- Structural Effects in Photoepoxidation Sensitized by α-Diketones
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A series of α-diketones and benzils were examined for their effectiveness as sensitizers in the photoepoxidation reaction.The reduction potentials of these α-diketones were also determined at a hanging-mercury-drop electrode.The reduction potentials of the p,p'-disubstituted-benzils were successfully correlated to the sum of the Hammett ? values.No evidence could be found that electron transfer plays an important role in the epoxidation mechanism.The mechanistic possibilities are briefly discussed.Studies of the photoepoxidation reaction in a variety of solvents have also shown that the reaction is very insensitive to solvent effects.
- Clennan, Edward L.,Speth, David R.,Bartlett, Paul D.
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- Antibody-Catalyzed Benzoin Oxidation as a Mechanistic Probe for Nucleophilic Catalysis by an Active Site Lysine
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Aldolase antibody 24H6, which was obtained by reactive immunization against a 1,3-diketone hapten, is shown to catalyze additional reactions, including H/D exchange and oxidation reactions. Comparison of the H/D exchange reaction at the α-position of a wide range of aldehydes and ketones by 24H6 and by other aldolase antibodies, such as 38C2, pointed at the significantly larger size of the 24H6 active site. This property allowed for the catalysis of the oxidation of substituted benzoins to benzils by potassium ferricyanide. This reaction was used as a mechanistic probe to learn about the initial steps of the 24H6-catalyzed aldol condensation reaction. The Hammett correlation (ρ=4.7) of log(kcat) versus the substituent constant, σ, revealed that the reaction involves rapid formation of a Schiff base intermediate from the ketone and an active site lysine residue. The rate-limiting step in this oxidation reaction is the conversion of the Schiff base to an enamine intermediate. In addition, linear correlation (ρ= 3.13) was found between log(KM) and σ, indicating that electronic rather than steric factors are dominant in the antibody-substrate binding phenomenon and confirming that the reversible formation of a Schiff base intermediate comprises part of the substrate-binding mechanism.
- Sklute, Genia,Oizerowich, Rachel,Shulman, Hagit,Keinan, Ehud
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- Electrochemical oxidation-induced benzyl C–H carbonylation for the synthesis of aromatic α-diketones
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Electrochemical oxidation-induced direct carbonylation of benzyl C–H bond for the synthesis of aromatic α-diketones is described. In this process, tetrabutylammonium iodide (nBu4NI) not only acts as an electrolyte, but its iodine anion is oxidized to an iodine radical at the anode, acting as a hydrogen atom transfer agent. The iodine radical extracts the benzyl hydrogen atom and causes the carbonylation of the benzyl position, where O2 in the air is used as an oxygen source.
- Tan, Yu-Fang,Chen, Yuan,Li, Rui-Xue,Guan, Zhi,He, Yan-Hong
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- Rhodium-Catalyzed Aerobic Decomposition of 1,3-Diaryl-2-diazo-1,3-diketones: Mechanistic Investigation and Application to the Synthesis of Benzils
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The conversion of 1,3-diaryl-2-diazo-1,3-diketones to 1,2-daryl-1,2-diketones (benzils) is reported based on a rhodium(II)-catalyzed aerobic decomposition process. The reaction occurs at ambient temperatures and can be catalyzed by a few dirhodium carboxylates (5 mol %) under a balloon pressure of oxygen. Moreover, an oxygen atom from the O2 reagent is shown to be incorporated into the product, and this is accompanied by the extrusion of a carbonyl unit from the starting materials. Mechanistically, it is proposed that the decomposition may proceed via the interaction of a ketene intermediate resulting from a Wolff rearrangement of the carbenoid, with a rhodium peroxide or peroxy radical species generated upon the activation of molecular oxygen. The proposed mechanism has been supported by the results from a set of controlled experiments. By using this newly developed strategy, a large array of benzil derivatives as well as 9,10-phenanthrenequinone were synthesized from the corresponding diazo substrates in varying yields. On the other hand, the method did not allow the generation of benzocyclobutene-1,2-dione from 2-diazo-1,3-indandione because of the difficulty of inducing the initial rearrangement.
- Zhu, Jia-Liang,Tsai, Yi-Ting
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p. 813 - 828
(2020/12/22)
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- Aerobic oxygenation of α-methylene ketones under visible-light catalysed by a CeNi3complex with a macrocyclic tris(salen)-ligand
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A hetero-tetranuclear CeNi3 complex with a macrocyclic ligand catalysed the aerobic oxygenation of a methylene group adjacent to a carbonyl group under visible-light radiation to produce the corresponding α-diketones. The visible-light induced homolysis of the Ce-O bond of a bis(enolate) intermediate is proposed prior to aerobic oxygenation.
- Fujiwara, Sakiko,Kon, Yoshihiro,Mashima, Kazushi,Nagae, Haruki,Okuda, Jun,Sakamoto, Kazutaka,Sato, Kazuhiko,Schindler, Tobias
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p. 11169 - 11172
(2021/11/04)
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- Visible-Light-Induced Photocatalytic Oxidative Decarboxylation of Cinnamic Acids to 1,2-Diketones
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A concerted metallophotoredox catalysis has been realized for the efficient decarboxylative functionalization of α,β-unsaturated carboxylic acids with aryl iodides in the presence of perylene bisimide dye to afford 1,2-diketones.
- Chand, Shiv,Pandey, Anand Kumar,Singh, Rahul,Singh, Krishna Nand
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p. 6486 - 6493
(2021/05/06)
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- One-pot cascade synthesis of α-diketones from aldehydes and ketones in water by using a bifunctional iron nanocomposite catalyst
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A new methodology for the synthesis of α-diketones was reportedviaa one-pot cascade process from aldehydes and ketones catalyzed by a bifunctional iron nanocomposite using H2O2as a green oxidant in water. The one-pot strategy showed excellent catalytic stability, comprehensive suitability of substrates and important practical utility for directly synthesizing biologically active and medicinally valuable N-heterocyclesviaan intermittent process.
- Song, Tao,Zhou, Xin,Wang, Xiaoxue,Xiao, Jianliang,Yang, Yong
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supporting information
p. 1955 - 1959
(2021/03/26)
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- 1-butyl-3-methylimidazol-2-ylidene as an efficient catalyst for cross-coupling between aromatic aldehydes and N-aroylbenzotriazoles
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Cross-coupling of aromatic aldehydes with N-aroylbenzotriazoles in [Bmim]Br in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) provided an efficient procedure for the synthesis of 1,2-diarylethane-1,2-diones.
- Phungpis, Baramee,Hahnvajanawong, Viwat
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p. 651 - 657
(2021/02/27)
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- Copper/Iodine-Cocatalyzed C-C Cleavage of 1,3-Dicarbonyl Compounds Toward 1,2-Dicarbonyl Compounds
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A new, general oxidative route to transformations of 1,3-dicarbonyl compounds to 1,2-dicarbonyl compounds by merging copper and I2 catalysis is described. This method is applicable to broad 1,3-dicarbonyl compounds, including 1,3-diketones, 1,3-keto esters and 1,3-keto amides. Mechanistical studies show that the reaction is achieved via the C–C bond cleavage and CO release cascades.
- Chen, Li-Sha,Zhang, Lu-Bing,Tian, Yue,Li, Jin-Heng,Liu, Yong-Quan
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supporting information
p. 5523 - 5526
(2020/09/02)
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- Palladium-Catalyzed Oxidative C≡C Triple Bond Cleavage of 2-Alkynyl Carbonyl Compounds Toward 1,2-Dicarbonyl Compounds?
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A new, general palladium-catalyzed oxidative strategy for the cleavage of the C≡C triple bond is presented. By employing PdCl2, CuBr2, TEMPO and air as the catalytic system and H2O as the carbonyl oxygen atom source, a wide range of 2-alkynyl carbonyl compounds, including 1,3-disubstituted prop-2-yn-1-ones, propiolamides and propiolates, lost an alkynyl carbon to access various 1,2-dicarbonyl compounds, e.g., 1,2-diones, 2-keto amides and 2-keto esters, through Wacker oxidation, intramolecular cyclization and C—C bond cleavage cascades.
- Hu, Ming,Li, Jin-Heng,Luo, Mu-Jia,Zhou, Ming-Bo
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p. 553 - 558
(2020/04/20)
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- Dimethyl Sulfoxide as an Oxygen Atom Source Enabled Tandem Conversion of 2-Alkynyl Carbonyls to 1,2-Dicarbonyls
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A tandem transformation of 2-alkynyl carbonyl compounds by means of a CuBr2/I2/DMSO/water system is developed, enabling the fromation of various functionalized 1,2-dicarbonyl compounds, including 1,2-diketones, α-keto amides and α-keto ester. This Cu-promoted iodine-mediated tandem procedure employs DMSO as the oxygen atom source of the formed carbonyl group through iodonium ion formation, nucleophilic DMSO addition and C?C bond cleavage cascades. (Figure presented.).
- Hu, Ming,Li, Jin-Heng,Li, Yang,Lu, Yuan,Luo, Mu-Jia
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supporting information
(2020/05/01)
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- Ruthenium/dendrimer complex immobilized on silica-functionalized magnetite nanoparticles catalyzed oxidation of stilbenes to benzil derivatives at room temperature
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A new ruthenium/dendrimer complex stabilized on the surface of silica-functionalized nano-magnetite was fabricated and well characterized. The nano-catalyst showed good activity in the synthesis of benzil derivatives via the oxidation of stilbenes with high turnover frequency (TOF) at room temperature. Moreover, the catalyst could also be reused up to fifteen times without any loss of its activity.
- Ghanaatzadeh, Niloofar,Hashemi, Hajar,Moghadam, Majid,Niknam, Khodabakhsh,Saberi, Dariush
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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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- Synthesis of unsymmetrical benzilsviapalladium-catalysed a-arylation-oxidation of 2-hydroxyacetophenones with aryl bromides
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A diverse set of unsymmetrically substituted benzils were facilely synthesised by a cross-coupling reaction between 2-hydroxyacetophenones and aryl bromides in the presence of a palladium catalyst. Experimental studies suggested a reaction mechanism involving a one-pot tandem palladium-catalysed a-arylation and oxidation, where aryl bromides play a dual role as mild oxidants as well as arylating agents.
- Matsuda, Takanori,Oyama, Souta
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supporting information
p. 3679 - 3683
(2020/06/03)
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- 1,2-dicarbonyl compound and synthesis method thereof
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The invention discloses a method for synthesizing a 1,2-dicarbonyl compound (1,2-dicarbonylamide or alpha-diketone compound), wherein 1,2-dicarbonyl thioester compounds used as 1,2-dicarbonyl reagentsreact with amine compounds or boric anhydride compounds under appropriate conditions to respectively synthesize a series of 1,2-dicarbonyl compounds. According to the present invention, the 1,2-dicarbonyl compound is obtained by using the stable 1,2-dicarbonyl thioester compound as the dicarbonylation reagent through one-step construction under mild conditions, such that the disadvantage that thetraditional method uses the unstable alpha-carbonyl acyl chloride to synthesize the 1,2-dicarbonyl compound is avoided.
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Paragraph 0055; 0157-0160
(2019/10/01)
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- Sequentially Pd/Cu-Catalyzed Alkynylation-Oxidation Synthesis of 1,2-Diketones and Consecutive One-Pot Generation of Quinoxalines
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We report a simple and efficient one-pot synthesis of 1,2-diketones by concatenation of two Pd/Cu-catalyzed processes: Pd0/CuI-catalyzed Sonogashira coupling of terminal alkynes with aryl (pseudo)halides furnishes internal alkynes, which are directly transformed by PdII/CuII-catalyzed Wacker-type oxidation with DMSO and oxygen as dual oxidants to furnish 1,2-diketones. With this efficient, catalyst economical process, various aryl iodides and triflates are efficiently transformed in high yields into symmetrically and unsymmetrically substituted 1,2-diketones with various functional groups. This process can be readily extended to a consecutive one-pot synthesis of quinoxalines in a diversity-oriented fashion.
- Niesobski, Patrik,Martínez, Ivette Santana,Kustosz, Sebastian,Müller, Thomas J. J.
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supporting information
p. 5214 - 5218
(2019/07/31)
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- Magnesium Aldimines Prepared by Addition of Organomagnesium Halides to 2,4,6-Trichlorophenyl Isocyanide: Synthesis of 1,2-Dicarbonyl Derivatives
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The selective addition of organomagnesium reagents to 2,4,6-trichlorophenyl isocyanide leading to magnesiated aldimines is reported. These aldimines react with Weinreb amides, ketones, or carbonates to provide the corresponding carbonyl derivatives after acidic cleavage. This allows for an efficient synthesis of 1,2-dicarbonyl compounds and α-hydroxy ketones.
- Schw?rzer, Kuno,Bellan, Andreas,Z?schg, Maximilian,Karaghiosoff, Konstantin,Knochel, Paul
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supporting information
p. 9415 - 9418
(2019/05/10)
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- Gold-Catalyzed Oxidation of Internal Alkynes into Benzils and its Application for One-Pot Synthesis of Five-, Six-, and Seven-Membered Azaheterocycles
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Internal alkynes have been shown to undergo oxidation to substituted benzils (1,2-diarylethane-1,2-diones) by α-picoline N-oxide in the presence of Ph3PAuNТf2 (5 mol-%). In addition to the unsubstituted benzil, the method allows preparing, under markedly mild conditions (50 °C in chlorobenzene), various non-symmetrical products, including heteroaromatic versions thereof which are much more difficult to obtain otherwise. This gold(I)-catalyzed transformation was integrated into one-pot reaction sequence delivering a range of 5- to 7-membered ring systems (imidazoles, quinoxalines, 1,2,4-triazines, pyrazines, and 1,4-diazepines), thus linking these important heterocyclic motifs to the internal alkyne reagent space.
- Dubovtsev, Alexey Yu.,Dar'in, Dmitry V.,Krasavin, Mikhail,Kukushkin, Vadim Yu.
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p. 1856 - 1864
(2019/02/19)
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- Rate Enhancement in CAN-Promoted Pd(PPh3)2Cl2-Catalyzed Oxidative Cyclization: Synthesis of 2-Ketofuran-4-carboxylate Esters
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Stoichiometric ceric ammonium nitrate (CAN) and a catalytic amount of Pd(PPh3)2Cl2 (5 mol %) can rapidly produce multisubstituted 2-ketofuran-4-carboxylate esters from 2-propargylic 1,3-ketoesters via oxidative O-cyclization reaction. Pd(PPh3)2Cl2 was found to be the crucial catalyst as its inclusion greatly enhanced the rate of the reaction and cleanly afforded the products within minutes. Over 30 substrates were successfully converted to the desired compounds in mostly moderate to good yields.
- Ruengsangtongkul, Sureeporn,Chaisan, Nattawadee,Thongsornkleeb, Charnsak,Tummatorn, Jumreang,Ruchirawat, Somsak
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p. 2514 - 2517
(2019/04/30)
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- E - Z isomerization in Suzuki cross-couplings of haloenones: Ligand effects and evidence for a separate catalytic cycle
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Suzuki cross-coupling of haloalkenes is generally assumed to occur with retention of the alkene stereochemistry. While studying Suzuki cross-couplings on E-1,2-dichlorovinyl phenyl ketone, we were surprised to observe extensive isomerization. More surprisingly, the ligand employed strongly influenced the degree of isomerization: DPEphos and Xantphos led to 96% isomerized cross-coupled product whereas reactions in the absence of a phosphine ligand, or reactions employing t-BuXantphos, gave 94% retention of stereochemistry. While E-Z isomerization in Pd-catalyzed vinylic couplings has previously been attributed to events within the cross-coupling catalytic cycle, we present experimental and computational evidence for a separate Pd-catalyzed isomerization process in these reactions.
- Chehal, Navneet K.,Budzelaar, Peter H. M.,Hultin, Philip G.
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supporting information
p. 1134 - 1143
(2018/02/22)
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- Two-Step One-Pot Synthesis of Unsymmetrical (Hetero)Aryl 1,2-Diketones by Addition-Oxygenation of Potassium Aryltrifluoroborates to (Hetero)Arylacetonitriles
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An efficient one-pot two-step procedure for the synthesis of unsymmetrical (hetero)aryl 1,2-diketones has been developed. The reaction proceeds through a palladium-catalyzed nucleophilic addition of potassium aryltrifluoroborates to aliphatic nitriles followed by a copper-catalyzed aerobic benzylic C–H oxygenation using molecular oxygen as a green oxidant. This represents the first example of the direct synthesis of unsymmetrical diaryl 1,2-diketones from arylacetonitriles. This method utilizes inexpensive, stable, nontoxic, and readily available starting materials, is highly effective in the presence of both electron-rich and electron-poor nitriles and aryltrifluoroborates, and tolerates a wide variety of functional groups. The synthetic utility of this transformation was shown by increasing the scale of the reaction and by carrying out the one-pot protocol for the preparation of quinoxaline and benzimidazole derivatives. A plausible reaction mechanism has also been proposed.
- Kumar, Yogesh,Jaiswal, Yogesh,Kumar, Amit
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p. 494 - 505
(2018/02/09)
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- Copper-catalyzed TEMPO oxidative cleavage of 1,3-diketones and β-keto esters for the synthesis of 1,2-diketones and α-keto esters
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A copper-catalyzed efficient and practical method has been developed for the synthesis of 1,2-diketones and α-keto esters. TEMPO was used as a radical initiator and scavenger, oxidizing the cleavage of α-methylene of 1,3-diketones and β-keto esters to form 1,2-diketones and α-keto esters. This method provided a general way for the formation of 1,2-dicarbonyl compounds.
- Zhou, Peng-Jun,Li, Cheng-Kun,Zhou, Shao-Fang,Shoberu, Adedamola,Zou, Jian-Ping
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p. 2629 - 2637
(2017/04/03)
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- Tandem and chemoselective synthesis of benzil derivatives from styrene and arene diazonium salts
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A facile and practically applied protocol for synthesis of benzil derivatives using styrene and arene diazonium salts is reported. Pd(OAc)2/SeO2 catalytic system was found to be efficient for chemoselective synthesis of benzil. Selenium dioxide works well as an oxidant under milder reaction conditions. Moderate to very good yields of the desired products were obtained.
- Jadhav, Vilas G.,Sarode, Sachin A.,Nagarkar, Jayashree M.
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supporting information
p. 1834 - 1838
(2017/04/21)
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- Preparation method of 1,2-diketone derivative
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The invention discloses a preparation method of a 1,2-diketone derivative. The method comprises the step of enabling a raw material 1,3-diketone derivative to react with a cheap and easily obtained industrial product 2,2,6,6-tetramethyl-1-piperidinyloxy under the catalysis of copper so as to obtain the product 1,2-diketone derivative. According to the preparation method, the 1,3-diketone derivative is used as an initiator, and the raw material is easy to obtain and wide in variety; by utilizing the preparation method, the obtained product types are varied, can be directly used, and can be used for other further reactions; in addition, the reagent dosage in the reaction is less, the pollution is reduced, and the production cost is lowered; moreover the reaction conditions are mild, the reaction operation and the after-treatment process are simple, the reaction time is short, the yield is high, and the preparation method is suitable for industrial production.
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Paragraph 0019
(2016/10/08)
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- Novel carbocationic rearrangements of 1-styrylpropargyl alcohols
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The dehydration and subsequent cyclization reactions of 1-styrylpropargyl alcohols was examined. In the course of these studies, numerous scaffolds were synthesized, including a furan, a cyclopentenone, an acyclic enone and even a naphthalenone. The diversity of these structural motifs lies in novel cascades of reactions originating from a common carbocationic manifold.
- Basmadjian, Christine,Zhang, Fan,Dsaubry, Laurent
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supporting information
p. 1017 - 1022
(2015/08/18)
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- Diversity-Oriented Synthesis of a Library of Star-Shaped 2H-Imidazolines
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A library of star-shaped 2H-imidazolines has been synthesized via Debus-Radziszewski condensation from 1,2-diketones and ketone starting materials. Selective reduction of one imine group of the 2H-imidazole intermediate with LiAlH4 or catalytic flow hydrogenation furnished 2H-imidazolines, which could be conveniently diversified by reacting the amine N with electrophiles, resulting in a set of 21 amide-, carbamate-, urea-, and allylamine-containing products. In total, five points of diversification could be used, which allow the production of a set of functionally diverse compounds. The synthesis of acylated 2H-imidazolidines resulted in intrinsically labile compounds, which spontaneously degraded to acyclic derivatives, as shown for the reaction of 2H-imidazolidine with hexylisocyanate.
- Yu, Xuepu,Guttenberger, Nikolaus,Fuchs, Elisabeth,Peters, Martin,Weber, Hansj?rg,Breinbauer, Rolf
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p. 682 - 690
(2015/11/17)
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- An unusual chemoselective oxidation strategy by an unprecedented exploration of an electrophilic center of DMSO: A new facet to classical DMSO oxidation
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A conceptually new dimethyl sulfoxide (DMSO) based oxidation process without the use of any activator has been demonstrated for the oxidation of active methylenes and benzhydrols. The developed protocol utilizes the electrophilic center of DMSO for oxidation, which was unexplored before. Mechanistic investigation has confirmed that the source of oxygen is DMSO.
- Chebolu, Rajesh,Bahuguna, Ashish,Sharma, Reena,Mishra, Vivek Kumar,Ravikumar
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supporting information
p. 15438 - 15441
(2015/10/20)
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- Mild Mn(OAc)3-Mediated Aerobic Oxidative Decarboxylative Coupling of Arylboronic Acids and Arylpropiolic Acids: Direct Access to Diaryl 1,2-Diketones
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A simple and efficient method for the synthesis of diaryl 1,2-diketones has been developed. The reaction represents the first example of diaryl 1,2-diketones that are synthesized directly from arylboronic acids and arylpropiolic acids by a radical pathway in moderate to good yields. This reaction proceeds under mild reaction conditions and with good tolerance of a variety of functional groups. Preliminary mechanistic studies were conducted.
- Lv, Wen-Xin,Zeng, Yao-Fu,Zhang, Shang-Shi,Li, Qingjiang,Wang, Honggen
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supporting information
p. 2972 - 2975
(2015/06/30)
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- Visible-light-induced C=C bond cleavage of enaminones for the synthesis of 1,2-diketones and quinoxalines in sustainable medium
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The C=C double bond cleavage of enaminones has been realized under ambient conditions through visible-light catalysis in the presence of Rose Bengal, which leads to the synthesis of a class of 1,2-diketones without using any metal catalyst. In addition, the one-pot synthesis of quinoxalines has also been achieved under identical photocatalytic conditions by making use of the in situ generated 1,2-diketones as intermediates.
- Cao, Shuo,Zhong, Shanshan,Xin, Luoting,Wan, Jie-Ping,Wen, Chengping
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p. 1478 - 1482
(2015/06/24)
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- Copper-catalyzed base-accelerated direct oxidation of C-H bond to synthesize benzils, isatins, and quinoxalines with molecular oxygen as terminal oxidant
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We describe herein an efficient and general copper (II)-catalyzed base-accelerated oxidation of the C-H bond to synthesize benzils and isatins. With similar oxidation system an efficient one-pot procedure for the synthesis of quinoxaline derivatives was realized. The two protocols feature using molecular oxygen as terminal oxidant, low catalyst loading, wide substrate scope, and high functional-group tolerance.
- Yu, Jing-Wen,Mao, Shuai,Wang, Yong-Qiang
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p. 1575 - 1580
(2015/03/14)
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- Molecular design, synthesis and evaluation of 2,3-diarylquinoxalines as estrogen receptor ligands
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Selective Estrogen Receptor Modulators (SERMs) are characteristically capable of being antagonist and agonist of estrogen receptors and, therefore, they can inhibit or stimulate estrogen production in different tissues. Aiming to contribute to the identification of new synthetic SERMs candidates, the basic skeletons of raloxifene and tamoxifene were used as model. Here of, a set of 2,3-diaryl-quinoxalines having 2-(piperidin-1-yl)ethanol in the side chain have been synthesized and evaluated against human mammary carcinoma cells estrogen dependent (MCF-7), as well as in recombinant yeast assays (RYA) expressing estrogen receptor. Compound LSPN332 showed 40% inhibition of MCF-7 and EC50=290.6 μM in RYA. The efficient synthesis of 2,3-diarylquinoxalines represents an excellent opportunity to identify new SERMs, and should therefore be of interest to the medicinal chemistry community.
- Sangi, Diego P.,Cominetti, Márcia R.,Becceneri, Amanda B.,Resende, Flavia A.,Varanda, Eliana A.,Montanari, Carlos A.,Paix?o, Marcio W.,Corrêa, Arlene G.
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p. 736 - 746
(2015/12/01)
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- Copper-catalyzed aerobic oxidative C-C bond cleavage of 1,3-diaryldiketones to synthesize 1,2-diketones
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An aerobic oxidative C-C bond cleavage of 1,3-diaryldiketones for the synthesis of 1,2-diketones by using O2 as the oxidant has been developed. Control experiments illustrate that the copper catalyst not only assist the aerobic oxidative process of 1,3-diketones, but also catalyze the 1,2-Wagner-Meerwein-type rearrangement process. Georg Thieme Verlag Stuttgart. New York.
- Zhang, Chun,Wang, Xiaoyang,Jiao, Ning
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supporting information
p. 1458 - 1460
(2014/06/23)
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- Asymmetric transfer hydrogenation of unsymmetrical benzils
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In this paper, the asymmetric transfer hydrogenation of unsymmetrical benzils with m, p-substituents was conducted with a substrate/catalyst molar ratio of 100 at 40°C for 24 h to produce (S,S)-hydrobenzoins in good yields (76.2% to 97.1%) with high diastereomeric (syn/anti = 10.8 to 29.7/1) and enantiomeric purities (86.1%ee syn to 98.9%ee syn). Unfortunately, the unsymmetrical benzils with the o-substituents such as electron-donating (R = CH3, OCH3) and electron-withdrawing groups (R = F, Cl, CF3) resulted in poor yields (0% to 31.2%), even at 40°C for 72 h. These products had inefficient diastereoselectivities (syn/anti = 1.5 to 5.0/1) caused by steric effects. Furthermore, the results of a dynamic-kinetic study were used to propose a plausible reaction pathway of unsymmetrical benzil using 3-methoxy-1,2-diphenyl ethanedione as an example.
- Zhang, Hao,Feng, Dandan,Sheng, Haibo,Ma, Xuebing,Wan, Jinwei,Tang, Qian
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p. 6417 - 6423
(2014/02/14)
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- Co3O4-decorated carbon nanotubes as a novel efficient catalyst in the selective oxidation of benzoins
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An efficient and facile air oxidation of benzoins in the presence of the heterogeneous catalyst, Co3O4-CNTs nanocomposite, has been developed. It thus constitutes a very simple, clean, economical and selective method for the aerobic preparation of benzils from the corresponding benzoins. The catalyst can be re-used a number of times without losing its catalytic activity to a greater extent.
- Safari, Javad,Mansouri Kafroudi, Zahra,Zarnegar, Zohre
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p. 958 - 963
(2014/08/18)
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- Copper-mediated aerobic oxidative cleavage of α,β-unsaturated ketones to 1,2-diketones
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The copper-mediated aerobic oxidative cleavage of α,β- unsaturated ketones to synthesize 1,2-diketones by using potassium acetate as a catalyst and sodium iodide as a promoter in acetic acid is described. The protocol has the advantages of using inexpensive and non-toxic raw materials, high yield and simple work-up procedure. the Partner Organisations 2014.
- Li, Zheng,Yin, Junjun,Wen, Gong,Li, Tianpeng,Shen, Xiaoli
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p. 32298 - 32302
(2014/08/18)
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- Copper-catalyzed direct synthesis of diaryl 1,2-diketones from Aryl iodides and propiolic acids
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Benzil derivatives such as diaryl 1,2-diketones are synthesized via the direct decarboxylative coupling reaction of aryl propiolic acids and their oxidation. The optimized conditions are that the reaction of aryl propiolic acids and aryl iodides is conducted at 140°C for 6 h in the presence of 10 mol % CuI/Cu(OTf)2 and Cs2CO3, after which HI (aq) is added and further reacted. The method shows good functional group tolerance toward ester, aldehyde, cyano, and nitro groups. In addition, symmetrical diaryl 1,2-diketones are obtained from aryl iodides and propiolic acid in the presence of palladium and copper catalysts.
- Min, Hongkeun,Palani, Thiruvengadam,Park, Kyungho,Hwang, Jinil,Lee, Sunwoo
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p. 6279 - 6285
(2014/07/21)
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- Oxidation cascade with oxone: Cleavage of olefins to carboxylic acids
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A variety of olefins is shown to be cleaved oxidatively to the corresponding acids with oxone as the reagent. The simple methodology that works well for a range of alkenes, i.e., styrenes, nitrostyrenes, stilbenes, cinnamic acids, chalcones, etc., involves heating of the reactant with oxone in acetonitrile-water mixture (1:1, v/v) at reflux. The oxidation cascade involves initial dihydroxylation followed by oxidative cleavage and oxidation of the resultant aldehydes to acids.
- Parida, Keshaba Nanda,Moorthy, Jarugu Narasimha
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p. 2280 - 2285
(2014/03/21)
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- Titanium-mediated reductive cross-coupling reactions of imines with nitriles: An efficient route for the synthesis of α-aminoketones or 1,2-diketones
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The reaction of imines with low-valent titanium species, generated in situ by using Ti(OiPr)4/2 c-C5H9MgCl reagent, affords titanium-imine complex, which can couple with nitriles to provide 2,5-diazatitanacyclop
- Chen, Haoyi,Fan, Guoqin,Li, Shi,Mao, Kebin,Liu, Yuanhong
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supporting information
p. 1593 - 1596
(2014/03/21)
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- Practical approach for preparation of unsymmetric benzils from β-ketoaldehydes
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An efficient and practical method for the synthesis of unsymmetric benzils from readily available β-ketoaldehydes has been developed. Various unsymmetric 1,2-diaryldiketones bearing functional groups have been obtained in good to excellent yields under mild reaction conditions. A plausible mechanism was proposed, and α,α-dichloroketone was considered as the key intermediate. The generation of α,α-dichloroketones from β-ketoaldehydes may undergo the following steps: (1) oxidation by sodium hypochlorite, (2) decarboxylation, and (3) chlorination by Cl2 generated from sodium hypochlorite.
- Ruan, Libo,Shi, Min,Li, Nian,Ding, Xu,Yang, Fan,Tang, Jie
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p. 733 - 735
(2014/03/21)
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- Mechanism of α-ketol-type rearrangement of benzoin derivatives under basic conditions
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The mechanism of base-catalyzed rearrangement of ring-substituted benzoins in aqueous methanol was examined by kinetic and product analyses. Substituent effects on the rate and equilibrium constants revealed that the kinetic process has a different electron demand compared to the equilibrium process. Reactions in deuterated solvents showed that the rate of H/D exchange of the α-hydrogen is similar to the overall rate toward the equilibrium state. A proton-inventory experiment using partially deuterated solvents showed a linear dependence of the rate on the deuterium fraction of the solvent, indicating that only one deuterium isotope effect contributes to the overall rate process. All these results point to a mechanism in which the rearrangement is initiated by the rate-determining α-hydrogen abstraction rather than a mechanism with initial hydroxyl hydrogen abstraction as in the general α-ketol rearrangement.
- Karino, Masahiro,Kubouchi, Daiki,Hamaoka, Kazuki,Umeyama, Shintaro,Yamataka, Hiroshi
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p. 7194 - 7198
(2013/08/23)
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- Copper-catalyzed oxidation of deoxybenzoins to benzils under aerobic conditions
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A novel copper-catalyzed approach to benzils from readily available deoxybenzoins under neutral conditions using air as the oxidant has been developed. The reaction tolerates a variety of useful substituents including chloro, bromo, iodo, keto, ester, and cyano groups. Georg Thieme Verlag Stuttgart, New York.
- Cacchi, Sandro,Fabrizi, Giancarlo,Goggiamani, Antonella,Iazzetti, Antonia,Verdiglione, Rosanna
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p. 1701 - 1707
(2013/07/27)
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- Iodine-catalyzed synthesis of 1,2-diaryldiketones by oxidative cleavage of 1,3-diaryldiketones with DMSO
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A metal-free, efficient, practical, and convenient process based on an iodine-catalyzed oxidative cleavage reaction has been developed to form 1,2-diaryldiketons in high yields from 1,3-diaryldiketones. The reaction is performed in DMSO and in air, and a mechanism was proposed according to the reaction evidence. Copyright
- Yuan, Yu,Zhu, Haitao
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experimental part
p. 329 - 333
(2012/02/04)
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- A new synthetic route for 1,2-diketo compounds using unexpected C-C bond cleavage by PCC
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An efficient method has been established for the preparation of 1,2-diketones by unexpected C-C bond cleavage in 4-keto-2-hydroxy esters using pyridiniumchlorochromate (PCC).
- Bhosale, Shrikar M.,Momin, Aadil A.,Gawade, Rupesh L.,Puranik, Vedavati G.,Kusurkar, Radhika S.
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p. 5327 - 5330
(2012/11/07)
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- Pyridazine-based N-heterocyclic carbene complexes and ruthenium-catalyzed oxidation reaction of alkenes
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[Ru2Cl(L)(CH3CN)4](PF6) 3 (1, L = 3,6-bis(N-(pyridylmethyl)imidazolylidenyl)pyridazine), [Cu3La3](PF6)3 (2, L a = 3-(N-(pyridylmethyl)imidazolylidenyl)-6-(N-(pyridylmethyl) imidazolylonyl)pyridazine), [Pd2(allyl)2L](PF 6)2 (3), [Pd2(allyl)2L b2](PF6)2 (4, Lb = N-pyridylmethylimidazole), and [NiLc2](PF 6)2 (5, Lc = 3-(N-(pyridylmethyl) imidazolylidenyl)-6-methoxylpyridazine) have been synthesized and fully characterized by NMR spectroscopy, elemental analysis, and X-ray diffraction analysis. In complex 1, ligand L binds to two Ru(II) centers, forming a well-behaved Ru2(L)Cl plane with a five-membered metallocyclic ring. Complex 2 is trinuclear, containing a triangular Cu3 unit bonded together by three 3-(N-(pyridylmethyl)imidazolylidenyl)-6-(N-(pyridylmethyl) imidazolylonyl)pyridazine, where one imidazolylidene was oxidized into imidazolone. Deprotonation reaction with Ag2O in CH3CN and CH3OH resulted in C-N cleavage of the imidazolium salt, and subsequent reaction with [Pd(allyl)Cl]2 and Ni(PPh3) 2Cl2 gave 4 and 5, respectively. Dinuclear Ru(II)-NHC complex 1 exhibits excellent catalytic activity for the oxidation of alkenes into diketones.
- Liu, Xiaolong,Chen, Wanzhi
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p. 6614 - 6622
(2012/11/06)
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- Iron-promoted C - C bond cleavage of 1,3-diketones: A route to 1,2-diketones under mild reaction conditions
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A conceptual method for the preparation of 1,2-diketones is reported. The selective C - C bond cleavage of 1,3-diketones affords the 1,2-diketones in high yields under mild reaction conditions in air by the use of FeCl3 as the catalyst and tert-butyl nitrite (TBN) as the oxidant without the use of solvent. The possible reaction mechanism is discussed. This protocol provides an expeditious route to the useful 1,2-diketones.
- Huang, Lehao,Cheng, Kai,Yao, Bangben,Xie, Yongju,Zhang, Yuhong
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experimental part
p. 5732 - 5737
(2011/08/22)
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- New reagent, manganese dioxide supported on kieselguhr, for effective oxidation of benzoins
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A new reagent, manganese dioxide supported on kieselguhr, for effective oxidation of benzoins into corresponding benzils under heterogeneous and reflux conditions is described. The present oxidations are completed within 10 h with yields of 86-95%. The main advantages of the present procedure are that the preparation of supported reagent is more convenient and the reaction times are relatively short.
- Huang, Li-Hong,Wang, Qiang,Ma, Yi-Chun,Lou, Ji-Dong,Zhang, Changhe
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experimental part
p. 1682 - 1687
(2011/06/22)
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- C-H oxidation using graphite oxide
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Graphite oxide was found to be an effective oxidant for use in a broad range of reactions, including the oxidation of olefins to their respective diones, methyl benzenes to their respective aldehydes, diarylmethanes to their respective ketones, and various dehydrogenations. The temperatures used in the reactions were typically mild (100-120 °C), and the heterogeneous nature of the oxidant facilitated isolation and purification of the desired products. In most cases, no by-products were observed and the desired products were isolated in good to excellent yields.
- Jia, Hong-Peng,Dreyer, Daniel R.,Bielawski, Christopher W.
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experimental part
p. 4431 - 4434
(2011/08/06)
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- Ruthenium-catalyzed oxidation of alkenes at room temperature: A practical and concise approach to α-diketones
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Chemical equations presented. The catalytic oxidation of alkenes to α-diketones is unprecedented. A new oxidation of alkenes, catalyzed by a ruthenium complex, which allows an efficient route to α-diketones using TBHP as an oxidant is described. This methodology is highly functional group tolerant, is practically convenient, requires no additional ligand, and operates under mild conditions with short reaction times. Based upon experimental observations, a plausible mechanism is proposed.
- Chen, Shulin,Liu, Zhaojun,Shi, Erbo,Chen, Long,Wei, Wei,Li, Hong,Cheng, Yannan,Wan, Xiaobing
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supporting information; experimental part
p. 2274 - 2277
(2011/06/27)
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- An efficient palladium-catalyzed synthesis of benzils from aryl bromides: Vinylene carbonate as a synthetic equivalent of glyoxal
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An expedient synthetic procedure of benzil derivatives from aryl bromides was developed using vinylene carbonate as a glyoxal equivalent in a palladium-catalyzed reaction. The reaction involved a sequential diarylation of vinylene carbonate to form 4,5-diaryl-1,3-dioxol-2-one, ring-opening to benzoin derivative, and an oxidation process.
- Kim, Ko Hoon,Park, Bo Ram,Lim, Jin Woo,Kim, Jae Nyoung
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experimental part
p. 3463 - 3466
(2011/06/27)
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- Synthesis of unsymmetrical benzils using N-heterocyclic carbene catalysis
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In this paper, we propose a novel and efficient method for the preparation of various unsymmetrical benzils. We first demonstrate the nucleophilic aroylation of N-phenylbenzimidoyl chlorides with aromatic aldehydes using N-heterocyclic carbene as the catalyst to afford 1-aryl-2-phenyl-2-(phenylimino) ethanones. These iminoethanones were then converted to 1,2-diaryl-1,2-diketones by acid-promoted hydrolysis.
- Suzuki, Yumiko,Bakar, Abu,Tanoi, Takashi,Nomura, Naoko,Sato, Masayuki
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experimental part
p. 4710 - 4715
(2011/06/27)
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- Gold-catalyzed synthesis of benzil derivatives and α-keto imides via oxidation of alkynes
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An efficient process based on the gold-catalyzed redox reaction has been developed to oxidize 1,2-diarylacetylene or ynamide to 1,2-diaryldiketone or α-keto imide respectively. This process can tolerate a variety of functional groups and affords 1,2-dicarbonyl compounds in excellent yields under mild reaction conditions.
- Xu, Cheng-Fu,Xu, Mei,Jia, Yi-Xia,Li, Chuan-Ying
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p. 1556 - 1559
(2011/04/26)
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- DABCO-catalyzed oxidation of deoxybenzoins to benzils with air and one-pot synthesis of quinoxalines
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Aerobic oxidation of deoxybenzoins could be efficiently catalyzed by 1,4-diazabicyclo[2.2.2]octane (DABCO) with air as the sole oxidant to give the corresponding benzils in excellent yields. The effects of reaction conditions, such as different bases, temperature, time and solvent, on the yield of the product were investigated. Moreover, the process has been successfully extended to a one-pot synthesis of quinoxalines from benzyl ketones and aromatic 1,2-diamines. Georg Thieme Verlag Stuttgart New York.
- Qi, Chaorong,Jiang, Huanfeng,Huang, Liangbin,Chen, Zhengwang,Chen, Huoji
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experimental part
p. 387 - 396
(2011/04/15)
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