- Chromium trioxide supported onto wet silica gel: Rapid oxidation of alcohols to carbonyl compounds under microwave irradiation in solventless system
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In an environmentally benign system, alcohols are rapidly oxidized to carbonyl compounds using CrO3 supported onto wet silica gel as an oxidant under microwave irradiation.
- Heravi, Majid M.,Farhangi, Nasrin,Beheshtiha, Yahya Sh.,Assadolah, Karim,Ghassemzadeh, Mitra,Tabar-Hydar, Koroush
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- Selective vapor-phase oxidation of o-xylene to phthalic anhydride over Co-Mn/H3PW12O40@TiO2 using molecular oxygen as a green oxidant
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The oxidation of o-xylene to phthalic anhydride over Co-Mn/H3PW12O40@TiO2 was investigated. The experimental results demonstrated that the prepared catalyst effectively catalyzed the oxidation of o-xylene to phthalic anhydride. Also, the synergistic effect between three metals plays vital roles in this reaction. From a green chemistry point of view, this method is environmentally friendly due to carrying out the oxidation in a fixed-bed reactor under solvent-free condition and using molecular oxygen as a green and cheap oxidizing agent. The resulting solid catalysts were characterized by FT-IR, XRD, XPS, ICP-OES, FESEM, TEM, EDX, DR-UV spectroscopy, BET and thermogravimetric analysis. The oxidation of o-xylene yields four products: o-tolualdehyde, phthaldialdehyde, phthalide and finally phthalic anhydride as the main product. The reaction conditions for oxidation of o-xylene were optimized by varying the temperature, weight hourly space velocity and oxygen flow rate (contact time). The optimum weight percentage of phosphotungstic acid (HPW) and Co/Mn for phthalic anhydride production were 15?wt % and 2?wt%, respectively. The best Co/Mn ratio was found to be 10/1. Oxygen flow rate was very important on the phthalic anhydride formation. The optimum conditions for oxidation of o-xylene were T?=?370?°C, WHSV?=?0.5?h?1 and oxygen flow rate?=?10?mL?min?1. Under optimized conditions, a maximum of 88.2% conversion and 75.5% selectivity to phthalic anhydride was achieved with the fresh catalyst. Moreover, reusability of the catalyst was studied and catalytic activity remained unchanged after at least five cycles.
- Masoomi, Kianoosh,Ghiaci, Mehran,Botelho do Rego
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- Synthesis of Oxetans by Photocycloaddition of Aromatic Aldehydes to Hexamethyl(Dewar benzene)
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U.v. irradiation of the aldehydes (3) in the presence of hexamethyl(Dewar benzene) yields the tricyclic oxetans (4) and (5) in competition with hexamethylbenzene formation.
- Carless, Howard A. J.,Trivedi, Harish S.
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- Palladium-Catalyzed ortho C?H Arylation of Benzaldehydes Using ortho-Sulfinyl Aniline as Transient Auxiliary
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A PdII-catalyzed ortho-(Csp2)–H arylation reaction of benzaldehydes using a catalytic amount of 2-(methylsulfinyl)aniline as transient auxiliary was developed. This reaction is compatible with a broad range of benzaldehyde and aryl iodide substrates. Compared with other related reaction systems, an excellent regioselectivity for ortho-C(sp2)?H bonds over benzylic C(sp3)?H bonds was obtained for ortho-alkyl-benzaldehyde substrates.
- Mu, Delong,He, Gang,Chen, Gong
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- A hierarchical Fe3O4@P4VP@MoO2(acac) 2 nanocomposite: Controlled synthesis and green catalytic application
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Magnetite/poly(4-vinylpyridine) composite nanospheres with multiple Fe 3O4 cores embedded in a P4VP shell were first synthesized by miniemulsion polymerization and then used as recoverable supports for MoO2(acac)2 complex. The supported complex, together with superparamagnetism and strong magnetic response, showed high efficiency for the catalytic epoxidation of cis-cyclooctene with aqueous H2O2 in ethanol. The response strongly facilitated the easy recovery of the catalyst, which was stable in recycling tests.
- Guo, Wanchun,Wang, Ge,Wang, Qian,Dong, Wenjun,Yang, Mu,Huang, Xiubing,Yu, Jie,Shi, Zhan
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- ULTRASOUND IN ORGANIC SYNTHESIS 10. SELECTIVE ORTHO-LITHIATION OF THE BOUVEAULT REACTION INTERMEDIATE
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The Bouveault reaction intermadiate prepared under sonochemical conditions easily undergoes orthodirected lithiation.The use of tetrahydropyran as a solvent dramatically increases the rates and yields of metallation which can be accomplished with an in situ generated alkyl-lithium.
- Einhorn, J.,Luche, J. L.
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- Oxidation of o-Xylene to Phthalic Anhydride over V2O5/TiO2 Catalysts. II. Transient Catalytic Behaviour
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The transient phase of the oxidation of o-xylene and o-tolualdehyde, before establishment of the steady state, has been studied over V2O5/TiO2 (anatase).At lower temperatures, an initial decrease in conversion and phthalic anhydride selectivity were observed, accompanied by an increase in selectivity to involatile products; at higher temperatures, the steady state was rapidly attained and no strong variations of conversion and selectivity were detected.For o-tolualdehyde oxidation, lower selectivities to involatile products were obtained, indicating that the adsorbed o-xylene molecules can lead more effectively to the formation of heavy organic compounds.Results obtained for selectivity to involatiles, time to reach steady state, and conversion indicate that catalyst deactivation can be ascribed to the formation of an organic residue on the catalyst surface.Such a residue can also desorb or undergo oxidation to CO2.
- Dias, Cristina R.,Portela, M. Farinha,Bond, Geoffrey C.
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- Oxidation of o-Xylene to Phthalic Anhydride over V2O5/TiO2 Catalysts. I. Influence of Catalyst Composition, Preparation Method and Operating Conditions on Conversion and Product Selectivities
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The oxidation of o-xylene and of o-tolualdehyde over V2O5/TiO2 (anatase) catalysts has been studied at 533-633 K under steady state conditions; catalysts were prepared either by wet impregnation employing NH4VO3 solution or by a grafting technique with VO(O-i-C4H9)3.At lower temperatures and lower contact times, for both o-xylene and o-tolualdehyde, part of the reactant feed disappeared due to the formation of an involatile polymeric residue, the formation of which was enhanced at lower temperatures, lower contact times, and higher organic reactant concentrations.At lower contact times, the part of the residue deposited on the catalyst surface constituted an important CO2 source.The catalyst prepared by grafting showed higher phthalic anhydride selectivity and less of the residue.The formation of nonselective oxidation products seems to be favoured by uncoated TiO2 since 0.6percent V2O5/TiO2 showed higher CO2 selectivity than other catalysts.Crystalline V2O5 caused greater residue formation.
- Dias, Cristina R.,Portela, M. Farinha,Bond, Geoffrey C.
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- Supported ionic-liquid layer on polystyrene-TEMPO resin: A highly efficient catalyst for selective oxidation of activated alcohols with molecular oxygen
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We report a facile, efficient procedure for selective oxidation of activated alcohols by use of a novel supported ionic-liquid catalyst produced by coating polystyrene-TEMPO resin with the ionic liquid [bmim]PF6 and CuCl2. The oxidat
- Liu, Lin,Liu, Dong,Xia, Zhiwei,Gao, Jiulin,Zhang, Tianlin,Ma, Juanjuan,Zhang, Dongen,Tong, Zhiwei
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- Confining task-specific ionic liquid in silica-gel matrix by sol-gel technique: A highly efficient catalyst for oxidation of alcohol with molecular oxygen
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A novel catalytic system was developed through confinement of TEMPO task-specific ionic liquid (TEMPO-IL) with CuCl2 in a silica-gel matrix by sol-gel technique. The obtained TEMPO-IL/CuCl2/silica-gel catalytic system was effective f
- Liu, Lin,Ma, Juanjuan,Xia, Jiyin,Li, Luodan,Li, Chunlong,Zhang, Xiaobo,Gong, Junyan,Tong, Zhiwei
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- Highly Efficient Aromatic C?H Oxidation with H2O2 in the Presence of Iron Complexes of the PDP Family
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The catalytic activity of a series of iron complexes of the PDP family (PDP=N,N′-bis(2-pyridylmethyl)-2,2′-bipyrrolidine) in the oxidation of aromatic substrates with H2O2 has been studied. In the presence of acetic acid, these complexes efficiently catalyze the oxidation of benzene and alkylbenzenes with high selectivity for oxygen incorporation into the aromatic ring (up to 93 %), performing up to 84 catalytic turnovers. The parent complex, [(PDP)(OTf)2], has demonstrated the highest catalytic efficiency and aromatic oxidation selectivity. The yield of products of oxidation of different substrates increases in line with increasing number of electron-donating alkyl groups of the substrates: halogenbenzenesH/kD (0.90–0.92), agrees with the SEAr oxidation mechanism. Low-temperature EPR studies have witnessed the presence of low-spin (g1=2.071, g2=2.008, g3=1.960) perferryl intermediates, demonstrating direct reactivity toward benzene. The oxidation of m-xylene in the presence of H218O has shown the same probability of 18O incorporation into the aromatic ring and the aliphatic moieties, which is indicative that both the aromatic and aliphatic oxidations are conducted by the same active species.
- Tkachenko, Nikolay V.,Ottenbacher, Roman V.,Lyakin, Oleg Y.,Zima, Alexandra M.,Samsonenko, Denis G.,Talsi, Evgenii P.,Bryliakov, Konstantin P.
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- One-Pot Direct Oxidation of Primary Amines to Carboxylic Acids through Tandem ortho-Naphthoquinone-Catalyzed and TBHP-Promoted Oxidation Sequence
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Biomimetic oxidation of primary amines to carboxylic acids has been developed where the copper-containing amine oxidase (CuAO)-like o-NQ-catalyzed aerobic oxidation was combined with the aldehyde dehydrogenase (ALDH)-like TBHP-mediated imine oxidation protocol. Notably, the current tandem oxidation strategy provides a new mechanistic insight into the imine intermediate and the seemingly simple TBHP-mediated oxidation pathways of imines. The developed metal-free amine oxidation protocol allows the use of molecular oxygen and TBHP, safe forms of oxidant that may appeal to the industrial application.
- Kim, Hun Young,Oh, Kyungsoo,Si, Tengda
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supporting information
p. 18150 - 18155
(2021/12/09)
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- α-MnO2 modified exfoliated porous g-C3N4 nanosheet (2D) for enhanced photocatalytic oxidation efficiency of aromatic alcohols
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Porous graphitic carbon nitride (g-C3N4) was synthesized by taking melamine and ammonium bicarbonate through single-step calcination method followed by ultrasonication to obtain exfoliated porous g-C3N4 (2D) nanosheets. Further enhancement of photocatalytic performance, g-C3N4 nanosheet (2D) was further modified with different weight percentage of (1, 3, 5, and 7) of MnO2. The introduction of α-MnO2 onto the g-C3N4 nanosheet establishes an interlayer channels to promote the migration of charge carriers through the valence band and conduction band of the prepared composite MnO2@g-C3N4. The transformation of photo induced charge carriers adopt the Z-scheme mechanism rather band-transfer mechanism. The accumulated photo generated electrons in conduction band of g-C3N4 is more electro negative than the potential of (O2/O2–.) and able to reduce oxygen to superoxide (O2–.) radical. At the same time, the holes in valence band of α-MnO2 are more electro positive than the potential of (OH–/OH.) and help in oxidate OH– to hydroxyl (OH.) radical. Among all the composites, 3 wt% MnO2 modified g-C3N4 shows the best photocatalytic oxidation efficiency towards all the aromatic alcohols. In presence of visible light, heterojuction formation, and formation of active charged species (OH. and O2–.) were mostly responsible for photocatalytic oxidation of aromatic alcohols through free radical mechanism.
- Nanda, Binita,Nanda, Braja B.,Pradhan, Manas Ranjan,Rath, Dharitri,Sethi, Ratikanta
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- Highly ordered mesoporous hybrid silica functionalized with ionic liquid framework supported copper and its application in the oxidation of alcohols
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A highly ordered organic-inorganic hybrid nanomaterial containing copper N-heterocyclic carbene complex (Cu-NHC@Pyrm-OMS) was synthesized and characterized using various techniques including FTIR, MAS NMR, XRD, TGA, SEM, and TEM. Cu-NHC@Pyrm-OMS nanomaterial is highly efficient heterogeneous system towards the selective oxidation of primary and secondary alcohols to corresponding aldehydes and ketones under mild conditions. Moreover, the supported copper nanocatalyst exhibited outstanding stability and could be reused at least ten times, remaining almost unchanged from initial activity. This work has focused on sustainable and green chemistry that use recoverable nanocatalyst, clean oxidant and aqueous media.
- Rajabi, Fatemeh,Bahrami, Nazli,Vessally, Esmail,Luque, Rafael
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- A green approach for aerobic oxidation of benzylic alcohols catalysed by CuI-Y zeolite/TEMPO in ethanol without additional additives
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An efficient and green protocol for aerobic oxidation of benzylic alcohols in ethanol using CuI-Y zeolite catalysts assisted by TEMPO (TEMPO = 2,2,6,6-tetramethyl-1-piperidine-N-oxyl) as the radical co-catalyst in the presence of atmospheric air under mild conditions is reported. The CuI-Y zeolite prepared via ion exchange between CuCl and HY zeolite was fully characterized by a variety of spectroscopic techniques including XRD, XPS, SEM, EDX and HRTEM. The incorporation of Cu(i) into the 3D-framework of the zeolite rendered the catalyst with good durability. The results of repetitive runs revealed that in the first three runs, there was hardly a decline in activity and a more substantial decrease in yield was observed afterwards, while the selectivity remained almost unchanged. The loss in activity was attributed to both the formation of CuO and the bleaching of copper into the liquid phase during the catalysis, of which the formation of CuO was believed to be the major contributor since the bleaching loss for each run was negligible (2%). In this catalytic system, except TEMPO, no other additives were needed, either a base or a ligand, which was essential in some reported catalytic systems for the oxidation of alcohols. The aerobic oxidation proceeded under mild conditions (60 °C, and 18 hours) to quantitatively and selectively convert a wide range of benzylic alcohols to corresponding aldehydes, which shows great potential in developing green and environmentally benign catalysts for aerobic oxidation of alcohols. The system demonstrated excellent tolerance against electron-withdrawing groups on the phenyl ring of the alcohols and showed sensitivity to steric hindrance of the substrates, which is due to the confinement of the pores of the zeolite in which the oxidation occurred. Based on the mechanism reported in the literature for homogenous oxidation, a mechanism was analogously proposed for the aerobic oxidation of benzylic alcohols catalysed by this Cu(i)-containing zeolite catalyst. This journal is
- Senthilkumar, Samuthirarajan,Zhong, Wei,Natarajan, Mookan,Lu, Chunxin,Xu, Binyu,Liu, Xiaoming
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p. 705 - 713
(2021/01/25)
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- Magneto-structural properties and reliability of (Mn/Ni/Zn) substituted cobalt-copper ferrite heterogeneous catalyst for selective and efficient oxidation of aryl alcohols
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Herein, M2+ substituted CoCuFe2O4 (M2+ = Mn, Zn, Ni) ferrites have been synthesized using the sol-gel auto combustion method. The structural, morphological and magnetic studies confirm the phase formation of pure magnetic cubic spinel MCoCuFe2O4 (M2+ = Mn, Zn, Ni) ferrites. The substitution with Mn, Ni and Zn does not show large variation in binding energies obtained from XPS of Cu (2p) that specifies identical copper concentration (Cu0.5) and substitution of only cobalt (Co2+) in Mn-F, Ni-F and Zn-F catalysts. Interestingly, MCoCuFe2O4 magnetic catalysts were explored for selective oxidation of a series of substituted benzyl alcohols. Catalyst Mn-F showed 93% conversion of benzyl alcohol while, Ni-F showed 95% conversion of 4-nitrobenzyl alcohol. Whereas, the catalyst Zn-F was showed 96% conversion for 4-methoxybenzyl alcohol. Additionally the results also indicate an efficient separation and recovery of the magnetic catalysts after four successive reuses without any considerable loss in its catalytic activity.
- Dhabbe, Rohant,Gaikwad, Pratapsingh,Kakade, Bhalchandra,Kamble, Prakash,Kurane, Rajnikant,Parase, Haridas,Sabale, Sandip
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- Palladium-Catalyzed Reductive Carbonylation of (Hetero) Aryl Halides and Triflates Using Cobalt Carbonyl as CO Source
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An efficient protocol for the reductive carbonylation of (hetero) aryl halides and triflates under CO gas-free conditions using Pd/Co2(CO)8 and triethylsilane has been developed. The mild reaction conditions, enhanced chemoselectivity and, easy access to heterocyclic and vinyl carboxaldehydes highlights its importance in organic synthesis.
- Dogga, Bhushanarao,Joseph, Jayan T.,Kumar, C. S. Ananda
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supporting information
p. 309 - 313
(2020/12/23)
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- Photocatalytic one-pot multidirectional N-alkylation over Pt/D-TiO2/Ti3C2: Ti3C2-based short-range directional charge transmission
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Visible-light-induced one-pot, multistep, and chemoselectivity adjustable reactions highlight the economical, sustainable, and green process. Herein, we report Pt nanoparticles dispersed on S and N co-doped titanium dioxide/titanium carbide (MXene) (3%Pt/
- Jiang, Heyan,Sheng, Meilin,Li, Yue,Kong, Shuzhen,Bian, Fengxia
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- Gold Catalysts Can Generate Nitrone Intermediates from a Nitrosoarene/Alkene Mixture, Enabling Two Distinct Catalytic Reactions: A Nitroso-Activated Cycloheptatriene/Benzylidene Rearrangement
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Gold-catalyzed reactions of cycloheptatrienes with nitrosoarenes yield nitrone derivatives efficiently. This reaction sequence enables us to develop gold-catalyzed aerobic oxidations of cycloheptatrienes to afford benzaldehyde derivatives using CuCl and nitrosoarenes as co-catalysts (10-30 mol %). Our density functional theory calculations support a novel nitroso-activated rearrangement, tropylium → benzylidene. With the same nitrosoarenes, we developed their gold-catalyzed [2 + 2 + 1]-annulations between nitrosobenzene and two enol ethers to yield 5-alkoxyisoxazolidines using 1,4-cyclohexadienes as hydrogen donors.
- Cheng, Mu-Jeng,Kardile, Rahul Dadabhau,Kuo, Tung-Chun,Liu, Rai-Shung,More, Sayaji Arjun
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supporting information
p. 5506 - 5511
(2021/07/31)
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- Synthesis and characterization of diacylgermanes: persistent derivatives with superior photoreactivity
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Acylgermanes are known as highly efficient photoinitiators. In this contribution, we present the synthesis of new diacylgermanes4a-eviaa multiple silyl abstraction methodology. The method outperforms the state-of-the-art approach (Corey-Seebach reaction)
- Fischer, Roland C.,Frühwirt, Philipp,Gescheidt, Georg,Griesser, Thomas,Haas, Michael,Kelterer, Anne-Marie,Müller, Stefanie M.,Püschmann, Sabrina D.,Torvisco, Ana,Wagner, Stefan H.
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p. 11965 - 11974
(2021/09/06)
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- Nitrosoarene-Catalyzed HFIP-Assisted Transformation of Arylmethyl Halides to Aromatic Carbonyls under Aerobic Conditions
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A rare metal-free nucleophilic nitrosoarene catalysis accompanied by highly hydrogen-bond-donor (HBD) solvent, 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP), organocatalytically converts arylmethyl halides to aromatic carbonyls. This protocol offers an effective means to access a diverse array of aromatic carbonyls with good chemoselectivity under mild reaction conditions. The activation of arylmethyl halides by HFIP to generate stable carbocation and autoxidation of in situ generated hydroxylamine to nitrosoarene in the presence of atmospheric O2 are the keys to success.
- Pradhan, Suman,Sharma, Vishali,Chatterjee, Indranil
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supporting information
p. 6148 - 6152
(2021/08/03)
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- Ferric ion concentration-controlled aerobic photo-oxidation of benzylic C–H bond with high selectivity and conversion
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A Fe(III)-promoted highly selective photo-oxidation of benzylic C–H bond delivering relative carbonyl products is reported. By altering the concentration of ferric salt, methylarenes can be selectively oxidized under UV irradiation to furnish aromatic aldehydes or acids, respectively. By this protocol, the oxidation of ethylarenes provides the corresponding acetophenones. The reaction is inferred to involve divergent pathways in different concentrations of catalyst for the alternative selectivity between aldehydes and aicds. The reusable catalyst, high conversion and selectivity make this oxidation a green and economic protocol for the synthesis of aromatic carbonyl compounds.
- Bu, Hongzhong,Gu, Jiefan,Li, Yufeng,Ma, Hongfei,Wan, Yuting,Wu, Zheng-Guang,Zhang, Weijian,Zhou, Ying'ao,Zhu, Hongjun
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- Photo-tunable oxidation of toluene and its derivatives catalyzed by TBATB
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In this report, tetrabutylammonium tribromide (TBATB) was introduced as an efficient visible light active catalyst to carry out the aerobic oxidation of toluene, its derivatives, and some of methyl arenes to benzaldehydes, benzoic acids and ketones in good to high yields. All the oxidation reactions were performed under mild conditions using oxygen as a green oxidant, a catalytic amount of TBATB under blue (460 nm), royal blue (430 nm), and violet LED (400 nm) irradiation. It was found that the reactions selectivity was significantly affected by changing the solvent (from CH3CN to EtOAc) and LED wavelength (from blue to violet). In the following, our mechanistic studies revealed that the visible light oxidation of toluenes and methyl arenes over TBATB could be following a benzyl peroxy radical intermediate.
- Mardani, Atefeh,Kazemi, Foad,Kaboudin, Babak
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- Core-shell Co-MOF-74@Mn-MOF-74 catalysts with Controllable shell thickness and their enhanced catalytic activity for toluene oxidation
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A series of core-shell Co-MOF-74@Mn-MOF-74 samples with different shell thicknesses were prepared by the seed growth method, which were characterized by powder X-ray diffraction (PXRD), thermogravimetric analysis (TGA), inductively coupled plasma mass spectrometry (ICP-MS), X-ray photoelectron spectroscopy, nitrogen adsorption-desorption and scanning electron microscopy (SEM). The shell thickness of these MOF samples were successfully controlled by adjusting the mass ratio between MnCl2·4H2O and Co-MOF-74. On this basis, these MOFs were applied to the catalytic oxidation of toluene. The results showed that with the growth of Mn-MOF-74 in the outer layer of Co-MOF-74, the oxidative selectivity of the substrate to benzaldehyde was greatly improved for the synergy between the core layer and shell layer. The conversion of toluene was 22.4%, and the selectivity of benzaldehyde was 98.1%. In addition, the catalyst can transform various substituted toluene into the corresponding aldehydes in highly selectivity and still keep good stability after four catalytic cycles. The selectivity of the corresponding aldehyde is generally above 80%.
- Gu, Xiangyu,Huang, Cheng,Xu, Zengchuang,Wu, Hao,Dong, Ruilan,Liu, Rui,Chen, Jing,Zhu, Hongjun
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- Metal- And additive-free C-H oxygenation of alkylarenes by visible-light photoredox catalysis
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A metal- and additive-free methodology for the highly selective, photocatalyzed C-H oxygenation of alkylarenes under air to the corresponding carbonyls is presented. The process is catalyzed by an imide-acridinium that forms an extremely strong photooxidant upon visible light irradiation, which is able to activate inert alkylarenes such as toluene. Hence, this is an easy to perform, sustainable and environmentally friendly oxidation that provides valuable carbonyls from abundant, readily available compounds.
- García Manche?o, Olga,Kuhlmann, Jan H.,Pérez-Aguilar, María Carmen,Piekarski, Dariusz G.,Uygur, Mustafa
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supporting information
p. 3392 - 3399
(2021/05/21)
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- Nickel catalyzed hydrosilane reduction of (het)arenecarboxylic acids into aldehydes
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Nickel-catalyzed reduction of (het)arenecarboxylic acids with hydrosilanes in the presence of dimethyl dicarbonate as the activator affords the corresponding aldehydes. The role of the activator is the conversion of the acids into their anhydrides undergoing C–O cleavage. The good yields were achieved in case of substrates bearing electron-donating and electron-neutral groups.
- Wang, Liang,Wang, Yaoyao,Tao, Yu,Zhang, Nana,Li, Shubai
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p. 271 - 273
(2021/05/04)
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- Method for generating benzaldehyde by catalyzing alpha-monosubstituted styrene to be oxidized by N-hydroxyphthalimide
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The invention discloses a method for generating benzaldehyde by catalyzing alpha-mono-substituted styrene to be oxidized through N-hydroxyphthalimide. According to the method, N-hydroxyphthalimide isused as a catalyst, oxygen is used as an oxidizing agent, and an alpha mono-substituted styrene compound is oxidized in an organic solvent to obtain the benzaldehyde derivative. The method has the advantages of simple reaction operation, low cost, mild conditions, high yield, no heavy metal pollution and the like.
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Paragraph 0060-0062
(2021/01/24)
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- Selective oxidation of alkenes to carbonyls under mild conditions
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Herein, a practical and sustainable method for the synthesis of aldehydes, ketones, and carboxylic acids from an inexpensive olefinic feedstock is described. This transformation features very sustainable and mild conditions and utilizes commercially available and inexpensive tetrahydrofuran as the additive, molecular oxygen as the sole oxidant and water as the solvent. A wide range of substituted alkenes were found to be compatible, providing the corresponding carbonyl compounds in moderate-to-good yields. The control experiments demonstrated that a radical mechanism is responsible for the oxidation reaction.
- Huo, Jie,Xiong, Daokai,Xu, Jun,Yue, Xiaoguang,Zhang, Pengfei,Zhang, Yilan
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supporting information
p. 5549 - 5555
(2021/08/16)
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- Aryl aldiketone and synthesis method thereof
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The invention discloses an aryl aldehyde ketone and a synthesis method thereof, wherein an aryl aldehyde is synthesized from cheap olefin as a raw material. A commercially available inexpensive olefin is used as a raw material, ether is used as an additive, molecular oxygen serves as a sole oxidizing agent, water is used as a solvent, and the aldehyde and ketone are synthesized by column chromatography under a photocatalytic condition. The invention has the advantages of mild reaction conditions, green and environmental protection, simple experimental operation, good reaction selectivity, high product yield and the like.
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Paragraph 0018
(2021/09/26)
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- Hydroxyl radical-mediated oxidative cleavage of CC bonds and further esterification reaction by heterogeneous semiconductor photocatalysis
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A hydroxyl radical-mediated aerobic cleavage of alkenes and further sequence esterification reaction for the preparation of carbonyl compounds have been developed by using tubular carbon nitride (TCN) as a general heterogeneous photocatalyst under an oxygen atmosphere with visible light irradiation. This protocol has an excellent substrate scope and gives the desired aldehydes, ketones and esters in moderate to high yields. Importantly, this metal-free procedure employed photogenerated hydroxyl radicals in situ as green oxidation active species, avoiding the present additional initiators. The reaction could be carried out under solar light irradiation and was applicable to large-scale reactions. Furthermore, the recyclable TCN catalyst could be used several times without a significant loss of activities.
- Hong, Mei,Jia, Rui,Miao, Hongyan,Ni, Bangqing,Niu, Tengfei,Wang, Hui
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p. 6591 - 6597
(2021/09/10)
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- Method for preparing aldehyde compounds by oxidative cleavage of carbon-carbon bonds of terminal alkene compounds
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The invention discloses a method for preparing aldehyde compounds by oxidizing and breaking carbon-carbon bonds of terminal alkene compounds. The method comprises the following steps: adding an alkene-terminated compound, an additive and a nitrogen-doped mesoporous carbon-loaded monatomic catalyst into a fatty primary alcohol solvent, putting into a pressure container, sealing, introducing oxygen source gas with a certain pressure, controlling the pressure of the oxygen source gas to be 0.1-1MPa and the reaction temperature to be 80-150 DEG C, and obtaining a reaction product, namely the aldehyde compound. The nitrogen-doped mesoporous carbon-loaded monatomic catalyst adopted by the invention is high in activity, the highest separation yield of the aldehyde compound as a reaction product reaches 99%, the method is wide in application range, the reaction conditions are easy to control, the catalyst can be recycled, the post-treatment is simple, and the method is suitable for industrial production.
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Paragraph 0037-0038; 0089-0090
(2021/06/06)
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- 1,2,3-Triazole framework: a strategic structure for C-H?X hydrogen bonding and practical design of an effective Pd-catalyst for carbonylation and carbon-carbon bond formation
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1,2,3-Triazole is an interesting N-heterocyclic framework which can act as both a hydrogen bond donor and metal chelator. In the present study, C-H hydrogen bonding of the 1,2,3-triazole ring was surveyed theoretically and the results showed a good agreement with the experimental observations. The click-modified magnetic nanocatalyst Pd@click-Fe3O4/chitosan was successfully prepared, in which the triazole moiety plays a dual role as both a strong linker and an excellent ligand and immobilizes the palladium species in the catalyst matrix. This nanostructure was well characterized and found to be an efficient catalyst for the CO gas-free formylation of aryl halides using formic acid (HCOOH) as the most convenient, inexpensive and environmentally friendly CO source. Here, the aryl halides are selectively converted to the corresponding aromatic aldehydes under mild reaction conditions and low Pd loading. The activity of this catalyst was also excellent in the Suzuki cross-coupling reaction of various aryl halides with phenylboronic acids in EtOH/H2O (1?:?1) at room temperature. In addition, this catalyst was stable in the reaction media and could be magnetically separated and recovered several times.
- Hajipour, Abdol Reza,Hosseini, Seyed Mostafa,Jahromi, Maryam Dehdashti,Mohammadsaleh, Fatemeh,Niknam, Khodabakhsh
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p. 20812 - 20823
(2021/07/01)
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- A Magnetically Recyclable Palladium-Catalyzed Formylation of Aryl Iodides with Formic Acid as CO Source: A Practical Access to Aromatic Aldehydes
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A magnetically recyclable palladium-catalyzed formylation of aryl iodides under CO gas-free conditions has been developed by using a bidentate phosphine ligand-modified magnetic nanoparticles-anchored- palladium(II) complex [2P-Fe 3O 4@SiO 2-Pd(OAc) 2] as catalyst, yielding a wide variety of aromatic aldehydes in moderate to excellent yields. Here, formic acid was employed as both the CO source and the hydrogen donor with iodine and PPh 3as the activators. This immobilized palladium catalyst can be obtained via a simple preparative procedure and can be facilely recovered simply by using an external magnetic field, and reused at least 9 times without any apparent loss of catalytic activity.
- You, Shengyong,Zhang, Rongli,Cai, Mingzhong
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p. 1962 - 1970
(2021/01/25)
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- Method for preparing aldehyde compound through olefin oxidation
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The invention provides a simple synthesis method for preparing an aldehyde compound through olefin oxidation, and the related preparation method is an olefin oxidative cracking reaction in which oxygen participates, and comprises the following specific steps: in the presence of a solvent and an oxidant, performing oxidative cracking on an olefin raw material to prepare a corresponding aldehyde product. Compared with a traditional method, the method does not need to add any catalyst or ligand, does not need to use high-pressure oxygen, has the advantages of simple and mild reaction conditions, environmental protection, low cost, high atom economy and the like, is wide in substrate application range and high in yield, and has wide application prospects in synthesis of aldehyde medical intermediates and chemical raw materials.
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Paragraph 0036-0041
(2021/06/09)
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- Method for preparing aldehyde ketone compound through olefin oxidation
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The invention provides a method for preparing an aldehyde ketone compound by olefin oxidation, which relates to an olefin oxidative cracking reaction in which oxygen participates. The method comprises the following specific steps: in the presence of a solvent and an oxidant, carrying out oxidative cracking on an olefin raw material to obtain a corresponding aldehyde ketone product. Compared with the traditional method, the method does not need to add any catalyst or ligand, does not need to use high-pressure oxygen, has the advantages of simple and mild reaction conditions, environment friendliness, low cost, high atom economy and the like, is wide in substrate application range and high in yield, and has a wide application prospect in the aspects of synthesis of aldehyde ketone medical intermediates and chemical raw materials.
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Paragraph 0019
(2021/04/07)
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- Poly(ethylene glycol) dimethyl ether mediated oxidative scission of aromatic olefins to carbonyl compounds by molecular oxygen
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A simple, and practical oxidative scission of aromatic olefins to carbonyl compounds using O2as the sole oxidant with poly(ethylene glycol) dimethyl ether as a benign solvent has been developed. A wide range of monosubstituted,gem-disubstituted, 1,2-disubstituted, trisubstituted and tetrasubstituted aromatic olefins was successfully converted into the corresponding aldehydes and ketones in excellent yields even with gram-scale reaction. Some control experiments were also conducted to support a possible reaction pathway.
- Yu, Tao,Guo, Mingqing,Wen, Simiaomiao,Zhao, Rongrong,Wang, Jinlong,Sun, Yanli,Liu, Qixing,Zhou, Haifeng
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p. 13848 - 13852
(2021/04/22)
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- Radical induced disproportionation of alcohols assisted by iodide under acidic conditions
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The disproportionation of alcohols without an additional reductant and oxidant to simultaneously form alkanes and aldehydes/ketones represents an atom-economical transformation. However, only limited methodologies have been reported, and they suffer from a narrow substrate scope or harsh reaction conditions. Herein, we report that alcohol disproportionation can proceed with high efficiency catalyzed by iodide under acidic conditions. This method exhibits high functional group tolerance including aryl alcohol derivatives with both electron-withdrawing and electron-donating groups, furan ring alcohol derivatives, allyl alcohol derivatives, and dihydric alcohols. Under the optimized reaction conditions, a 49% yield of 5-methyl furfural and a 49% yield of 2,5-diformylfuran were obtained simultaneously from 5-hydroxymethylfurfural. An initial mechanistic study suggested that the hydrogen transfer during this redox disproportionation occurred through the inter-transformation of HI and I2. Radical intermediates were involved during this reaction.
- Huang, Yang,Jiang, Haiwei,Li, Teng,Peng, Yang,Rong, Nianxin,Shi, Hexian,Yang, Weiran
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supporting information
p. 8108 - 8115
(2021/10/29)
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- Catalytic Selective Oxidation of Primary and Secondary Alcohols Using Nonheme [Iron(III)(Pyridine-Containing Ligand)] Complexes
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The selective oxidation of different primary and secondary alcohols to carbonyl compounds by hydrogen peroxide was found to be catalyzed in conversion ranging from good to excellent by an iron(III) complex of a pyridine-containing macrocyclic ligand (Pc-L), without the need of any additive. The choice of the counteranion (Cl, Br, OTf) appeared to be of fundamental importance and the best results in terms of selectivity (up to 99 %) and conversion (up to 98 %) were obtained using the well-characterized [Fe(III)(Br)2(Pc-L)]Br complex, 4c. Magnetic moments in solid-state, also confirmed in solution ([D6]DMSO) by Evans NMR method, were calculated and point out to an iron metal center in the high spin state of 5/2. The crystal structure shows that the iron(III) center is coordinated by the four nitrogen atoms of the macrocycle and two bromide anions to form a distorted octahedral coordination environment. The catalytic oxidation of benzyl alcohol in acetonitrile was found occurring with better conversions and selectivities than in other solvents. The reaction proved to be quite general, tolerating aromatic and aliphatic alcohols, although very low yields were obtained for terminal aliphatic alcohols. Preliminary mechanistic studies are in agreement with a catalytic cycle promoted by a high-spin iron complex.
- Caselli, Alessandro,Gallo, Emma,Panza, Nicola,Rizzato, Silvia,Tseberlidis, Giorgio,di Biase, Armando
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supporting information
p. 6635 - 6644
(2020/10/30)
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- Clean and Selective Oxidation of Alcohols with Oxone and Phase-Transfer Catalysts in Water
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Abstract: A new, simple, metal-free, and eco-friendly procedure has been proposed forthe oxidation of alcohols with Oxone (potassium peroxymonosulfate) in water inthe presence of six phase-transfer catalysts (PTC). Phase-transfer catalystswere found to display high catalytic activity in water solution. Furthermore,the oxidation of alcohols was also carried out with relatively good conversionand selectivity in water without any catalyst.
- An, X. Q.,Kang, M.,Ma, H. C.,Yang, Y. X.,Yang, Z. W.,Zeng, W.
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p. 1790 - 1794
(2020/12/01)
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- Rhodium-catalyzed reductive carbonylation of aryl iodides to arylaldehydes with syngas
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The reductive carbonylation of aryl iodides to aryl aldehydes possesses broad application prospects. We present an efficient and facile Rh-based catalytic system composed of the commercially available Rh salt RhCl3·3H2O, PPh3 as phosphine ligand, and Et3N as the base, for the synthesis of arylaldehydes via the reductive carbonylation of aryl iodides with CO and H2 under relatively mild conditions with a broad substrate range affording the products in good to excellent yields. Systematic investigations were carried out to study the experimental parameters. We explored the optimal ratio of Rh salt and PPh3 ligand, substrate scope, carbonyl source and hydrogen source, and the reaction mechanism. Particularly, a scaled-up experiment indicated that the catalytic method could find valuable applications in industrial productions. The low gas pressure, cheap ligand and low metal dosage could significantly improve the practicability in both chemical researches and industrial applications.
- Chen, Suqing,Liu, Zhenghui,Mu, Tiancheng,Wang, Peng,Yan, Zhenzhong,Yu, Dongkun,Zhao, Xinhui
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p. 645 - 656
(2020/05/14)
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- Nickel complex containing meta-carborane triazole ligand and preparation method and application of nickel complex
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The invention relates to a nickel complex containing a meta-carborane triazole ligand and a preparation method and application of the nickel complex. The nickel complex is prepared by the following steps of: (1) dropwise adding an n-BuLi solution into a meta-carborane m-C2B10H12 solution, stirring and reacting; then adding 3-propargyl bromide for a reaction, and separating after the reaction is finished so as to obtain 1, 3-dipropargyl meta-carborane; and (2) carrying out a reaction between 1, 3-dipropargyl meta-carborane and aryl azide under the catalytic condition of a catalyst CuI, then adding NiCl2 into the reaction system, continuing the reaction, carrying out separation after the reaction is finished so as to obtain the nickel complex containing the meta-carborane triazole ligand. The nickel complex is applied to preparation of aldehyde by catalyzing partial oxidation of primary alcohol. Compared with the prior art, the preparation method is simple and green, the complex can efficiently catalyze partial oxidation of primary alcohol to prepare aldehyde, the reaction conditions are mild, the universality is good, the catalytic efficiency is high, and few byproducts are produced; and the catalyst has high stability and is not sensitive to air and water.
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Paragraph 0043; 0045-0047
(2020/08/07)
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- Cu(ii) vitamin C tunes photocatalytic activity of TiO2 nanoparticles for visible light-driven aerobic oxidation of benzylic alcohols
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The incorporation of Cu(OAc)2 into ascorbic acid coated TiO2 nanoparticles easily provided a new heterogeneous visible-light active titania-based photocatalyst (TiO2-AA-Cu(ii)) which was characterized by different techniques such as FT-IR, XPS, ICP-AES, TGA and TEM. A red-shift of the band-edge and a reduction of the band-gap (2.8 eV vs. 3.08 for TiO2) were demonstrated by UV-DRS and Tauc plots. The combination of the as-prepared TiO2-AA-Cu(ii) nanoparticles with TEMPO and molecular oxygen (air) afforded an active catalytic system for the selective oxidation of diverse set of benzylic alcohols under solvent-free conditions. A photoassisted pathway was confirmed for oxidation reactions evidenced by good correlation between apparent quantum yield (AQY) and diffuse reflectance spectra (DRS) of the as-prepared nanohybrid. The spectral data and recycling experiments demonstrated the structural stability of the title copper photocatalyst during oxidation reactions.
- Pourmorteza, Narges,Jafarpour, Maasoumeh,Feizpour, Fahimeh,Rezaeifard, Abdolreza
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p. 12053 - 12059
(2020/04/27)
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- Magnetic nanoparticle supported ionic liquid phase catalyst for oxidation of alcohols
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Anew magnetic nanoparticle supported ionic liquid phase (SILP) catalyst containing perruthenate anions was prepared by a multistep procedure. The various analytical techniques such as FT-IR spectroscopy, X-ray photoelectron spectroscopy, transmission elec
- Naikwade, Altafhusen,Jagadale, Megha,Kale, Dolly,Rashinkar, Gajanan
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p. 1088 - 1097
(2020/10/20)
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- Tungstate ion (WO42-) confined in hydrophilic/hydrophobic nanomaterials functionalized br?nsted acidic ionic liquid as highly active catalyst in the selective aerobic oxidation of alcohols in water
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A Br?nsted acidic Ionic Liquid containing tungstate anion functionalized polysiloxane network (PMO-IL-WO42-) was synthesized by simple self-condensation of tungstic acid and zwitterionic organosilane precursor possessing both imidazolium and sulfonate groups. Characterization by scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD), thermal gravimetric analysis TGA, nitrogen porosimetry, solid-state NMR spectroscopy and elemental analysis confirmed that both imidazolium cation and tungstate anion of zwitterion are successfully incorporated inside the organosilica framework. The catalytic activity of resulting hybrid PMO-IL- WO42- material was studied in the selective aerobic oxidation of primary and secondary alcohols using an atmospheric pressure of air in pure water. Due to the ionic liquid-based charged surface containing hydrophilic sulfonic acid and tungstate group, the synergistic hydrophilic/hydrophobic and redox effect of PMO-IL-WO42- as water-friendly catalyst facilitates and enhances the activity and selectivity toward the target oxidative products in water and proved to have a particularly broad substrate scope for reliable aerobic oxidation reaction. Furthermore, the catalyst showed outstanding stability and could be easily separated and reused at least ten reactions run under the same conditions as fresh catalyst without any loss of catalytic activity and product selectivity.
- Luque, Rafael,Nafe, Mostafa,Rajabi, Fatemeh,Rezanejad Bardajee, Ghasem
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- FeCl3-catalyzed oxidative decarboxylation of aryl/heteroaryl acetic acids: Preparation of selected API impurities
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There is an ever-increasing demand for impurity compounds for use in impurity profiling as regulatory agencies seek information during registration. Herein, we report the FeCl3-catalyzed oxidative decarboxylation of aryl- and heteroaryl acetic acids to the corresponding carbonyl compounds. A variety of useful aldehydes and ketones were prepared in a simple one-pot transformation by employing an environmentally benign, low-cost, and readily available iron salt. The utility of this method has been demonstrated by preparing five valuable API impurities including a multi-gram-scale synthesis of ketorolac impurity B for the first time. This journal is
- Gangadurai, Chinnakuzhanthai,Illa, Giri Teja,Reddy, D. Srinivasa
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p. 8459 - 8466
(2020/11/05)
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- Oxidative C-S Bond Cleavage of Benzyl Thiols Enabled by Visible-Light-Mediated Silver(II) Complexes
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The oxidative cleavage reaction of the C-S bond using singlet oxygen is challenging because of its uncontrollable nature. We have developed a novel method for the singlet-oxygen-mediated selective C-S bond cleavage reaction using silver(II)-ligand complexes. Visible-light-induced silver catalysis enables the controlled oxidative cleavage of benzyl thiols to afford carbonyl compounds, such as aldehydes or ketones, which are important synthetic components.
- Hong, Boseok,Aganda, Kim Christopher C.,Lee, Anna
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supporting information
p. 4395 - 4399
(2020/06/05)
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- Decarboxylative formylation of aryl halides with glyoxylic acid by palladium catalysis under oxygen
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A new free radical/palladium cooperative catalyzed formylation of aryl halides with glyoxylic acid as the formyl source under oxygen conditions has been developed. Various aromatic and heteroaromatic aldehydes were produced in medium to good yields.
- Cao, Hualiang,Pu, Weiwen,Zhang, Jie,Yan, Peijun,Zhang, Jun,Xu, Sheng
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supporting information
p. 1287 - 1290
(2020/08/21)
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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 0064-0067
(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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- 1,1,1,3,3,3-Hexafluoroisopropanol as an efficient medium for the room temperature oxidation of styrenes to benzaldehydes
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A room temperature N-hydroxyphthalimide-catalyzed oxidation of styrene derivatives to the corresponding aldehydes has been developed. The use of 1,1,1,3,3,3-hexafluoroisopropanol as the solvent was determined as being key for efficient oxidation. The incorporated oxygen atom originates from molecular dioxygen.
- Zhang, Zhuyong,Chen, Weidong,Luo, Junfei
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supporting information
(2020/10/23)
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- Iodobenzene-catalyzed oxidative cleavage of olefins to carbonyl compounds
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A metal-free approach for the oxidative cleavage of carbon–carbon double bonds of olefins to carbonyl compounds was established by using oxidant m-CPBA and non-metallic organocatalyst PhI in toluene/H2O. A broad scope of aromatic olefins was used. All the reactions proceeded smoothly at 35 °C in short reaction time to furnish the respective mono- and double carbonyl compounds selectively in moderate to good yields.
- Du, Lele,Wang, Zechao,Wu, Junliang
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supporting information
(2020/07/20)
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- Powerful and Phosphine-Free Palladium-Catalyzed Selective Formylation of Aryl Halides with Formic Acid as CO Source
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The phosphine-free palladium-based catalytic system Pd(OAC)2/DABCO has been developed for the carbonylative transformations of aryl halides with formic acid. The DABCO acts as a base as well as N-donor ligand to coordinate with metal ions and stabilize Pd-catalytic sites during the reaction process. Using DCC as the activator of formic acid and PEG as the reaction media. The aryl halides have been conveniently transformed into the corresponding aldehydes in moderate to excellent yields. Graphic Abstract: An efficient catalytic system Pd(OAc)2/ DABCO/ DCC for selective carbonylation of aryl halides with formic acid is described.[Figure not available: see fulltext.].
- Molaei, Elahe,Mohammadsaleh, Fatemeh,Niknam, Khodabakhsh
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p. 1970 - 1975
(2020/01/28)
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- Continuous flow synthesis of aryl aldehydes by Pd-catalyzed formylation of phenol-derived aryl fluorosulfonates using syngas
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This communication describes the palladium-catalyzed reductive carbonylation of aryl fluorosulfonates (ArOSO2F) using syngas as an inexpensive and sustainable source of carbon monoxide and hydrogen. The conversion of phenols to aryl fluorosulfonates can be conveniently achieved by employing the inexpensive commodity chemical sulfuryl fluoride (SO2F2) and base. The developed continuous flow formylation protocol requires relatively low loadings for palladium acetate (1.25 mol%) and ligand (2.5 mol%). Good to excellent yields of aryl aldehydes were obtained within 45 min for substrates containing electron withdrawing substituents, and 2 h for substrates containing electron donating substituents. The optimal reaction conditions were identified as 120 °C temperature and 20 bar pressure in dimethyl sulfoxide (DMSO) as solvent. DMSO was crucial in suppressing Pd black formation and enhancing reaction rate and selectivity. This journal is
- Hanselmann, Paul,Hone, Christopher A.,Hu, Guixian,K?ckinger, Manuel,Kappe, C. Oliver
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p. 22449 - 22453
(2020/07/03)
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- Heterogeneous carbon nitride photocatalyst for C-C bond oxidative cleavage of vicinal diols in aerobic micellar medium
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A green and efficient visible-light promoted aerobic oxidative C-C bond cleavage of vicinal diols in micellar medium has been developed. This protocol used graphitic carbon nitride with nitrogen vacancies (CN620) as a metal-free recyclable photocatalyst and CTAB as surfactant in water. Control experiments and the ESR results indicated that superoxide radicals and valence band holes played an important role in the reaction. Further isotope experiments suggested both a β-scission/HAT pathway and an oxidation/hydrolysis/dehydration pathway for the reaction, which is different from previous reports. The semiconductor/micellar catalyst system can be recycled at least 10 times without a significant reduction in activity. Furthermore, this reaction could be carried out under solar light irradiation and was applicable to large-scale reactions with similar results.
- Chen, Jiayang,Chen, Shengjun,Dong, Xinyu,Hong, Mei,Ni, Bangqing,Niu, Tengfei,Zhang, Tianhao
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supporting information
p. 5042 - 5049
(2020/08/25)
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- Lignin-fueled photoelectrochemical platform for light-driven redox biotransformation
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The valorization of lignin has significant potential in producing commodity chemicals and fuels from renewable resources. However, the catalytic degradation of lignin is kinetically challenging and often requires noble metal catalysts to be used under harsh and toxic conditions. Here, we report the bias-free, solar reformation of lignin coupled with redox biotransformation in a tandem structure of a BiVO4 photoanode and perovskite photovoltaic. The tandem structure compensates for the potential gap between lignin oxidation and biocatalytic reduction through artificial Z-schematic absorption. We found that the BiVO4-catalyzed photoelectrochemical oxidation of lignin facilitated the fragmentation of higher molecular weight lignin into smaller carboxylated aliphatic and aromatic acids. Lignin oxidation induced photocurrent generation at the photoanode, which enabled efficient electroenzymatic reactions at the cathode. This study successfully demonstrates the oxidative valorization of lignin as well as biocatalytic reductions (e.g., CO2-to-formate and α-ketoglutarate-to-l-glutamate) in an unbiased biocatalytic PEC platform, which provides a new strategic approach for photo-biocatalysis using naturally abundant renewable resources.
- Boonmongkolras, Passarut,Choi, Eun-Gyu,Han, Seunghyun,Kim, Jinhyun,Kim, Kayoung,Kim, Yong Hwan,Lee, Sahng Ha,Lee, Yang Woo,Park, Chan Beum,Shin, Byungha,Trang, Nguyen Vu Thien,Wang, Ding
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supporting information
p. 5151 - 5160
(2020/08/25)
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- Palladium-catalyzed external-CO-free reductive carbonylation of aryl sulfonates
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Pd-catalyzed reductive carbonylation of aryl sulfonates using N-formylsaccharin as a carbon monoxide (CO) surrogate was developed. This external-CO-free carbonylation provides a safe and practical access to aldehydes from phenol derivatives. The reaction has a broad substrate scope, rendering it an attractive method for synthesizing aldehydes.
- Konishi, Hideyuki,Kumon, Minoru,Yamaguchi, Miyuki,Manabe, Kei
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- 3-BocNH-ABNO-catalyzed aerobic oxidation of alcohol at room temperature and atmospheric pressure
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A transition-metal-free catalytic system has been developed for selective transformation of alcohol to aldehydes or ketones. The reactions were performed with 3-(tert-butoxycarbonylamino)-9-azabicyclo[3.3.1]nonane N-oxyl (3-BocNH-ABNO) as the catalyst, NaNO2 as the co-catalyst, molecular oxygen as the terminal oxidant, and AcOH as the solvent under room temperature. This catalytic system exhibited broad functional group tolerance. A series of alcohol substrates, including primary and secondary benzylic alcohols, heteroaromatic analogues, primary and secondary aliphatic alcohols, could be converted into their corresponding aldehydes and ketones in good conversions and selectivities.
- Zhao, Yajing,Li, Yutong,Shen, Zhenlu,Hu, Xinquan,Hu, Baoxiang,Jin,Sun, Nan,Li, Meichao
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supporting information
(2019/08/06)
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- 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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- Iron-catalyzed one-pot sequential transformations: Synthesis of quinazolinones via oxidative Csp3–H bond activation using a new metal-organic framework as catalyst
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A new mixed-linker iron-based MOF VNU-21 [Fe3(BTC)(EDB)2·12.27H2O] was synthesized via mixed-linker synthetic strategy using 1,3,5-benzenetricarboxylic acid, 4,4′-ethynylenedibenzoic acid, and FeCl2. The VNU-21 was consequently used as a recyclable heterogeneous catalyst in the one-pot synthesis of quinazolinones via two steps under oxygen atmosphere. The synthetic scheme involved iron-catalyzed oxidative Csp3–H bond activation to achieve decarboxylation of phenylacetic acids, and succeeding metal-free oxidative cyclization with 2-aminobenzamides. The VNU-21 was more effective than a series of heterogeneous and homogeneous catalysts. It was possible to reutilize the iron-based framework without a considerable deterioration in catalytic performance. To our best knowledge, this one-pot synthesis of quinazolinones was not previously performed using a recyclable catalyst.
- To, Tuong A.,Vo, Yen H.,Nguyen, Hue T.T.,Ha, Phuong T.M.,Doan, Son H.,Doan, Tan L.H.,Li, Shuang,Le, Ha V.,Tu, Thach N.,Phan, Nam T.S.
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- Photocatalytic Oxidation of Α-C?H Bonds in Unsaturated Hydrocarbons through a Radical Pathway Induced by a Molecular Cocatalyst
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To improve the photocatalytic oxidation of α-C?H bonds in unsaturated hydrocarbons, N-hydroxyphthalimide (NHPI) was used as a molecular cocatalyst with CdS as the photoabsorber. Compared with previously reported photocatalysts involving solid cocatalysts, metal-free NHPI offers better sustainability in addition to the significantly enhanced performance as cocatalyst. The photogenerated holes were transferred into the more active phthalimide-N-oxyl radical (PINO) by reacting with NHPI. In this way, α-C?H bond oxidation was significantly improved through the activation by PINO; even for the sluggish toluene oxidation, the apparent quantum efficiency was as high as 36.5 %. The effects of substrates/NHPI concentration ratio, reaction temperature, and time as well as the reaction intermediates were comprehensively studied. It was possible to identify ketones/aldehydes as the primary products, and overoxidation was controlled by adjusting the substrates/NHPI concentration ratio and reaction time. Thus, the radical path induced by the NHPI–PINO redox pair is an efficient alternative to boost the sluggish photocatalytic oxidation of α-C?H bonds.
- Zhao, Guixia,Hu, Bin,Busser, G. Wilma,Peng, Baoxiang,Muhler, Martin
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p. 2795 - 2801
(2019/06/24)
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