- Mild and Selective Rhodium-Catalyzed Transfer Hydrogenation of Functionalized Arenes
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Diboron-mediated rhodium-catalyzed transfer hydrogenation of functionalized arenes is reported. In addition to good functional group tolerance, the reaction features operational simplicity and controllable chemoselectivity. The general applicability of this procedure is demonstrated by the selective hydrogenation of a range of arenes, including functionalized benzenes, biphenyls, and polyaromatics.
- Wang, Yuhan,Chang, Zhiqian,Hu, Yan,Lin, Xiao,Dou, Xiaowei
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supporting information
p. 1910 - 1914
(2021/03/08)
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- PRODUCTION METHOD OF CYCLIC COMPOUND
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PROBLEM TO BE SOLVED: To provide an industrially simple production method of a cyclic compound. SOLUTION: A production method of a cyclic compound includes a step to obtain a reduced form (B) by reducing an unsaturated bond in a ring structure of an aromatic compound (A) by means of catalytic hydrogenation of the aromatic compound (A) or its salt using palladium carbon as a catalyst under a normal pressure, in which the aromatic compound (A) has one or more ring structures selected from a group consisting of a five membered-ring, a six membered-ring, and a condensed ring of the five membered-ring or the six membered-ring with another six membered-ring, a hetero atom can be included in the ring structure, and the aromatic compound (A) can have one or two side chains bonded to the ring structure and does not have any carbon-carbon triple bond in the side chain. SELECTED DRAWING: None COPYRIGHT: (C)2021,JPOandINPIT
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Paragraph 0057-0058; 0062-0063
(2021/05/05)
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- Trifluoromethyl Thianthrenium Triflate: A Readily Available Trifluoromethylating Reagent with Formal CF3+, CF3?, and CF3-Reactivity
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Here we report the synthesis and application of trifluoromethyl thianthrenium triflate (TT-CF3+OTf-) as a novel trifluoromethylating reagent, which is conveniently accessible in a single step from thianthrene and triflic anhydride. We demonstrate the use of TT-CF3+OTf- in electrophilic, radical, and nucleophilic trifluoromethylation reactions.
- Jia, Hao,H?ring, Andreas P.,Berger, Florian,Zhang, Li,Ritter, Tobias
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supporting information
p. 7623 - 7628
(2021/05/26)
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- Direct C(sp3)?H Trifluoromethylation of Unactivated Alkanes Enabled by Multifunctional Trifluoromethyl Copper Complexes
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A mild and operationally simple C(sp3)?H trifluoromethylation method was developed for unactivated alkanes by utilizing a bench-stable CuIII complex, bpyCu(CF3)3, as the initiator of the visible-light photoinduced reaction, the source of a trifluoromethyl radical as a hydrogen atom transfer reagent, and the source of a trifluoromethyl anion for functionalization. The reaction was initiated by the generation of reactive electrophilic carbon-centered CF3 radical through photoinduced homolytic cleavage of bpyCu(CF3)3, followed by hydrogen abstraction from an unactivated C(sp3)?H bond. Comprehensive mechanistic investigations based on a combination of experimental and computational methods suggested that C?CF3 bond formation was enabled by radical–polar crossover and ionic coupling between the resulting carbocation intermediate and the anionic CF3 source. The methylene-selective reaction can be applied to the direct, late-stage trifluoromethylation of natural products and bioactive molecules.
- Choi, Geunho,Lee, Geun Seok,Park, Beomsoon,Kim, Dongwook,Hong, Soon Hyeok
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supporting information
p. 5467 - 5474
(2021/01/20)
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- Can Heteroarenes/Arenes Be Hydrogenated Over Catalytic Pd/C Under Ambient Conditions?
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Hydrogenation of over a dozen aromatic compounds, including both heteroarenes and arenes, over palladium on carbon (Pd/C, 1–100 molpercent) with H2-balloon pressure at room temperature is reported. Analyses using pyridine as a model substrate revealed that acetic acid was the best solvent, as using only 1 molpercent Pd/C provided piperidine quantitatively. Substrate scope analysis and density functional theory calculations indicated that reaction rates are highly dependent on frontier molecular orbital characteristics and the steric bulkiness of substituents. Moreover, the established method was used for the concise synthesis of the anti-Alzheimer drug donepezil (Aricept?).
- Tanaka, Nao,Usuki, Toyonobu
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p. 5514 - 5522
(2020/07/24)
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- Iterative Preparation of Platinum Nanoparticles in an Amphiphilic Polymer Matrix: Regulation of Catalytic Activity in Hydrogenation
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We demonstrate that iteration of the seeded preparation of platinum nanoparticles dispersed in an amphiphilic polystyrene-poly(ethylene glycol) resin (ARP-Pt) regulates their catalytic activity in the hydrogenation of aromatic compounds in water. The catalytic activity of the fifth generation of ARP-Pt [G5] prepared through four iterations of the seeded preparation was far superior to that of the initial ARP-Pt [G1] in the hydrogenation of aromatic compounds in water.
- Hamasaka, Go,Osako, Takao,Srisa, Jakkrit,Torii, Kaoru,Uozumi, Yasuhiro
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supporting information
p. 147 - 152
(2020/01/23)
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- Accessing Difluoromethylated and Trifluoromethylated cis-Cycloalkanes and Saturated Heterocycles: Preferential Hydrogen Addition to the Substitution Sites for Dearomatization
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Reported here is a straightforward process in which a cyclic (alkyl)(amino)carbene/Rh catalyst system facilitates the preferential addition of hydrogen to the substitution sites of difluoromethylated and trifluoromethylated arenes and heteroarenes, leading to dearomative reduction. This strategy enables the diastereoselective synthesis of cis-difluoromethylated and cis-trifluoromethylated cycloalkanes and saturated heterocycles, and even allows formation of all-cis multi-trifluoromethylated cyclic products with a defined equatorial orientation of the di- and trifluoromethyl groups. Deuterium-labeling studies indicate that hydrogen preferentially attacks the substitution sites of planar arenes, resulting in dearomatization, possibly with heterogeneous Rh as the reactive species, followed by either reversible or irreversible hydrogen addition to the nonsubstitution sites.
- Zhang, Xue,Ling, Liang,Luo, Meiming,Zeng, Xiaoming
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supporting information
p. 16785 - 16789
(2019/11/11)
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- Csp3-Csp3 Bond-Forming Reductive Elimination from Well-Defined Copper(III) Complexes
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Carbon-carbon bond-forming reductive elimination from elusive organocopper(III) complexes has been considered the key step in many copper-catalyzed and organocuprate reactions. However, organocopper(III) complexes with well-defined structures that can undergo reductive elimination are extremely rare, especially for the formation of Csp3-Csp3 bonds. We report herein a general method for the synthesis of a series of [alkyl-CuIII-(CF3)3]- complexes, the structures of which have been unequivocally characterized by NMR spectroscopy, mass spectrometry, and X-ray crystal diffraction. At elevated temperature, these complexes undergo reductive elimination following first-order kinetics, forming alkyl-CF3 products with good yields (up to 91%). Both kinetic studies and DFT calculations indicate that the reductive elimination to form Csp3-CF3 bonds proceeds through a concerted transition state, with a ΔH? = 20 kcal/mol barrier.
- Paeth, Matthew,Tyndall, Sam B.,Chen, Liang-Yu,Hong, Jia-Cheng,Carson, William P.,Liu, Xingwu,Sun, Xiaodong,Liu, Jinjia,Yang, Kundi,Hale, Elizabeth M.,Tierney, David L.,Liu, Bin,Cao, Zhi,Cheng, Mu-Jeng,Goddard, William A.,Liu, Wei
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supporting information
p. 3153 - 3159
(2019/03/06)
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- Polysilane-Immobilized Rh-Pt Bimetallic Nanoparticles as Powerful Arene Hydrogenation Catalysts: Synthesis, Reactions under Batch and Flow Conditions and Reaction Mechanism
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Hydrogenation of arenes is an important reaction not only for hydrogen storage and transport but also for the synthesis of functional molecules such as pharmaceuticals and biologically active compounds. Here, we describe the development of heterogeneous Rh-Pt bimetallic nanoparticle catalysts for the hydrogenation of arenes with inexpensive polysilane as support. The catalysts could be used in both batch and continuous-flow systems with high performance under mild conditions and showed wide substrate generality. In the continuous-flow system, the product could be obtained by simply passing the substrate and 1 atm H2 through a column packed with the catalyst. Remarkably, much higher catalytic performance was observed in the flow system than in the batch system, and extremely strong durability under continuous-flow conditions was demonstrated (>50 days continuous run; turnover number >3.4 × 105). Furthermore, details of the reaction mechanisms and the origin of different kinetics in batch and flow were studied, and the obtained knowledge was applied to develop completely selective arene hydrogenation of compounds containing two aromatic rings toward the synthesis of an active pharmaceutical ingredient.
- Miyamura, Hiroyuki,Suzuki, Aya,Yasukawa, Tomohiro,Kobayashi, Shu
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supporting information
p. 11325 - 11334
(2018/09/06)
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- Hydrogenation of arenes, nitroarenes, and alkenes catalyzed by rhodium nanoparticles supported on natural nanozeolite clinoptilolite
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Abstract Nanozeolite clinoptilolite supported rhodium nanoparticles (Rh/NZ-CP) has been prepared and characterized by a variety of techniques, including XRD, BET, TEM, EDX, ICP-OES and XPS analysis. This nanomaterial contains 2 wt% Rh in the range of 5-20 nm metallic nanoparticles distributed on nanozeolite. The catalytic performance of Rh/NZ-CP was evaluated by the hydrogenation of arenes, nitroarenes, and alkenes under moderate reaction conditions. The prepared nanocatalyst can be facilely recovered and reused many times without significant decrease in activity and selectivity. The high catalytic activity, thermal stability and reusability, simple recovery and eco-friendly nature make present catalyst as a unique catalytic system, which is particularly attractive in green chemistry.
- Baghbanian, Seyed Meysam,Farhang, Maryam,Vahdat, Seyed Mohammad,Tajbakhsh, Mahmood
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p. 128 - 136
(2015/07/15)
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- Copper-promoted trifluoromethylation of primary and secondary alkylboronic acids
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New couple: The Cu-promoted trifluoromethylation of primary and secondary alkylboronic acids with TMSCF3 extends the scope of transition-metal-catalyzed trifluoromethylation reactions to sp 3-hybridized carbon centers. It also repres
- Xu, Jun,Xiao, Bin,Xie, Chuan-Qi,Luo, Dong-Fen,Liu, Lei,Fu, Yao
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supporting information
p. 12551 - 12554
(2013/02/22)
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- Hydrogenation of arenes and N-heteroaromatic compounds over ruthenium nanoparticles on poly(4-vinylpyridine): A versatile catalyst operating by a substrate-dependent dual site mechanism
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A nanostructured catalyst composed of Ru nanoparticles immobilized on poly(4-vinylpyridine) (PVPy) has been synthesized by NaBH4 reduction of RuCl3·3H2O in the presence of the polymer in methanol at room temperature. TEM measurements show well-dispersed Ru nanoparticles with an average diameter of 3.1 nm. Both powder XRD patterns and XPS data indicate that the Ru particles are predominantly in the zerovalent state. The new catalyst is efficient for the hydrogenation of a wide variety of aromatic hydrocarbons and N-heteroaromatic compounds representative of components of petroleum-derived fuels. The experimental data indicate the existence of two distinct active sites in the nanostructure that lead to two parallel hydrogenation pathways, one for simple aromatics involving conventional homolytic hydrogen splitting on Ru and a second one for N-heteroaromatics taking place via a novel heterolytic hydrogen activation on the catalyst surface, assisted by the basic pyridine groups of the support.
- Fang, Minfeng,MacHalaba, Nataliya,Sanchez-Delgado, Roberto A.
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experimental part
p. 10621 - 10632
(2011/11/29)
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- Convenient synthesis of fluorinated alkanes and cycloalkanes by hydrogenation of perfluoroalkylalkenes under ultrasound irradiation
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Synthesis of several 1,4-disubstituted cyclohexanes, by hydrogenation of sterically hindered and electron poor perfluoroalkyl alkenes, was performed, at room temperature under hydrogen at atmospheric pressure. Hydrogenation was difficult to achieve without ultrasound whatever catalyst and pressure (from 1 to 120 bar) used. Coupling of ultrasonic irradiation with metallic catalysis dramatically increased the efficiency of hydrogenation of perfluoroalkyl alkenes.
- Carcenac,Tordeux,Wakselman,Diter
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p. 1347 - 1355
(2007/10/03)
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- Synthetic uses of thioesters of trifluoromethylated acids. Part 2: Reactions with alkenes
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The photolysis of trifluoromethanethiosulfonates (CF3SO2SR) or trifluorothioacetates (CF3COSR) in the presence of alkenes provides (trifluoromethyl)alkanes or β-sulfanyl (trifluoromethyl)alkanes. The formation of these compounds can be controlled by the nature and the ratio of the reactants. (C) 2000 Published by Elsevier Science Ltd.
- Billard, Thierry,Roques, Nicolas,Langlois, Bernard R.
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p. 3069 - 3072
(2007/10/03)
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- A novel trifluoromethylation method of saturated organic halides
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Treatment of methyl chlorodifluoroacetate with aliphatic halides in the presence of equivalent ammount of potassium fluoride, copper iodide and cadmium iodide at 120°C in HMPA for 8 h gave the corresponding trifluoromethyl derivatives in moderate yields.
- Chen, Qing-Yun,Duan, Jian-Xing
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p. 4241 - 4244
(2007/10/02)
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- Conformational Preference of the Trimethylsilyl Group
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Hydrogenations of (4-methylphenyl)trimethylsilane, trimethylsilane, and 1,4-bis(trimethylsilyl)benzene provide the corresponding predominantly cis (ca. 80percent) 4-substituted cyclohexyltrimethylsilanes on the basis of 1H, 13C,
- Kitching, William,Olszowy, Henry A.,Drew, Gregory M.,Adcock, William
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p. 5153 - 5156
(2007/10/02)
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- Trifluoromethyl derivatives of cyclohexanol and cyclohexanone and their reactions
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The catalytic hydrogenation of mono- and bistrifluoromethylphenols was investigated, and the structure of the obtained trifluoromethylcyclohexanols was established.Methods were developed for the production of trifluoromethyl derivatives of caprolactam and adipic acid.
- Zalesskaya, I. M.,Blakitnyi, A. N.,Saenko, E. P.,Fialkov, Yu. A.,Yagupol'skii, L. M.
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p. 1031 - 1038
(2007/10/02)
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- Synthesis of trifluoromethyl-substituted compounds
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Trifluoromethyl-substituted compounds are formed in a corona discharge or glow discharge plasma of trifluoromethyl radicals from an organic trifluoromethyl source. A substrate possessing easily replaceable ligands such as halogen or carbonyl, is initially contacted either in the plasma and within a short distance from a downstream visible edge of the plasma or outside of the visible portion of the plasma and within a short distance from the downstream visible edge, to effect a substitution of the halogen or carbonyl ligand on the substrate with a trifluoromethyl radical without substantial decomposition of the substrate.
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