- Nickel-Catalyzed Selective Synthesis of α-Alkylated Ketones via Dehydrogenative Cross-Coupling of Primary and Secondary Alcohols
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Herein, we describe an isolable, air-stable, homogeneous, nickel catalyst that performs dehydrogenative cross-coupling reaction between secondary and primary alcohols to result α-alkylated ketone products selectively. The sequence of steps involve in this one-pot reaction is dehydrogenation of both alcohols, condensation between the ketone and the aldehyde, and hydrogenation of the in situ-generated α,β-unsaturated ketone. Preliminary mechanistic investigation hints a radical mechanism following borrowing hydrogen reaction. (Figure presented.).
- Bains, Amreen K,Biswas, Ayanangshu,Adhikari, Debashis
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supporting information
p. 47 - 52
(2021/10/14)
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- Synthesis of α-Alkylated Ketones via Selective Epoxide Opening/Alkylation Reactions with Primary Alcohols
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A new method for converting terminal epoxides and primary alcohols into α-alkylated ketones under borrowing hydrogen conditions is reported. The procedure involves a one-pot epoxide ring opening and alkylation via primary alcohols in the presence of an N-heterocyclic carbene iridium(I) catalyst, under aerobic conditions, with water as the side product.
- Gen?, Serta?,Gülcemal, Süleyman,Günnaz, Salih,?etinkaya, Bekir,Gülcemal, Derya
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supporting information
p. 5229 - 5234
(2021/07/19)
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- Iridium Complexes as Efficient Catalysts for Construction of α-Substituted Ketones via Hydrogen Borrowing of Alcohols in Water
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Ketones are of great importance in synthesis, biology, and pharmaceuticals. This paper reports an iridium complexes-catalyzed cross-coupling of alcohols via hydrogen borrowing, affording a series of α-alkylated ketones in high yield (86 %–95 %) and chemoselectivities (>99 : 1). This methodology has the advantages of low catalyst loading (0.1 mol%) and environmentally benign water as the solvent. Studies have shown the amount of base has a great impact on chemoselectivities. Meanwhile, deuteration experiments show water plays an important role in accelerating the reduction of the unsaturated ketones intermediates. Remarkably, a gram-scale experiment demonstrates this methodology of iridium-catalyzed cross-coupling of alcohols has potential application in the practical synthesis of α-alkylated ketones.
- Luo, Nianhua,Zhong, Yuhong,Wen, Huiling,Shui, Hongling,Luo, Renshi
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p. 1355 - 1364
(2021/03/03)
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- Unveiling the catalytic nature of palladium-N-heterocyclic carbene catalysts in the α-alkylation of ketones with primary alcohols
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We report herein the synthesis of four new Pd-PEPPSI complexes with backbone-modified N-heterocyclic carbene (NHC) ligands and their application as catalysts in the α-alkylation of ketones with primary alcohols using a borrowing hydrogen process and tandem Suzuki-Miyaura coupling/α-alkylation reactions. Among the synthesized Pd-PEPPSI complexes, complex2chaving 4-methoxyphenyl groups at the 4,5-positions and 4-methoxybenzyl substituents on the N-atoms of imidazole exhibited the highest catalytic activity in the α-alkylation of ketones with primary alcohols (18 examples) with yields reaching up to 95%. Additionally, complex2cwas demonstrated to be an effective catalyst for the tandem Suzuki-Miyaura-coupling/α-alkylation of ketones to give biaryl ketones with high yields. The heterogeneous nature of the present catalytic system was verified by mercury poisoning and hot filtration experiments. Moreover, the formation of NHC-stabilized Pd(0) nanoparticles during the α-alkylation reactions was identified by advanced analytical techniques.
- ?etinkaya, Bekir,Ero?lu, Zafer,Gülcemal, Süleyman,Metin, ?nder,Ovezova, Mamajan
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supporting information
p. 10896 - 10908
(2021/08/17)
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- Method for preparing alpha-alkyl substituted ketone compound
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The invention relates to a method for preparing an alpha-alkyl substituted ketone compound, which comprises the following steps: preparing a primary alcohol compound and a secondary alcohol compound as raw materials, adding alkali; with a cyclic iridium complex as a catalyst and water as a reaction medium, heating and stirring the mixture and reacting for 10 to 24 hours under the protection of inert gas, and cooling a reaction product to room temperature after the reaction is finished; carrying out reduced pressure distillation and concentration to obtain a crude product, and carrying out column chromatography purification to obtain a series of alpha alkyl substituted ketone compounds. The method is simple to operate, available in raw materials, low in price, high in reaction efficiency and selectivity, good in adaptability to various functional groups and wide in substrate universality; since water is used as a reaction medium to meet the green and environment-friendly requirements, the method is environmentally friendly and is carried out at gram level, so that the potential of industrially synthesizing the alpha alkyl substituted ketone compound is achieved; therefore, The method has expanded application in the fields of medicines, organic synthesis and the like.
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Paragraph 0117-0124
(2020/12/29)
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- Phosphine-free pincer-ruthenium catalyzed biofuel production: High rates, yields and turnovers of solventless alcohol alkylation
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Phosphine-free pincer-ruthenium carbonyl complexes based on bis(imino)pyridine and 2,6-bis(benzimidazole-2-yl) pyridine ligands have been synthesized. For the β-alkylation of 1-phenyl ethanol with benzyl alcohol at 140 °C under solvent-free conditions, (Cy2NNN)RuCl2(CO) (0.00025 mol%) in combination with NaOH (2.5 mol%) was highly efficient (ca. 93% yield, 372?000 TON at 12?000 TO h-1). These are the highest reported values hitherto for a ruthenium based catalyst. The β-alkylation of various alcohol combinations was accomplished with ease which culminated to give 380?000 TON at 19?000 TO h-1 for the β-alkylation of 1-phenyl ethanol with 3-methoxy benzyl alcohol. DFT studies were complementary to mechanistic studies and indicate the β-hydride elimination step involving the extrusion of acetophenone to be the overall RDS. While the hydrogenation step is favored for the formation of α-alkylated ketone, the alcoholysis step is preferred for the formation of β-alkylated alcohol. The studies were extended for the upgradation of ethanol to biofuels. Among the pincer-ruthenium complexes based on bis(imino)pyridine, (Cy2NNN)RuCl2(CO) provided high productivity (335 TON at 170 TO h-1). Sterically more open pincer-ruthenium complexes such as (Bim2NNN)RuCl2(CO) based on the 2,6-bis(benzimidazole-2-yl) pyridine ligand demonstrated better reactivity and gave not only good ethanol conversion (ca. 58%) but also high turnovers (ca. 2100) with a good rate (ca. 710 TO h-1). Kinetic studies indicate first order dependence on concentration of both the catalyst and ethanol. Phosphine-free catalytic systems operating with unprecedented activity at a very low base loading to couple lower alcohols to higher alcohols of fuel and pharmaceutical importance are the salient features of this report. This journal is
- Das, Babulal,Das, Kanu,Kumar, Akshai,Srivastava, Hemant Kumar,Yasmin, Eileen
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p. 8347 - 8358
(2020/12/31)
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- Cyclometalated Ruthenium Pincer Complexes as Catalysts for the α-Alkylation of Ketones with Alcohols
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Ruthenium PNP pincer complexes bearing supplementary cyclometalated C,N-bound ligands have been prepared and fully characterized for the first time. By replacing CO and H? as ancillary ligands in such complexes, additional electronic and steric modifications of this topical class of catalysts are possible. The advantages of the new catalysts are demonstrated in the general α-alkylation of ketones with alcohols following a hydrogen autotransfer protocol. Herein, various aliphatic and benzylic alcohols were applied as green alkylating agents for ketones bearing aromatic, heteroaromatic or aliphatic substituents as well as cyclic ones. Mechanistic investigations revealed that during catalysis, Ru carboxylate complexes are predominantly formed whereas neither the PNP nor the CN ligand are released from the catalyst in significant amounts.
- Piehl, Patrick,Amuso, Roberta,Alberico, Elisabetta,Junge, Henrik,Gabriele, Bartolo,Neumann, Helfried,Beller, Matthias
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supporting information
p. 6050 - 6055
(2020/03/13)
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- Method for synthesizing alpha-alkylated ketone in water
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The invention discloses a method for synthesizing alpha-alkylated ketone in water. The method comprises the following steps: adding ketone, compound alcohol, a transition metal iridium catalyst, an alkali and a solvent, namely water into a reaction container, carrying out a reflux reaction on a reaction mixture in the air for several hours, carrying out cooling to room temperature, carrying out rotary evaporation to remove the solvent, and carrying out column separation (ethyl acetate/petroleum ether) to obtain a target compound, namely alpha-alkylated ketone. A reaction equivalent substrate is used in the reaction process, so raw material waste is avoided; equivalent alkali is used, so better environmental protection performance is obtained; water reflux reaction conditions are milder; and non-toxic and harmless pure water is used as the solvent in the reaction, only water is generated as a by-product, so atom reaction economy is high, and the requirements of green chemistry are met.
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Paragraph 0077-0081
(2020/08/22)
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- Metal-Free Cyclopropanol Ring-Opening C(sp3)-C(sp2) Cross-Couplings with Aryl Sulfoxides
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A metal-free method for formal β-arylation/heteroarylation of ketones through efficient cyclopropanol ring-opening cross-couplings with aryl sulfoxides at room temperature has been developed. This protocol shows a broad substrate scope and promising scalability. In addition, the utility of the β-arylated ketones is further demonstrated through a variety of postcoupling transformations and synthetic applications.
- Chen, Dengfeng,Fu, Yuanyuan,Cao, Xiaoji,Luo, Jinyue,Wang, Fei,Huang, Shenlin
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p. 5600 - 5605
(2019/08/01)
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- Nickel-Catalyzed Alkylation of Ketone Enolates: Synthesis of Monoselective Linear Ketones
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Herein we have developed a Ni-catalyzed protocol for the synthesis of linear ketones. Aryl, alkyl, and heteroaryl ketones as well as alcohols yielded the monoselective ketones in up to 90% yield. The catalytic protocol was successfully applied in to a gram-scale synthesis. For a practical utility, applications of a steroid derivative, oleyl alcohol, and naproxen alcohol were employed. Preliminary catalytic investigations involving the isolation of a Ni intermediate and defined Ni-H species as well as a series of deuterium-labeling experiments were performed.
- Das, Jagadish,Vellakkaran, Mari,Banerjee, Debasis
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p. 769 - 779
(2019/01/24)
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- Organocatalyzed biomimetic selective reduction of c=c double bonds of chalcones
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In this article, we reported a biomimetic approach for chemoselective reduction of C=C double bonds in chalcones under metal and acid free conditions, that relies on olefin activation by hydrogen bond formation. The process requires only catalytic amount of ephedrine as hydrogen bond donor and utilizes Hantzsch esters for transfer hydrogenation.
- Tripathi, Vishwa Deepak,Jha, Anand Mohan
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p. 2322 - 2324
(2018/09/09)
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- Method for synthesizing alpha-alkyl ketone
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The invention discloses a method for synthesizing alpha-alkyl ketone, and especially includes the following steps of: in a reaction vessel, adding secondary alcohol, a transition metal catalyst, and a solvent tertiary amyl alcohol; and heating and refluxing a reaction mixture in an oil bath for several hours, cooling the mixture to a room temperature; then adding primary alcohol and alkali, heating and refluxing the reaction mixture for several hours, and then obtaining a target compound through column separation. The method for synthesizing the alpha-alkyl ketone starts from the primary alcohol and the secondary alcohol. With the participation of the transition metal catalyst, the alpha-alkyl ketone is generated through a serial secondary alcohol non-acceptor dehydrogenation oxidation reaction/alpha-alkylation reaction of ketone. The reaction shows three obvious advantages that 1) non-toxic alcohols are used as the starting materials; 2) only hydrogen and water are generated in the reaction without environmental hazards; 3) atomic economy is high in the reaction; and 4) only 0.1 equivalents of carbonate is needed for the reaction, and the reaction only takes 3-6 hours. Therefore, the reaction meets the requirements of green chemistry and has broad development prospects.
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Paragraph 0088; 0089; 0090; 0091; 0092
(2017/04/12)
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- Hydrogen autotransfer and related dehydrogenative coupling reactions using a rhenium(i) pincer catalyst
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A novel rhenium complex bearing a non-innocent PNP pincer ligand was prepared. This novel catalyst is active in hydrogen autotransfer reactions to form new C-C and C-N bonds. More specifically, valuable alkylations of ketones and sulfonamides with primary alcohols are herein presented. In addition, the first examples of rhenium-catalysed synthesis of pyrroles are described by dehydrogenative coupling of diols, amines and ketones.
- Piehl, Patrick,Pe?a-López, Miguel,Frey, Anna,Neumann, Helfried,Beller, Matthias
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supporting information
p. 3265 - 3268
(2017/03/20)
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- Bifunctional Ru(II) complex catalysed carbon-carbon bond formation: an eco-friendly hydrogen borrowing strategy
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The atom economical borrowing hydrogen methodology enables the use of alcohols as alkylating agents for selective C-C bond formation. A bifunctional 2-(2-pyridyl-2-ol)-1,10-phenanthroline (phenpy-OH) based Ru(ii) complex (2) was found to be a highly efficient catalyst for the one-pot β-alkylation of secondary alcohols with primary alcohols and double alkylation of cyclopentanol with different primary alcohols. Exploiting the metal-ligand cooperativity in complex 2, several aromatic, aliphatic and heteroatom substituted alcohols were selectively cross-coupled in high yields using significantly low catalyst loading (0.1 mol%). An outer-sphere mechanism is proposed for this system as exogenous PPh3 has no significant effect on the rate of the reaction. Notably, this is a rare one-pot strategy for β-alkylation of secondary alcohols using a bifunctional Ru(ii)-complex. Moreover, this atom-economical methodology displayed the highest cumulative turn over frequency (TOF) among all the reported transition metal complexes in cross coupling of alcohols.
- Chakrabarti, Kaushik,Paul, Bhaskar,Maji, Milan,Roy, Bivas Chandra,Shee, Sujan,Kundu, Sabuj
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p. 10988 - 10997
(2016/12/06)
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- Bifunctional RuII-Complex-Catalysed Tandem C?C Bond Formation: Efficient and Atom Economical Strategy for the Utilisation of Alcohols as Alkylating Agents
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Catalytic activities of a series of functional bipyridine-based RuIIcomplexes in β-alkylation of secondary alcohols using primary alcohols were investigated. Bifunctional RuIIcomplex (3 a) bearing 6,6’-dihydroxy-2,2’-bipyridine (6DHBP) ligand exhibited the highest catalytic activity for this reaction. Using significantly lower catalyst loading (0.1 mol %) dehydrogenative carbon?carbon bond formation between numerous aromatic, aliphatic and heteroatom substituted alcohols were achieved with high selectivity. Notably, for the synthesis of β-alkylated secondary alcohols this protocol is a rare one-pot strategy using a metal–ligand cooperative RuIIsystem. Remarkably, complex 3 a demonstrated the highest reactivity compared to all the reported transition metal complexes in this reaction.
- Roy, Bivas Chandra,Chakrabarti, Kaushik,Shee, Sujan,Paul, Subhadeep,Kundu, Sabuj
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supporting information
p. 18147 - 18155
(2016/12/16)
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- Manganese-Catalyzed Hydrogen-Autotransfer C?C Bond Formation: α-Alkylation of Ketones with Primary Alcohols
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A novel catalytic hydrogen-autotransfer protocol for the atom-efficient α-alkylation of ketones with readily available alcohols is presented. The use of manganese complexes bearing non-innocent PNP pincer ligands enabled the functionalization of a broad range of valuable ketones, including 2-oxindole, estrone 3-methyl ether, and testosterone. Mechanistic investigations suggest the participation of an intramolecular amidate-assisted alcohol-dehydrogenation process.
- Pe?a-López, Miguel,Piehl, Patrick,Elangovan, Saravanakumar,Neumann, Helfried,Beller, Matthias
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supporting information
p. 14967 - 14971
(2016/11/25)
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- Method for synthesizing alpha-alkyl ketone
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The invention discloses a method for synthesizing alpha-alkyl ketone. The method comprises the following steps: adding ketone, a compound alcohol, an iridium complex catalyst, an alkali and a solvent tert-amyl alcohol in a reaction container, carrying out a refluxing reaction on the above obtained reaction mixture in air for several hours, cooling the obtained reaction product to room temperature, carrying out rotary evaporation to remove the solvent, and carrying out column separation to obtain the target compound. The meta-organic bifunctional iridium complex is used, only 0.1 equivalent carbonate is added in the reaction process, and the reaction is carried in air for 6h, so obvious advantages are displayed; and the reaction accords with green chemistry requirements, and has wide development prospect.
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Paragraph 0080; 0081; 0082; 0083; 0084
(2016/10/07)
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- A chemoselective α-aminoxylation of aryl ketones: a cross dehydrogenative coupling reaction catalysed by Bu4NI
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Tetrabutyl ammonium iodide (TBAI) catalyzed α-aminoxylation of ketones using aq. TBHP as an oxidant has been accomplished. We have shown that the CDC (cross dehydrogenative coupling) reactions of ketones with N-hydroxyimidates such as N-hydroxysuccinimide (NHSI), N-hydroxyphthalimide (NHPI), N-hydroxybenzotriazole (HOBt) and 1-hydroxy-7-azabenzotriazole (HOAt) lead to the corresponding oxygenated products in good to moderate yields. The application of this method has been demonstrated by transforming a few coupled products into synthetically useful intermediates and products.
- Siddaraju, Yogesh,Prabhu, Kandikere Ramaiah
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supporting information
p. 11651 - 11656
(2015/12/08)
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- Synthesis of a-Alkylated Ketones via Tandem Acceptorless Dehydrogenation/a-Alkylation from Secondary and Primary Alcohols Catalyzed by Metal-Ligand Bifunctional Iridium Complex [CpIr(2,2′-bpyO)(H2O)]
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A new strategy for the synthesis of α-alkylated ketones via tandem acceptorless dehydrogenation/α-alkylation from secondary and primary alcohols was proposed and accomplished. In the presence of metal-ligand bifunctional iridium complex [CpIr(2,2′-bpyO)(H2O)], various desirable products were obtained in high yields. Compared with previous methods for the direct dehydrogenative coupling of secondary alcohols with primary alcohols to α-alkylated ketones, this protocol has obvious advantages including complete selectivity for α-alkylated ketones and more environmentally benign conditions. Notably, the study also exhibited the potential to develop tandem reactions catalyzed using a metal-ligand bifunctional iridium complex.
- Wang, Rongzhou,Ma, Juan,Li, Feng
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p. 10769 - 10776
(2015/11/18)
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- Catalyst-free dehydrative α-alkylation of ketones with alcohols: Green and selective autocatalyzed synthesis of alcohols and ketones
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Direct dehydrative α-alkylation reactions of ketones with alcohols are now realized under simple, practical, and green conditions without using external catalysts. These catalyst-free autocatalyzed alkylation methods can efficiently afford useful alkylated ketone or alcohol products in a one-pot manner and on a large scale by Ci£C bond formation of the in situ generated intermediates with subsequent controllable and selective Meerwein-Pondorf-Verley-Oppenauer-type redox processes. Plain and simple: The title reaction has been realized under simple and practical conditions without using external catalysts, and can afford alkylated ketone or alcohol products in a one-pot manner and on a large scale. The reaction proceeds by Ci£C bond formation of the in situ generated intermediates with subsequent controllable and selective Meerwein-Pondorf-Verley-Oppenauer-type redox processes. Copyright
- Xu, Qing,Chen, Jianhui,Tian, Haiwen,Yuan, Xueqin,Li, Shuangyan,Zhou, Chongkuan,Liu, Jianping
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p. 225 - 229
(2014/01/17)
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- Rhodium(I)-catalyzed arylation of β-chloro ketones and related derivatives through domino dehydrochlorination/conjugate addition
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Highly efficient arylations of β-chloro ketones and their ester and amide derivatives were achieved by means of domino dehydrochlorination/Rh(I)- catalyzed conjugate addition. In situ generated vinyl ketones and their analogues were identified as the reaction intermediates. The present synthetic protocol provides a concise route to (chiral) β-aryl ketones, esters, and amides. Copyright
- Jiang, Quanbin,Guo, Tenglong,Wang, Qingfu,Wu, Ping,Yu, Zhengkun
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supporting information
p. 1874 - 1880
(2013/07/19)
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- Aldehyde-catalyzed transition metal-free dehydrative β-alkylation of methyl carbinols with alcohols
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Different to the borrowing hydrogen strategy in which alcohols were activated by transition metal-catalyzed anaerobic dehydrogenation, the direct addition of aldehydes was found to be an effective but simpler way of alcohol activation that can lead to efficient and green aldehyde-catalyzed transition metal-free dehydrative C-alkylation of methyl carbinols with alcohols. Mechanistic studies revealed that the reaction proceeds via in situ formation of ketones by Oppenauer oxidation of the methyl carbinols by external aldehydes, aldol condensation, and Meerwein-Ponndorf-Verley (MPV)-type reduction of α,β-unsatutated ketones by substrate alcohols, affording the useful long chain alcohols and generating aldehydes and ketones as the by-products that will be recovered in the next condensation to finish the catalytic cycle. Copyright
- Xu, Qing,Chen, Jianhui,Liu, Quan
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supporting information
p. 697 - 704
(2013/04/10)
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- Reduction of activated conjugated alkenes by the InCl3-NaBH 4 reagent system
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A combination of a catalytic amount of indium (III) chloride and sodium borohydride in acetonitrile reduces selectively the carbon-carbon double bonds in conjugated alkenes such as α,α-dicyano olefins, α,β-unsaturated nitriles, cyanoesters, cyanophosphonate and dicarboxylic esters. However, reduction of chalcones is little different. They are reduced to a mixture of saturated ketones and alcohols if the reaction mixture is quenched with H2O, whereas quenching with MeOH leads to saturated alcohols only.
- Ranu, Brindaban C.,Samanta, Sampak
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p. 7901 - 7906
(2007/10/03)
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- Use of indium hydride (Cl2InH) for chemoselective reduction of the carbon-carbon double bond in conjugated alkenes
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Indium hydride (Cl2InH) generated in situ from a combination of a catalytic amount of indium(III) chloride and sodium borohydride selectively reduces the carbon-carbon double bond in conjugated alkenes such as α,α-dicyano olefins, α,β-unsaturated nitriles, cyano esters, cyanophosphonate, diesters and ketones.
- Ranu, Brindaban C.,Samanta, Sampak
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p. 7405 - 7407
(2007/10/03)
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- Ruthenium-catalyzed regioselective α-alkylation of ketones with primary alcohols
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Ketones are regioselectively alkylated with an array of primary alcohols in dioxane at 80°C in the presence of a catalytic amount of a ruthenium catalyst together with KOH and a hydrogen acceptor.
- Cho, Chan Sik,Kim, Bok Tae,Kim, Tae-Jeong,Chul Shim, Sang
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p. 7987 - 7989
(2007/10/03)
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- Arylation of α-substituted acrylates in ionic liquids catalyzed by a Pd-benzothiazole carbene complex
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A Pd-catalyst with benzothiazole carbene as ligands allows, in tetrabutylammonium bromide melt as solvent, very fast and efficient reactions of bromoaromatics with 3-hydroxy-2-methylenealkanoates to give β-arylketones.
- Calò, Vincenzo,Nacci, Angelo,Lopez, Luigi,Napola, Annalisa
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p. 4701 - 4703
(2007/10/03)
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- Selective Hydrogenation of Carbon-Carbon Double bonds of Chalcones by Corynebacterium equi IFO 3730
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1,3-Diphenyl-2-propen-1-one (chalcone) was selectively hydrogenated at the carbon-carbon double bond on incubation with Corynebacterium equi IFO 3730. to give the corresponding saturated ketone, 1,3-diphenyl-1-propanone.Practically no alcoholic compounds were detected in the reaction mixture.This highly selective hydrogenation reaction was also successful with substrates having substituents on aromatic rings.On the other hand, two hydrogen atoms on the olefinic carbons were essential, because substitution of either one of the hydrogens by a methyl group completely inhibited the reaction.
- Ohta, Hiromichi,Konishi, Jin,Tsuchihashi, Gen-ichi
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p. 665 - 670
(2007/10/02)
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