- 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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- 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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- 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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- Synthesis of 1,2-diketones by mercury-catalyzed alkyne oxidation
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The first mercury-catalyzed synthesis of 1,2-diketones by alkyne oxidation has been developed. This inexpensive method extends the potential of mercury catalysis and allows the rapid construction of various 1,2-diketones and α-carbonyl amides in good yields with high functional group tolerance.
- Mei, Xiaochuan,Hu, Weican,Gao, Kexin,Gao, Haotian,Wang, Chaoyang,Qian, Guoying,Rong, Zhouting
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supporting information
p. 2661 - 2667
(2021/07/09)
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- Catalyst-Free and Transition-Metal-Free Approach to 1,2-Diketones via Aerobic Alkyne Oxidation
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A catalyst-free and transition-metal-free method for the synthesis of 1,2-diketones from aerobic alkyne oxidation was reported. The oxidation of various internal alkynes, especially more challenging aryl-alkyl acetylenes, proceeded smoothly with inexpensive, easily handled, and commercially available potassium persulfate and an ambient air balloon, achieving the corresponding 1,2-diketones with up to 85% yields. Meanwhile, mechanistic studies indicated a radical process, and the two oxygen atoms in the 1,2-diketons were most likely from persulfate salts and molecular oxygen, respectively, rather than water.
- Shen, Duyi,Wang, Hongyan,Zheng, Yanan,Zhu, Xinjing,Gong, Peiwei,Wang, Bin,You, Jinmao,Zhao, Yulei,Chao, Mianran
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p. 5354 - 5361
(2021/05/05)
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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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- 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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- Preparing method of photocatalytic alpha-diketone compound
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The invention belongs to the technical field of medical and chemical intermediates and related chemicals, and provides a preparing method of photocatalytic alpha-diketone compound. Phenylacetylene and the derivative thereof are used as raw materials, and under the lighting condition, under the combined action of a semiconductor photocatalyst and an additive, alpha-diketone compound is generated through air oxygen in organic solvent. The preparing method has the advantages of being easy to operate, mild in condition and environmentally friendly, has probability of industrialization and obtains the alpha-diketone compound at the high yield, and the catalyst is recyclable. The alpha-diketone compound synthesized through the method can be further functionalized to obtain various compounds applied to development and research of natural products, function materials and fine chemicals.
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Paragraph 0043-0045
(2017/08/28)
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- 1,2-diaryl ethylenediamine compound preparation method
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The invention discloses a 1,2-diaryl ethylenediamine compound preparation method, which comprises: (1) under the catalysis of B(C6F5)3, by adopting H2 as a reduction agent, carrying out a reduction reaction on a compound represented by a formula II to obtain a compound (1,2-diaryl ethylenediamine compound) represented by a formula I, wherein Ar1 and Ar2 in the formulas I and II are phenyl or substituted phenyl, the substituting position of the substituting group is any one or any two selected from ortho, meta and para in the substituted phenyl, and the substituting group is methyl, methoxy, fluorine atom or bromine atom. According to the present invention, B(C6F5)3 is adopted as the catalyst and the 1,2-diaryldiimine is adopted as the substrate to synthesize the 1,2-diaryl ethylenediamine compound in the high-yield and high-diastereoselectivity (dr is more than 99:1) manner; and the method has characteristics of easily available raw materials, mild reaction conditions, high reaction activity, wide substrate application range, and great industrial potential.
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-
Paragraph 0047; 0048
(2017/02/28)
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- A method for synthesizing derivatives benzil
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The invention discloses a method for synthesizing a benzil derivative. The method comprises the following steps: adding epoxy chalcone compound shown in the formula I, a Selectfluor oxidizing agent and inorganic base into a mixed solvent of acetonitrile and water, stirring for reaction for 4-8 h at 60-100 DEG C, and treating a reaction liquid obtained after the reaction is finished to prepare the benzil derivative shown in the formula II. The synthesis method has the advantages that the raw materials are cheap and easy to obtain, transition metal catalysis is not needed, the oxygen source is easy to obtain and environment-friendly, the reaction condition is mild, the target substrate can be synthesized efficiently, the universality of the functional group is good, and the operation is simple and convenient.
- -
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Paragraph 0029-0032
(2020/02/07)
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- Synthesis of 1,2-Diketones via a Metal-Free, Visible-Light-Induced Aerobic Photooxidation of Alkynes
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1,2-Diketones were synthesized by the oxidation of corresponding alkynes using air as the oxidant under metal-free conditions upon irradiation of blue light. A cheap and readily available organic dye, eosin Y, was used as the photocatalyst. For various substituents on the aryl ring, the reaction proceeded smoothly to give the dicarbonylation products in moderate to good yields. Some oxidation-sensitive groups, such as formyl and the carbon-carbon double bond, were tolerated under the developed reaction conditions.
- Liu, Xu,Cong, Tiantian,Liu, Ping,Sun, Peipei
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p. 7256 - 7261
(2016/08/30)
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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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supporting information
p. 682 - 690
(2015/11/17)
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- Efficient synthetic route to bisaryl ketones via copper-catalyzed C-C triple bonds cleavage
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An efficient copper-catalyzed aerobic synthesis of bisaryl ketones from 1,2-diarylalkynes via C-C triple bonds cleavage has been demonstrated. The aniline compounds were found to be crucial in our conditions and a plausible mechanism was put forward. This reaction constitutes a new transformation from 1,2-diarylalkynes into bisaryl ketones with a practical, neutral, and mild synthetic approach.
- Li, Xiangguang,Huang, Wenzhong,Liang, Deqiang,Yuan, Lin,Ma, Yinhai,Gu, Lijun
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p. 1045 - 1049
(2015/01/30)
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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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- 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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- Selective oxygenation of alkynes: A direct approach to diketones and vinyl acetate
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Arylalkynes can be converted into α-diketones with the use of a copper catalyst, and also be transformed into vinyl acetates under metal-free conditions, both in the presence of PhI(OAc)2 as an oxidant at room temperature. A series of substituted α-diketones were prepared in moderate to good yields. A variety of vinyl halides could be regio- and stereo-selectively synthesized under mild conditions, and I, Br and Cl could be all easily embedded into the alkynes. This journal is
- Xia, Xiao-Feng,Gu, Zhen,Liu, Wentao,Wang, Ningning,Wang, Haijun,Xia, Yongmei,Gao, Haiyan,Liu, Xiang
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supporting information
p. 9909 - 9913
(2015/01/09)
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- Catalyst-controlled highly selective coupling and oxygenation of olefins: A direct approach to alcohols, ketones, and diketones
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Oxygen? That's radical! A method for the direct synthesis of substituted alcohols, ketones, and diketones through a catalyst-controlled highly chemoselective coupling and oxygenation of olefins has been developed. The method is simple and practical, can be switched by the selection of different catalysts, and employs molecular oxygen as both an oxidant and a reagent. Copyright
- Su, Yijin,Sun, Xiang,Wu, Guolin,Jiao, Ning
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supporting information
p. 9808 - 9812
(2013/09/23)
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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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- Facile and highly chemoselective synthesis of benzil derivatives via oxidation of stilbenes in an I2-H2O system
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A facile and highly chemoselective protocol for the synthesis of benzil derivatives has been developed by oxidation of stilbenes in an I 2-H2O system under air. Notably, the method was applicable to 26 examples and provided up to 98% yield, avoiding the use of acid, metal catalysts and so on.
- Zeng, Xianghua,Miao, Chengxia,Wang, Shoufeng,Xia, Chungu,Sun, Wei
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p. 9666 - 9669
(2013/09/02)
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- Ruthenium-catalyzed oxidation of alkynes to 1,2-diketones under room temperature and one-pot synthesis of quinoxalines
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A ruthenium-catalyzed alkyne oxidation to 1,2-diketones using Oxone under room temperature is reported. Both substrate scope and mechanism were discussed. Notably, combination of the alkyne oxidation and condensation cyclization in one pot offers a very efficient and convenient entry into quinoxaline derivatives.
- Xu, Yuan,Wan, Xiaobing
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supporting information
p. 642 - 645
(2013/02/23)
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- A combination of copper(0) powder and selectfluor enables generation of cationic copper species for mild 1,2-dicarbonylation of alkynes
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A combination of copper powder and Selectfluor permits the generation of cationic copper species that efficiently catalyze 1,2-dicarbonylation of alkynes under mild conditions with water and dioxygen as inexpensive and environmentally benign sources of oxygen. Georg Thieme Verlag Stuttgart New York.
- Zhang, Wenxia,Zhang, Jian,Liu, Yunkui,Xu, Zhenyuan
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supporting information
p. 2709 - 2714
(2014/01/06)
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- Structure based design of iminohydantoin BACE1 inhibitors: Identification of an orally available, centrally active BACE1 inhibitor
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From an initial lead 1, a structure-based design approach led to identification of a novel, high-affinity iminohydantoin BACE1 inhibitor that lowers CNS-derived Aβ following oral administration to rats. Herein we report SAR development in the S3 and F′ subsites of BACE1 for this series, the synthetic approaches employed in this effort, and in vivo data for the optimized compound.
- Cumming, Jared N.,Smith, Elizabeth M.,Wang, Lingyan,Misiaszek, Jeffrey,Durkin, James,Pan, Jianping,Iserloh, Ulrich,Wu, Yusheng,Zhu, Zhaoning,Strickland, Corey,Voigt, Johannes,Chen, Xia,Kennedy, Matthew E.,Kuvelkar, Reshma,Hyde, Lynn A.,Cox, Kathleen,Favreau, Leonard,Czarniecki, Michael F.,Greenlee, William J.,McKittrick, Brian A.,Parker, Eric M.,Stamford, Andrew W.
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scheme or table
p. 2444 - 2449
(2012/05/19)
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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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- 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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- Pyridine N-oxide mediated oxidation of diarylalkynes with palladium on carbon
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Pyridine N-oxide works as an effective oxidant of 1,2-diarylalkynes at 120 °C to form benzil derivatives under Pd/C-catalyzed solvent-free conditions, and Pd/C could be reused up to five times after simple filtration.
- Sawama, Yoshinari,Takubo, Masato,Mori, Shigeki,Monguchi, Yasunari,Sajiki, Hironao
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experimental part
p. 3361 - 3367
(2011/07/29)
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- Ruthenium-catalyzed alkyne oxidation with part-per-million catalyst loadings
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Using a catalytic system of the (cymene)ruthenium dichloride dimer, [Ru(cymene)Cl2]2, (0.001 mol%) and iodine (10 mol%), a variety of alkynes bearing different functional groups were oxidized with tert-butyl hydroperoxide (TBHP; 70% solution in water) under mild conditions to give 1,2diketones in good to excellent yields. Two noteworthy features of the method are the extremely high catalyst productivity (TON up to 420,000) and scale-up to 1 mol. Preliminary mechanism investigations showed that iodonium ion and water were involved in the transformation.
- Ren, Wei,Liu, Jinfeng,Chen, Long,Wan, Xiaobing
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supporting information; experimental part
p. 1424 - 1428
(2010/08/19)
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- TRANSITION-METAL CHARGE-TRANSPORT MATERIALS, METHODS OF FABRICATION THEREOF, AND METHODS OF USE THEREOF
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Briefly described, embodiments of this disclosure include transition-metal charge-transport materials, methods of forming transition-metal charge-transport materials, and methods of using the transition-metal charge-transport materials.
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Page/Page column 79; Sheet 63
(2010/02/15)
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