- Palladium-Catalyzed C(sp3)-H Oxygenation via Electrochemical Oxidation
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Palladium-catalyzed C-H activation/C-O bond-forming reactions have emerged as attractive tools for organic synthesis. Typically, these reactions require strong chemical oxidants, which convert organopalladium(II) intermediates into the PdIII or PdIV oxidation state to promote otherwise challenging C-O reductive elimination. However, previously reported oxidants possess significant disadvantages, including poor atom economy, high cost, and the formation of undesired byproducts. To overcome these issues, we report an electrochemical strategy that takes advantage of anodic oxidation of PdII to induce selective C-O reductive elimination with a variety of oxyanion coupling partners.
- Yang, Qi-Liang,Li, Yi-Qian,Ma, Cong,Fang, Ping,Zhang, Xiu-Jie,Mei, Tian-Sheng
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- Organic luminescent material containing 6-silicon-based substituted isoquinoline ligand
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Disclosed is an organic light-emitting material containing a 6silicon-based substituted isoquinoline ligand. The organic light-emitting material is a metal complex containing a 6silicon-based substituted isoquinoline ligand, and can be used as a light-emitting material in a light-emitting layer of an organic light-emitting device. These novel complexes can provide more red and saturated emissions,and can also exhibit significantly improved lifetime and high efficiency excellent device performance. An electroluminescent device and a compound formulation comprising the metal complex are also disclosed.
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- Metal complex containing three different ligands
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A metal complex containing three different ligands is disclosed. The metal complex contains three different ligands, and can be used as a luminescent material in a luminescent layer of an organic electroluminescent device. The novel complexes not only can achieve the device performance expected to be regulated or improved by regulating substituent groups, but also can achieve the effect of effectively controlling the rise of the evaporation temperature. An electroluminescent device and a compound formulation comprising the metal complex are also disclosed.
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- Selective liquid-phase semihydrogenation of functionalized acetylenes and propargylic alcohols with silica-supported bimetallic palladium-copper catalysts
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Silica-supported, bimetallic palladium-copper catalysts were prepared in solution under mild conditions by reacting lithium di(4-tolyl)cuprate with palladium acetate in the presence of silica particles. Small bimetallic palladium-copper particles were deposited on the silica surface as confirmed with TEM-EDAX and EXAFS. The new material has been applied as catalyst in the liquid-phase semihydrogenation of mono- and disubstituted alkynes and showed high selectivity toward the cis-alkenes. The influence of addition of quinoline or potassium hydroxide to the semihydrogenation reaction mixture and the effects of exposure of the catalyst to air before use have been investigated. Silica-supported, bimetallic palladium-copper catalysts were prepared in solution under mild conditions by reacting lithium di(4-tolyl)cuprate with palladium acetate in the presence of silica particles. Small bimetallic palladium-copper particles were deposited on the silica surface as confirmed with TEM-EDAX and EXAFS. The new material has been applied as catalyst in the liquid-phase semihydrogenation of mono- and disubstituted alkynes and showed high selectivity toward the cis-alkenes. The influence of addition of quinoline or potassium hydroxide to the semihydrogenation reaction mixture and the effects of exposure of the catalyst to air before use have been investigated.
- Spee,Boersma,Meijer,Slagt,Van Koten,Geus
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p. 1647 - 1656
(2007/10/03)
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- A novel synthesis of 3-aryl-5-tert-butyl-4-oxazolin-2-ones
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An efficient synthetic method for 3-aryl-5-tert-butyl-4-oxazolin-2-ones (6) is described. The reaction of ethyl N-arylcarbamates (10) with 1-bromo- 3,3-dimethyl-2-butanone (9a) or 1-bromo-3-ethyl-3-methyl-2-pentanone (9b) using 2.2 eq of lithium his(trime
- Kudo, Noriaki,Taniguchi, Misa,Sato, Kazuo
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p. 699 - 702
(2007/10/03)
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- Synthesis of 6-t-alkyl-3-pyridazinones
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A class of 6-t-alkyl-3-pyridazinones are prepared from 3-t-alkanoyl-2-propenoic acids by irradiation with strong light and reaction with hydrazine.
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- Synthesis of acetyl-T-alkanes
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Acetyl-tertiary-alkanes are prepared by hydrolytic decarboxylation of tertiary-alkanoylacetonitriles with hydrochloric acid.
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- Wanderungstendenzen cyclischer, polycyclischer und methylverzweigter Alkylreste bei der Beckmann-Umlagerung
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The migration aptitudes of polycyclic bridgehead groups, cycloalkyl groups as well as of β-, γ- and δ-branched alkyl groups in the Chapman variant of the Beckmann rearrangement were determined.From these data it is concluded that at transition state 2 the migrating group is not resembling a planarised carbenium ion R+, but rather a pentacoordinated carbonium ion structure.Because only small geometrical changes occur in the migrating group vertical stabilisation of charge at transition state is believed to have significant influence on the migration aptitudes.
- Langhals, Heinz,Ruechardt, Christoph
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p. 3831 - 3854
(2007/10/02)
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- Minor and Trace Sterols in Marine Invertebrates. 27. Isolation, Structure Elucidation, and Partial Synthesis of 25-Methylxestosterol, a New Sterol Arising from Quadruple Biomethylation in the Side Chain
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A novel C31 sterol, 25-methylxestosterol, resulting from quadruple biomethylation in the side chain has been isolated as a trace constituent of the sterol fraction from a Caribbean sponge (Xestospongia sp.).Its structure (1, 24-methylene-25,26,27-trimethylcholesterol) has been elucidated by spectroscopic methods and confirmed by partial synthesis.A biosynthetic route leading to 1 is proposed that is consistent with the hypothesis of stepwise biomethylations and with earlier discoveries of "extended" side chains among marine sterols.
- Li, Lian Niang,Sjoestrand, Ulf,Djerassi, Carl
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p. 3867 - 3870
(2007/10/02)
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- ACTION DES DIALKYLCUPRATES DE LITHIUM SUR LES ALDEHYDES α,β-ETHYLENIQUES
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Nearly exclusive 1-4 addition products are obtained by action of lithium dialkylcuprates with α,β-ethylenic aldehydes.Non polar solvents and low temperatures favor this reaction.Only α,β-ethylenic aldehydes having a trisubstituted double bond give a relatively important proportion of 1-2 addition product.
- Chuit, C.,Foulon, J. P.,Normant, J. F.
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p. 2305 - 2310
(2007/10/02)
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