- Synthesis of 1,3-diketones by reaction of α-haloketones with acyl cynides promoted by samarium diiodide
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α-Haloketones reacted with acyl cyanides to form 1,3-diketones in the presence of samarium diiodide. The reaction was assumed to proceed via a mechanism involving samarium enolates in situ from α-haloketones.
- Baek, Heung Soo,Yoo, Byung Woo,Keum, Sam Rok,Yoon, Cheol Min,Kim, Sung Hoon,Kim, Joong Hyup
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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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- Metal-Free, DBU-Mediated, Microwave-Assisted Synthesis of Benzo[c]xanthones by Tandem Reactions of Alkynyl-1,3-diketones
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A base-mediated, green, microwave-assisted efficient preparation of a diverse benzoxanthone library from variety of readily accessible γ-alkynyl 1,3-diketones is reported. The synthesis is based on tandem reactions involving intramolecular cyclization, propargyl-allenyl isomerization, and electrocyclization in one pot. Some of the benzoxanthones are also synthesized by the one-pot reaction of 1,3-diketone and alkynyl bromide under basic heating conditions. This transformation also results in the construction of one new C?C bond and one new C?O bond. (Figure presented.).
- Liang, Yi-En,D. Barve, Balaji,Kuo, Yao-Haur,Fang, Hsu-Wei,Kuo, Ting-Shen,Li, Wen-Tai
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supporting information
p. 505 - 511
(2020/12/01)
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- Method for synthesizing 1, 3-dicarbonyl compound based on terminal alkyne and acyl halide by one-pot process
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The invention belongs to the technical field of catalytic synthesis, and discloses a method for synthesizing a 1, 3-dicarbonyl compound by a one-pot process, and the method comprises the following steps: by using simple palladium and copper salts as catalysts, reacting terminal alkyne with acyl halide at 0-80 DEG C for 0.5-12 hours under the action of trifluoromethanesulfonic acid to obtain the 1,3-dicarbonyl compound, wherein the molar ratio of the terminal alkyne to the acyl halide to the palladium salt to the copper salt to the trifluoromethanesulfonic acid is 1 to (1 to 2) to (0.00001 to0.10) to (0.00001 to 0.10) to (0.00004 to 0.40); the catalysts used in the method are common the commercialized palladium salt and copper salt, reagents used in the reaction are commercialized reagents, in addition, the raw materials are cheap and easy to obtain, functional group tolerance is good, reaction conditions are mild, operation is easy and convenient, and atom economy is high.
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Paragraph 0069-0074; 0081-0083
(2020/07/21)
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- Ru-Catalyzed Chemo- and Enantioselective Hydrogenation of β-Diketones Assisted by the Neighboring Heteroatoms
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A highly chemo- and enantioselective hydrogenation of β-diketones was achieved by using [Ru(benzene)(S)-SunPhosCl]Cl for consistency in THF. The neighboring heteroatoms played important roles in guaranteeing the reactivity and controlling the chemoselectivity. These results suggested a potential approach for the clean and facile synthesis of functionalized chiral β-hydroxy ketones, which could otherwise be prepared through much less step-economic transformations.
- Li, Wanfang,Lu, Bin,Xie, Xiaomin,Zhang, Zhaoguo
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supporting information
p. 5509 - 5513
(2019/08/01)
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- An effective preparation of both 1,3-diketones and nitriles from alkynones with oximes as hydroxide sources
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An effective phosphine-catalyzed protocol has been established for the syntheses of 1,3-diketones and nitriles from alkynones with oximes as hydroxide surrogates. This method features the use of a phosphine catalyst, compatibility with various functional groups and ambient temperature, which makes this approach very practical. A plausible mechanism was proposed.
- Chen, Pei,Zhang, Qian-Qian,Guo, Jia,Chen, Lu-Lu,Wang, Yan-Bo,Zhang, Xiao
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p. 6958 - 6966
(2018/10/02)
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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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- Influence of substituent on UV absorption and keto-enol tautomerism equilibrium of dibenzoylmethane derivatives
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UV absorption spectra of dibenzoylmethane and its 23 derivatives with acetamide, tert-butyl, chloride, fluoride, hydroxyl, methyl, methoxy and nitro substituents in aromatic rings were collected. General influence of substituent on absorption maxima and absorption intensity was defined. Hyperchromic effects were observed for diketones with electron-donating groups in para postion. The keto-enol tautomerism equilibrium constant of obtained compounds was investigated with 1H NMR spectroscopy. Significant changes of equilibrium were observed only for ortho substituted compounds. Results revealed dissimilarity of substituent effects on absorption and keto-enol tautomerism of aromatic β-diketones.
- Zawadiak, Jan,Mrzyczek, Marek
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p. 815 - 819
(2012/11/13)
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- Transition-metal-free intramolecular Ullmann-type O-arylation: Synthesis of chromone derivatives
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(Chemical Equation Presented) Expect the upexpected: A transition-metal- free approach to access chromone derivatives has been developed. The intramolecular O-arylation of substituted 1-(2-haloaryl)-propane-1,3-diones in DMF in the presence of K2CO3 gave the corresponding target products in good to excellent yields (see scheme; DMF = N,N′- dimethylformamide).
- Zhao, Jie,Zhao, Yufen,Fu, Hua
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supporting information; experimental part
p. 3769 - 3773
(2011/05/15)
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- The EPR D-parameter of 1,3-diarylcyclopentane-1,3-diyl triplet diradicals as a probe for steric substituent effects in benzyl-type radicals
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The zero-field splitting D parameter of a set of ortho-substituted-1,3-diarylcyclopentane-1,3-diyl triplet diradicals 3 has been determined by EPR spectroscopy in a 2-methyltetrahydrofuran glass matrix at 77 K. While for meta- and para-substituted triplet
- Adam, Waldemar,Van Barneveld, Claus,Gerke, Jan-Stefan,Klaerner, Frank Gerrit
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p. 2723 - 2728
(2007/10/03)
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- Synthesis of some β-diketone complexes of lanthanides and study of their shift reagent effects
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A series of complexes of ortho, meta and para substituted dibenzoylmethane(DBM) with lanthanides(Ln) have been synthesized and the induced shifts in 1H NMR spectra on n-pentanol have been studied. The studies of the shift behaviour of trivalent
- Salar Amoli,Aziz,Mohanazadeh
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p. 1004 - 1005
(2007/10/03)
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