,Xiao, Yongmei
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p. 3380 - 3388
(2019/11/05)
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- Metal-free mechanochemical oxidations in Ertalyte jars
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The authors acknowledge Form-Tech Scientific for the loan of the FTS-1000 Shaker Mill apparatus (Form-Tech Scientific, Canada, https://formtechscientific.com/). Authors are grateful to MIUR (Italy, PRIN project: multifunctional polymer composites based on grown materials). A. P. is grateful to MIUR for “Finanziamento delle Attività Base di Ricerca (FABR 2017)“.
- Porcheddu, Andrea,Delogu, Francesco,De Luca, Lidia,Fattuoni, Claudia,Colacino, Evelina
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supporting information
p. 1786 - 1794
(2019/08/07)
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- Acid-Promoted Hydroformylative Synthesis of Alcohol with Carbon Dioxide by Heterobimetallic Ruthenium-Cobalt Catalytic System
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The acid-aided heterobimetallic ruthenium-cobalt catalytic system for the reductive hydroformylation with carbon dioxide was established. Various alkenes, including waste from biomass and petroleum industry, could be upgraded to valuable alcohols with this protocol. Acid-promoted reverse water-gas shift (RWGS), thereby accelerating the hydroformylative synthesis of alcohol. The theoretical computations revealed that acid promoted RWGS by facilitating the dehydroxylation of ruthenium hydroxy carbonyl intermediate.
- Zhang, Xuehua,Tian, Xinxin,Shen, Chaoren,Xia, Chungu,He, Lin
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p. 1986 - 1992
(2019/03/17)
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- Polymer-incarcerated palladium-catalyzed facile: In situ carbonylation for the synthesis of aryl aldehydes and diaryl ketones using CO surrogates under ambient conditions
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In this existing work, an efficient polymer-supported palladium catalyst, a furfurylamine-functionalized Merrifield complex of palladium [Pd@(Merf-FA)], was synthesized and characterized, showing excellent catalytic activity towards in situ carbonylation reactions using carbon monoxide surrogates like formic acid and chloroform. Herein, we examined the catalytic activity of the Pd@(Merf-FA) catalyst for the formylation of aryl iodides and carbonylative Suzuki-Miyaura coupling reactions. The Pd@(Merf-FA) catalyst was systematically characterized by several techniques like HRTEM, elemental mapping, PXRD, TGA-DTA, FESEM, UV-vis, EDAX, CHN and AAS analysis. The catalyst is highly recyclable, able to be recycled up to six times without showing any significant decrease in catalytic activity. The [Pd@(Merf-FA)] catalyst proved to be more efficient compared to the corresponding homogeneous palladium catalyst. In addition, the leaching experiment of the synthesized catalyst was studied, which showed that negligible leaching of metal occurred from the polymeric support.
- Dey, Tusar Kanto,Basu, Priyanka,Riyajuddin, Sk,Ghosh, Aniruddha,Ghosh, Kaushik,Manirul Islam, Sk
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p. 9802 - 9814
(2019/07/04)
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- Ligand-Controlled Direct Hydroformylation of Trisubstituted Olefins
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The direct hydroformylation of trisubstituted olefins has been achieved with a combination of a Rh(I) catalyst and a π-acceptor phosphorus (briphos) ligand. A sterically bulky briphos ligand with a large cone angle that forms a 1:1 complex with Rh(I) is found to be reactive for the hydroformylation of trisubstituted olefins. The aldehyde products were obtained with high diastereoselectivity (>99:1) and regioselectivity (49%-81%).
- Shin, Taeil,Kim, Hyungsoo,Kim, Sungmin,Lee, Ansoo,Seo, Min-Seob,Choi, Jonghoon,Kim, Hyungjun,Kim, Hyunwoo
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p. 5789 - 5792
(2019/06/24)
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- Hydroformylation of vinyl acetate and cyclohexene over TiO2 nanotube supported Rh and Ru nanoparticle catalysts
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TiO2 nanotube (TNT) supported Rh and Ru nanoparticle catalysts were prepared via impregnation-photoreducing procedure and characterized with various methods. Their catalytic performances in hydroformylation were evaluated by using vinyl acetate and cyclohexene as substrates. The results indicate that the presence of Ru in the catalysts can enhance the catalytic activity of catalysts for the hydroformylation of vinyl acetate, but do not play the same role in the hydroformylation of cyclohexene; the sequence of loading metal has a significant effect on the catalytic performances of the title catalysts. Additionally, it is found that Ru/TNTs shows catalytic activity for the hydroformylation of vinyl acetate though it does not for the hydroformylation of cyclohexene.
- Chuai, Hongyuan,Liu, Xiaotong,Chen, Ya,Zhu, Baolin,Zhang, Shoumin,Huang, Weiping
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p. 12053 - 12059
(2018/04/12)
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- Supported rhodium liquid metal catalysts for the hydroformylation of olefins
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The hydroformylation of olefins in supported room temperature liquid metals was developed, and the supported Rh liquid metal catalysts (Rh SLMCs) showed unprecedented activity and high selectivity for the hydroformylation of olefins to aldehydes. The turnover frequency is up to 7000?h?1, much higher than that of homogeneous RhCl3?+?3PPh3 catalyst. Moreover, the Rh SLMCs can be recovered conveniently without obvious deactivation, and the total turnover number is up to 250?000. The active Rh(I) catalyst formed in situ can be reduced back to Rh(0) by the free electrons in liquid metal when H2/CO gas is emitted, and thus Rh is not leaked into the organic solvent. Long-chain olefins, cycloolefins and styrenes were applied, and the corresponding aldehydes were obtained in good to excellent yields.
- Sun, Hao,Guo, Wanwan,Liu, Junmei,Feng, Zhipeng,Li, Ruyue,Zhou, Xuyang,Huang, Jun
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- Green and selective oxidation of alcohols by immobilized Pd onto triazole functionalized Fe 3O 4 magnetic nanoparticles
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Abstract: Carbonyl compounds were prepared by selective oxidation of alcohols in the presence of recoverable Fe 3O 4@ SiO 2@ Pd magnetic nanocatalyst in aqueous media as a green solvent. Molecular oxygen served as an oxidant. The catalyst was removed from the reaction media by external magnetic field, washed with methanol, and reused for six more times without any considerable reduction in its reactivity. The chemoselectivity and regioselectivity of the catalyst can serve for selective oxidation of primary alcohols in the presence of secondary ones, and for oxidation of unhindered alcohols in the presence of hindered ones. Graphical Abstract: Selective and facile oxidation of alcohols to their corresponding carbonyl compounds in the presence of immobilized, recoverable, and magnetic nano Pd-particles in water by molecular oxygen. [Figure not available: see fulltext.].
- Dadras, Arefeh,Naimi-Jamal, M Reza,Moghaddam, F Matloubi,Ayati, Seyed Ebrahim
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- Copper diisobutyl-t-butoxyaluminum hydride: A novel reagent for chemoselective reduction of tertiary amides over esters
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We demonstrate that copper diisobutyl-t-butoxyaluminum hydride, readily prepared from lithium diisobutyl-t-butoxyaluminum hydride and CuI, effectively and chemoselectively reduces tertiary amides over esters at ambient temperature, affording the corresponding aldehydes in excellent yields.
- Im, So Hee,Shin, Won Kyu,Jaladi, Ashok Kumar,An, Duk Keun
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p. 2335 - 2340
(2018/05/16)
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- METHOD FOR PRODUCING CARBONYL COMPOUND
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PROBLEM TO BE SOLVED: To provide a method for producing a carbonyl compound, allowing for improvement of ease of production and furthermore allowing for reduction of production cost, by positively utilizing inexpensive iodine. SOLUTION: A carbonyl compound is produced by mixing primary alcohol or secondary alcohol, and iodic acid (HIO3) in a non-solvent or an aprotic polar solvent based on the following general formula (1), where R1 is an optionally substituted linear- or branched 1-12C aliphatic group, or an optionally substituted aromatic group; R2 is a hydrogen atom, an optionally substituted linear- or branched 1-12C alkyl group, or an optionally substituted aromatic group; R1 and R2 each may be coupled with each other to form a ring of aromatic group or a non-aromatic group. SELECTED DRAWING: None COPYRIGHT: (C)2018,JPOandINPIT
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-
Paragraph 0032-0035; 0037-0040
(2018/03/23)
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- Hexafluoroisopropanol as the Acid Component in the Passerini Reaction: One-Pot Access to β-Amino Alcohols
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A new Passerini-type reaction in which hexafluoroisopropanol functions as the acid component is reported. The reaction tolerates a broad range of isocyanides and aldehydes, and the formed imidates can be reduced toward β-amino alcohols under mild and metal-free conditions. In addition, the imidate products were shown to undergo an unprecedented retro-Passerini-type reaction under microwave conditions, providing valuable mechanistic information about the Passerini reaction and its variations.
- Saya, Jordy M.,Berabez, Rayan,Broersen, Pim,Schuringa, Imme,Kruithof, Art,Orru, Romano V. A.,Ruijter, Eelco
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supporting information
p. 3988 - 3991
(2018/07/15)
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- Selective ligand-free cobalt-catalysed reduction of esters to aldehydes or alcohols
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Cobalt(ii) salts combined with NaBHEt3 and eventually a base catalyse efficiently and selectively the reduction of esters to aldehydes or alcohols through hydrosilylation by using phenylsilane. Catalyst characterisation by XRD, XPS, TEM and STEM analyses indicates the materials were partially crystalline with the presence of cobalt nanoparticles. Control experiments suggested low valent Co(0) was the active catalytic species involved.
- Rysak, Vincent,Descamps-Mandine, Armel,Simon, Pardis,Blanchard, Florent,Burylo, Laurence,Trentesaux, Martine,Vandewalle, Maxence,Collière, Vincent,Agbossou-Niedercorn, Francine,Michon, Christophe
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p. 3504 - 3512
(2018/07/29)
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- Base-Free and Acceptorless Dehydrogenation of Alcohols Catalyzed by an Iridium Complex Stabilized by a N, N, N-Osmaligand
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The preparation of a N,N,N-osmaligand, its coordination to iridium to afford an efficient catalyst precursor, and the catalytic activity of the latter in dehydrogenation reactions of hydrogen carriers based on alcohols are reported. Complex OsH2Cl2(PiPr3)2 (1) reacts with 3-(2-pyridyl)pyrazol to give the osmium(II) complex 2H, which contains an acidic hydrogen atom. Deprotonation of the latter by the bridging methoxy groups of the dimer [Ir(μ-OMe)(n4-COD)]2 (COD = 1,5-cyclooctadiene) leads to Ir(2)( n 4-COD) (3), where osmaligand 2 has a free-nitrogen atom. Iridium complex 3 catalyzes the dehydrogenation of secondary and primary alcohols to ketones and aldehydes or esters, respectively, and the dehydrogenation of diols to lactones. Cyclooctatriene is detected during the catalysis by GC-MS, suggesting that the true catalyst of the reactions is a dihydride IrH2(2)-species with osmaligand 2 acting as N,N,N-pincer. The presence of a phenyl group in the substrates favors the catalytic processes. The dehydrogenative homocoupling of primary alcohols to esters appears to take place via the transitory formation of hemiacetals.
- Alabau, Roberto G.,Esteruelas, Miguel A.,Martínez, Antonio,Oliván, Montserrat,O?ate, Enrique
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p. 2732 - 2740
(2018/09/10)
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- Catalytic oxidation of alcohols with novel non-heme N4-tetradentate manganese(ii) complexes
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We report the preparation and characterisation of a series of novel non-heme N4-tetradentate Mn(OTf)2 complexes of the type, [(L)MnOTf2], where L = R,R and S,S enantiomers of BPMCN, its 6-methyl and 6-bromo derivatives as well as the novel ligand BMIMCN (BPMCN = N,N′-dimethyl-N,N′-bis(2-pyridylmethyl)-(R,R/S,S)-1,2-diaminocyclohexane, BMIMCN = N,N′-dimethyl-N,N′-bis(1-methyl-2-imidazolemethyl)-(R,R/S,S)-1,2-diaminocyclohexane). Solid state structural analysis of the BMIMCN-ligated Mn-triflate complexes (R,R-C4 and S,S-C4) revealed opposite helicity but identical metal site accessibility. This feature was exploited in the catalytic oxidation of primary and secondary alcohols, with hydrogen peroxide as oxidant and acetic acid as co-catalyst. Complexes R,R-C4 and S,S-C4 displayed the highest activity in benzyl alcohol oxidation, attributed to the electron-donating property of the BMIMCN ligand. Complex S,S-C4, displayed high activity for a variety of primary alcohol substrates, but the reaction suffered from reduced selectivity and side-reactions due to the presence of acetic acid. In contrast, secondary alcohol substrates could be oxidised to the corresponding ketone products in excellent isolated yields under mild reaction conditions and short reaction times.
- Vermaak, Vincent,Young, Desmond A.,Swarts, Andrew J.
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supporting information
p. 16534 - 16542
(2018/12/05)
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- O→S Relay Deprotection: A General Approach to Controllable Donors of Reactive Sulfur Species
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Reactive sulfur species (RSS) are biologically important molecules. Among them, H2S, hydrogen polysulfides (H2Sn, n>1), persulfides (RSSH), and HSNO are believed to play regulatory roles in sulfur-related redox biology. However, these molecules are unstable and difficult to handle. Having access to their reliable and controllable precursors (or donors) is the prerequisite for the study of these sulfur species. Reported in this work is the preparation and evaluation of a series of O-silyl-mercaptan-based sulfur-containing molecules which undergo pH- or F?-mediated desilylation to release the corresponding H2S, H2Sn, RSSH, and HSNO in a controlled fashion. This O→S relay deprotection serves as a general strategy for the design of pH- or F?-triggered RSS donors. Moreover, we have demonstrated that the O-silyl groups in the donors could be changed into other protecting groups like esters. This work should allow the development of RSS donors with other activation mechanisms (such as esterase-activated donors).
- Kang, Jianming,Xu, Shi,Radford, Miles N.,Zhang, Wenjia,Kelly, Shane S.,Day, Jacob J.,Xian, Ming
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supporting information
p. 5893 - 5897
(2018/04/25)
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- Selective aerobic oxidation of halides and amines with an inorganic-ligand supported zinc catalyst
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A practical, efficient and environmentally benign catalytic protocol for the oxidative cross-coupling reaction of halides with amines, oxidative self-coupling of amines and oxidation of halides was developed with inorganic-ligand supported ZnPOM (NH4)4[ZnMo6O18(OH)6] using molecular oxygen. This method mainly utilizes an inorganic polymolybdate ligand to support the Zn2+ ion, avoiding the use of complicated organic ligands.
- Wang, Jingjing,Zhai, Yongyan,Wang, Ying,Yu, Han,Zhao, Wenshu,Wei, Yongge
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supporting information
p. 13323 - 13327
(2018/10/15)
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- A novel modified MIL-101-NH2 ligand for CuI-catalyzed and air promoted oxidation of secondary alcohols
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An efficient Cu(i)-catalyzed aerobic alcohol oxidation system was developed utilizing a novel metal-organic framework (MOF) ligand at room temperature. Several relatively inert secondary alcohols were converted to their corresponding ketones in high yields and selectivities in the presence of a Cu(i) catalyst and air as the oxidant. This newly developed Cu(i)/MOF ligand system can also be easily extended to the aerobic oxidation of primary alcohols including aliphatic ones. Furthermore, the MIL-101-N-2-pyc ligand can be recycled several times without compromising reaction activity.
- Liu, Hui,Ramella, Daniele,Yu, Peng,Luan, Yi
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p. 22353 - 22359
(2017/07/10)
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- Chemoselective hydrogen peroxide oxidation of primary alcohols to aldehydes by a water-soluble and reusable iron(iii) catalyst in pure water at room temperature
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Hydrogen peroxide oxidation of primary alcohols to aldehydes is described, which is catalyzed by a novel, reusable and water-soluble FeCl3 complex in situ-formed with quaternary ammonium salt-functionalized 8-aminoquinoline. This reaction exhibits unique chemoselectivity and broad functional-group tolerance, and it can operate efficiently in pure water at room temperature.
- Yan, Qi,Fang, Ye Chen,Jia, Yun Xue,Duan, Xin Hong
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p. 2372 - 2377
(2017/03/21)
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- Water as a proton mediator for dioxygen-selective oxidation of alcohols by a planar dinuclear butterfly-like CuCu bonding complex: A combined experimental and computational study
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The selective catalytic oxidation of alcohols is important both in laboratory and industrial production, and traditional oxidants cause environmentally lethal wastes. The development of dioxygen selective oxidation efficient has been pursued from atom-efficient, economic and environmental view of points. Using DFT calculation and ESI-MS experiments, we studied the activation of the CuCu bonded planar complex Cu2(ophen)2 to dioxygen and the application of the dioxygen-copper system for the selective oxidation of alcohols. For practical application and green chemistry, this catalytic system avoided the use of a large excess of base and expensive nitroxyl derivatives. In the cycle of oxidation, two oxidative dehydrogenation processes featuring superoxide/peroxide (I) and hydroperoxide (II) occurred along with a series of conformational changes of the butterfly-like Cu-complex from stretched to folded to stretched. Additionally, we characterized the role of the water molecule as a proton mediator in the dioxygen-copper system.
- Zhang, Lingjuan,Liu, Jie,Zhang, Fuqiang,Zhang, Xian-Ming
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-
- Synthesis of a series of iridium complexes bearing substituted 2-pyridonates and their catalytic performance for acceptorless dehydrogenation of alcohols under neutral conditions
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A series of Cp*Ir complexes bearing 5- and 4,5-substituted 2-pyridonate ligands have been synthesized and their catalytic performance for acceptorless dehydrogenation of alcohols has been investigated under neutral conditions. Electron-withdrawing groups such as methoxycarbonyl, trifluoromethyl, cyano, and nitro groups at the 5-position promoted the acceptorless dehydrogenation of 1-phenylethanol, whereas electron-donating methyl group at the 5-position retarded the reaction. Furthermore, introduction of methyl group at the 4-position improved the catalytic performance. Thus, Cp*Ir(5-trifluoromethyl-4-methyl-2-pyridonate)Cl (2bc) exhibited the highest catalytic performance among the complexes examined, and also showed good catalytic performance for acceptorless dehydrogenation of primary alcohols.
- Yamaguchi, Ryohei,Kobayashi, Daiki,Shimizu, Mineyuki,Fujita, Ken-ichi
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-
- Efficient and Highly Selective Solvent-Free Oxidation of Primary Alcohols to Aldehydes Using Bucky Nanodiamond
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Selective oxidation of alcohols to aldehydes is widely applicable to the synthesis of various green chemicals. The poor chemoselectivity for complicated primary aldehydes over state-of-the-art metal-free or metal-based catalysts represents a major obstacle for industrial application. Bucky nanodiamond is a potential green catalyst that exhibits excellent chemoselectivity and cycling stability for the selective oxidation of primary alcohols in diverse structures (22 examples, including aromatic, substituted aromatic, unsaturated, heterocyclic, and linear chain alcohols) to their corresponding aldehydes. The results are comparable to reported transition-metal catalysts including conventional Pt/C and Ru/C catalysts for certain substrates under solvent-free conditions. The possible activation process of the oxidant and substrates by the surface oxygen groups and defect species are revealed with model catalysts, ex situ electrochemical measurements, and ex situ attenuated total reflectance. The zigzag edges of sp2 carbon planes are shown to play a key role in these reactions.
- Lin, Yangming,Wu, Kuang-Hsu Tim,Yu, Linhui,Heumann, Saskia,Su, Dang Sheng
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p. 3497 - 3505
(2017/09/15)
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- Merging visible light photocatalysis of dye-sensitized TiO2 with TEMPO: The selective aerobic oxidation of alcohols
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The selective oxidation of alcohols to aldehydes or ketones is very difficult to accomplish when the oxidant is molecular oxygen (O2) and the reaction is carried out under ambient conditions. To meet these challenges, visible light photocatalysis was exploited to enable the use of O2 for the selective oxidation of alcohols at room temperature. In this scheme, eosin Y, an organic dye, was connected with TiO2 to capture visible light, leading to consequential photocatalytic processes. More importantly, these photocatalytic processes can be neatly merged with the redox catalytic cycles of TEMPO, which in turn induce the oxidation of alcohols under visible light irradiation. This work suggests that the merger of visible light photocatalysis and TEMPO catalysis has great potential for execution of challenging oxidative transformations.
- Zhang, Yichi,Wang, Zhan,Lang, Xianjun
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p. 4955 - 4963
(2017/11/09)
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- Green method for preparation of aldehyde or ketone by iron catalyzed alcohol oxidation
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The invention provides a green method for preparation of aldehyde or ketone by iron catalyzed alcohol oxidation. The method adopts a common iron salt as the catalyst, uses an oxynitride as the cocatalyst, can realize oxidation of various alcohols in a non-halogen solvent and under open air room temperature conditions, and especially can achieve oxidation of high selectivity non-active fatty primary alcohol. The catalytic system uses a cheap and easily available, non-toxic and high activity iron catalyst system, and uses economical, safe and green air as the oxidant. The reaction temperature can be set at room temperature condition. The catalytic system has few components, and additional adding of a ligand or alkali compound is unnecessary. The reaction is easy in operation, and especially can realize oxidation of non-active fatty primary alcohol into aldehyde or ketone efficiently. The method provided by the invention has very mild requirements for reaction conditions, and has good research and industrial application prospects.
- -
-
Paragraph 0034; 0035; 0036
(2017/08/29)
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- Synthesis, Characterization, and Relative Study on the Catalytic Activity of Zinc Oxide Nanoparticles Doped MnCO3, -MnO2, and -Mn2O3 Nanocomposites for Aerial Oxidation of Alcohols
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Zinc oxide nanoparticles doped manganese carbonate catalysts [X% ZnOx-MnCO3] (where X = 0-7) were prepared via a facile and straightforward coprecipitation procedure, which upon different calcination treatments yields different manganese oxides, that is, [X% ZnOx-MnO2] and [X% ZnOx-Mn2O3]. A comparative catalytic study was conducted to evaluate the catalytic efficiency between carbonates and oxides for the selective oxidation of secondary alcohols to corresponding ketones using molecular oxygen as a green oxidizing agent without using any additives or bases. The prepared catalysts were characterized by different techniques such as SEM, EDX, XRD, TEM, TGA, BET, and FTIR spectroscopy. The 1% ZnOx-MnCO3 calcined at 300°C exhibited the best catalytic performance and possessed highest surface area, suggesting that the calcination temperature and surface area play a significant role in the alcohol oxidation. The 1% ZnOx-MnCO3 catalyst exhibited superior catalytic performance and selectivity in the aerial oxidation of 1-phenylethanol, where 100% alcohol conversion and more than 99% product selectivity were obtained in only 5 min with superior specific activity (48 mmol·g-1·h-1) and 390.6 turnover frequency (TOF). The specific activity obtained is the highest so far (to the best of our knowledge) compared to the catalysts already reported in the literatures used for the oxidation of 1-phenylethanol. It was found that ZnOx nanoparticles play an essential role in enhancing the catalytic efficiency for the selective oxidation of alcohols. The scope of the oxidation process is extended to different types of alcohols. A variety of primary, benzylic, aliphatic, allylic, and heteroaromatic alcohols were selectively oxidized into their corresponding carbonyls with 100% convertibility without overoxidation to the carboxylic acids under base-free conditions.
- Assal, Mohamed E.,Kuniyil, Mufsir,Shaik, Mohammed Rafi,Khan, Mujeeb,Al-Warthan, Abdulrahman,Siddiqui, Mohammed Rafiq H.,Adil, Syed Farooq
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- Transition-Metal-Free Homologative Cross-Coupling of Aldehydes and Ketones with Geminal Bis(boron) Compounds
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We report a transition-metal-free coupling of aldehydes and ketones with geminal bis(boron) building blocks which provides the coupled, homologated carbonyl compound upon oxidation. This reaction not only extends an alkyl chain containing a carbonyl group, it also simultaneously introduces a new carbonyl substituent. We demonstrate that enantiopure aldehydes with an enolizable stereogenic center undergo this reaction with complete retention of stereochemistry.
- Stephens, Thomas C.,Pattison, Graham
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supporting information
p. 3498 - 3501
(2017/07/15)
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- Synthesis and application of PNP pincer ligands in rhodium-catalyzed hydroformylation of cycloolefins
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Two new phosphorus ligands (L1 and L2) were developed for rhodium-catalyzed hydroformylation of cycloolefins. L1 produced high conversion for cyclohexene (94.7%) and high dialdehyde selectivity for NBD (97.1%) and DCPD (98.4%). Analogue pincer ligands L3-L6 with different steric and electronic character were also investigated in these hydroformylations.
- Wu, Qianhui,Zhou, Fanding,Shu, Xiao,Jian, Lei,Xu, Bin,Zheng, Xueli,Yuan, Maolin,Fu, Haiyan,Li, Ruixiang,Chen, Hua
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p. 107305 - 107309
(2016/11/29)
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- Strongly coupled Mn3O4-porous organic polymer hybrid: A robust, durable and potential nanocatalyst for alcohol oxidation reactions
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Herein we describe a novel strategy for noble-metal-free Mn3O4@POP (porous organic polymer) hybrid synthesis by encapsulation of Mn3O4-NP in the interior cavity of a porous organic polymer which exhibited enhanced catalytic activity and stability for oxidation of diverse activated and nonactivated alcohols relative to the conventional catalysts to demonstrate the benefits of such a nanoarchitecture in heterogeneous nanocatalysis. The use of a non precious catalyst, tremendous recyclability (upto 15 catalytic runs) and exceptional stability make our system innovative in nature, addressing all the profound challenges in the noble-metal-free heterogeneous catalysts development community.
- Dhanalaxmi, Karnekanti,Singuru, Ramana,Kundu, Sudipta K.,Reddy, Benjaram Mahipal,Bhaumik, Asim,Mondal, John
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p. 36728 - 36735
(2016/05/24)
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- Visible-Light-Induced Efficient Selective Oxidation of Nonactivated Alcohols over {001}-Faceted TiO2 with Molecular Oxygen
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In the presence of molecular oxygen, a {001}-faceted nanocrystalline anatase TiO2 catalyst enabled the selective oxidation of nonactivated aliphatic alcohols to the corresponding aldehydes or ketones under visible light. The reaction shows excellent conversion and selectivity towards the formation of the carbonyl products without over-oxidation to the corresponding carboxylic acids. The exceptional reactivity of the catalyst is possibly due to the absorption of visible light originating from a stronger interaction of alcohol with the {001} facet, which facilitates the modification of the band structure of TiO2, thus facilitating the photogenerated hole transfer and subsequent oxidation processes. The experimental results have also been corroborated by first-principles quantum chemical DFT calculations.
- Vadakkekara, Raji,Biswas, Abul Kalam,Sahoo, Tapan,Pal, Provas,Ganguly, Bishwajit,Ghosh, Subhash Chandra,Panda, Asit Baran
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supporting information
p. 3084 - 3089
(2016/11/13)
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- Synthetic utility of iodic acid in the oxidation of benzylic alcohols to aromatic aldehydes and ketones
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Various primary and secondary benzylic alcohols were efficiently oxidized to aromatic aldehydes and aromatic ketones with iodic acid in DMF at 60?°C for 2?h and with iodic acid in the presence of TEMPO (5?mol?%) in DMF at room temperature, respectively. The former method was effective for the oxidation of sterically hindered alcohols at 60?°C and the latter method was effective for the oxidation of less sterically hindered alcohols at room temperature.
- Imai, Sho,Togo, Hideo
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p. 6948 - 6954
(2016/10/13)
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- Highly efficient transformation of alcohol to carbonyl compounds under a hybrid bifunctional catalyst originated from metalloporphyrins and hydrotalcite
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The development of a highly active and selective catalytic system that is economical, environmentally benign, and easily recoverable is highly desirable. Bifunctional hybrid catalysts originated from metalloporphyrins (MTSPP; M = Co, Fe, and Mn), and hydrotalcite have been synthesized, characterized, and investigated in the aerobic oxidation of alcohols in the presence of isobutyraldehyde. The designed catalysts exhibited excellent activity, broad applicable scope, and good stability in the oxidation. The effect of surface basicity on the catalytic performance has been studied in detail. The research results showed that as well as protecting the metalloporphyrin molecule, the surface basicity of hydrotalcite also contributed to improving the catalytic activity and the selectivity of aldehyde, and a synergistic effect was observed in the catalytic system. A proposed mechanism for the reaction involving the formation of high-valence cobalt-oxo porphyrin intermediate was postulated based on catalytic results and Hammett and H218O experiments.
- Zhou, Wei-You,Tian, Peng,Sun, Fu'An,He, Ming-Yang,Chen, Qun
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p. 105 - 116
(2016/01/26)
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- Iron/ABNO-Catalyzed Aerobic Oxidation of Alcohols to Aldehydes and Ketones under Ambient Atmosphere
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We report a new Fe(NO3)3·9H2O/9-azabicyclo[3.3.1]nonan-N-oxyl catalyst system that enables efficient aerobic oxidation of a broad range of primary and secondary alcohols to the corresponding aldehydes and ketones at room temperature with ambient air as the oxidant. The catalyst system exhibits excellent activity and selectivity for primary aliphatic alcohol oxidation. This procedure can also be scaled up. Kinetic analysis demonstrates that C-H bond cleavage is the rate-determining step and that cationic species are involved in the reaction.
- Wang, Lianyue,Shang, SenSen,Li, Guosong,Ren, Lanhui,Lv, Ying,Gao, Shuang
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p. 2189 - 2193
(2016/03/15)
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