- Aryl palladium carbene complexes and carbene-aryl coupling reactions
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Transmetalation of an aminocarbene moiety from [W(CO) 5{C(NEt2)R}] to palladium leads to isolable monoaminocarbene palladium aryl complexes [{Pd(μ-Br)Pf[C(NEt 2)R]}2] (R = Me, Ph; Pf = C6F5). When [W(CO)5{C(OMe)R}] is used, the corresponding palladium carbenes cannot be isolated since these putative, more electrophilic carbenes undergo a fast migratory insertion process to give alkyl palladium complexes. These complexes could be stabilized in the η3-allylic form for R = 2-phenylethenyl or in the less stable η3-benzylic fashion for R = Ph. Hydrolysis products and a pentafluorophenylvinylic methyl ether (when R = Me) were also observed. The monoaminocarbenes slowly decompose through carbene-aryl coupling to produce the corresponding iminium salts and, depending on the reaction conditions, the corresponding hydrolysis products. The electrophilicity of the carbene carbon, which is mainly determined by the nature of the heteroatom group, controls the ease of evolution by carbene-aryl coupling. Accordingly, no carbene-aryl coupling was observed for a diaminocarbene palladium aryl complex.
- Albeniz, Ana C.,Espinet, Pablo,Manrique, Raul,Perez-Mateo, Alberto
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- London Dispersion Interactions Rather than Steric Hindrance Determine the Enantioselectivity of the Corey–Bakshi–Shibata Reduction
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The well-known Corey–Bakshi–Shibata (CBS) reduction is a powerful method for the asymmetric synthesis of alcohols from prochiral ketones, often featuring high yields and excellent selectivities. While steric repulsion has been regarded as the key director of the observed high enantioselectivity for many years, we show that London dispersion (LD) interactions are at least as important for enantiodiscrimination. We exemplify this through a combination of detailed computational and experimental studies for a series of modified CBS catalysts equipped with dispersion energy donors (DEDs) in the catalysts and the substrates. Our results demonstrate that attractive LD interactions between the catalyst and the substrate, rather than steric repulsion, determine the selectivity. As a key outcome of our study, we were able to improve the catalyst design for some challenging CBS reductions.
- Eschmann, Christian,Song, Lijuan,Schreiner, Peter R.
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supporting information
p. 4823 - 4832
(2021/02/01)
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- Decarboxylative Cross-Coupling of Acyl Fluorides with Potassium Perfluorobenzoates
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We report the transition metal-free decarboxylative cross-coupling reactions of acyl fluorides with potassium perfluorobenzoates. Compared with traditional transition metal-catalyzed cross-couplings, this protocol presents an extremely environmentally ben
- Fu, Liyan,Chen, Qiang,Nishihara, Yasushi
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supporting information
p. 6388 - 6393
(2020/08/24)
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- A Bifunctional Iron Nanocomposite Catalyst for Efficient Oxidation of Alkenes to Ketones and 1,2-Diketones
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We herein report the fabrication of a bifunctional iron nanocomposite catalyst, in which two catalytically active sites of Fe-Nx and Fe phosphate, as oxidation and Lewis acid sites, were simultaneously integrated into a hierarchical N,P-dual doped porous carbon. As a bifunctional catalyst, it exhibited high efficiency for direct oxidative cleavage of alkenes into ketones or their oxidation into 1,2-diketones with a broad substrate scope and high functional group tolerance using TBHP as the oxidant in water under mild reaction conditions. Furthermore, it could be easily recovered for successive recycling without appreciable loss of activity. Mechanistic studies disclose that the direct oxidation of alkenes proceeds via the formation of an epoxide as intermediate followed by either acid-catalyzed Meinwald rearrangement to give ketones with one carbon shorter or nucleophilic ring-opening to generate 1,2-diketones in a cascade manner. This study not only opens up a fancy pathway in the rational design of Fe-N-C catalysts but also offers a simple and efficient method for accessing industrially important ketones and 1,2-diketones from alkenes in a cost-effective and environmentally benign fashion.
- Ma, Zhiming,Ren, Peng,Song, Tao,Xiao, Jianliang,Yang, Yong,Yuan, Youzhu
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p. 4617 - 4629
(2020/05/19)
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- Pd(II)-Catalyzed Denitrogenative and Desulfinative Addition of Arylsulfonyl Hydrazides with Nitriles
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A Pd(II)-catalyzed denitrogenative and desulfinative addition of arylsulfonyl hydrazides with nitriles has been successfully achieved under mild conditions. This transformation is a new method for the addition reaction to nitriles with arylsulfonyl hydrazides as arylating agent, thus providing an alternative synthesis of aryl ketones. The reported addition reaction is tolerant to many common functional groups, and works well in the presence of electron-donating and electron-withdrawing substituents. Notably, the reported denitrogenative and desulfinative addition was also appropriate for alkyl nitriles, making this newly developed transformation attractive.
- Meng, Mengting,Yang, Liangfeng,Cheng, Kai,Qi, Chenze
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p. 3275 - 3284
(2018/03/25)
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- Preparation method of aromatic ketone
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The invention discloses a preparation method of aromatic ketone. Under the effects of a palladium catalyst and a nitrogen-containing ligand, nitrile compounds and arylsulfonylhydrazide take desulfurization addition reaction in an organic solvent; after the reaction is completed, post treatment is performed to obtain aromatic ketone. The reaction is applicable to aromatic nitrile compounds, and isalso applicable to aliphatic nitrile compounds; the reaction realizes the wide substrate applicability and functional group tolerance; the potential application value is realized in the aspect of aryl-carbonyl building.
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Paragraph 0046; 0047; 0048; 0050
(2018/09/11)
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- Method for preparing aromatic ketone in aqueous phase
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The invention discloses a method for preparing aromatic ketone in an aqueous phase, comprising the following steps: enabling aryl formyl potassium formate and aryl potassium fluoborate to generate decarboxylation acylation reaction in water under the actions of a silver catalyst and an oxidizing agent, and performing treatment after reaction is ended to obtain the disclosed aromatic ketone. According to the preparation method, the silver catalyst replaces a noble metal catalyst, water is taken as a solvent, an aromatic ketone product is obtained with relatively high yield, the adopted catalystis low in cost and easy to obtain, reaction conditions are mild, and meanwhile, the product is good in university, and therefore, the method has good application potential.
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Paragraph 0042-0045
(2018/04/26)
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- Ag(i)/persulfate-catalyzed decarboxylative coupling of α-oxocarboxylates with organotrifluoroborates in water under room temperature
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The decarboxylative coupling reaction of α-oxocarboxylates and organotrifluoroborates was carried out smoothly in the presence of catalytic AgNO3 using K2S2O8 as oxidant to generate diarylketone products in high
- Chang, Sheng,Wang, Jian Feng,Dong, Lin Lin,Wang, Dan,Feng, Bo,Shi, Yuan Tai
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p. 51928 - 51934
(2017/11/22)
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- Carbonylative coupling of aryl tosylates/triflates with arylboronic acids under CO atmosphere
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The carbonylative Suzuki-Miyaura reaction between aryl tosylates/triflates with arylboronic acid is herein reported, using base-free conditions and a balloon pressure of carbon monoxide. Under these conditions, unsymmetrical biaryl ketones were obtained in modest to excellent yields. This method was adapted to the synthesis of oxybenzone and ketoprofen in good yields under mild conditions.
- Hao, Cheng Yi,Wang, Dan,Li, Ya Wei,Dong, Lin Lin,Jin, Ying,Zhang, Xiu Rong,Zhu, He Yun,Chang, Sheng
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p. 86502 - 86509
(2016/09/23)
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- Method for preparing diaryl ketone from aryl sulfonate
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The invention discloses a method for preparing diaryl ketone from aryl sulfonate. The method includes following steps: in the presence of a catalyst and carbon monoxide, allowing aryl sulfonate and aryl boronic acid to react in an organic solvent; after reaction is finished, performing aftertreatment to obtain diaryl ketone. Aryl sufonate is adopted as an electrophilic reagent for Suzuki cross carbonylation coupling reaction, diaryl ketone is directly synthesized through carbon monoxide, aryl sulfonate and aryl boronic acid, reaction conditions are milk, functional groups are high in tolerance, a substrate is cheap and easy to get, and diaryl ketone can be prepared with high yield.
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Paragraph 0051
(2017/01/12)
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- Carbonylative Hiyama coupling of aryl halides with arylsilanes under balloon pressure of CO
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An efficient protocol has been developed for the carbonylative Hiyama coupling of aryl halides using the cesium fluoride as a promoter by palladium-catalyzed in NMP. This protocol was applied to a wide variety of functionalized and hindered aryl iodides and bromides with arylsilanes, to afford the desired biaryl ketones in good to excellent yields.
- Chang, Sheng,Jin, Ying,Zhang, Xiu Rong,Sun, Yong Bing
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supporting information
p. 2017 - 2020
(2016/04/26)
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- C-H activation dependent Pd-catalyzed carbonylative coupling of (hetero)aryl bromides and polyfluoroarenes
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The carbonylative coupling of aryl and heteroaryl bromides with polyfluoroarenes via palladium-catalyzed C-H activation is presented. This transformation proceeds efficiently at moderate reaction temperatures and does not require strong base or reactive intermediates. A near stoichiometric amount of CO is sufficient and the methodology can thus be easily expanded to include the preparation of [13C]-acyl labeled benzopolyfluorophenones.
- Lian, Zhong,Friis, Stig D.,Skrydstrup, Troels
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supporting information
p. 1870 - 1873
(2015/01/30)
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- Approaches to prepare perfluoroalkyl and pentafluorophenyl copper couples for cross-coupling reactions with organohalogen compounds
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The reactions of iodoperfluoroalkanes CnF2n+1I (n = 2, 3, 4) and n-BuLi at low temperatures give NMR spectroscopic evidence for LiCnF2n+1 which were converted into LiCu(CnF2n+1)2 derivatives upon treatment with 0.5 mol copper(i) bromide, CuBr. An alternative route to obtain perfluoroorgano copper couples, Cu(Rf)2Ag (Rf = n-C3F7, n-C4F9, C6F5) was achieved from the reactions of the corresponding perfluoroorgano silver(i) reagents, AgRf, and elemental copper through redox transmetallations. The composition of the resulting reactive intermediates was investigated by means of 19F NMR spectroscopy and ESI mass spectrometry. Perfluoro-n-propyl and perfluoro-n-butyl copper-silver reagents prepared by the oxidative transmetallation route exhibited good properties in C-C bond formation reactions with acid chlorides even under moderate conditions. Substitution of bromine directly bound to aromatics for perfluoroalkyl groups was achieved at elevated temperatures, while success in halide substitution reactions using lithium copper couples remained poor.
- Kremlev, Mikhail M.,Mushta, Aleksej I.,Tyrra, Wieland,Yagupolskii, Yurii L.,Naumann, Dieter,Sch?fer, Mathias
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p. 19693 - 19699
(2015/11/27)
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- Silver-catalyzed decarboxylative acylation of arylglyoxylic acids with arylboronic acids
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The silver-catalyzed coupling of arylboronic acids with arylglyoxylic acids was found to be an extremely efficient route for the synthesis of unsymmetrical diaryl ketones. It can be conducted on a gram scale under mild and open-flask conditions with good functional group compatibility, avoiding the addition of expensive and/or toxic metals. This journal is
- Cheng, Kai,Zhao, Baoli,Qi, Chenze
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p. 48698 - 48702
(2014/12/10)
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- Steric and electronic effects influencing β-aryl elimination in the Pd-catalyzed carbon-carbon single bond activation of triarylmethanols
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An analysis of the palladium-catalyzed activation of carbon-carbon single bonds within triarylmethanols has led to a greater understanding of factors influencing the β-aryl elimination process responsible for C-C bond cleavage. A series of competition reactions were utilized to determine that β-aryl elimination of aryl substituents containing ortho-substitution proceeds with significant preference to unsubstituted phenyl rings. Further experiments indicate that substrates containing either strongly donating or withdrawing substituents are cleaved from triarylmethanols more readily than relatively neutral species.
- Bour, James R.,Green, Jacob C.,Winton, Valerie J.,Johnson, Jeffrey B.
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p. 1665 - 1669
(2013/03/28)
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- Highly fluorinated aryl-substituted tris(indazolyl)borate thallium complexes: Diverse regiochemistry at the B-N bond
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The synthesis and characterization (mainly by 19F NMR and X-ray diffraction) of highly fluorinated aryl-4,5,6,7-tetrafluoroindazoles and their corresponding thallium hydrotris(indazolyl)borate complexes are reported [aryl = phenyl, pentafluorophenyl, 3,5-dimethylphenyl, 3,5-bis(trifluoromethyl)phenyl]. Thanks to N-H???N hydrogen bonds, the indazoles crystallize as dimers that pack differently depending on the nature of the aryl group. The thallium hydrotris(indazolyl)borate complexes Tl[Fn-Tp4Bo,3aryl] resulting from the reaction of aryl-4,5,6,7-tetrafluoroindazoles [aryl = phenyl, 3,5-dimethylphenyl, 3,5-bis(trifluoromethyl)phenyl] with thallium borohydride adopt overall C3v symmetry with the indazolyl groups bound to boron via their N-1 nitrogen in a conventional manner. When the perfluorinated pentaphenyl-4,5,6,7-tetrafluoroindazole is reacted with thallium borohydride, a single regioisomer of Cs symmetry having one indazolyl ring bound to boron via its N-2 nitrogen, TlHB(3-pentafluorophenyl-4,5,6,7-tetrafluoroindazol- 1-yl)2(3-pentafluorophenyl-4,5,6,7-tetrafluoroindazol-2-yl) Tl[F27-Tp(4Bo,3C6F5)*], is obtained for the first time. Surprisingly, the perfluorinated dihydrobis(indazolyl)borate complex Tl[F 18-Bp3Bo,3C6F5], an intermediate on the way to the hydrotris(indazolyl)borate complex, has Cs symmetry with two indazolyl rings bound to boron via N-2. The distortion of the coordination sphere around Tl and the arrangement of the complexes in the crystal are discussed.
- Ojo, Wilfried-Solo,Jacob, Kane,Despagnet-Ayoub, Emmanuelle,Munoz, Bianca K.,Gonell, Sergio,Vendier, Laure,Nguyen, Viet-Hoang,Etienne, Michel
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scheme or table
p. 2893 - 2901
(2012/04/23)
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- Observation of the direct products of migratory insertion in aryl palladium carbene complexes and their subsequent hydrolysis
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The interaction of an electrophilic carbene carbon atom with the π-electron density of an aryl group favors an intramolecular migratory insertion reaction (see scheme; Pf = C6F5). This reaction gives alkyl compounds (2 or 3) which ca
- Albeniz, Ana C.,Espinet, Pablo,Manrique, Raul,Perez-Mateo, Alberto
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p. 2363 - 2366
(2007/10/03)
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- A Convenient Preparation of Functionalized Arylzinc Compounds by the Reaction of Zinc/Silver-Graphite with Aryl Iodides.
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Aryl- and hetero-aryl iodides react under very mild conditions (THF, 25 deg C) with a Zn(Ag) couple deposited on graphite leading to the corresponding zinc reagents in excellent yields.In the presence of CuCN*2LiCl or catalytic amounts of Pd(O), these unsaturated zinc species can be acylated, allylated or coupled with iodoalkenes.
- Fuerstner, Alois,Singer, Robert,Knochel, Paul
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p. 1047 - 1050
(2007/10/02)
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- Preparation of Aryl, Alkynyl, and Vinyl Organocopper Compounds by the Oxidative Addition of Zerovalent Copper to Carbon-Halogen Bonds
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A highly reactive copper slurry can be prepared by the reduction of CuI*PEt3 with 1 equiv of lithium naphthalide.The highly reactive copper is found to undergo rapid oxidative addition to alkyl, aryl, alknyl, and vinyl halides under mild conditions.The aryl, alkynyl, and vinyl organocopper compounds are stable at room temperature.These organocopper compounds can bee prepared with variety of functional groups such nitro, nitrile, ester, and ketone.The arylcopper compounds can be cross-coupled in moderate to high yields with acid chlorides and with alkyl-halides.A comparison of different methods for producing activated copper is presented, and the scope and limitations are discussed.
- Ebert, Greg W.,Rieke, Reuben D.
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p. 4482 - 4488
(2007/10/02)
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- Metallic Nickel-Mediated Synthesis of Ketones by the Reaction of Benzylic, Allylic, Vinylic, and Pentafluorophenyl Halides with Acid Halides
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Metallic nickel was investigated as a convenient coupling reagent for the synthesis of ketones by the reaction of benzylic, allylic, vinylic, and pentafluorophenyl halides with acid halides at 85 deg C in glyme.A variety of benzylic ketones with functional groups including halogen, cyano, methoxycarbonyl, and hydroxycarbonyl groups were prepared in good yields by this method.The reaction was demonstrated to proceed via organonickel halide intermediates formed by the smooth oxidative addition of benzylic and acyl halides to metallic nickel, which were trapped with electron-deficient olefins. (?-Allyl)nickel halides, prepared in situ at 85 deg C from allylic halides and the nickel, also worked for the preparation of ketones.Vinylic and pentafluorophenyl halides but not alkyl halides reacted with acid halides to give the corresponding ketones in moderate yields.
- Inaba, Shin-ichi,Rieke, Reuben D.
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p. 1373 - 1381
(2007/10/02)
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- Direct Formation of Organocopper Compounds by Oxidative Addition of Zerovalent Copper to Organic Halides
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Mixing a solution of CuI*P(Et)3 with a stoichiometric amount of lithium naphthalide in THF affords a zerovalent copper species that is sufficiently reactive to add to organic halides to give the corresponding organocopper compounds.
- Ebert, Greg W.,Rieke, Reuben D.
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p. 5280 - 5282
(2007/10/02)
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- FLUORO-KETONES. V REACTIONS OF ALKYL AND ARYLLITHIUM COMPOUNDS WITH PERFLUOROALKYLETHER ESTERS
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n-Butyllithium and a variety of aryllithium compounds have been shown to react with a perfluoroalkylether ester (RfORfCO2R) at -78 deg C to produce perfluoroalkylether ketones.In the absence of competing reactions, which may be due to additional reactive groups on the ester, high yields of ketones can be prepared.Steric hindrance adjacent to the carbonyl group has an important effect on rates of reactions.Low reaction temperature (-78 deg C) is an important factor when secondary esters are used.At higher reaction temperatures (> -30 deg C), the secondary esters produce decreased yields of ketone due to the instability of the intermediate lithium salt of the hemiketal which decomposes to an aryl ester and a perfluorinated olefin.
- Chen, Loomis S.,Tamborski, Christ
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