- 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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- Selective Electrochemical Oxygenation of Alkylarenes to Carbonyls
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An efficient electrochemical method for benzylic C(sp3)-H bond oxidation has been developed. A variety of methylarenes, methylheteroarenes, and benzylic (hetero)methylenes could be converted into the desired aryl aldehydes and aryl ketones in moderate to excellent yields in an undivided cell, using O2 as the oxygen source and lutidinium perchlorate as an electrolyte. On the basis of cyclic voltammetry studies, 18O labeling experiments, and radical trapping experiments, a possible single-electron transfer mechanism has been proposed for the electrooxidation reaction.
- Li, Xue,Bai, Fang,Liu, Chaogan,Ma, Xiaowei,Gu, Chengzhi,Dai, Bin
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supporting information
p. 7445 - 7449
(2021/10/02)
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- Photoredox-Catalysis-Modulated, Nickel-Catalyzed Divergent Difunctionalization of Ethylene
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Divergent synthesis that enables a catalytic reaction to selectively produce different products from common substrates will allow the charting of wider chemical space and the unveiling of distinct mechanistic paradigms. A common strategy for it employs different ligands to modulate organometallic catalysts. Dramatic developments in photocatalysis have enabled previously inaccessible transformations. In particular, photoredox catalysis modulates the oxidation state of transition-metal complexes, offering enormous opportunities for methodology development. Herein, we developed a photo-mediated divergent ethylene difunctionalization via modulating oxidation states of the nickel catalyst by using different photoredox catalysts. This work will inspire new perspectives for value-added chemical synthesis using ethylene as a feedstock and shed light on photoredox-catalyst-based divergent synthesis, which fundamentally differs from ligand-controlled transition-metal catalysis.Divergent synthesis represents a powerful strategy for directly accessing different molecular scaffolds originating from the same starting materials. Access to different end products via transition-metal catalysis is conventionally achieved by ligand control. We herein demonstrate the use of ethylene feedstock and commercially available aryl halides to accomplish the divergent synthesis of 1,2-diarylethanes, 1,4-diarylbutanes, or 2,3-diarylbutanes in a highly selective fashion through the synergistic combination of nickel and photoredox catalysis. Mechanistic studies suggest that the observed selectivity was due to different active states of Ni(I) and Ni(0) modulated by Ru- and Ir-based photoredox catalysts, respectively. The ability to access different organometallic oxidation states via photoredox catalysis promises to inspire new perspectives for synergistic transition-metal-catalyzed divergent synthesis.Functionalization of ethylene without polymerization is challenging under photo-irradiation conditions. We have demonstrated that the photo-transformation of ethylene can be controllable by merging photoredox and transition-metal catalysis. In our study, the use of different photoredox catalysts was able to modulate the oxidation state of the nickel catalyst. Through different oxidation states, the nickel-catalyzed couplings proceeded via distinct pathways to generate divergent ethylene difunctionalization products selectively from the same feedstock.
- Li, Jiesheng,Luo, Yixin,Cheo, Han Wen,Lan, Yu,Wu, Jie
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supporting information
p. 192 - 203
(2019/01/21)
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- Pd-Catalyzed Alkylation of (Iso)quinolines and Arenes: 2-Acylpyridine Compounds as Alkylation Reagents
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The first Pd-catalyzed alkylation of (iso)quinolines and arenes is reported. The readily available and bench-stable 2-acylpyridine compounds were used as an alkylation reagent to form the structurally versatile alkylated (iso)quinolines and arenes. The method affords a convenient pathway for the introduction of alkyl groups into organic molecules.
- Wu, Qingsong,Han, Shuaijun,Ren, Xiaoxiao,Lu, Hongtao,Li, Jingya,Zou, Dapeng,Wu, Yangjie,Wu, Yusheng
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supporting information
p. 6345 - 6348
(2018/10/20)
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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 0084-0087
(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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- CERAMIDE GALACTOSYLTRANSFERASE INHIBITORS FOR THE TREATMENT OF DISEASE
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Described herein are compounds, methods of making such compounds, pharmaceutical compositions and medicaments containing such compounds, and methods of using such compounds to treat or prevent diseases or disorders associated with the enzyme ceramide galactosyltransferase (CGT), such as, for example, lysosomal storage diseases. Examples of lysosomal storage diseases include, for example, Krabbe disease and Metachromatic Leukodystrophy.
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Paragraph 000474; 000475
(2018/01/17)
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- Nanosized gold-catalyzed selective oxidation of alkyl-substituted benzenes and n-alkanes
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We report the synthesis of nanoporous silica-supported gold nanoparticle catalysts and their selective and efficient catalytic properties toward oxidation reactions of various substituted alkylbenzenes and linear alkanes. The Au nanoparticles were synthesized by reducing Au(III) ions in situ within the nanopores of hemiaminal-functionalized mesoporous silica by using the supported hemiaminal groups as reducing agents. The resulting mesoporous silica-supported gold nanoparticles efficiently catalyzed the oxidation reactions of different alkyl-substituted benzenes and linear alkanes with t-butyl hydroperoxide (TBHP) as an oxidant. The catalytic reactions gave up to ~99% reactant conversion and up to ~100% selectivity toward ketone products in some cases. This high selectivity toward ketone products by the catalysts was unprecedented, especially considering the fact that only mild reaction conditions and no additives were employed during the reactions.
- Biradar, Ankush V.,Asefa, Tewodros
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experimental part
p. 19 - 26
(2012/10/08)
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- Selective oxidation of alkyl benzenes using CrO3 combined with Ce(SO4)2
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A novel system of oxidant-CrO3 combined with Ce(SO 4)2, has been demonstrated to be an effective and economic oxidant for the oxidation of alkyl benzenes to ketones or aldehydes with little by-products and high yields. Including 1-(2,4-diethylphenyl)ethanone (3), seven alkyl benzenes have been studied, the products have been characterized by the elemental analyses, 1H, 13C NMR and EI-MS. The possible mechanisms of this oxidation reaction were also proposed. The obtained 5-acetyl-3- methylisobenzofuran-1(3H)-one (5), the by-product of 3 was also confirmed by the crystal structure.
- Song, Guang-Liang,Liu, Yuan-Yuan,Chen, Lei,Zhu, Hong-Jun
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experimental part
p. 7267 - 7274
(2012/07/28)
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- A general and efficient suzuki-miyaura cross-coupling protocol using weak base and no water: The essential mole of acetate
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A weak base, CsOAc, promotes Suzuki-Miyaura cross-coupling and related Pd-catalyzed reactions under anhydrous conditions as effectively as stronger bases. Aryl triflates exhibit unusual reaction rates, which are comparable to that: of bromoarenes. A negle
- Wang, Bing,Sun, Hui-Xia,Sun, Zhi-Hua
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experimental part
p. 3688 - 3692
(2009/12/03)
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- Benzylic oxidation of aromatics with cerium(IV) triflate; Synthetic scope and mechanistic insight
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The synthetic utility of cerium(IV) triflate Ce(OTf)4 as a reagent for benzylic oxidation has been tested for a variety of aromatic compounds. Insight is provided into various factors that govern these oxidations and their progress. It has been shown that the mode of preparation of Ce(OTf)4 and the % H2O present in the sample have a marked influence on oxidation ability. A variety of mono- and dialkylbenzenes, haloalkylbenzenes, bicyclic and tricyclic ring systems, and alkoxybenzenes have been surveyed. The method offers an easy to perform one-pot reaction for the room temperature synthesis of aromatic ketones and aldehydes from aromatics and has the potential to find wider application.
- Laali, Kenneth K.,Herbert, Mark,Cushnyr, Brad,Bhatt, Anand,Terrano, David
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p. 578 - 583
(2007/10/03)
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- UNE VOIE ORIGINALE ET SELECTIVE DE FONCTIONNALISATION EN POSITION META DU FLUORO- ET DE L'ETHYLBENZENE
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An original and regioselective method for the meta functionalisation of fluoro- and ethylbenze is reported.This process involves a 2,5-disilylation of these subtrates using trimethylchlorosilane in the presence of lithium in THF as the solvent.After aromatisation, monodesilylation in position 2- and electrophilic substitution of the trimethylsilyl group in position 5-, meta acetyl-, senecioyl-, benzoyl-, and iodofluorobenzenes and ethylbenzenes as well as the sodium salts of metafluoro or meta ethylbenzenesulfonic acid and 3-aminosulfonylfluorobenzene were obtained in good yields. pair of diastereomeric triamines 15 and 16.A tricyclic diazasystem 19 was formed from the reaction of cyanide with the carbamoylated chloroenamine 18.Monochloroenamine 10a and dichloroenamine 12a showed a significant mutagenic behaviour in the Ames test.
- Bennetau, Bernhard,Krempp, Michele,Dunogues, Jacques,Ratton, Serge
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p. 8131 - 8142
(2007/10/02)
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