- Pure acetonitrile as solvent for the efficient electrochemical conversion of aryl bromides in organozinc species and their coupling reaction with acetyl chloride
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Conversion of functionalized aryl bromides in an electrochemical cell fitted with a sacrificial anode and in the presence of cobalt bromide without ligand in acetonitrile as solvent affords the corresponding organozinc species in good yields. Their coupling with acetyl chloride is efficient using a palladium catalyst.
- Fillon, Hyacinthe,Le Gall, Erwan,Gosmini, Corinne,Périchon, Jacques
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Read Online
- Development of a Flow Photochemical Aerobic Oxidation of Benzylic C-H Bonds
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A continuous mesofluidic process has been developed for benzylic C-H oxidation with moderate to good yields using a photocatalyst (riboflavin tetraacetate, RFT) activated by a UV lamp and an iron additive [Fe(ClO4)2] via incorporation of singlet oxygen (1O2) for the direct formation of oxidized C=O or CH-OH compounds.
- Lesieur, Mathieu,Genicot, Christophe,Pasau, Patrick
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Read Online
- TBHP-promoted direct oxidation reaction of benzylic Csp3-H bonds to ketones
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A metal-free oxidation system employing tert-butyl hydroperoxide (TBHP) has been developed for selective oxidation of structurally diverse benzylic sp3 C-H bonds. This low-cost methodology allows for rapid generation of synthetically and biologically valued arylketones in good to excellent yields from readily available alkylarenes and diarylmethanes.
- Tan, Jiajing,Zheng, Tianyu,Yu, Yuqi,Xu, Kun
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- Dioxygen-promoted regioselective oxidative Heck arylations of electron-rich olefins with arylboronic acids
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Arylations of electron-rich heteroatom-substituted olefins were performed with arylboronic acids. This appears to constitute the first example of palladium(II)-catalyzed internal Heck arylations. The novel protocol exploits oxygen gas for environmentally benign reoxidation and a stable 1,10-phenanthroline bidentate ligand to promote the palladium(II) regeneration and to control the regioselectivity. Internal arylation is strongly favored with electron-rich arylboronic acids. DFT calculations support a charge-driven selectivity rationale, where phenyls substituted with electron-donating groups prefer the electron-poor α-carbon of the olefin. Experiments, verified by calculations, confirm the cationic nature of the catalytic route. This Heck methodology provides a facile and mild access to functionalized enamides. Controlled microwave heating and increased oxygen pressure were used to further reduce the reaction time to 1 h.
- Andappan, Murugaiah M. S.,Nilsson, Peter,Von Schenck, Henrik,Larhed, Mats
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- Ni-based catalysts derived from a metal-organic framework for selective oxidation of alkanes
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Ni nanoparticles embedded in nitrogen-doped carbon (Ni@C-N) materials were prepared by thermolysis of a Ni-containing metal-organic framework (Ni-MOF) under inert atmosphere. The as-synthesized Ni@C-N materials were characterized by powder X-ray diffraction, N2 adsorption-desorption analysis, scanning electron microscopy, transmission electron microscopy, atomic absorption spectroscopy, and X-ray photoelectron spectroscopy. The MOF-derived Ni-based materials were then examined as heterogeneous catalysts for the oxidation of alkanes under mild reaction conditions. The Ni@C-N composites displayed high activity and selectivity toward the oxidation of a variety of saturated C-H bonds, affording the corresponding oxidation products in good-to-excellent yields. Furthermore, the catalysts could be recycled and reused for at least four times without any significant loss in activity and selectivity under the investigated conditions.
- Zhou, Ying,Long, Jilan,Li, Yingwei
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- Electrochemical Aerobic Oxidative Cleavage of (sp3)C-C(sp3)/H Bonds in Alkylarenes
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An electrochemistry-promoted oxidative cleavage of (sp3)C-C(sp3)/H bonds in alkylarenes was developed. Various aryl alkanes can be smoothly converted into ketones/aldehydes under aerobic conditions using a user-friendly undivided cell setup. The features of air as oxidant, scalability, and mild conditions make them attractive in synthetic organic chemistry.
- Liu, Shuai,Liu, Zhong-Quan,Shen, Tong,Shen, Xu,Wang, Nengyong,Wu, Jintao,Yang, Le,Zhao, Jianyou
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p. 3286 - 3295
(2022/03/14)
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- Selective electrochemical oxidation of aromatic hydrocarbons and preparation of mono/multi-carbonyl compounds
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A selective electrochemical oxidation was developed under mild condition. Various mono-carbonyl and multi-carbonyl compounds can be prepared from different aromatic hydrocarbons with moderate to excellent yield and selectivity by virtue of this electrochemical oxidation. The produced carbonyl compounds can be further transformed into α-ketoamides, homoallylic alcohols and oximes in a one-pot reaction. In particular, a series of α-ketoamides were prepared in a one-pot continuous electrolysis. Mechanistic studies showed that 2,2,2-trifluoroethan-1-ol (TFE) can interact with catalyst species and generate the corresponding hydrogen-bonding complex to enhance the electrochemical oxidation performance. [Figure not available: see fulltext.]
- Li, Zhibin,Zhang, Yan,Li, Kuiliang,Zhou, Zhenghong,Zha, Zhenggen,Wang, Zhiyong
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p. 2134 - 2141
(2021/09/29)
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- Efficient Aliphatic C-H Oxidation and C═C Epoxidation Catalyzed by Porous Organic Polymer-Supported Single-Site Manganese Catalysts
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Bioinspired manganese complexes have emerged over recent decades as attractive catalysts for a number of selective oxidation reactions. However, these catalysts still suffer from oxidative degradation. In the present study, we prepared a series of porous Mn-N4 catalysts in which the catalytic units are embedded in the skeleton of porous organic polymers (POPs). These POP-based manganese catalysts demonstrated high reactivity in the oxidation of aliphatic C-H bonds and the asymmetric epoxidation of olefins. Furthermore, these catalysts could be readily recycled and reused due to their heterogeneous nature. Morphological characterization revealed that the Mn-N4 complex was individually distributed over a porous polymer network. Remarkably, the nature of the single-site catalyst prevented oxidative degradation during the reaction. The present work has thus developed a successful approach for bioinspired single-site manganese catalysts in which the oxidation reaction is confined to a specific channel in an enzyme-like mode.
- Wang, Bingyang,Lin, Jin,Sun, Qiangsheng,Xia, Chungu,Sun, Wei
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p. 10964 - 10973
(2021/09/08)
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- HCl-Catalyzed Aerobic Oxidation of Alkylarenes to Carbonyls
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The construction of C?O bonds through C?H bond functionalization remains fundamentally challenging. Here, a practical chlorine radical-mediated aerobic oxidation of alkylarenes to carbonyls was developed. This protocol employed commercially available HCl as a hydrogen atom transfer (HAT) reagent and air as a sustainable oxidant. In addition, this process exhibited excellent functional group tolerance and a broad substrate scope without the requirement for external metal and oxidants. The mechanistic hypothesis was supported by radical trapping, 18O labeling, and control experiments.
- Ding, Ling,Liu, Yuxiu,Niu, Kaikai,Shi, Xiaodi,Song, Hongjian,Wang, Qingmin
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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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- Visible-light photocatalytic selective oxidation of C(sp3)-H bonds by anion-cation dual-metal-site nanoscale localized carbon nitride
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Selective oxidation of C(sp3)-H bonds to carbonyl groups by abstracting H with a photoinduced highly active oxygen radical is an effective method used to give high value products. Here, we report a heterogeneous photocatalytic alkanes C-H bonds oxidation method under the irradiation of visible light (λ= 425 nm) at ambient temperature using an anion-cation dual-metal-site modulated carbon nitride. The optimized cation (C) of Fe3+or Ni2+, with an anion (A) of phosphotungstate (PW123?) constitutes the nanoscale dual-metal-site (DMS). With a Fe-PW12dual-metal-site as a model (FePW), we demonstrate a A-C DMS nanoscale localized carbon nitride (A-C/g-C3N4) exhibiting a highly enhanced photocatalytic activity with a high product yield (86% conversion), selectivity (up to 99%), and a wide functional group tolerance (52 examples). The carbon nitride performs the roles of both the visible light response, and improves the selectivity for the oxidation of C(sp3)-H bonds to carbonyl groups, along with the function of A-C DMS in promoting product yield. Mechanistic studies indicate that this reaction follows a radical pathway catalyzed by a photogenerated electron and hole on A-C/g-C3N4that is mediated by thetBuO˙ andtBuOO˙ radicals. Notably, a 10 g scale reaction was successfully achieved for alkane photocatalytic oxidation to the corresponding product with a good yield (80% conversion), and high selectivity (95%) under natural sunlight at ambient temperature. In addition, this A-C/g-C3N4photocatalyst is highly robust and can be reused at least six times and the activity is maintained.
- Duan, Limei,Li, Peihe,Li, Wanfei,Liu, Jinghai,Liu, Ying,Liu, Zhifei,Lu, Ye,Sarina, Sarina,Wang, Jinghui,Wang, Yin,Wang, Yingying,Zhu, Huaiyong
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p. 4429 - 4438
(2021/07/12)
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- Photoinduced Acetylation of Anilines under Aqueous and Catalyst-Free Conditions
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A green and efficient visible-light induced functionalization of anilines under mild conditions has been reported. Utilizing nontoxic, cost-effective, and water-soluble diacetyl as photosensitizer and acetylating reagent, and water as the solvent, a variety of anilines were converted into the corresponding aryl ketones, iodides, and bromides. With advantages of environmentally friendly conditions, simple operation, broad substrate scope, and functional group tolerance, this reaction represents a valuable method in organic synthesis.
- Yang, Yu-Ming,Yan, Wei,Hu, Han-Wei,Luo, Yimin,Tang, Zhen-Yu,Luo, Zhuangzhu
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p. 12344 - 12353
(2021/09/02)
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- Oxidative Cleavage of Alkenes by O2with a Non-Heme Manganese Catalyst
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The oxidative cleavage of C═C double bonds with molecular oxygen to produce carbonyl compounds is an important transformation in chemical and pharmaceutical synthesis. In nature, enzymes containing the first-row transition metals, particularly heme and non-heme iron-dependent enzymes, readily activate O2 and oxidatively cleave C═C bonds with exquisite precision under ambient conditions. The reaction remains challenging for synthetic chemists, however. There are only a small number of known synthetic metal catalysts that allow for the oxidative cleavage of alkenes at an atmospheric pressure of O2, with very few known to catalyze the cleavage of nonactivated alkenes. In this work, we describe a light-driven, Mn-catalyzed protocol for the selective oxidation of alkenes to carbonyls under 1 atm of O2. For the first time, aromatic as well as various nonactivated aliphatic alkenes could be oxidized to afford ketones and aldehydes under clean, mild conditions with a first row, biorelevant metal catalyst. Moreover, the protocol shows a very good functional group tolerance. Mechanistic investigation suggests that Mn-oxo species, including an asymmetric, mixed-valent bis(μ-oxo)-Mn(III,IV) complex, are involved in the oxidation, and the solvent methanol participates in O2 activation that leads to the formation of the oxo species.
- Bennett, Elliot L.,Brookfield, Adam,Guan, Renpeng,Huang, Zhiliang,Mcinnes, Eric J. L.,Robertson, Craig M.,Shanmugam, Muralidharan,Xiao, Jianliang
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supporting information
p. 10005 - 10013
(2021/07/19)
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- Hydration of Alkynes to Ketones with an Efficient and Practical Polyoxomolybdate-based Cobalt Catalyst
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Hydration of alkynes to ketones is one of the most atom economical and universal methods for the synthesis of carbonyl compounds. However, the basic reaction usually requires organic ligand catalysts or harsh reaction conditions to insert oxygen into the C≡C bond. Here, we report an inorganic ligand supported cobalt (III) catalyst, (NH4)3[CoMo6O18(OH)6], which is supported by a central cobalt (III) mononucleus and a ring-shaped pure inorganic ligand composed of six MoVIO6 octahedrons to avoid the disadvantages of expensive and unrecyclable organic ligand catalysts or noble metal catalysts. Under mild conditions, the cobalt (III) catalyst can be used for the hydration of alkynes to ketones. The catalyst is non-toxic, green, and environment friendly. The catalyst can be recycled at least six times with high activity. According to control experiments, a reasonable mechanism is provided.
- Xie, Ya,Wang, Jingjing,Wang, Yunyun,Han, Sheng,Yu, Han
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p. 4985 - 4989
(2021/10/12)
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- Acceptorless dehydrogenation of amines and alcohols using simple ruthenium chloride
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A highly efficient, economic and environmental friendly catalyst system has been developed for the dehydrogenation of alcohols and amines using simple RuCl3·nH2O and N-benzylhexamethylenetetramine. The in situ catalyst system efficiently oxidized the primary and secondary amines and secondary alcohols into nitrile, imine and ketone products, respectively in moderate to excellent yields. The developed catalyst system was also found to be efficient for the dehydrogenation of N-heterocyles. A detailed mechanism study revealed the first example of N-benzylhexamethylenetetramine (HMTA-Bz) being simultaneously acting as base, reducing agent and hydride source to generate the [Ru(II)(H)2] species as the active catalyst. The mechanism studies also revealed both the alcohol and amine oxidation involves dehydrogenative pathway with the evolution of hydrogen as the only by-product. The developed catalyst system also provides possible platform for the release of hydrogen from liquid organic hydrogen carriers (LOHCs).
- Barteja, Parul,Devi, Preeti,Kannan, Muthukumar,Muthaiah, Senthilkumar
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- Light and oxygen-enabled sodium trifluoromethanesulfinate-mediated selective oxidation of C-H bonds
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Visible light-induced organic reactions are important chemical transformations in organic chemistry, and their efficiency highly depends on suitable photocatalysts. However, the commonly used photocatalysts are precious transition-metal complexes and elaborate organic dyes, which hamper large-scale production due to high cost. Here, for the first time, we report a novel strategy: light and oxygen-enabled sodium trifluoromethanesulfinate-mediated selective oxidation of C-H bonds, allowing high-value-added aromatic ketones and carboxylic acids to be easily prepared in high-to-excellent yields using readily available alkyl arenes, methyl arenes and aldehydes as materials. The mechanistic investigations showed that the treatment of inexpensive and readily available sodium trifluoromethanesulfinate with oxygen under irradiation of light could in situ form a pentacoordinate sulfide intermediate as an efficient photosensitizer. The method represents a highly efficient, economical and environmentally friendly strategy, and the light and oxygen-enabled sodium trifluoromethanesulfinate photocatalytic system represents a breakthrough in photochemistry. This journal is
- Fu, Hua,Liu, Can,Liu, Yong,Yang, Haijun,Zhu, Xianjin
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supporting information
p. 4357 - 4363
(2020/07/14)
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- Selective Oxidation of Benzylic C-H Bonds Catalyzed by Cu(II)/{PMo12}
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Precise catalytic regulation of carbon radical generation by a highly active oxygen radical to abstract the H atom in a C-H bond is an effective method for the selective activation of C-H synthetic chemistry. Herein, we report a facile catalyst system with commercially available copper(II)/{PMo12} to form a tert-butanol radical intermediate for the selective oxidation of benzylic C-H bonds. The reaction shows a broad range of substrates (benzyl methylene, benzyl alcohols) with good functional group tolerance and chemical selectivity. The corresponding carbonyl compounds were synthesized with good yields under mild conditions. DFT calculations and experimental analysis further demonstrated a reasonable carbon radical mechanism for this type of organic transformation reaction.
- Li, Peihe,Wang, Yingying,Wang, Xia,Wang, Yin,Liu, Ying,Huang, Keke,Hu, Jing,Duan, Limei,Hu, Changwen,Liu, Jinghai
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p. 3101 - 3109
(2020/03/23)
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- Efficient and selective oxidation of tertiary benzylic C[sbnd]H bonds with O2 catalyzed by metalloporphyrins under mild and solvent-free conditions
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The direct and efficient oxidation of tertiary benzylic C[sbnd]H bonds to alcohols with O2 was accomplished in the presence of metalloporphyrins as catalysts under solvent-free and additive-free conditions. Based on effective inhibition on the unselective autoxidation and deep oxidation, systematical investigation on the effects of porphyrin ligands and metal centers, and apparent kinetics study, the oxidation system employing porphyrin manganese(II) (T(2,3,6-triCl)PPMn) with bulkier substituents as catalyst, was regarded as the most promising and efficient one. For the typical substrate, the conversion of cumene could reach up to 57.6% with the selectivity of 70.5% toward alcohol, both of them being higher than the current documents under similar conditions. The superiority of T(2,3,6-triCl)PPMn was mainly attributed to its bulkier substituent groups preventing metalloporphyrins from oxidative degradation, its planar structure favoring the interaction between central metal with reactants, and the high efficiency of Mn(II) in the catalytic transformation of hydroperoxides to alcohols.
- Hu, Meng-Yun,Liu, Lei,Qi, Bei,She, Yuan-Bin,Shen, Hai-Min,Ye, Hong-Liang
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- Hydration of terminal alkynes catalyzed by cobalt corrole complex
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Cobalt(III) corrole was firstly applied to the hydration of terminal alkynes. The alkyne hydration proceeded in good to excellent yield with 0.03 to 0.3 mol% cobalt corrole catalyst loading. A wide range of substrates were tolerated. Particularly, the reaction can give 90% yield in a gram scale experiment.
- Lai, Jia-Wei,Liu, Zhao-Yang,Chen, Xiao-Yan,Zhang, Hao,Liu, Hai-Yang
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supporting information
(2020/10/02)
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- Iron-catalyzed oxidative functionalization of C(sp3)-H bonds under bromide-synergized mild conditions
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An efficient oxidation and functionalization of C-H bonds with an inorganic-ligand supported iron catalyst and hydrogen peroxide to prepare the corresponding ketones was achieved using the bromide ion as a promoter. Preliminary mechanistic investigations indicated that the bromide ion can bind to FeMo6 to form a supramolecular species (FeMo6·2Br), which can effectively catalyze the reaction.
- Yu, Han,Zhao, Qixin,Wei, Zheyu,Wu, Zhikang,Li, Qi,Han, Sheng,Wei, Yongge
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supporting information
p. 7840 - 7843
(2019/07/12)
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- Sonochemical Preparation of Dipicolinamide Mn-complexes and Their Application as Catalysts Towards Sono-synthesis of Ketones
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A series of non-heme Mn-complexes has been synthesized by the sonication of manganese (II)chloride and bis-amides (condensation products of 2-picolinic acid and o-phenylenediamines). The Mn-complexes effectively promote the oxidation of unactivated aliphatic and benzylic C─H and N-bearing heterocycles substrates with low catalyst loading using eco-friendly hydrogen peroxide in the presence of acetic acid as additive under ultrasonic irradiation. Chromatographic studies revealed that the corresponding ketones are the only detectable products. Noteworthy, the presence of electron donors in the catalyst structure significantly increased the reaction yields. The substantial lowering of the oxidation reaction yields by adding ionol (2,6-di-tert-butyl-4-methylphenol) as a free radical trap suggesting a free radical reaction pathway.
- Arafa, Wael A. A.
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p. 1403 - 1412
(2019/02/25)
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- Efficient Palladium(0) supported on reduced graphene oxide for selective oxidation of olefins using graphene oxide as a ‘solid weak acid’
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Selective oxidation of olefin derivatives to ketones has made innovative development over palladium(0) supported on reduced graphene oxide. Compared to traditional Wacker oxidation, the novel method offers an economical and environment-friendly option by using graphene oxide (GO) as a ‘solid weak acid’ instead of classical homogeneous catalysts like H2SO4 and CF3COOH. X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscope and transmission electron microscopy images of Pd0/RGO showed that the nanoscaled Pd particles generated at the flake structure of reduced graphene oxide. Under optimized condition, up to 44 kinds of ketones with different structures can be prepared with excellent yields.
- Gao, Xi,Zhou, Jianhao,Peng, Xinhua
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- Bispentiptycenyl-N-Heterocyclic Carbene (NHC) Gold Complexes: Highly Active Catalysts for the Room Temperature Hydration of Alkynes
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The virtually quantitative, room temperature hydration of various terminal and internal alkynes in methanol/water requires between 0.01–0.05 molpercent of [AuCl(NHC)] activated with 1.5 equiv. of silver triflate and 45 equiv. of triflic acid (both relative to gold complex) with ton of up to 300.000. Iptycenyl-substituted NHC ligands play the key role and the most efficient NHC ligand is characterized by a hemispherical shape formed by two N-pentiptycenyl substituents. (Figure presented.).
- Bergmann, Marvin,Heidrich, Maximillian,Müller-Borges, Dorian,Plenio, Herbert
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p. 3572 - 3578
(2018/09/22)
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- Thiyl radical promoted chemo- and regioselective oxidation of CC bonds using molecular oxygen: Via iron catalysis
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The first example of the thiyl radical promoted ligand-free iron-catalyzed oxidative cleavage of alkenes using molecular oxygen (1 atm) has been developed. The reaction proceeds under mild reaction conditions with high efficiency and high chemo- and regioselectivity. It features a broad substrate scope and excellent functional group compatibility, enabling facile access to valuable molecules for application in medicinal chemistry. Preliminary mechanistic studies reveal that a vital intermediate dioxetane might be involved in the reaction and a thiyl radical plays a synergistic role in facilitating the selective oxidation of the CC bond.
- Xiong, Baojian,Zeng, Xiaoqin,Geng, Shasha,Chen, Shuo,He, Yun,Feng, Zhang
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supporting information
p. 4521 - 4527
(2018/10/17)
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- Acceptorless Alcohol Dehydrogenation: OH vs NH Effect in Bifunctional NHC-Ir(III) Complexes
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Bifunctional complexes bearing N-heterocyclic carbene (NHC) ligands functionalized with hydroxy or amine groups were synthesized to measure the beneficial effect of different modes of metal-ligand cooperation in the acceptorless dehydrogenation of alcohols. In comparison to complexes with an amine moiety, hydroxy-functionalized iridium catalysts showed superior activity. In contrast to alcohols, 1,4-diols underwent cyclization to give the corresponding tetrahydrofurans without involving dehydrogenation processes. Mechanistic investigations to rationalize the "OH effect" in these types of complexes have been undertaken.
- González Miera, Greco,Martínez-Castro, Elisa,Martín-Matute, Belén
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supporting information
p. 636 - 644
(2018/03/21)
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- Transformation of Alkynes into Chiral Alcohols via TfOH-Catalyzed Hydration and Ru-Catalyzed Tandem Asymmetric Hydrogenation
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A novel full atom-economic process for the transformation of alkynes into chiral alcohols by TfOH-catalyzed hydration coupled with Ru-catalyzed tandem asymmetric hydrogenation in TFE under simple conditions has been developed. A range of chiral alcohols was obtained with broad functional group tolerance, good yields, and excellent stereoselectivities.
- Liu, Sensheng,Liu, Huan,Zhou, Haifeng,Liu, Qixing,Lv, Jinliang
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supporting information
p. 1110 - 1113
(2018/02/23)
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- One-pot synthesis of chiral alcohols from alkynes by CF3SO3H/ruthenium tandem catalysis
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A practical one-pot synthesis of chiral alcohols from readily available alkynes via tandem catalysis by the combination of CF3SO3H and a fluorinated chiral diamine Ru(ii) complex in aqueous CF3CH2OH is described. Very interestingly, the combination of fluorinated catalysts and solvent exhibits a positive fluorine effect on the reactivity and enantioselectivity. A range of chiral alcohols with wide functional group tolerance was obtained in high yield and excellent stereoselectivity under simple and mild conditions.
- Liu, Huan,Liu, Sensheng,Zhou, Haifeng,Liu, Qixing,Wang, Chunqin
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p. 14829 - 14832
(2018/04/30)
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- An efficient approach for enhancing the catalytic activity of Ni-MOF-74: Via a relay catalyst system for the selective oxidation of benzylic C-H bonds under mild conditions
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Although nickel-based materials exhibit similar catalytic activity to palladium in organic synthesis, the selective oxidation of inert C-H bonds in the absence of other co-catalysts remains a largely unsolved challenge. This paper introduces a facile and efficient approach for enhancing the catalytic activity of Ni-MOF-74 with [bmim]Br via a relay catalysis strategy, which is excellent for the selective oxidation of benzylic C-H bonds. Notably, the catalyst recycling and scale up experiments demonstrated the practicability of the protocol. This method combines the catalytic advantages of MOFs and ionic liquids (ILs), and provides an insight into oxidation reactions by cheap and efficient Ni-based catalysts.
- Guo, Changyan,Zhang, Yonghong,Zhang, Yi,Wang, Jide
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supporting information
p. 3701 - 3704
(2018/04/17)
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- Acceptorless Dehydrogenation of Alcohols Catalyzed by CuI N-Heterocycle Thiolate Complexes
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CuI N-heterocycle thiolate clusters efficiently catalyze the acceptorless dehydrogenation of alcohols at 70 °C. A variety of secondary/primary benzylic, allylic, and aliphatic alcohols are dehydrogenated to the corresponding ketones and aldehydes in high yields of isolated product upon release of H2. This simple catalytic system is involved in the synthesis of imines through the one-pot reaction of alcohols and amines.
- Tan, Da-Wei,Li, Hong-Xi,Zhang, Meng-Juan,Yao, Jian-Lin,Lang, Jian-Ping
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p. 1113 - 1118
(2017/03/27)
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- Method for preparing 4'-acetylacetophenone through homogeneous-phase oxidation of p-diethylbenzene
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The invention relates to a method for preparing 4'-acetylacetophenone through homogeneous-phase oxidation of p-diethylbenzene. The method is characterized by taking p-diethylbenzene as the raw material, taking a soluble metal salt as a catalyst, adding an oxidation agent, additives and a solvent, uniformly stirring and carrying out reaction to obtain a product which is 4'-acetylacetophenone. The method is mild in reaction conditions, simple to operate, high in conversation rate of p-diethylbenzene and higher in yield of 4'-acetylacetophenone, has multiple advantages such as small catalyst consumption, low energy consumption, high reaction safety and high economic benefit, and has a broad industrial application prospect.
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Paragraph 0033-0064
(2017/11/04)
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- Method for directly oxidizing benzyl-position C-H bond into ketone
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The invention discloses a method for directly oxidizing a benzyl-position C-H bond into ketone, wherein aryl ethyl compounds are catalyzed and oxidized by nitrite ester; a synergistic catalytic system of free radical initiator and nitrite ester is adopted, and a catalytic system of non-metallic catalyst and oxygen is adopted, the oxidization of the C-H bond of a free radical-activated aryl side chain is simple in operation; after completing the reaction, petroleum ether/ethyl acetate at a volume ratio of (50-1):1 is used as an eluent; column chromatography separation is performed to obtain a target product. The catalytic system in the invention uses oxygen as an oxygen source and has high atomic economy; the invention is a non-metallic catalytic system and provides a novel method for avoid metal residues in synthetic drugs; for diethyl aromatic hydrocarbon, the method provided by the invention can be adopted to selectively oxidize diethyl aromatic hydrocarbon into monoketone and diketone; the method of the invention can be adopted to efficiently synthesize tranquillizer lenperone, so that a novel method for synthesizing lenperone is provided.
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Paragraph 0078; 0079; 0082; 0083
(2017/08/29)
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- Organopromoted Selectivity-Switchable Synthesis of Polyketones
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In this work, an organopromoted metal-free pharmaceutical-oriented selectivity-switchable benzylic oxidation was developed, affording mono-, di-, and trioxygenation products, respectively, using oxygen as the oxidant under mild conditions. This process facilitates dioxygenation of 2,6-benzylic positions of heterocycles, which could be inhibited by heterocycle chelation to the metal cocatalysts. Enantiopure chiral ketones could also be prepared. The noninvolvement of transition metals and toxins avoids metal or hazardous residues, consequently ensuring a final-stage gram-scale synthesis of Lenperone.
- Liu, Jie,Hu, Kang-Fei,Qu, Jian-Ping,Kang, Yan-Biao
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supporting information
p. 5593 - 5596
(2017/10/25)
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- Transition-Metal- and Halogen-Free Oxidation of Benzylic sp 3 C-H Bonds to Carbonyl Groups Using Potassium Persulfate
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Aryl carbonyl compounds including acetophenones, benzophenones, imides, and benzoic acids are prepared from benzyl substrates using potassium persulfate as oxidant with catalytic pyridine in acetonitrile under mild conditions. Neither transition metals nor halogens are involved in the reactions.
- Hu, Yixin,Zhou, Lihong,Lu, Wenjun
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supporting information
p. 4007 - 4016
(2017/08/29)
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- Gold Nanoparticle-Polydopamine-Reduced Graphene Oxide Ternary Nanocomposite as an Efficient Catalyst for Selective Oxidation of Benzylic C(sp3)-H Bonds under Mild Conditions
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A ternary nanocomposite comprising of Au nanoparticles (NPs), polydopamine, and reduced graphene oxide exhibits excellent activity and selectivity towards the oxidation of C-H bonds in benzylic hydrocarbons under mild conditions in the presence of N-hydroxyphthalimide. All the components in the nanocomposite play an important role in the effectiveness of the catalyst. Sufficient electron transfer from polydopamine to the Au NPs afforded a more negatively charged nanoparticle surface and was favorable for molecular oxygen activation, leading to C-H bond oxidation. The reaction followed a free radical pathway as shown by detailed mechanistic studies. Further, easy separation and excellent reusability without significant loss in activity over several iterations make the ternary nanocomposite an excellent heterogeneous catalyst for C-H oxidation reactions. Cooperativity for C-H oxidation: Au nanoparticles embedded on reduced graphene oxide and polydopamine 2D support acts as efficient and selective heterogeneous catalyst for benzylic C-H oxidation under mild reaction conditions in the presence of N-hydroxyphthalimide.
- Majumdar, Biju,Bhattacharya, Tamalika,Sarma, Tridib K.
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p. 1825 - 1835
(2016/06/01)
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- Metal-Free Markovnikov-Type Alkyne Hydration under Mild Conditions
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A Markovnikov-type alkyne hydration protocol is presented using 20% CF3SO3H (TfOH) as the catalyst under unprecedented mild conditions applicable to various alkynes, including terminal arylalkynes, terminal nonfunctionalized aliphatic alkynes, and internal alkynes with excellent regioselectivity in good to excellent yields (average yields >85%). The reaction procedure operates under mild conditions (25-70°C), with broad functional group compatibility, and uses only slightly more than a stoichiometric amount of water in the absence of any transition metal. The success of this protocol hinges upon the utilization of trifluoroethanol as the solvent.
- Liu, Wenbo,Wang, Haining,Li, Chao-Jun
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supporting information
p. 2184 - 2187
(2016/06/01)
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- Ligand Effects in the Gold Catalyzed Hydration of Alkynes
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In the gold(I) (e. g. L-Au-OTf) catalyzed hydration of alkynes, the steric hindrance of ligands has a significant influence on the kinetics of the reaction, whereas their electronic effects are less influential. Very low loadings (ppm levels) of a gold catalyst containing a highly sterically hindered phosphine ligand (e. g. L4-Au-OTf) (L4=Me3(OMe)tBuXPhos) is able to catalyze the hydration of a wide range of alkyne substrates in good yields, at relatively low temperature.
- Ebule, Rene E.,Malhotra, Deepika,Hammond, Gerald B.,Xu, Bo
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supporting information
p. 1478 - 1481
(2016/05/19)
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- Exploring the Catalytic Reactivity of Nickel Phosphine-Phosphite Complexes
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In this study, we present an investigation into various nickel phosphite and phosphite-phosphine complexes for use in the Mizoroki-Heck and Suzuki-Miyaura cross-coupling reactions and the ammonia arylation reaction. In these coupling reactions, it was discovered that the Ni[P(OEt)3]4, (dppf)Ni[P(OPh)3]2, and (binap)Ni[P(OPh)3]2 catalysts were the most effective. In addition, an optimisation process for these catalytic systems as well as functional group compatibility are discussed.
- Kampmann, Sven S.,Man, Nikki Y. T.,McKinley, Allan J.,Koutsantonis, George A.,Stewart, Scott G.
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p. 1842 - 1853
(2015/12/26)
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- Silver-containing microemulsion as a high-efficient and recyclable catalytic system for hydration of alkynes
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A silver-catalyzed highly efficient and regioselective synthesis of ketones from a wide range of alkynes is described. The reaction is dramatically accelerated by its performance in aqueous emulsion, which is self-assembled by the addition of silver perfluorooctanesulfonate (1) and perfluorooctanesulfonic acid (PFOS) to water. The reaction is conducted under convenient conditions with broad substrate scope, including a variety of aromatic and aliphatic terminal alkynes and internal alkynes. Furthermore, the air- and light-stable silver catalytic microemulsion can be reused for 4 times with minimal change in catalytic efficiency.
- Dong, Qizhi,Li, Ningbo,Qiu, Renhua,Wang, Jinying,Guo, Cancheng,Xu, Xinhua
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p. 122 - 127
(2015/10/12)
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- Direct photocatalytic fluorination of benzylic C-H bonds with N-fluorobenzenesulfonimide
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The late-stage fluorination of common synthetic building blocks and drug leads is an appealing reaction for medicinal chemistry. In particular, fluorination of benzylic C-H bonds provides a means to attenuate drug metabolism at this metabolically labile position. Here we report two complimentary strategies for the direct fluorination of benzylic C-H bonds using N-fluorobenzenesulfonimide and either a decatungstate photocatalyst or AIBN-initiation.
- Nodwell, Matthew B.,Bagai, Abhimanyu,Halperin, Shira D.,Martin, Rainer E.,Knust, Henner,Britton, Robert
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supporting information
p. 11783 - 11786
(2015/07/15)
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- Green and Efficient: Iron-Catalyzed Selective Oxidation of Olefins to Carbonyls with O2
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A mild and operationally simple iron-catalyzed protocol for the selective aerobic oxidation of aromatic olefins to carbonyl compounds is described. Catalyzed by a Fe(III) species bearing a pyridine bisimidazoline ligand at 1 atm of O2, α- and β-substituted styrenes were cleaved to afford benzaldehydes and aromatic ketones generally in high yields with excellent chemoselectivity and very good functional group tolerance, including those containing radical-sensitive groups. With α-halo-substituted styrenes, the oxidation took place with concomitant halide migration to afford α-halo acetophenones. Various observations have been made, pointing to a mechanism in which both molecular oxygen and the olefinic substrate coordinate to the iron center, leading to the formation of a dioxetane intermediate, which collapses to give the carbonyl product. (Chemical Equation).
- Gonzalez-De-Castro, Angela,Xiao, Jianliang
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supporting information
p. 8206 - 8218
(2015/07/15)
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- Double-supported silica-metal-organic framework palladium nanocatalyst for the aerobic oxidation of alcohols under batch and continuous flow regimes
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Stable and easily synthesized metal-organic framework MIL-88B-NH2 represents an attractive support for catalysts employed in oxidation reactions, which are typically performed under relatively harsh conditions. However, MIL-88B-NH2, the thermodynamic polymorph of the more popular MIL-101-NH2, has been rarely employed in catalytic applications because of a difficult impregnation process caused by the flexible nature of the framework. We report herein a new catalyst denoted Pd@MIL-88B-NH2 (8 wt % Pd), the first example of metallic nanoparticles successfully impregnated in the pores of MIL-88B-NH2. Furthermore, by enclosing the MOF crystals in a tailored protective coating of SiO2 nanoparticles, an even more enduring material was developed and applied to the aerobic oxidation of benzylic alcohols. This doubly supported catalyst Pd@MIL-88B-NH2@nano-SiO2 displayed high activity and excellent performance in terms of endurance and leaching control. Under batch conditions, a very convenient and efficient recycling protocol is illustrated, using a teabag approach. Under continuous flow, the catalyst was capable of withstanding 7 days of continuous operation at 110 °C without deactivation. During this time, no leaching of metallic species was observed, and the material maintained its structural integrity.
- Pascanu, Vlad,Bermejo Gómez, Antonio,Ayats, Carles,Platero-Prats, Ana Eva,Carson, Fabian,Su, Jie,Yao, Qingxia,Pericàs, Miquel à.,Zou, Xiaodong,Martín-Matute, Belén
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p. 472 - 479
(2015/06/16)
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- Green photocatalytic organic transformations by polyoxometalates vs. mesoporous TiO2 nanoparticles: Selective aerobic oxidation of alcohols
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In this study, the catalytic activity of decatungstate (W10O324-) supported on mesoporous TiO2 nanoparticle assemblies (DT-MTA) was compared with that of homogeneous [Bu4N]4W10O32 catalysts under mild conditions. Our experiments showed that both catalytic systems achieve exceptionally high activity and selectivity under UV-visible light oxidation of various para-substituted aryl alcohols, using molecular oxygen as a "green" oxidant. The chemoselective transformation of aryl alcohols into the corresponding ketones was investigated with gas chromatography (GC) and NMR spectroscopy. Product analysis and kinetic results also indicated that these photooxidation reactions proceed via both electron transfer (ET) and hydrogen atom transfer (HAT) mechanisms over the DT-MTA catalyst, with the former one as the predominant, whereas a HAT route was adopted to account for the decatungstate homogeneous catalyzed reactions. This journal is
- Symeonidis, Theodoros S.,Tamiolakis, Ioannis,Armatas, Gerasimos S.,Lykakis, Ioannis N.
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p. 563 - 568
(2015/03/14)
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- Regioselective hydration of terminal alkynes catalyzed by a neutral gold(I) complex [(IPr)AuCl] and one-pot synthesis of optically active secondary alcohols from terminal alkynes by the combination of [(IPr)AuCl] and Cp?RhCl[(R, R)-TsDPEN]
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A neutral gold(I) complex [(IPr)AuCl] (IPr = 1,3-bis(diisopropylphenyl)imidazol-2-ylidene) was found to be a highly effective catalyst for the hydration of terminal alkynes, including aromatic alkynes and aliphatic alkynes. The desired methyl ketones were obtained in high yields with complete regioselectivities. Furthermore, a series of optically active secondary alcohols could be obtained in high yield with good to excellent enatioselectivities via one-pot sequential hydration/asymmetric transfer hydrogenation (ATH) from terminal alkynes by the combination of of [(IPr)AuCl] and Cp?RhCl[(R,R)-TsDPEN] (Cp? = pentamethylcyclopentadienyl, TsDPEN = N-(p-toluenesulfonyl)-1,2-diphenylethylenediamine). Notably, this research exhibited the potential of the direct use of neutral gold(I) complexes instead of cationic ones as catalysts for the activation of multiple bonds for organic synthesis.
- Li, Feng,Wang, Nana,Lu, Lei,Zhu, Guangjun
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p. 3538 - 3546
(2015/04/14)
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- Supported Gold Nanoparticle-Catalyzed Hydration of Alkynes under Basic Conditions
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TiO2-supported nanosize gold particles catalyze the hydration of alkynes using morpholine as a basic cocatalyst. Unlike most homogeneous cationic gold catalysts, the TiO2-Au/morpholine system is weakly basic and is compatible with acid-sensitive functional groups (e.g., silyl ethers, ketals) or with a strongly coordinating group such as pyridine. What's more, this gold catalyst can be recycled by simple filtration and works well in flow reactors. (Chemical Equation Presented).
- Liang, Shengzong,Jasinski, Jacek,Hammond, Gerald B.,Xu, Bo
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supporting information
p. 162 - 165
(2015/07/28)
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- Efficient hydration of alkynes through acid-assisted Bronsted acid catalysis
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The combined acid catalyzed hydration of alkynes is an efficient one-step synthesis of carbonyl compounds. This atom-economical method is effective with a wide range of substrates, and the products are obtained in very good yields with low catalyst loading (0.2%). Furthermore, solid acids like Nafion were also efficient and could be easily recycled multiple times without loss of reactivity.
- Liang, Shengzong,Hammond, Gerald B.,Xu, Bo
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supporting information
p. 903 - 906
(2015/01/09)
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- Efficient benzylic and aliphatic C-H oxidation with selectivity for methylenic sites catalyzed by a bioinspired manganese complex
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A benzimidazole-based nonheme manganese complex efficiently catalyzes benzylic, aliphatic C-H as well as tertiary C-H oxidation with hydrogen peroxide as the oxidant in the presence of acetic acid as additive. 18O labeling experiments suggest the reaction may proceed via a high-valent manganese-oxo intermediate.
- Shen, Duyi,Miao, Chengxia,Wang, Shoufeng,Xia, Chungu,Sun, Wei
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supporting information
p. 1108 - 1111
(2014/03/21)
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- Oxidation of alkylaromatics to aromatic ketones catalyzed by metalloporphyrins under the special temperature control method
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The aerobic oxidation of alkylaromatics to aromatic ketones catalyzed by metalloporphyrins under the special temperature control method was systematically investigated. Three novel and key points were found to have significant functions in this process, that is, the special temperature control method (initiation at higher temperature and reaction at lower temperature), the synergistic effect of the composite catalysts comprising cobalt and manganese porphyrins, and the amount of catalysts in the reaction. Subsequently, the effects of substitutes on alkylaromatics were also explored under the same conditions. Results showed that alkylaromatic conversions gradually increased from 8.5% to 54.3% with the para-substituents shifting from the electron-donating group to the electron-withdrawing group (i.e., methoxy hydro bromo acyl nitro). A possible mechanism for this reaction was also proposed.
- Wang, Pan,She, Yuanbin,Fu, Haiyan,Zhao, Wenbo,Wang, Meng
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p. 1059 - 1065
(2015/01/08)
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- Hydration of aromatic terminal alkynes catalyzed by iron(III) sulfate hydrate under chlorine-free conditions
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The hydration of aromatic terminal alkynes performed in acetic acid in the presence of catalytic hydrate ironIII sulfate, Fe2(SO 4)3·nH2O (4-9 mol %), yields the derived aryl methyl ketones with good to excellent yields. Under comparable conditions (18 mol %, 95 C, 24 h), bifunctional substrates were transformed into the monoacetyl or the diacetyl derivatives, depending on the structure of the aromatic diyne. The reaction is compatible with aryl substituents of different nature and ring positions, including hydroxyl, carbonyl groups, and cumulated hydrocarbons. The soft character of the non nucleophilic sulfate anion allows for activation of the triple bond toward carbonoxygen bond formation in the Br?nsted acidic medium. The proposed protocol is based on readily available and non toxic materials, in the absence of chlorine atoms in either the solvent or the metal catalyst.
- Bassetti, Mauro,Ciceri, Samuele,Lancia, Federico,Pasquini, Chiara
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p. 1608 - 1612
(2014/03/21)
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- The indium-catalysed hydration of alkynes using substoichiometric amounts of PTSA as additive
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A general, efficient and highly regioselective protocol using an indium(III) trifluoromethanesulfonate and PTSA (TsOH·H2O) catalytic system for the transformation of various alkynes to the corresponding ketones has been successfully developed.
- Gao, Qi,Li, Shenyan,Pan, Yingming,Xu, Yanli,Wang, Hengshan
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p. 3775 - 3781
(2013/06/26)
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- Oxidation of benzylic methylenes to ketones with Oxone-KBr in aqueous acetonitrile under transition metal free conditions
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A green and highly efficient protocol for the oxidation of benzylic methylenes to their corresponding ketones with a combination of Oxone and KBr in aqueous acetonitrile is developed. The H218O labeling experiment demonstrated that the oxygen introduced into ketone originated from water. A plausible mechanism was also suggested.
- Yin, Lixia,Wu, Jingjing,Xiao, Juan,Cao, Song
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supporting information; experimental part
p. 4418 - 4421
(2012/09/25)
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- Nickel-catalyzed intermolecular insertion of aryl iodides to nitriles: A novel method to synthesize arylketones
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A novel procedure for the NiCl2(DME)/dppp/Zn system catalyzed intermolecular insertion of aryl iodides to nitriles was developed, which afforded variously substituted arylketone derivatives in moderate to good yields with tolerance of a wide variety of functional groups.
- Hsieh, Jen-Chieh,Chen, Yen-Chung,Cheng, An-Yi,Tseng, Hsiao-Chun
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supporting information; experimental part
p. 1282 - 1285
(2012/04/23)
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- CARBOCATALYSTS FOR CHEMICAL TRANSFORMATIONS
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The disclosure relates to catalytically active carbocatalysts, e.g., a graphene oxide or graphite oxide catalyst suitable for use in a variety of chemical transformations. In one embodiment, it relates to a method of catalyzing a chemical reaction of an organic molecule by reacting the organic molecule in the presence of a sufficient amount of graphene oxide or graphite oxide for a time and at a temperature sufficient to allow catalysis of a chemical reaction. According to other embodiments, the reaction may be an oxidation reaction, a hydration reaction, a dehydrogenation reaction, a condensation reaction, or a polymerization reaction. Some reactions may include auto-tandem reactions. The disclosure further provides reaction mixtures containing an organic molecule and graphene oxide or graphite oxide in an amount sufficient to catalyze a reaction of the organic molecule.
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Page/Page column 50-51
(2011/12/14)
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