- Self-Assembled 2,3-Dicyanopyrazino Phenanthrene Aggregates as a Visible-Light Photocatalyst
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In this study, 2,3-dicyanopyrazino phenanthrene (DCPP), a commodity chemical that can be prepared at an industrial scale, was used as a photocatalyst in lieu of Ru or Ir complexes in C-X (X = C, N, and O) bond-forming reactions under visible-light irradiation. In these reactions, [DCPP]n aggregates were formed in situ through physical π-πstacking of DCPP monomers in organic solvents. These aggregates exhibited excellent photo- and electrochemical properties, including a visible light response (430 nm), long excited-state lifetime (19.3 μs), high excited-state reduction potential (Ered([DCPP]n*/[DCPP]n·-) = +2.10 V vs SCE), and good reduction stability. The applications of [DCPP]n aggregates as a versatile visible-light photocatalyst were demonstrated in decarboxylative C-C cross-coupling, amidation, and esterification reactions.
- He, Min,Yu, Xiaoqiang,Wang, Yi,Li, Fei,Bao, Ming
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- High-Throughput Synthesis of Alkylbenzophenones with Indium Triflate in the Absence of Solvents Using Microwave
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A series of alkylbenzophenones were rapidly and efficiently prepared from alkylbenzenes and benzoyl chlorides by Friedel-Crafts acylation catalyzed with indium triflate under solvent-free conditions by microwave heating.
- Koshima, Hideko,Kubota, Masashi
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- Merging Photoredox and Nickel Catalysis: The Direct Synthesis of Ketones by the Decarboxylative Arylation of α-Oxo Acids
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The direct decarboxylative arylation of α-oxo acids has been achieved by synergistic visible-light-mediated photoredox and nickel catalysis. This method offers rapid entry to aryl and alkyl ketone architectures from simple α-oxo acid precursors via an acyl radical intermediate. Significant substrate scope is observed with respect to both the oxo acid and arene coupling partners. This mild decarboxylative arylation can also be utilized to efficiently access medicinal agents, as demonstrated by the rapid synthesis of fenofibrate. The direct decarboxylative arylation of α-oxo acids has been achieved by synergistic visible-light-mediated photoredox and nickel catalysis. This method offers rapid entry to aryl and alkyl ketone architectures from simple α-oxo acid precursors via an acyl radical intermediate. Significant substrate scope is observed with respect to both the oxo acid and arene coupling partners.
- Chu, Lingling,Lipshultz, Jeffrey M.,Macmillan, David W. C.
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- Iodine Promoted Conversion of Esters to Nitriles and Ketones under Metal-Free Conditions
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We report a novel strategy to prepare valuable nitriles and ketones through the conversion of esters under metal-free conditions. By using the I2/PCl3 system, various substrates including aliphatic and aromatic esters could react with acetonitrile and arenes to afford the desired products in good to excellent yields. This method is compatible with a number of functional groups and provides a simple and practical approach for the synthesis of nitrile compounds and aryl ketones.
- Xiao, Jing,Guo, Fengzhe,Li, Yinfeng,Li, Fangshao,Li, Qiang,Tang, Zi-Long
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p. 2028 - 2035
(2021/02/03)
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- Synthesis of Diverse Aromatic Ketones through C?F Cleavage of Trifluoromethyl Group
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An efficient synthetic method of aromatic ketones through C?F cleavage of trifluoromethyl group is disclosed. The high functional group tolerance of the transformation and the remarkable stability of trifluoromethyl group in various reactions enabled mult
- Ikeda, Mai,Matsuzawa, Tsubasa,Morita, Takamoto,Hosoya, Takamitsu,Yoshida, Suguru
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supporting information
p. 12333 - 12337
(2020/09/09)
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- Biaryl Ketones by Suzuki–Miyaura Cross-Coupling of Organotrifluoroborates and Acyl Chlorides
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A procedure for the synthesis of biaryl ketones by a palladium-catalyzed Suzuki–Miyaura cross-coupling reaction between phenyltrifluoroborates and benzoyl chlorides is described. Organotrifluoroborates are unique to other cross-coupling reagents as they have a high functional-group tolerance and are moisture-stable. Moderate to excellent yields were obtained for all substrates tested.
- Forbes, Alaina M.,Meier, G. Patrick,Jones-Mensah, Ebenezer,Magolan, Jakob
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p. 2983 - 2987
(2016/07/11)
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- Room-Temperature Decarboxylative Couplings of α-Oxocarboxylates with Aryl Halides by Merging Photoredox with Palladium Catalysis
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Enabled by merging iridium photoredox catalysis and palladium catalysis, α-oxocarboxylate salts can be decarboxylatively coupled with aryl halides to generate aromatic ketones and amides at room temperature. DFT calculations suggest that this reaction proceeds through a Pd0-PdII-PdIII pathway, in which the PdIII intermediate is responsible for reoxidizing IrII to complete the IrIII-IrIII-IrII photoredox cycle. Like a mergin': Enabled by merging iridium photoredox catalysis and palladium catalysis, palladium-catalyzed decarboxylative coupling of α-oxocarboxylates with aryl halides can proceed at room temperature. DFT calculations suggest that a Pd0-PdII-PdIII catalytic cycle is merged with an IrIII-IrIII-IrII photoredox cycle, in which PdIII is responsible for oxidizing IrII to complete the photoredox cycle.
- Cheng, Wan-Min,Shang, Rui,Yu, Hai-Zhu,Fu, Yao
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supporting information
p. 13191 - 13195
(2015/09/15)
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- DECARBOXYLATIVE CROSS-COUPLING AND APPLICATIONS THEREOF
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Methods described herein enable the production of numerous molecular species through decarboxylative cross-coupling via use of photoredox and transition metal catalysts. For example, methods described herein enable the production of numerous molecular species through decarboxylative cross-coupling via use of photoredox and transition metal catalysts. A method described herein, in some embodiments, comprises providing a reaction mixture including a photoredox catalyst, a transition metal catalyst, a coupling partner and a substrate having a carboxyl group. The reaction mixture is irradiated with a radiation source resulting in cross-coupling of the substrate and coupling partner via a mechanism including decarboxylation, wherein the coupling partner is selected from the group consisting of a substituted aromatic compound and a substituted aliphatic compound.
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Page/Page column 31; 32; 33
(2015/12/09)
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- Catalytic Friedel-Crafts acylation: Magnetic nanopowder CuFe 2O4 as an efficient and magnetically separable catalyst
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Catalytic regioselective Friedel-Crafts acylation of an array of anisoles/arenes with various acid chlorides using 5-20 mol % of magnetic nanopowder CuFe2O4 is reported. Unlike the conventional Friedel-Crafts reactions, which are catalyzed by moisture sensitive homogeneous catalysts/promoters, the nanopowder CuFe2O4 catalyst is moisture insensitive and the product/ketone-catalyst isolation is easily achieved using the magnetic properties of CuFe2O4.
- Parella, Ramarao,Naveen,Kumar, Amit,Babu, Srinivasarao Arulananda
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p. 1738 - 1742
(2013/03/28)
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- Facile preparation of aromatic ketones from aromatic bromides and arenes with aldehydes
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Aromatic ketones were efficiently prepared in good yields by the reactions of aryl bromides with n-BuLi, followed by the reactions with aromatic aldehydes or aliphatic aldehydes and the subsequent treatment with molecular iodine and K2CO3, in a one-pot method. The same treatment of arenes, instead of aromatic bromides, also provided the corresponding aromatic ketones in good yields. Using these methods, various diaryl ketones and alkyl aryl ketones bearing electron-rich aromatics and electron-deficient aromatics could be prepared efficiently by a simple, transition-metal-free, and therefore environmentally benign experimental procedure.
- Ushijima, Sousuke,Dohi, Souya,Moriyama, Katsuhiko,Togo, Hideo
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experimental part
p. 1436 - 1442
(2012/03/09)
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- Development of decarboxylative coupling processes for the synthesis of azomethines and ketones
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A bimetallic catalyst system has been developed that allows the synthesis of azomethines by a one-pot three-component decarboxylative coupling, starting from simple, nontoxic precursors, i.e. potassium α-oxo carboxylates, aryl halides and primary amines. In the presence of 15 mol-% copper/phenanthroline and 1 mol-% Pd/dppf, a wide range of valuable imines is conveniently accessible in high yields at 100 °C, an unprecedentedly low temperature for redox-neutral decarboxylative cross-coupling reactions. Hydrogenation of the azomethine products leads to secondary amines. Alternatively, they can be hydrolyzed in situ to aryl ketones. The resulting ketone synthesis via azomethine intermediates is also of interest as it gives higher yields at much lower temperatures than the direct decarboxylative coupling of α-oxo carboxylates with aryl halides. A convenient synthesis of azomethines by a one-pot three-component decarboxylative coupling, starting from potassium α-oxo carboxylates, aryl halides and primary amines is described. Combined with in situ hydrolysis, ketones are obtained. Thisamine-mediated ketone synthesis gives higher yields at lower temperatures than the direct coupling of α-oxo carboxylates. Copyright
- Collet, Florence,Song, Bingrui,Rudolphi, Felix,Goossen, Lukas J.
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experimental part
p. 6486 - 6501
(2011/12/05)
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- PROCESS FOR PREPARING KETONES FROM ALPHA-OXO CARBOXYLATES AND ARYL BROMIDES
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A process for preparing ketones of the general formula (III) where R is an optionally substituted carbocyclic aromatic radical having 6 to 24 carbon atoms or an optionally substituted alkyl radical or an optionally substituted heteroaromatic radical having 5 to 24 carbon atoms, andR1 is an optionally substituted carbocyclic aromatic radical having 6 to 24 carbon atoms or an optionally substituted heteroaromatic radical having 5 to 24 carbon atoms, by reacting alpha-oxo carboxylates of the general formula (I) wherein n and m is a number in the range from 1 to 6, M(m+) is a cation, and R has the meaning indicated for formula (III), with aryl bromides of the general formula (II) [in-line-formulae]R1—Br ??(II)[/in-line-formulae] where R1 has the meaning indicated for formula (III), in the presence of two transition metals or compounds thereof as catalyst, is described.
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Page/Page column 3-4
(2009/09/08)
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- STUDIES IN TRIFLUOROMETHANESULPHONIC ACID-IV KINETICS AND MECHANISM OF ACYLATION OF AROMATIC COMPOUNDS
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A detailed kinetic study has been made of acylation reactions in solvent trifluoromethane sulphonic acid (CF3SO3H) using carboxylic acids as the electrophilic species involved.These species were shown to be probably the protonated form of the mixed anhydride.The reactions show high substrate selectivity characterised by high negative values of p+.Substituents in the carboxylic acids have a relatively small influence on the reactions rates due to a cancellation of substituents effects on the protonation of the mixed anhydride with those operating on the subsequent slow reaction of these species with the aromatic substrate.Anomalous effects were found for certain ortho substituents.The overall mechanism is discussed in terms of polar and steric effects in conjunction with the competing protonation of the aromatic bases, together with evidence from isotope effects.
- Roberts, R. M. G.,Sadri, A. R.
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p. 137 - 142
(2007/10/02)
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- Carboxylic Trifluoromethanesulfonic Anhydrides as Highly Effective Acylation Agents. - Perfluoroalkanesulfonic Acid Catalyzed Acylation of Arenes
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Arene- and alkanecarboxylic trifluoromethanesulfonic anhydrides 2 and 5 are highly effective acylation agents, which react without Friedel-Crafts catalysts even with deactivated aromatics to yield aryl ketones 3 and 6, respectively.Acylation of arenes with carbonyl chlorides 4 and catalytic amounts of perfluoroalkanesulfonic acid gives ketones 3 and 6, resp., in good yields.Under similar conditions other strong Broensted acids show a considerably smaller degree of catalytic effect.
- Effenberger, Franz,Sohn, Erich,Epple, Gerhard
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p. 1195 - 1208
(2007/10/02)
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