- Syntheses and catalytic application of hydrido iron(ii) complexes with [P,S]-chelating ligands in hydrosilylation of aldehydes and ketones
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Four hydrido iron(ii) complexes (1-4) with [P,S]-chelating ligands were synthesized by the reactions of (2-diphenylphosphanyl)thiophenols, C6H3(1-SH) (2-PPh2) (4-R1) (6-R2), abbreviated as (P^SH), with Fe(PMe3)4. (1: R1 = R2 = H; 2: R1 = H, R2 = SiMe3; 3: R1 = CH3, R2 = H; 4: R1 = SiMe3, R2 = H). Among them, complexes 2-4 are new and were completely characterized by spectroscopic methods. The molecular structures of complexes 2, 3, and 4 were confirmed by X-ray single crystal diffraction. The catalytic properties of hydrido iron(ii) complexes 1-4 were explored in the hydrosilylation of aldehydes and ketones. They showed a good activity in catalytic hydrosilylation of aldehydes and ketones by using (EtO)3SiH as a hydrogen source under mild conditions.
- Xue, Benjing,Sun, Hongjian,Li, Xiaoyan
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Read Online
- Hydrosilylation of aldehydes and ketones catalyzed by hydrido iron complexes bearing imine ligands
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Two new hydrido iron complexes (2 and 4) were synthesized by the reactions of (4-methoxyphenyl)phenylketimine ((4-MeOPh)PhCNH) with Fe(PMe 3)4 or FeMe2(PMe3)4. The molecular structures of complexes 2 and 4 were confirmed by X-ray single crystal diffraction. Using hydrido iron complexes (1-4) as catalysts, the hydrosilylations of aldehydes and ketones were investigated. The four complexes were effective catalysts for this reduction reaction. Complex 1 among them is the best catalyst. This journal is the Partner Organisations 2014.
- Zuo, Zhenyu,Sun, Hongjian,Wang, Lin,Li, Xiaoyan
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Read Online
- Synthesis and catalytic activity of N-heterocyclic silylene (NHSi) iron (II) hydride for hydrosilylation of aldehydes and ketones
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A novel silylene supported iron hydride [Si, C]FeH (PMe3)3 (1) was synthesized by C (sp3)-H bond activation with zero-valent iron complex Fe (PMe3)4. Complex 1 was fully characterized by spectroscopic methods and single crystal X-ray diffraction analysis. To the best of our knowledge, 1 is the first example of silylene-based hydrido chelate iron complex produced through activation of the C (sp3)?H bond. It was found that complex 1 exhibited excellent catalytic activity for hydrosilylation of aldehydes and ketones. The catalytic system showed good tolerance and catalytic activity for the substrates with different functional groups on the benzene ring. It is worth mentioning that, the experimental results showed that both ketones and aldehydes could be reduced in good to excellent yields under the same catalytic conditions. Based on the experiments and literature reports, a possible catalytic mechanism was proposed.
- Du, Xinyu,Qi, Xinghao,Li, Kai,Li, Xiaoyan,Sun, Hongjian,Fuhr, Olaf,Fenske, Dieter
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- Homoleptic Zinc-Catalyzed Hydroboration of Aldehydes and Ketones in the Presence of HBpin
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Here, we report the reaction between N-phenyl-o-phenylenediamine and pyrrole-2-carboxaldehyde to afford the N-phenyl-o-phenyl-enediiminopyrrole ligand {L-H2} in quantitative yield. A one-pot reaction between {L-H2} and diethylzinc (ZnEt2) in a 2:1 ratio afforded the homoleptic zinc metal complex [{L-H}2Zn] (1). The solid-state structures of ligand {L-H2} and zinc complex 1 were confirmed using X-ray crystallography. Further, complex 1 was used for chemoselective hydroboration of aldehydes and ketones in the presence of pinacolborane (HBpin) at ambient temperature to produce the corresponding boronate esters in high yield.
- Kumar, Gobbilla Sai,Harinath, Adimulam,Narvariya, Rajrani,Panda, Tarun K.
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supporting information
p. 467 - 474
(2020/02/04)
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- Reduction of Aldehydes with Formic acid in Ethanol using Immobilized Iridium Nanoparticles on a Triazine-phosphanimine Polymeric Organic Support
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A novel triazine-phosphanimine polymeric organic support (TPA) was synthesized successfully by a controllable one-pot method using melamine (1,3,5-triazine-2,4,6-triamine) and trichlorophosphane (PCl3). The TPA substrate is a material incorporating P and N atoms which can coordinate with metals as a pincer ligand to stabilize them, providing an efficient heterogeneous support to prepare recyclable transition metal catalyst systems. In this study, TPA was used as support to immobilize iridium nanoparticles in the range of ~8 nm on its surface, resulting in the generation of a novel iridium nanocatalyst system (INP-TPA-POP). This catalyst system was characterized using different microscopic and spectroscopic techniques such as FT-IR, TEM, XPS, XRD, SEM, EDX, elemental analysis, ICP and BET analysis. The INP-TPA-POP nanocatalyst exhibited remarkable activity in reduction of aldehydes to alcohols using formic acids as reducing agent in ethanol as solvent.
- Panahi, Farhad,Haghighi, Fatemeh,Khalafi-Nezhad, Ali
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- Pyridine: N-oxide promoted hydrosilylation of carbonyl compounds catalyzed by [PSiP]-pincer iron hydrides
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Five [PSiP]-pincer iron hydrides 1-5, [(2-Ph2PC6H4)2HSiFe(H)(PMe3)2 (1), (2-Ph2PC6H4)2MeSiFe(H)(PMe3)2 (2), (2-Ph2PC6H4)2PhSiFe(H)(PMe3)2 (3), (2-(iPr)2PC6H4)2HSiFe(H)(PMe3) (4), and (2-(iPr)2PC6H4)2MeSiFe(H)(PMe3)2 (5)], were used as catalysts to study the effects of pyridine N-oxide and the electronic properties of [PSiP]-ligands on the catalytic hydrosilylation of carbonyl compounds. It was proved for the first time that this catalytic process could be promoted with pyridine N-oxide as the initiator at 30 °C because the addition of pyridine N-oxide is beneficial for the formation of an unsaturated hydrido iron complex, which is the key intermediate in the catalytic mechanism. Complex 4 as the best catalyst shows excellent catalytic performance. Among the five complexes, complex 3 was new and the molecular structure of complex 3 was determined by single crystal X-ray diffraction. A proposed mechanism was discussed.
- Chang, Guoliang,Fenske, Dieter,Fuhr, Olaf,Li, Xiaoyan,Sun, Hongjian,Xie, Shangqing,Yang, Wenjing,Zhang, Peng
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p. 9349 - 9354
(2020/09/09)
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- A tunable synthesis of either benzaldehyde or benzoic acid through blue-violet LED irradiation using TBATB
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In this paper, a highly efficient, metal-free, and homogeneous method for the selective aerobic photooxidation of alcohols and photooxidative-desilylation of tert-butyldimethylsilyl ethers (TBDMS) in the presence of tetrabutylammonium tribromide (TBATB) under irradiation of visible light was reported. The light source: blue (460 nm) and violet (400 nm) LED, can control selective oxidation to aldehyde or carboxylic acid.
- Mardani, Atefeh,Heshami, Marouf,Shariati, Yadollah,Kazemi, Foad,Abdollahi Kakroudi, Mazaher,Kaboudin, Babak
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- Synthesis and Catalytic Activity of Iron Hydride Ligated with Bidentate N-Heterocyclic Silylenes for Hydroboration of Carbonyl Compounds
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We report the synthesis of a novel bidentate N-heterocyclic silylene (NHSi) ligand, N-(LSi:)-N-methyl-2-pyridinamine (1) (L = PhC(NtBu)2), and the first bischelate disilylene iron hydride, [(Si,N)(Si,C)Fe(H)(PMe3)] (2), and monosilylene iron hydride, [(Si,C)Fe(H)(PMe3)3] (2′), through Csp2-H activation of the NHSi ligand. Compounds 1 and 2 were fully characterized by spectroscopic methods and single-crystal X-ray diffraction analysis. Density functional theory calculations indicated the multiple-bond character of the Fe-Si bonds and the π back-donation from Fe(II) to the Si(II) center. Moreover, the strong donor character of ligand 1 enables 2 to act as an efficient catalyst for the hydroboration reaction of carbonyl compounds at room temperature. Chemoselective hydroboration is attained under these conditions. This might be the first example of hydroboration of ketones and aldehydes catalyzed by a silylene hydrido iron complex. A catalytic mechanism was suggested and partially experimentally verified.
- Qi, Xinghao,Zheng, Tingting,Zhou, Junhao,Dong, Yanhong,Zuo, Xia,Li, Xiaoyan,Sun, Hongjian,Fuhr, Olaf,Fenske, Dieter
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p. 268 - 277
(2019/01/21)
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- Efficient transfer hydrogenation of carbonyl compounds catalyzed by selenophenolato hydrido iron(II) complexes
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Selenophenolato hydrido iron(II) complexes 1–3 cis-[(H)(SeAr)Fe(PMe3)4] (Ar = C6H5 (1), p-MeOC6H4 (2) and o-MeC6H4 (3)) could catalyze transfer hydrogenation of aldehydes and ketones. Among the three complexes, catalyst 1 exhibited the highest catalytic activity. The catalytic reactions took place under very mild conditions, using isopropanol as solvent and hydrogen source, tBuONa as base under 60–80 °C. This catalytic system has good tolerance for many functional groups, such as halides, C[dbnd]C double bonds, nitro groups and cyano groups at the phenyl ring of the substrates.
- Wang, Yangyang,Du, Zhengyin,Zheng, Tingting,Sun, Hongjian,Li, Xiaoyan
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- Method of fluorination using iodonium ylides
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A process for fluorination of aromatic compounds employing iodonium ylides and applicable to radiofluorination using 18F is described. Processes, intermediates, reagents and radiolabelled compounds are described.
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Page/Page column 60; 76-77
(2019/04/30)
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- Spiro compounds, preparation method thereof, intermediate, pharmaceutical composition and application
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The invention discloses a spiro compound as shown in a formula I, a pharmaceutically acceptable salt, a hydrate, a solvate, an optical isomer or a prodrug of the spiro compound, as well as a preparation method, an intermediate, a pharmaceutical composition and an application of the spiro compound. The spiro compound disclosed by the invention has the activity of serving as protein kinase inhibitors and tyrosine kinase inhibitors such as c-Met, and the spiro compound can be used for treating diseases caused by the abnormal activity of kinases, such as cancer, or used for preparing medicaments for treating the diseases.
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Paragraph 0142; 0143; 0144
(2018/04/02)
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- Method of reducing carbonyl compound into alcohol in air atmosphere at room temperature
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The invention belongs to the field of organic synthesis and relates to a method of reducing carbonyl compound into alcohol in air atmosphere at room temperature. The method includes: firstly, adding methanol, a catalyst and the carbonyl compound into a reaction bottle and slowly adding silane into the reaction bottle, magnetically stirring the components and carrying out a reaction for 10 min to 8hours in air atmosphere at room temperature to obtain a mixture containing a benzyl compound after the reaction is finished; secondly, extracting the mixture containing the benzyl compound with an extraction agent dichloromethane, mixing organic phases, and washing the organic phases with a washing agent deionized water, drying the organic phases with anhydrous sodium sulfate, and evaporating theorganic phases to remove a solvent and obtain a crude product of a benzyl alcohol compound; finally, separating and purifying the crude product through column chromatography to prepare a pure productof the benzyl alcohol compound. In the method, a reducing agent is low in toxicity and is clean and environment-friendly. The method is free of a noble metal catalyst and is low in cost, is gentle inreaction conditions, and can reach high selectivity and yield.
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Paragraph 0049; 0050
(2019/01/08)
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- Transfer hydrogenation of aldehydes catalyzed by silyl hydrido iron complexes bearing a [PSiP] pincer ligand
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The synthesis and characterization of a series of silyl hydrido iron complexes bearing a pincer-type [PSiP] ligand (2-R2PC6H4)2SiH2 (R = Ph (1) and iPr (5)) or (2-Ph2PC6H4)2SiMeH (2) were reported. Preligand 1 reacted with Fe(PMe3)4 to afford complex ((2-Ph2PC6H4)SiH)Fe(H)(PMe3)2 (3) in toluene, which was structurally characterized by X-ray diffraction. ((2-iPr2PC6H4)SiH)Fe(H)(PMe3) (6) could be obtained from the reaction of preligand 5 with Fe(PMe3)4 in toluene. Furthermore, complex ((2-iPr2PC6H4)Si(OMe))Fe(H)(PMe3) (7) was isolated by the reaction of complex 6 with 2 equiv. MeOH in THF. The molecular structure of complex 7 was also determined by single-crystal X-ray analysis. Complexes 3, 4, 6 and 7 showed good to excellent catalytic activity for transfer hydrogenation of aldehydes under mild conditions, using 2-propanol as both solvent and hydrogen donor. α,β-Unsaturated aldehydes could be selectively reduced to corresponding α,β-unsaturated alcohols. The catalytic activity of penta-coordinate complex 6 or 7 is stronger than that of hexa-coordinate complex 3 or 4.
- Zhang, Peng,Li, Xiaoyan,Qi, Xinghao,Sun, Hongjian,Fuhr, Olaf,Fenske, Dieter
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p. 14092 - 14099
(2018/04/25)
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- Synthesis of silyl iron hydride: Via Si-H activation and its dual catalytic application in the hydrosilylation of carbonyl compounds and dehydration of benzamides
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The hydrido silyl iron complex (o-Ph2PC6H4SiMe2)Fe(PMe3)3H (2) was obtained via the activation of the Si-H bond of the bidentate silyl ligand o-Ph2P(C6H4)SiMe2H (1) by Fe(PMe3)4. 2 showed good to excellent catalytic activity in both the reduction of aldehydes/ketones and the dehydration of benzamide. In addition, with complex 2 as a catalyst, α,β-unsaturated carbonyls could be selectively reduced to the corresponding α,β-unsaturated alcohols. The mechanisms of the formation of 2 and the catalytic dehydration process are proposed and partly experimentally verified.
- Ren, Shishuai,Xie, Shangqing,Zheng, Tingting,Wang, Yangyang,Xu, Shilu,Xue, Benjing,Li, Xiaoyan,Sun, Hongjian,Fuhr, Olaf,Fenske, Dieter
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p. 4352 - 4359
(2018/03/26)
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- Novel leucine ureido derivatives as aminopeptidase N inhibitors using click chemistry
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The over-expression of aminopeptidase N on diverse malignant cells is associated with the tumor angiogenesis and metastasis. In this report, one new series of leucine ureido derivatives containing the triazole moiety was designed, synthesized and evaluated as APN inhibitors. Among them, compound 13v showed the best APN inhibition with an IC50 value of 0.089 ± 0.007 μM, which was two orders of magnitude lower than that of bestatin (IC50 = 9.4 ± 0.5 μM). Compound 13v also showed dose-dependent anti-angiogenesis activities. Even at the lower concentration (10 μM), compound 13v presented similar anti-angiogenesis activity compared with bestatin at 100 μM in both the human umbilical vein endothelial cells (HUVECs) capillary tube formation assay and the rat thoracic aorta rings test. Moreover, compared with bestatin, 13v exhibited comparable, if not better in vivo anti-metastasis activity in a mouse H22 pulmonary metastasis model.
- Cao, Jiangying,Ma, Chunhua,Zang, Jie,Gao, Shuai,Gao, Qianwen,Kong, Xiujie,Yan, Yugang,Liang, Xuewu,Ding, Qin'ge,Zhao, Chunlong,Wang, Binghe,Xu, Wenfang,Zhang, Yingjie
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p. 3145 - 3157
(2018/06/01)
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- Syntheses of hydrido selenophenolato iron(II) complexes and their catalytic application in hydrosilylation of aldehydes and ketones
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Three novel selenophenolato hydrido iron(II) complexes [cis-(H)(SeAr)Fe(PMe3)4] (4–6) (Ar=C6H5 (4), p-MeOC6H4 (5) and o-MeC6H4 (6)) were prepared through the reaction of Fe(PMe3)4 with selenophenols ArSeH (1–3) via Se–H activation. The iron hydrido complexes 4, 5 and 6 could catalyze the hydrosilylation of aldehydes and ketones. Among them complex 5 is the best catalyst for this process. Furthermore, α,β-unsaturated alcohols could be obtained from the selective reduction reactions of the corresponding α,β-unsaturated carbonyls catalyzed by hydrido iron(II) complex 5. This catalytic system has good tolerance for some common groups but it is easy to reduce the nitro group to an amino group. The experiments indicate that the chemoselectivity for this catalytic system is –CHO>–NO2>–C([dbnd]O)CH3. The crystal structure of 6 was determined by X-ray diffraction.
- Wang, Yangyang,Ren, Shishuai,Zhang, Wenbo,Xue, Benjing,Qi, Xinghao,Sun, Hongjian,Li, Xiaoyan,Fuhr, Olaf,Fenske, Dieter
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- Synthesis and catalytic application of [PPP]-pincer iron, nickel and cobalt complexes for the hydrosilylation of aldehydes and ketones
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A new synthetic strategy for the novel diphosphine-phosphine oxide ligand (1) (Ph2P-(C6H4))2P(O)H was designed. A series of [PPP]-pincer Fe, Ni, and Co complexes were prepared. All of them were formed by chelate-assisted P-H activation. Two metal hydrides [(Ph2P-(C6H4))2P(O)]Fe(H)(PMe3)2 (2) and [(Ph2P-(C6H4))2P(O)]Ni(H)(PMe3) (3) were obtained at room temperature. The combination of ligand 1 with Co(PMe3)4Me or Co(PMe3)4 afforded the same Co(i) complex [(Ph2P-(C6H4))2P(O)]Co(PMe3)2 (4) via P-H bond activation. The catalytic performance of the Fe, Ni, and Co complexes for the hydrosilylation of aldehydes and ketones was explored. At a catalyst loading of 2 mol%, complex 2 displayed the best catalytic activity for the hydrosilylation by using (EtO)3SiH as the hydrogen source under mild conditions. Complexes 2, 3, and 4 were characterized by spectroscopic methods and X-ray diffraction analysis.
- Qi, Xinghao,Zhao, Hua,Sun, Hongjian,Li, Xiaoyan,Fuhr, Olaf,Fenske, Dieter
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p. 16583 - 16590
(2018/10/23)
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- Synthesizing method of 2,6-dichlorobenzyl alcohol
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The invention discloses a synthesizing method of 2,6-dichlorobenzyl alcohol and relates to the technical field of the chemical synthesis of the 2,6-dichlorobenzyl alcohol. The synthesizing method hasthe advantages that due to the fact that zinc borohydride is strong in reducing capacity and mild in reaction, the method uses anhydrous ethanol as the reaction solvent and the zinc borohydride as thereducing agent to perform reaction, raw materials can be completely reduced into the 2,6-dichlorobenzyl alcohol in water, direct extraction can be performed after the reaction, high product purity and simple aftertreatment are achieved, and high-quality 2,6-dichlorobenzyl alcohol can be effectively prepared by the method.
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Paragraph 0007; 0008; 0009
(2018/12/03)
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- RORγ MODULATORS
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The invention provides an RORγ receptor agonist comprising a compound of formula (I), wherein the variables are as defined herein. These compounds are analogous to known RORγ receptor antagonists. The invention further provides a method of activating -the nuclear receptor RORγ, comprising -contacting the RORγ with an effective amount or concentration of a compound of the invention; and a method of treating cancer in a patient, comprising administering to the patient an effective dose of a compound of the invention.
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Page/Page column 21; 38; 62
(2018/04/13)
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- Efficient carbon-supported heterogeneous molybdenum-dioxo catalyst for chemoselective reductive carbonyl coupling
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Reductive coupling of various carbonyl compounds to the corresponding symmetric ethers with dimethylphenylsilane is reported using a carbon-supported dioxo-molybdenum catalyst. The catalyst is air- and moisture-stable and can be easily separated from the reaction mixture for recycling. In addition, the catalyst is chemoselective, thus enabling the synthesis of functionalized ethers without requiring sacrificial ligands or protecting groups.
- Liu, Shengsi,Li, Jiaqi,Jurca, Titel,Stair, Peter C.,Lohr, Tracy L.,Marks, Tobin J.
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p. 2165 - 2169
(2017/07/22)
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- Catalytic hydrosilylation of carbonyl compounds by hydrido thiophenolato iron(II) complexes
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The hydrosilylation of aldehydes and ketones under mild conditions with hydrido thiophenolato iron(II) complexes [cis–Fe(H)(SAr)(PMe3)4] (1–4) as catalysts is reported using (EtO)3SiH as an efficient reducing agent in the yields up to 95%. Among them complex 1 is the best catalyst. Complex 1 could also be used as catalyst to reduce the α,β-unsaturated carbonyl compounds selectively to the α,β-unsaturated alcohols in high yields.
- Xue, Benjing,Sun, Hongjian,Niu, Qingfen,Li, Xiaoyan,Fuhr, Olaf,Fenske, Dieter
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- Highly selective transfer hydrogenation of α,β-unsaturated carbonyl compounds using Cu-based nanocatalysts
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Simultaneous dehydrogenation of cyclohexanol to cyclohexanone and hydrogenation of α,β-unsaturated carbonyl compounds to corresponding α,β-unsaturated alcohols was carried out in a single pot reaction without addition of any external hydrogen donor. Cu nanoclusters supported on nanocrystalline MgO were found to be the active catalyst for the chemoselective transfer hydrogenation of unsaturated carbonyl compounds to produce the corresponding alcohols with very high yields. Transfer hydrogenation of cyclohexanol and cinnamaldehyde produced cyclohexanone and cinnamyl alcohol with 100% selectivity. This Cu/MgO catalyst can be easily recovered and recycled up to more than five times without any significant loss of activity, which confirmed the true heterogeneous nature of this catalyst. Several α,β-unsaturated compounds were also tested for this reaction and it was found that for all the cases the yield is >95%. The ease of handling without requiring high pressure H2 or a hazardous hydrogen source makes this transfer hydrogenation more practical and useful.
- Siddqui, Nazia,Sarkar, Bipul,Pendem, Chandrashekar,Khatun, Rubina,Sivakumar Konthala,Sasaki, Takehiko,Bordoloi, Ankur,Bal, Rajaram
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p. 2828 - 2837
(2017/07/15)
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- REACTIONS OF STANNYL CATIONS
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The present invention relates to a method of reducing, cleaving and/or coupling at least one C=O, C-O, C=C or C=N bond of a compound, using a reagent comprising a stannyl cation.
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Page/Page column 19; 20
(2018/01/17)
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- Functionalised [(NHC)Pd(allyl)Cl] complexes: Synthesis, immobilisation and application in cross-coupling and dehalogenation reactions
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A novel NHC–palladium(II) (NHC?=?N-heterocyclic carbene) complex and its immobilised version have been prepared and fully characterised. Optimisation studies led to good catalytic activities in Suzuki-Miyaura cross coupling and chloroarene dehalogenation reactions. Furthermore, the unexpected palladium-mediated transfer hydrogenation of a carbonyl compound is reported.
- Collinson, John-Michael,Wilton-Ely, James D.E.T.,Díez-González, Silvia
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- N-Arylsulfonyl Indolines as Retinoic Acid Receptor-Related Orphan Receptor γ (RORγ) Agonists
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The nuclear retinoic acid receptor-related orphan receptor γ (RORγ; NR1F3) is a key regulator of inflammatory gene programs involved in T helper 17 (TH17) cell proliferation. As such, synthetic small-molecule repressors (inverse agonists) targeting RORγ have been extensively studied for their potential as therapeutic agents for various autoimmune diseases. Alternatively, enhancing TH17 cell proliferation through activation (agonism) of RORγ may boost an immune response, thereby offering a potentially new approach in cancer immunotherapy. Herein we describe the development of N-arylsulfonyl indolines as RORγ agonists. Structure–activity studies reveal a critical linker region in these molecules as the major determinant for agonism. Hydrogen/deuterium exchange coupled to mass spectrometry (HDX-MS) analysis of RORγ–ligand complexes help rationalize the observed results.
- Doebelin, Christelle,Patouret, Rémi,Garcia-Ordonez, Ruben D.,Chang, Mi Ra,Dharmarajan, Venkatasubramanian,Kuruvilla, Dana S.,Novick, Scott J.,Lin, Li,Cameron, Michael D.,Griffin, Patrick R.,Kamenecka, Theodore M.
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supporting information
p. 2607 - 2620
(2016/12/09)
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- Selective C-F and C-H Activation of Fluoroarenes by Fe(PMe3)4 and Catalytic Performance of Iron Hydride in Hydrosilylation of Carbonyl Compounds
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The reactions of perfluorinated toluene (CF3C6F5), pentafluoropyridine (C5NF5), and hexafluorobenzene (C6F6) with the iron(0) complex Fe(PMe3)4 were investigated. The Fe(I) complexes (4-CF3C6F4)Fe(PMe3)4 (1), (4-C5NF4)Fe(PMe3)4 (2), and (C6F5)Fe(PMe3)4 (3) were obtained by selective activation of the C-F bonds. However, under similar reaction conditions, the reaction of Fe(PMe3)4 with perfluoronaphthalene (C10F8) afforded a π-coordinated Fe(0) complex, (η4-1,2,3,4-C10F8)Fe(PMe3)3 (4), and the expected C-F bond activation reaction was not observed. The expected iron hydride (C6F5)FeH(PMe3)4 (6) could be obtained in a yield of 80% by the reaction of bromopentafluorobenzene with Fe(PMe3)4 and subsequent reduction with NaBH4. The molecular structures of complexes 2, 4, and 6 were determined by single-crystal X-ray diffraction. Complexes 1-4 and 6 could be used as catalysts for the hydrosilylation of carbonyl compounds. Among them, complex 6 is the best catalyst. The selective reduction of carbonyl groups of α,β-unsaturated aldehydes and ketones was also realized with 6 as catalyst.
- Zheng, Tingting,Li, Junye,Zhang, Shumiao,Xue, Benjing,Sun, Hongjian,Li, Xiaoyan,Fuhr, Olaf,Fenske, Dieter
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p. 3538 - 3545
(2016/11/06)
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- Facile Protocol for Water-Tolerant "Frustrated Lewis Pair"-Catalyzed Hydrogenation
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Despite rapid advances in the field of metal-free, "frustrated Lewis pair" (FLP)-catalyzed hydrogenation, the need for strictly anhydrous reaction conditions has hampered wide-scale uptake of this methodology. Herein, we report that, despite the generally perceived moisture sensitivity of FLPs, 1,4-dioxane solutions of B(C6F5)3 actually show appreciable moisture tolerance and can catalyze hydrogenation of a range of weakly basic substrates without the need for rigorously inert conditions. In particular, reactions can be performed directly in commercially available nonanhydrous solvents without subsequent drying or use of internal desiccants.
- Scott, Daniel J.,Simmons, Trevor R.,Lawrence, Elliot J.,Wildgoose, Gregory G.,Fuchter, Matthew J.,Ashley, Andrew E.
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p. 5540 - 5544
(2015/09/15)
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- Synthesis and catalytic property of iron pincer complexes generated by Csp3-H activation
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When the diphosphinito PCP ligand (Ph2P(C6H 4))2CH2 (1) was treated with Fe(PMe 3)4 and FeMe2(PMe3)4, the Csp3-H activation products [(Ph2P(C 6H4))2CH]Fe(H)(PMe3)2 (2) and [(Ph2P(C6H4))(PhP(C6H 4)2)CH]Fe(PMe3)2 (3) were obtained at room temperature. The generation of product 3 underwent one C sp3-H and one Csp2-H bond activation process. The new iron hydride complex 2 showed good activity in the catalytic hydrosilylation of aldehydes and ketones by using (EtO)3SiH as the hydrogen source under mild conditions. Complexes 2 and 3 were characterized by spectroscopic methods and X-ray diffraction analysis.
- Zhao, Hua,Sun, Hongjian,Li, Xiaoyan
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p. 3535 - 3539
(2014/08/05)
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- Electrophilicity and nucleophilicity of commonly used aldehydes
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The present approach for determining the electrophilicity (E) and nucleophilicity (N) of aldehydes includes a kinetic study of KMNO4 oxidation and NaBH4 reduction of aldehydes. A transition state analysis of the KMNO4 promoted aldehyde oxidation reaction has been performed, which shows a very good correlation with experimental results. The validity of the experimental method has been tested using the experimental activation parameters of the two reactions. The utility of the present approach is further demonstrated by the theoretical versus experimental relationship, which provides easy access to E and N values for various aldehydes and offers an at-a-glance assessment of the chemical reactivity of aldehydes in various reactions. the Partner Organisations 2014.
- Pratihar, Sanjay
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p. 5781 - 5788
(2014/07/22)
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- Nonmetal catalyzed hydrogenation of carbonyl compounds
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Solutions of the Lewis acid B(C6F5)3 in 1,4-dioxane are found to effectively catalyze the hydrogenation of a variety of ketones and aldehydes. These reactions, the first to allow entirely metal-free catalytic hydrogenation of carbonyl groups under relatively mild reaction conditions, are found to proceed via a "frustrated Lewis pair" mechanism in which the solvent, a weak Bronsted base yet moderately strong donor, plays a pivotal role.
- Scott, Daniel J.,Fuchter, Matthew J.,Ashley, Andrew E.
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supporting information
p. 15813 - 15816
(2015/02/19)
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- Synthesis and catalytic application in hydrosilylation of the complex mer-hydrido(2-mercaptobenzoyl)tris(trimethylphosphine)cobalt(III)
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The sulfur-coordinated acyl(hydrido)cobalt(III) complex 1 was synthesized by reaction of thiosalicylaldehyde with CoMe(PMe3)4. The crystal structure of 1 was determined by X-ray diffraction. Complex 1 is an excellent catalyst for the hydrosilylation of aldehydes and ketones under mild conditions. This might be the first example of hydrosilylation of aldehydes and ketones catalyzed by (hydrido)cobalt complexes.
- Niu, Qingfen,Sun, Hongjian,Li, Xiaoyan,Klein,Floerke, Ulrich
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p. 5235 - 5238
(2013/10/08)
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- Direct, metal-free synthesis of benzyl alcohols and deuterated benzyl alcohols from p-toluenesulfonylhydrazones using water as solvent
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A novel library of diverse alcohols was synthesized by metal-free couplings of diazoalkanes derived from p-toluenesulfonylhydrazones to water under reflux and microwave conditions, in high yields. In addition, this protocol was successfully applied in the synthesis of deuterium-labeled alcohols using deuterium oxide. Georg Thieme Verlag Stuttgart New York.
- Garcia-Munoz, Angel,Ortega-Arizmendi, Aldo I.,Garcia-Carrillo, Mario A.,Diaz, Eduardo,Gonzalez-Rivas, Nelly,Cuevas-Yanez, Erick
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supporting information; experimental part
p. 2237 - 2242
(2012/09/22)
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- Process for producing cyclopropanecarboxylates
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There is disclosed a process process for producing a cyclopropanecarboxylate of formula (1): 1which process comprises reacting cyclopropanecarboxylic acid of formula (2): 2with a monohydroxy compound of formula (3): R6OH??(3),in the presence of a catalyst compound comprising an element of to Group 4 of the Periodic Table of Elements.
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- Magnesium-mediated carbon-carbon bond formation in aqueous media: Barbier-Grignard allylation and pinacol coupling of aldehydes
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Magnesium-mediated Barbier-Grignard type alkylation of aldehydes with alkyl halides was studied in aqueous media. The reaction of aromatic aldehydes with allyl halides is highly effective with either THF or water as the reaction solvent but poor in a mixture of THF/water. It was found that the magnesium-mediated allylation of aldehydes with allyl bromide and iodide proceeds effectively in aqueous 0.1 N HCl or 0.1 N NH4Cl. Aromatic aldehydes reacted chemoselectively in the presence of aliphatic aldehydes. An exclusive selectivity was also observed when both aliphatic and aromatic aldehyde functionalities are present in the same molecule. In the absence of allyl halides, aldehydes and ketones reacted with magnesium in aqueous 0.1 N NH4Cl to form the corresponding pinacol coupling products in high yields. The effectiveness of the pinacol reaction was strongly influenced by the steric environment surrounding the carbonyl group. Aliphatic aldehydes and simple alkyl halides appear inert under the reaction conditions for either alkylation or the pinacol coupling reaction.
- Zhang, Wen-Chun,Li, Chao-Jun
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p. 3230 - 3236
(2007/10/03)
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- Magnesium in water: Simple and effective for pinacol-coupling
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A simple and effective pinacol-coupling has been carried out with magnesium. The reaction is highly effective in water in the presence of a catalytic amount of ammonium chloride. Under these conditions, various aromatic aldehydes and ketones undergo carbonyl coupling, generating 1,2-diols in good yields. The effectiveness of the reaction is strongly influenced by the steric environment surrounding the carbonyl group. Aliphatic aldehydes appear inert under the reaction conditions.
- Zhang, Wen-Chun,Li, Chao-Jun
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p. 3131 - 3132
(2007/10/03)
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- Synthesis and Conformational Study of 9,18-(Ethylenedioxy)-2,11-dithiametacyclophane: The Propelling Behavior of the Three Bridges in a (1,2,3)Cyclophane
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A general approach which involved first the introduction of the central oxy or dioxy bridge and subsequent intramolecular coupling reactions to form the two thia bridges was employed in the syntheses of the 1,2,3-triply bridged cyclophanes 2,3, and 4.The attempted routes to potential precursors of 2 were unsuccessful while the tetrabromide 16 could be synthesized.Intramolecular cyclizations of the latter, however, failed to yield 4, possibly due to the unfavorable stereochemistry of the intermediate leading to the second intramolecular coupling reaction.The tetrabromide 18, with a central bridge of an appropriate length, successfully led to the formation of 3.The conformational behavior of 3 was analyzed by dynamic 1H NMR spectroscopy.The ethylenedioxy bridge is believed to adopt the symmetrical "boat" conformation.All three bridges, however, undergo unrestricted pseudorotation, represented by free conformational interconversion 3b 3c, at room temperature.A relatively frozen conformation 3b(3c) was observed at the low-temperature limit.Flipping processes of the ethylenedioxy bridge and the two thia bridges are found to be interdependent, resulting in an propelling process with a common conformational barrier estimated at ca. 45 kJ mol-1.
- Lai, Yee-Hing,Tan, Chin-Wee
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p. 264 - 267
(2007/10/02)
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- Cobalt-mediated Reactions in Synthesis. The Degradation of Carboxylic Acids to Functionalised Noralkanes via Acylcobalt Salophen Intermediates
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Arylmethyl- and allyl-carbonylcobalt salophen complexes, e.g. (7), (8), (9), and (22), readily undergo carbon-to-cobalt-bond homolysis and in situ decarbonylation, producing new alkyl radical centres which can be intercepted with oxygen-, nitrogen-, halogen-, sulphur-, and selenium-containing trapping agents leading to functionalised noralkanes.The sequence constitutes a useful, and in some cases more flexible, variant of the classical Hunsdiecker reaction, and amounts to a cobalt equivalent of the Barton radical decarboxylation reaction of carboxylic acids via their corresponding thiohydroxamic esters.In a similar manner, irradiation of the oxy-substituted acylcobalt salen reagents (25) and (26) in the presence of tetramethylpiperidine oxide produces the products (14) and (27), respectively, resulting from homolysis-decarboxylation and alkyl-radical trapping.In the absence of radical-trapping agents, irradiation of (7c) produces (18), and irradiation of (29) leads to the but-2-enolide (32).
- Patel, Vinod F.,Pattenden, Gerald,Thompson, David M.
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p. 2729 - 2734
(2007/10/02)
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- FREE RADICAL REACTIONS INITIATED BY ORGANOCOBALT COMPLEXES. A NEW METHOD FOR THE DEGRADATION OF CARBOXYLIC ACIDS TO FUNCTIONALISED NOR-ALKANES VIA ACYLCOBALT SALOPHEN INTERMEDIATES.
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Arylmethyl- and allyl-acylcobalt salophens, undergo facile C-Co bond homolysis and in situ decarbonylation, producing new (alkyl) radical centres which can be intercepted with oxygen, nitrogen, halogen, sulphur and selenium containing radical trapping agents, leading to functionalised nor-alkanes (Scheme).
- Patel, Vinod F.,Pattenden, Gerald
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p. 707 - 710
(2007/10/02)
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- CHEMOSELECTIVE REDUCTION OF ALDEHYDES WITH TETRA-n-BUTYLAMMONIUM TRIACETOXYBOROHYDRIDE
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Aldehydes, but not ketones, are smoothly reduced to alcohols by tetra-n-butylammonium triacetoxyborohydride in refluxing benzene.
- Nutaitis, Charles F.,Gribble, Gordon W.
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p. 4287 - 4290
(2007/10/02)
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- Mercury-assisted solvolyses of alkyl halides. Simple procedures for the preparation of nitrate esters, acetate esters, alcohols and ethers
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The reactions of a wide variety of alkyl halides with mercury(I) and/or (II) nitrate in 1,2-dimethoxyethane, mercury(II) acetate in acetic acid, aqueous mercury(II) perchlorate, and mercury(II) perchlorate in alcohol solvents have been investigated; as a result, simple high yield procedures for the conversion of alkyl halides into the corresponding nitrate esters, acetate esters, alcohols and ethers have been developed.
- McKillop,Ford
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p. 2467 - 2475
(2007/10/05)
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