- Iridium-Catalyzed Asymmetric Hydrogenation of Halogenated Ketones for the Efficient Construction of Chiral Halohydrins
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Iridium-catalyzed asymmetric hydrogenation of prochiral halogenated ketones was successfully developed to prepare various chiral halohydrins with high reactivities and excellent enantioselectivities under basic reaction condition (up to >99% conversion, 99% yield, >99% ee). Moreover, gram-scale experiment was performed well in the presence of just 0.005 mol% (S/C=20 000) Ir/f-amphox catalyst with 99% yield and >99% ee. (Figure presented.).
- Yin, Congcong,Wu, Weilong,Hu, Yang,Tan, Xuefeng,You, Cai,Liu, Yuanhua,Chen, Ziyi,Dong, Xiu-Qin,Zhang, Xumu
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supporting information
p. 2119 - 2124
(2018/04/30)
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- Difunctionalization of Alkenes Using 1-Chloro-1,2-benziodoxol-3-(1H)-one
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Difunctionalization of alkenes with 1-chloro-1,2-benziodoxol-3-(1H)-one (1) was investigated. Various additional nucleophiles were tested, and oxychlorination, dichlorination, azidochlorination, chlorothiocyanation, and iodoesterfication were demonstrated. The oxychlorination product was obtained efficiently when the reaction was operated in water. Dichlorination occurred in the presence of a Lewis basic promoter, such as 4-phenylpyridine N-oxide, as an additive. The reaction with in situ-generated azido anion afforded azidochlorinated compounds with a chlorine atom at the terminal position, while the reaction with trimethylsilyl isothiocyanate produced chlorothiocyanation adducts with a chlorine atom at the benzylic position. On the other hand, when 1 was treated with tetra-n-butylammonium iodide prior to the addition of alkenes, only iodoesterification occurred selectively. These mild reactions enable convenient site-selective difunctionalizations of substrates having two alkene moieties. NMR experiments suggested that the electrophilic reactive species in each reaction varied depending on the nature of the added nucleophile.
- Egami, Hiromichi,Yoneda, Takahiro,Uku, Minako,Ide, Takafumi,Kawato, Yuji,Hamashima, Yoshitaka
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p. 4020 - 4030
(2016/06/09)
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- Catalytic Friedel-Crafts acylation and benzoylation of aromatic compounds using activated hematite as a novel heterogeneous catalyst
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Catalytic Friedel-Crafts acylation of benzene and unactivated benzenes such as chlorobenzene and nitrobenzene have been successfully carried out using activated hematite (α-Fe2O3) as a new, heterogeneous and green catalyst. Sonication of neat α-Fe2O3 in a water bath under air atmosphere at room temperature followed by heating at 200°C, dramatically increase the activity of α-Fe2O 3. With the catalyst loading as low as 5.0mol%, a wide variety of benzene derivatives were easily converted into the corresponding acylated products in a clean and high-yielding acylation reaction. It was found that the activated α-Fe2O3 could be efficiently recycled and reused several times by simple washing with ethyl acetate, this cannot be attained with most of the traditional catalysts. Copyright
- Sharghi, Hashem,Jokar, Mahboubeh,Doroodmand, Mohammad Mahdi,Khalifeh, Reza
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experimental part
p. 3031 - 3044
(2011/02/21)
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- Friedel-Crafts acylation of aromatic compounds with carboxylic acids in the presence of P2O5/SiO2 under heterogeneous conditions
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A convenient and efficient procedure for the Friedel-Crafts acylation of aromatic compounds with carboxylic acids in the presence of P2O5/SiO2 is described. Both aromatic and aliphatic carboxylic acids reacted easily to afford the corresponding aromatic ketones. The use of non-toxic and inexpensive materials, simple and clean work-up, short reaction times and good yields of the products are the advantages of this method.
- Zarei, Amin,Hajipour, Abdol R.,Khazdooz, Leila
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scheme or table
p. 6715 - 6719
(2009/04/07)
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- Copper(I)-promoted synthesis of chloromethyl ketones from trichloromethyl carbinols
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(Chemical Equation Presented) Reaction of several trichloromethyl carbinols with 2 equiv of CuCl/bpy in refluxing DCE for 3 h afforded chloromethyl ketones in excellent yield by 1,2-H shift in the copper-chlorocarbenoid intermediate.
- Ram, Ram N.,Manoj
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p. 5633 - 5635
(2008/12/21)
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- Novel building blocks: 1-Aryl-2-chloro-1-ethoxyethenes - Preparations and transformations
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We described here a simple method for the preparation of 1-aryl-2-chloro-1-ethoxyethenes 2a-u, which are prodrugs for Alzheimer's disease, by the reaction of dichloroacetaldehyde diethyl acetal with various aryl and alkenyllithium compounds in high yields. Wiley-VCH Verlag GmbH & Co. KGaA, 2007.
- Yoshimatsu, Mitsuhiro,Sakai, Miho,Moriura, Eri
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p. 498 - 507
(2008/02/06)
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- Kinetics of Oxidation of Ketones by Trichloroisocyanuric Acid in Acid Medium: Anomalous Behaviour of Alkoxyacetophenones
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Kinetics of oxidation of aliphatic, aryl aliphatic and cyclic ketones by trichloroisocyanuric acid has been studied in aqueous acetic acid medium in the presence of HClO4.The reaction is acid-catalysed exhibiting first order dependence each in and and zero order dependence in .This supports the acid catalyzed enolisation of ketone as the rate-determining step and reaction between enol and oxidant as the fast step.Alkoxyacetophenones exhibit an anomalous behaviour in that there is first order dependence on the halogenating agent.This has been attributed to the fact that in the case of alkoxyacetophenones the rates of halogenation may be less than the rates of enolisation.The decrease in dielectric constant of the medium slightly enhances the rate of reaction.The ρ? relationship in the case of acetophenones is linear with ρ as -0.2 indicating the simultaneous operation of equilibrium protonation of ketone and deprotonation of conjugate acid.Arrhenius activation parameters have been computed.A plausible mechanism consistent with the experimental results is postulated.
- Radhakrishnamurti, P. S.,Rath, Nabeen Kumar
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p. 300 - 303
(2007/10/02)
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- NOVEL SELECTIVE SYNTHESIS OF α-CHLOROMETHYL, α,α-DICHLOROMETHYL, AND α,α,α-TRICHLOROMETHYL KETONES FROM ALDEHYDE UTILIZING ELECTROREDUCTION AS KEY REACTIONS
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A variety of α-chloromethyl, α,α-dichloromethyl, and α,α,α-trichloromethyl ketones were synthesized from aldehyde utilizing cathodic reduction as key reactions.
- Shono, Tatsuya,Kise, Naoki,Yamazaki, Akira,Ohmizu, Hiroshi
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p. 1609 - 1612
(2007/10/02)
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