- Radiation-induced C-C Bond Cleavage in 1,2-Diarylethanes as Model compounds of Coal. Part 1.- Pulse and Steady-state Radiolysis of 1,2-Di(1-naphthyl)ethane
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1,2-Di(1-naphthyl)ethane (1,2-DNE) has been used to study the radiation-induced C-C bond cleavage of the ethane linkage.Pulse radiolysis was applied both in the absence and presence of NaAlH4 and NaAlH2(OR)2 used as scavengers for solvent cations.In the presence of the sodium aluminium hydrides the radical anions of 1,2-DNE are stabilized by the metal cation, resulting in the formation of radical anion/sodium cation pairs (Na+, 1,2-DNE.-), these species have a rather long lifetime (τ>2 ms) in DME as well as in THF, and show three absorption bands at 330, 370 and 750 nm.In THF ε370=14000 dm3 mol-1 cm-1 and ε750=5000 dm3 mol-1 cm-1 were established.Cleavage of the ethano bridge of 1,2-DNE was achieved by means of steady-state as well as multi-pulse radiolysis in the presence of alkali-metal aluminium hydrides.The efficiency of this process was studied by using NaAlH4, NaAlH2(OR)2, NaAlH2Et2, NaAlEt4 and LiAlH4 in THF as well as in DME.The most efficient C-C bond cleavage results from the successive attack of two sodium cation/electron ion pairs (Na+, e-) forming the unstable dianions (2 Na+, 1,2-DNE2-).These decompose under scission of the ethano bridge, producing naphthylmethyl carbanionic fragments C10H7CH2-Na+ which supposedly form aluminate salts, e.g.C10H7CH2AlH3-Na+, with AlH3 generated in the scavenging processes.From these aluminate salts 1-methylnaphthalene is obtained through hydrolysis.
- Haenel, Matthias W.,Richter, Udo-Burckhard,Solar, Sonja,Getoff, Nikola
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- Vibronic Absorption Spectra of Naphthalene and Substituted Naphthalene Cations in Solid Argon
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Naphthalene and methyl- and halonaphthalene cations have been produced by one- and two-photon matrix photoionization techniques and trapped in solid argon for absorption spectroscopic study.Five transitions in the visible and ultraviolet regions have been assigned to the radical cations.The argon matrix absorption spectra are in agreement with photoelectron and photodissociation spectra, absorption spectra of the ions in Freon glasses, and simple HMO calculations.Substituent effects were observed for the origins of the five transitions.The repeating vibronic intervals in the red N+ transitions due to the C(9)-C(10) stretching fundamentals for this group of substituted naphthalene cations are 40 - 50 cm-1 above the Raman fundamentals for the molecules whereas the vibronic intervals due to ring deformation modes are up to 30 cm-1 below the appropriate Raman fundamentals, and vibronic intervals in the sharp UV band are 30 - 45 cm-1 below Raman fundamentals, which correlate with HMO ? bond orders.
- Andrews, Lester,Kelsall, Benuel J.,Blankenship, Terry A.
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- Metal-Organic Framework-Confined Single-Site Base-Metal Catalyst for Chemoselective Hydrodeoxygenation of Carbonyls and Alcohols
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Chemoselective deoxygenation of carbonyls and alcohols using hydrogen by heterogeneous base-metal catalysts is crucial for the sustainable production of fine chemicals and biofuels. We report an aluminum metal-organic framework (DUT-5) node support cobalt(II) hydride, which is a highly chemoselective and recyclable heterogeneous catalyst for deoxygenation of a range of aromatic and aliphatic ketones, aldehydes, and primary and secondary alcohols, including biomass-derived substrates under 1 bar H2. The single-site cobalt catalyst (DUT-5-CoH) was easily prepared by postsynthetic metalation of the secondary building units (SBUs) of DUT-5 with CoCl2 followed by the reaction of NaEt3BH. X-ray photoelectron spectroscopy and X-ray absorption near-edge spectroscopy (XANES) indicated the presence of CoII and AlIII centers in DUT-5-CoH and DUT-5-Co after catalysis. The coordination environment of the cobalt center of DUT-5-Co before and after catalysis was established by extended X-ray fine structure spectroscopy (EXAFS) and density functional theory. The kinetic and computational data suggest reversible carbonyl coordination to cobalt preceding the turnover-limiting step, which involves 1,2-insertion of the coordinated carbonyl into the cobalt-hydride bond. The unique coordination environment of the cobalt ion ligated by oxo-nodes within the porous framework and the rate independency on the pressure of H2 allow the deoxygenation reactions chemoselectively under ambient hydrogen pressure.
- Antil, Neha,Kumar, Ajay,Akhtar, Naved,Newar, Rajashree,Begum, Wahida,Manna, Kuntal
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supporting information
p. 9029 - 9039
(2021/06/28)
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- A New Protocol for Catalytic Reduction of Alkyl Chlorides Using an Iridium/Bis(benzimidazol-2′-yl)pyridine Catalyst and Triethylsilane
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The reduction of alkyl chlorides using triethylsilane is investigated. Primary, secondary, tertiary, and benzylic C-Cl bonds are effectively converted into C-H bonds using an [IrCl(cod)] 2/2,6-bis(benzimidazol-2′-yl)pyridine catalyst system. This catalyst system is quite simple since the tridentate N-ligand can be easily prepared in one step from commercially available reagents.
- Fukuyama, Takahide,Hamada, Yuki,Ryu, Ilhyong
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p. 3404 - 3408
(2021/07/14)
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- Preparation method of naphthalene ring C marked α .
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The invention discloses C labeled α - naphthalene acetic acid preparation method and belongs to the field of radioisotope C labeled compounds. C-labeled α - naphthylacetic acid preparation method, C radioisotope labeling is introduced on a naphthalene ring structure α -naphthol acid, C labeling site is in α-position. The method has the advantages that the reaction raw materials are easily available, the synthesis steps are high in yield, the total yield is more 60%, C marker isotopes are less in use amount, and waste is generated. The marker site α-position on the naphthalene ring is less likely to be metabolized compared to C-labeled branched acetic acid, and the synthesized C-labeled compound provides a better study of α -naphthoic acid in the environment.
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Paragraph 0046-0047; 0049; 0056-0057; 0059; 0066-0067; 0069
(2021/10/05)
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- Cobalt?NHC Catalyzed C(sp2)?C(sp3) and C(sp2)?C(sp2) Kumada Cross-Coupling of Aryl Tosylates with Alkyl and Aryl Grignard Reagents
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The first cobalt-catalyzed cross-coupling of aryl tosylates with alkyl and aryl Grignard reagents is reported. The catalytic system uses CoF3 and NHCs (NHC=N-heterocyclic carbene) as ancillary ligands. The reaction proceeds via highly selective C?O bond functionalization, leading to the corresponding products in up to 98 % yield. The employment of alkyl Grignard reagents allows to achieve a rare C(sp2)?C(sp3) cross-coupling of C?O electrophiles, circumventing isomerization and β-hydride elimination problems. The use of aryl Grignards leads to the formation of biaryls. The C?O cross-coupling sets the stage for a sequential cross-coupling by exploiting the orthogonal selectivity of the catalytic system.
- Piontek, Aleksandra,Och?dzan-Siod?ak, Wioletta,Bisz, Elwira,Szostak, Michal
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p. 202 - 206
(2020/12/01)
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- Synthesis of renewable alkylated naphthalenes with benzaldehyde and angelica lactone
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Herein, we report a new route for the synthesis of renewable alkylated naphthalenes (ANs) with benzaldehyde and angelica lactone, two platform compounds that can be derived from lignocellulose.
- Cong, Yu,Li, Guangyi,Li, Ning,Wang, Aiqin,Wang, Ran,Wang, Xiaodong,Xu, Jilei,Zhang, Tao
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supporting information
p. 5474 - 5480
(2021/08/16)
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- Method for hydrogenolysis of halides
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The invention discloses a method for hydrogenolysis of halides. The invention discloses a preparation method of a compound represented by a formula I. The preparation method comprises the following step: in a polar aprotic solvent, zinc, H2O and a compound represented by a formula II are subjected to a reaction as shown in the specification, wherein X is halogen; Y is -CHRR or R; hydrogenin H2O exists in the form of natural abundance or non-natural abundance. According to the preparation method, halide hydrogenolysis can be simply, conveniently and efficiently achieved through a simple and mild reaction system, and good functional group compatibility and substrate universality are achieved.
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Paragraph 0232; 0299-0301
(2021/01/11)
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- Catalytic Reductions Without External Hydrogen Gas: Broad Scope Hydrogenations with Tetrahydroxydiboron and a Tertiary Amine
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Facile reduction of aryl halides with a combination of 5% Pd/C, B2(OH)4, and 4-methylmorpholine is reported. Aryl bromides, iodides, and chlorides were efficiently reduced. Aryl dihalides containing two different halogen atoms underwent selective reduction: I over Br and Cl, and Br over Cl. Beyond these, aryl triflates were efficiently reduced. This combination was broadly general, effectuating reductions of benzylic halides and ethers, alkenes, alkynes, aldehydes, and azides, as well as for N-Cbz deprotection. A cyano group was unaffected, but a nitro group and a ketone underwent reduction to a low extent. When B2(OD)4 was used for aryl halide reduction, a significant amount of deuteriation occurred. However, H atom incorporation competed and increased in slower reactions. 4-Methylmorpholine was identified as a possible source of H atoms in this, but a combination of only 4-methylmorpholine and Pd/C did not result in reduction. Hydrogen gas has been observed to form with this reagent combination. Experiments aimed at understanding the chemistry led to the proposal of a plausible mechanism and to the identification of N,N-bis(methyl-d3)pyridin-4-amine (DMAP-d6) and B2(OD)4 as an effective combination for full aromatic deuteriation. (Figure presented.).
- Korvinson, Kirill A.,Akula, Hari K.,Malinchak, Casina T.,Sebastian, Dellamol,Wei, Wei,Khandaker, Tashrique A.,Andrzejewska, Magdalena R.,Zajc, Barbara,Lakshman, Mahesh K.
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supporting information
p. 166 - 176
(2020/01/02)
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- Iron-Catalyzed Direct Julia-Type Olefination of Alcohols
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Herein, we report an iron-catalyzed, convenient, and expedient strategy for the synthesis of styrene and naphthalene derivatives with the liberation of dihydrogen. The use of a catalyst derived from an earth-abundant metal provides a sustainable strategy to olefins. This method exhibits wide substrate scope (primary and secondary alcohols) functional group tolerance (amino, nitro, halo, alkoxy, thiomethoxy, and S- A nd N-heterocyclic compounds) that can be scaled up. The unprecedented synthesis of 1-methyl naphthalenes proceeds via tandem methenylation/double dehydrogenation. Mechanistic study shows that the cleavage of the C-H bond of alcohol is the rate-determining step.
- Landge, Vinod G.,Babu, Reshma,Yadav, Vinita,Subaramanian, Murugan,Gupta, Virendrakumar,Balaraman, Ekambaram
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p. 9876 - 9886
(2020/09/03)
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- C-F activation for C(sp2)-C(sp3) cross-coupling by a secondary phosphine oxide (SPO)-nickel complex
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A secondary phosphine oxide (SPO)-nickel catalyst allowed the activation of otherwise inert C-F bonds of unactivated arenes in terms of challenging couplings with primary and secondary alkyl Grignard reagents. The C-F activation is characterized by mild reaction conditions and high levels of branched selectivity. Electron-rich and electron-deficient arenes were suitable electrophiles for this transformation. In addition, this strategy also proved suitable to heterocycles and for the activation of C-O bonds under slightly modified conditions.
- Müller, Valentin,Ghorai, Debasish,Capdevila, Lorena,Messinis, Antonis M.,Ribas, Xavi,Ackermann, Lutz
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supporting information
p. 7034 - 7040
(2020/09/15)
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- Generation of Organozinc Reagents by Nickel Diazadiene Complex Catalyzed Zinc Insertion into Aryl Sulfonates
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The generation of arylzinc reagents (ArZnX) by direct insertion of zinc into the C?X bond of ArX electrophiles has typically been restricted to iodides and bromides. The insertions of zinc dust into the C?O bonds of various aryl sulfonates (tosylates, mesylates, triflates, sulfamates), or into the C?X bonds of other moderate electrophiles (X=Cl, SMe) are catalyzed by a simple NiCl2–1,4-diazadiene catalyst system, in which 1,4-diazadiene (DAD) stands for diacetyl diimines, phenanthroline, bipyridine and related ligands. Catalytic zincation in DMF or NMP solution at room temperature now provides arylzinc sulfonates, which undergo typical catalytic cross-coupling or electrophilic substitution reactions.
- Klein, Philippe,Lechner, Vivien Denise,Schimmel, Tanja,Hintermann, Lukas
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supporting information
p. 176 - 180
(2019/12/11)
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- Catalytic Methylation of Aromatic Hydrocarbons using CO2/H2 over Re/TiO2 and H-MOR Catalysts
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A combined catalyst comprising TiO2-supported Re (Re(1)/TiO2; Re=1 wt%) and H-MOR (SiO2/Al2O3=90) was found to promote the methylation of benzene using CO2 and H2. This catalytic system exhibited high performance with regard to the synthesis of methylated benzenes and gave high yields of total methylated products (up to 52 % benzene-based yield and 42 % CO2-based yield) under the reaction conditions employed in this study (pCO2=1 MPa; pH2=5 MPa; T=250 °C; t=20 h) in a batch reactor. Catalyst screening demonstrated that a combination of Re(1)/TiO2 and H-MOR (SiO2/Al2O3=90) exhibited superior performance compared to other combinations of supported metal catalysts and zeolites in terms of both yield and selectivity for methylated benzenes.
- Hakim Siddiki, S. M. A.,Kamakura, Haruka,Maeno, Zen,Matsushita, Koichi,Poly, Sharmin S.,Shimizu, Ken-ichi,Ting, Kah Wei,Toyao, Takashi
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- A methylation platform of unconventional inert aryl electrophiles: Trimethylboroxine as a universal methylating reagent
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Methylation is one of the most fundamental conversions in medicinal and material chemistry. Extension of substrate types from aromatic halides to other unconventional aromatic electrophiles is a highly important yet challenging task in catalytic methylation. Disclosed herein is a series of transition metal-catalyzed methylations of unconventional inert aryl electrophiles using trimethylboroxine (TMB) as the methylating reagent. This transformation features a broad substrate type, including nitroarenes, benzoic amides, benzoic esters, aryl cyanides, phenol ethers, aryl pivalates and aryl fluorides. Another important merit of this work is that these widespread "inert"functionalities are capable of serving as directing or activating groups for selective functionalization of aromatic rings before methylation, which greatly expands the connotation of methylation chemistry.
- Feng, Boya,Yang, Yudong,You, Jingsong
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p. 6031 - 6035
(2020/07/10)
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- Reductive Deamination with Hydrosilanes Catalyzed by B(C6F5)3
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The strong boron Lewis acid tris(pentafluorophenyl)borane B(C6F5)3 is known to catalyze the dehydrogenative coupling of certain amines and hydrosilanes at elevated temperatures. At higher temperature, the dehydrogenation pathway competes with cleavage of the C?N bond and defunctionalization is obtained. This can be turned into a useful methodology for the transition-metal-free reductive deamination of a broad range of amines as well as heterocumulenes such as an isocyanate and an isothiocyanate.
- Fang, Huaquan,Oestreich, Martin
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supporting information
p. 11394 - 11398
(2020/05/25)
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- Cleavage of C(sp3)-F Bonds in Trifluoromethylarenes Using a Bis(NHC)nickel(0) Complex
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The first example of the oxidative addition of a C(sp3)-F bond in trifluoromethylarenes to a nickel(0) complex is described. A nickel(0) complex that bears two N-heterocyclic carbene (NHC) ligands of low steric demand is able to cleave C(sp3)-F bonds of trifluoromethylarenes to afford the corresponding trans-difluorobenzyl nickel(II) fluoride complexes. Isolation and characterization studies suggested that the cleavage of the C(sp3)-F bond proceeds via an η2-arene nickel(0) complex. Taking advantage of the reactivity of these nickel(II) fluoride complexes, we developed a catalytic hydrodefluorination of trifluoromethylarenes using hydrosilanes. A computational study indicated that the electron-rich nickel(0) center supported by two relatively small NHC ligands cleaves the C(sp3)-F bond via a syn-SN2′ mechanism.
- Imiya, Hiroto,Iwamoto, Hiroaki,Ogoshi, Sensuke,Ohashi, Masato
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supporting information
p. 19360 - 19367
(2020/11/13)
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- Ni-Catalyzed Iterative Alkyl Transfer from Nitrogen Enabled by the in Situ Methylation of Tertiary Amines
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Current methods to achieve transition-metal-catalyzed alkyl carbon-nitrogen (C-N) bond cleavage require the preformation of ammonium, pyridinium, or sulfonamide derivatives from the corresponding alkyl amines. These activated substrates permit C-N bond cleavage, and their resultant intermediates can be intercepted to affect carbon-carbon bond-forming transforms. Here, we report the combination of in situ amine methylation and Ni-catalyzed benzalkyl C-N bond cleavage under reductive conditions. This method permits iterative alkyl group transfer from tertiary amines and demonstrates a deaminative strategy for the construction of Csp3-Csp3 bonds. We demonstrate PO(OMe)3 (trimethylphosphate) to be a Ni-compatible methylation reagent for the in situ conversion of trialkyl amines into tetraalkylammonium salts. Single, double, and triple benzalkyl group transfers can all be achieved from the appropriately substituted tertiary amines. Transformations developed herein proceed via recurring events: The in situ methylation of tertiary amines by PO(OMe)3, Ni-catalyzed C-N bond cleavage, and concurrent Csp3-Csp3 bond formation.
- Nwachukwu, Chideraa Iheanyi,McFadden, Timothy Patrick,Roberts, Andrew George
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p. 9979 - 9992
(2020/09/03)
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- Dehalogenative Deuteration of Unactivated Alkyl Halides Using D2O as the Deuterium Source
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The general dehalogenation of alkyl halides with zinc using D2O or H2O as a deuterium or hydrogen donor has been developed. The method provides an efficient and economic protocol for deuterium-labeled derivatives with a wide substrate scope under mild reaction conditions. Mechanistic studies indicated that a radical process is involved for the formation of organozinc intermediates. The facile hydrolysis of the organozinc intermediates provides the driving force for this transformation.
- Xia, Aiyou,Xie, Xin,Hu, Xiaoping,Xu, Wei,Liu, Yuanhong
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p. 13841 - 13857
(2019/10/17)
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- Phosphonic acid mediated practical dehalogenation and benzylation with benzyl halides
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For the first time, by using H3PO3/I2 system, various benzyl chlorides, bromides and iodides were dehalogenated successfully. In the presence of H3PO3, benzyl halides underwent electrophilic substitution reactions with electron-rich arenes, leading to a broad range of diarylmethanes in good yields. These transformations feature green, cheap reducing reagents and metal-free conditions. A possible mechanism was proposed.
- Gao, Jing,Han, Li-Biao,Ma, Yonghao,Tang, Zilong,Wu, Xiaofang,Xiao, Jing
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p. 22343 - 22347
(2019/07/31)
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- Water and Sodium Chloride: Essential Ingredients for Robust and Fast Pd-Catalysed Cross-Coupling Reactions between Organolithium Reagents and (Hetero)aryl Halides
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Direct palladium-catalysed cross-couplings between organolithium reagents and (hetero)aryl halides (Br, Cl) proceed fast, cleanly and selectively at room temperature in air, with water as the only reaction medium and in the presence of NaCl as a cheap additive. Under optimised reaction conditions, a water-accelerated catalysis is responsible for furnishing C(sp3)–C(sp2), C(sp2)–C(sp2), and C(sp)–C(sp2) cross-coupled products, in competition with protonolysis, within a reaction time of 20 s, in yields of up to 99 %, and in the absence of undesired dehalogenated/homocoupling side products even when challenging secondary organolithiums serve as the starting material. It is worth noting that the proposed protocol is scalable and the catalyst and water can easily and successfully be recycled up to 10 times, with an E-factor as low as 7.35.
- Dilauro, Giuseppe,Quivelli, Andrea Francesca,Vitale, Paola,Capriati, Vito,Perna, Filippo Maria
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supporting information
p. 1799 - 1802
(2019/01/25)
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- Nickel-Catalyzed C(sp2)?C(sp3) Kumada Cross-Coupling of Aryl Tosylates with Alkyl Grignard Reagents
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Aryl tosylates are an attractive class of electrophiles for cross-coupling reactions due to ease of synthesis, low price, and the employment of C?O electrophiles, however, the reactivity of aryl tosylates is low. Herein, we report the Ni-catalyzed C(sp2)?C(sp3) Kumada cross-coupling of aryl tosylates with primary and secondary alkyl Grignard reagents. The method delivers valuable alkyl arenes by cross-coupling with challenging alkyl organometallics possessing β-hydrogens that are prone to β-hydride elimination and homo-coupling. The reaction is catalyzed by an air- and moisture stable-Ni(II) precatalyst. A broad range of electronically-varied aryl tosylates, including bis-tosylates, underwent this transformation, and many examples are suitable at mild room temperature conditions. The combination of Ar?X cross-coupling with the facile Ar?OH activation/cross-coupling strategy permits for orthogonal cross-coupling with challenging alkyl organometallics. Furthermore, we demonstrate that the method operates with TON reaching 2000, which is one of the highest turnovers observed to date in Ni-catalyzed cross-couplings. (Figure presented.).
- Piontek, Aleksandra,Och?dzan-Siod?ak, Wioletta,Bisz, Elwira,Szostak, Michal
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supporting information
p. 2329 - 2336
(2019/04/13)
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- Synthesis of mesoporous ZSM-5 zeolites and catalytic cracking of ethanol and oleic acid into light olefins
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Conversion of biomass-derived chemicals into light olefins is a promising method to maintain sustainable development of light olefin industry. In this study, three mesoporous ZSM-5 zeolites (MZSM-5-A, MZSM-5-B and MZSM-5-C) with major pore diameter about 4.8 nm, 16 nm and 22 nm were synthesized using a hydrothermal method by utilizing different templates. The catalytic activity of catalysts was studied by catalytic cracking of ethanol and oleic acid. The influence of reaction temperature on conversion and product selectivity was investigated. The characterization of ZSM-5 samples showed that the orders of the external surface area and mesopore volume were MZSM-5-C > MZSM-5-B > MZSM-5-A > conventional HZSM-5. In ethanol to light olefin reaction, MZSM-5-C achieved the highest light olefin yield (318.3 mL g?1) and ethylene selectivity (42.3%) at 400 °C. In oleic acid to light olefin reaction, MZSM-5-B achieved a complete conversion of oleic acid at 500 °C, and obtained the highest light olefin selectivity (38.1%) at 550 °C. The difference may be relevant to the size and chemical structure of feedstock molecular as well as the acidity of catalysts. Regardless of ethanol or oleic acid as feedstock, introduction of mesopore in zeolites significantly enhanced the light olefin yield and selectivity.
- Zhao, Tingting,Li, Fuwei,Yu, Hongchang,Ding, Shilei,Li, Zhixia,Huang, Xinyuan,Li, Xiang,Wei, Xiaohan,Wang, Zhenlin,Lin, Hongfei
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p. 101 - 110
(2019/02/24)
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- Photocatalytic carbanion generation-benzylation of aliphatic aldehydes to secondary alcohols
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We present a redox-neutral method for the photocatalytic generation of carbanions. Benzylic carboxylates are photooxidized by single electron transfer; immediate CO2 extrusion and reduction of the in situ formed radical yields a carbanion capable of reacting with aliphatic aldehydes as electrophiles giving the Grignard analogous reaction product.
- Donabauer, Karsten,Maity, Mitasree,Berger, Anna Lucia,Huff, Gregory S.,Crespi, Stefano,K?nig, Burkhard
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p. 5162 - 5166
(2019/06/05)
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- Catalytic Carboxylation of Heteroaromatic Compounds: Double and Single Carboxylation with CO 2
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In the presence of PdCl 2 [P(n -Bu) 3 ] 2 (10 mol%) and ZnEt 2, 2-furyl and 2-pyrrolylmethyl acetate were carboxylated with CO 2 (1 atm), affording doubly carboxylated products in good yields. In this dearomative transformation, α,?-dicarboxylic acids were obtained selectively, in contrast to our previous report in which α,γ-dicarboxylic acids were selectively produced from 2-indolylmethyl acetates. In contrast, 5-thiazolylmethyl acetate and naphthylmethyl acetates predominantly underwent single carboxylation.
- Mita, Tsuyoshi,Masutani, Hiroki,Ishii, Sho,Sato, Yoshihiro
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supporting information
p. 841 - 845
(2019/04/25)
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- Method for synthesizing aromatic compound by coupling palladium/imidazole salt with nitroaromatic hydrocarbon and boric acid compound (by machine translation)
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The invention discloses a method, for coupling a palladium/imidazole salt with a nitroaromatic hydrocarbon and a boric acid compound to synthesize an aromatic compound. The method comprises: in organic solvent, taking nitroaromatic hydrocarbon and boric acid compound as substrate, palladium/imidazole salt as a catalyst, carrying out coupling reaction under the action of alkali, and carrying out post-treatment to obtain the aromatic compound. The method is simple, easy to store, low in price, relatively low in ligand consumption, high in product yield, good in substrate applicability, and suitable for alkyl boronic acid. The process of the invention can be used to synthesize a series of aromatic compounds, for example. The compound has wide application value in the fields of pesticides, medicines, materials and the like. (by machine translation)
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Paragraph 0149-0153
(2019/10/01)
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- Sterically hindered N-heterocyclic carbene/palladium(ii) catalyzed Suzuki-Miyaura coupling of nitrobenzenes
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Palladium-catalyzed denitrative Suzuki coupling of nitroarenes using 2-aryl-5-(2,4,6-triisopropylphenyl)-2,3-imidazolylidene[1,5-a]pyridines as the ligands is described. The key to success is the use of the NHC ligands which show strong donating ability and suitable steric hindrance allowing the successful oxidative addition of Ar-NO2 bonds. Both aromatic and aliphatic boronic acids are tolerated, and a variety of biphenyls and alkylarenes were obtained in good to excellent yields.
- Chen, Kai,Chen, Wei,Yi, Xiaofei,Chen, Wanzhi,Liu, Miaochang,Wu, Huayue
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supporting information
p. 9287 - 9290
(2019/08/08)
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- Acceptorless Dehydrogenation of Hydrocarbons by Noble-Metal-Free Hybrid Catalyst System
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A hybrid catalysis that comprises an acridinium photoredox catalyst, a thiophosphate organocatalyst, and a nickel catalyst-enabled acceptorless dehydrogenation of hydrocarbons is reported. The cationic nickel complex played a critical role in the reactivity. This is the first example of acceptorless dehydrogenation of hydrocarbons by base metal catalysis under mild reaction conditions of visible light irradiation at room temperature.
- Fuse, Hiromu,Kojima, Masahiro,Mitsunuma, Harunobu,Kanai, Motomu
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supporting information
p. 2042 - 2045
(2018/04/16)
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- Decarbonylative Methylation of Aromatic Esters by a Nickel Catalyst
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A Ni-catalyzed decarbonylative methylation of aromatic esters was achieved using methylaluminums as methylating agents. Dimethylaluminum chlorides uniquely worked as the methyl source. Because of the Lewis acidity of aluminum reagents, less reactive alkyl esters could also undergo the present methylation. By controlling the Lewis acidity of aluminum reagents, a chemoselective decarbonylative cross-coupling between alkyl esters and phenyl esters was successful.
- Okita, Toshimasa,Muto, Kei,Yamaguchi, Junichiro
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p. 3132 - 3135
(2018/05/28)
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- Pd-Ni BMNPs Encapsulated in UiO-66 as an Efficient Catalyst for the Activation of “Inert” C?O Bonds
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A catalytic system based on Pd?Ni bimetallic nanoparticles (BMNPs) encapsulated in the nanocavities of UiO-66 was established for the activation of C?O bonds in ethers. Pd0.25Ni4@UiO-66 catalyst show excellent catalytic performance in the directly methylation and arylation of ethers under a mild reaction condition. High catalytic activity of the catalyst could be ascribed to the “synergistic effect” between the two metal components and strong interaction between BMNPs and the carrier (UiO-66). BMNPs encapsulated in UiO-66 also guarantee a good reusability of the catalyst, the catalyst delivered high catalytic activity for at least four cycles. Our work highlights the great potential value of ethers as powerful alternatives for aryl halides as well as the bright future of BMNPs and MOFs in the catalysis field.
- Zhang, Jia-Wei,Li, Dan-Dan,Lu, Guo-Ping,Deng, Tao,Cai, Chun
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p. 4258 - 4263
(2018/09/14)
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- Ru-Catalyzed Completely Deoxygenative Coupling of 2-Arylethanols through Base-Induced Net Decarbonylation
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Substituted arylethanols can be coupled by using a readily available Ru catalyst in a fully deoxygenative manner to produce hydrocarbon chains in one step. Control experiments indicate that the first deoxygenation occurs through an aldol condensation, whereas the second occurs through a base-induced net decarbonylation. This double deoxygenation enables further development in the use of alcohols as versatile and green alkylating reagents, as well as in other fields, such as deoxygenation and upgrading of overfunctionalized biomass to produce hydrocarbons.
- Manojveer, Seetharaman,Forrest, Sebastian J. K.,Johnson, Magnus T.
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supporting information
p. 803 - 807
(2018/01/27)
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- Methylation of Arenols through Ni-catalyzed C—O Activation with Methyl Magnesium Bromide
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Direct alkylation of arenols with alkyl organometallic reagents has never been approached. Herein we reported the first successful example of nickel-catalyzed methylation of arenols with methyl Grignard reagents to construct C(sp2)-C(sp3/
- Shi, Wen-Juan,Shi, Zhang-Jie
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supporting information
p. 183 - 186
(2018/01/15)
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- Palladium-Catalyzed Ligand-Controlled Regioselective Nucleophilic Aromatic Substitution of 1-(Chloromethyl)naphthalenes with Arylacetonitriles
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The palladium-catalyzed reaction of 1-(chloromethyl)naphthalenes 1 with (hetero)arylacetonitriles 2 gives either para- or ortho-acylated naphthalenes (3 or 4) in good to high yields. The regioselectivity can be controlled by the ligand of a palladium catalyst. A sterically bulky ligand, tBuPPh2, affords para-acylated products 3, whereas a sterically less bulky ligand, Me2PPh, provides ortho-acylated products 4. Further, direct substitution product 5 at the benzylic position is not obtained essentially, although such a reaction at the benzylic position is favorable in ordinary nucleophilic substitutions. In this paper, it was revealed that the benzylpalladium intermediate could react through a different mode (η3-benzylpalladium intermediate or η1-benzylpalladium intermediate) in nucleophilic aromatic substitution. In addition to the interesting mechanistic aspect, the present reaction provides a facile synthetic method for a wide range of diaryl ketones, some of which are not easily available through the previously known procedures.
- Zhang, Sheng,Yamamoto, Yoshinori,Bao, Ming
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p. 13981 - 13990
(2018/11/30)
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- Palladium-Catalyzed Reductive Conversion of Acyl Fluorides via Ligand-Controlled Decarbonylation
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Ligand-controlled non-decarbonylative and decarbonylative conversions of acyl fluorides were developed using a Pd(OAc)2/Et3SiH combination. When tricyclohexylphosphine (PCy3) was used as the ligand, aldehydes were obtained as simple reductive conversion products. The use of 1,2-bis(dicyclohexylphosphino)ethane (Cy2P(CH2)2PCy2, DCPE) as the ligand, however, favored the formation of hydrocarbons, which are decarbonylative reduction products.
- Ogiwara, Yohei,Sakurai, Yuka,Hattori, Hiroyuki,Sakai, Norio
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supporting information
p. 4204 - 4208
(2018/07/29)
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- Nickel-Catalyzed Reductive Cleavage of Carbon-Oxygen Bonds in Anisole Derivatives Using Diisopropylaminoborane
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The catalytic removal of a methoxy group on an aromatic ring allows this group to be used as a traceless activating and directing group for aromatic functionalization reactions. Although several catalytic methods for the reductive cleavage of anisole derivatives have been reported, all are applicable only to π-extended aryl ethers, such as naphthyl and biphenyl ethers, while monocyclic aryl ethers cannot be reduced. Herein, we report a nickel-catalyzed reductive cleavage reaction of C-O bonds in aryl ethers using diisopropylaminoborane as the reducing agent. Unlike previously reported methods, this reducing reagent allows effective C-O bond reduction in a much wider range of aryl ether substrates, including monocyclic and heterocyclic ethers bearing various functional groups.
- Igarashi, Takuya,Haito, Akira,Chatani, Naoto,Tobisu, Mamoru
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p. 7475 - 7483
(2018/07/21)
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- Ni-Catalyzed cross-coupling of aryl thioethers with alkyl Grignard reagents via C-S bond cleavage
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A Ni-catalyzed cross-coupling of aryl thioethers with alkyl Grignard reagents, accompanied by the cleavage of the C(aryl)-SMe bond, has been presented. This method is distinguished by its mild conditions and moderate functional group tolerance, such as hydroxyl, halogen, and heterocycles, which should provide a straightforward access to the modification of sulfur-containing molecules.
- Zhu, Dan,Shi, Lei
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supporting information
p. 9313 - 9316
(2018/08/29)
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- Palladium triggered diene formation from nitro allylic compounds: A versatile entry into naphthalene derivatives
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Nitro allylic derivatives were converted into dienes through the elimination of the nitro group under basic treatment, in the presence of a palladium catalyst. This reaction probably involves the formation of a palladium π-allyl complex followed by a base-promoted β-hydride elimination. This reaction, combined with the condensation of ketones with nitromethane and the functionalization of the resulting nitrocycloalkenes, constitutes a very powerful synthetic tool for the formation of dienes. Particular attention has been brought to the application of this methodology to the formation of 1-substituted naphthalenes from 1-tetralone.
- Kerim, Mansour Dolè,Jia, Shuanglong,Theodorakidou, Chrysoula,Prévost, Sébastien,El Ka?m, Laurent
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supporting information
p. 10917 - 10920
(2018/10/02)
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- Trimethylphosphate as a Methylating Agent for Cross Coupling: A Slow-Release Mechanism for the Methylation of Arylboronic Esters
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A methyl group on an arene, despite its small size, can have a profound influence on biologically active molecules. Typical methods to form a methylarene involve strong nucleophiles or strong and often toxic electrophiles. We report a strategy for a new, highly efficient, copper and iodide co-catalyzed methylation of aryl- and heteroarylboronic esters with the mild, nontoxic reagent trimethylphosphate, which has not been used previously in coupling reactions. We show that it reacts in all cases tested in yields that are higher than those of analogous copper-catalyzed reactions of MeOTs or MeI. The combination of C-H borylation and this methylation with trimethylphosphate provides a new approach to the functionalization of inert C-H bonds and is illustrated by late-stage methylation of four medicinally active compounds. In addition, reaction on a 200 mmol scale demonstrates reliability of this method. Mechanistic studies show that the reaction occurs by a slow release of methyl iodide by reaction of PO(OMe)3 with iodide catalyst, rather than the typical direct oxidative addition to a metal center. The low concentration of the reactive electrophile enables selective reaction with an arylcopper intermediate, rather than nucleophilic groups on the arylboronate, and binding of tert-butoxide to the boronate inhibits reaction of the electrophile with the tert-butoxide activator to form methyl ether.
- He, Zhi-Tao,Li, Haoquan,Haydl, Alexander M.,Whiteker, Gregory T.,Hartwig, John F.
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supporting information
p. 17197 - 17202
(2018/12/14)
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- Manganese-Catalyzed Direct Deoxygenation of Primary Alcohols
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Deoxygenation of alcohols is an important tool in the repertoire of defunctionalization methods in modern synthetic chemistry. We report the base-metal-catalyzed direct deoxygenation of benzylic and aliphatic primary alcohols via oxidative dehydrogenation/Wolff-Kishner reduction. The reaction is catalyzed by a well-defined PNP pincer complex of Earth-abundant manganese, evolving H2, N2, and water as the only byproducts.
- Bauer, Jonathan O.,Chakraborty, Subrata,Milstein, David
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p. 4462 - 4466
(2017/07/24)
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- Aminopyridine-Borane Complexes as Hydrogen Atom Donor Reagents: Reaction Mechanism and Substrate Selectivity
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Lewis base-borane complexes are shown to be potent hydrogen atom donors in radical chain reduction reactions. Results obtained in 1H, 11B, and 13C NMR measurements and kinetic experiments support a complex reaction mechanism involving the parent borane as well as its initial reaction products as active hydrogen atom donors. Efficient reduction reactions of iodides, bromides, and xanthates in apolar solvents rely on initiator systems generating oxygen-centered radicals under thermal conditions and pyridine-borane complexes carrying solubilizing substituents. In contrast to tin hydride reagents, the pyridine-boranes reduce xanthates faster than the corresponding iodides.
- Barth, Florian,Achrainer, Florian,Pütz, Alexander M.,Zipse, Hendrik
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p. 13455 - 13464
(2017/10/05)
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- Oxygen Activated, Palladium Nanoparticle Catalyzed, Ultrafast Cross-Coupling of Organolithium Reagents
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The discovery of an ultrafast cross-coupling of alkyl- and aryllithium reagents with a range of aryl bromides is presented. The essential role of molecular oxygen to form the active palladium catalyst was established; palladium nanoparticles that are highly active in cross-coupling reactions with reaction times ranging from 5 s to 5 min are thus generated in situ. High selectivities were observed for a range of heterocycles and functional groups as well as for an expanded scope of organolithium reagents. The applicability of this method was showcased by the synthesis of the [11C]-labeled PET tracer celecoxib.
- Heijnen, Dorus,Tosi, Filippo,Vila, Carlos,Stuart, Marc C. A.,Elsinga, Philip H.,Szymanski, Wiktor,Feringa, Ben L.
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supporting information
p. 3354 - 3359
(2017/03/17)
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- Reductive Homocoupling of Organohalides Using Nickel(II) Chloride and Samarium Metal
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A homocoupling method for organohalides and organosulfonates promoted by samarium metal and HMPA, and catalyzed by NiCl2 has been developed. Various organohalides (benzyl, aryl, heterocyclic, alkenyl and alkyl halides), α-haloacetophenones, and phenyl organosulfonates were tolerated, and the reaction afforded coupling products with high efficiency. Excellent chemoselectivity was exhibited between halides and other groups, such as ?COOH, ?NO2, halogen, heterocyclic ring, ester, and ketone groups. The stereoselectivity suggested that the reaction mechanism might involve an organosamarium species.
- Liu, Yongjun,Xiao, Shuhuan,Qi, Yan,Du, Feng
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p. 673 - 678
(2017/03/22)
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- Arylation of hydrocarbons enabled by organosilicon reagents and weakly coordinating anions
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Over the past 80 years, phenyl cation intermediates have been implicated in a variety of C-H arylation reactions. Although these examples have inspired several theoretical and mechanistic studies, aryl cation equivalents have received limited attention in organic methodology. Their high-energy, promiscuous reactivity profiles have hampered applications in selective intermolecular processes. We report a reaction design that overcomes these challenges. Specifically, we found that b-silicon-stabilized aryl cation equivalents, generated via silylium-mediated fluoride activation, undergo insertion into sp3 and sp2 C-H bonds. This reaction manifold provides a framework for the catalytic arylation of hydrocarbons, including simple alkanes such as methane. This process uses low loadings of Earth-abundant initiators (1 to 5 mole percent) and occurs under mild conditions (30° to 100°C).
- Shao, Brian,Bagdasarian, Alex L.,Popov, Stasik,Nelson, Hosea M.
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- Hybrid Catalysis Enabling Room-Temperature Hydrogen Gas Release from N-Heterocycles and Tetrahydronaphthalenes
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Hybrid catalyst systems to achieve acceptorless dehydrogenation of N-heterocycles and tetrahydronaphthalenes-model substrates for liquid organic hydrogen carriers-were developed. A binary hybrid catalysis comprising an acridinium photoredox catalyst and a Pd metal catalyst was effective for the dehydrogenation of N-heterocycles, whereas a ternary hybrid catalysis comprising an acridinium photoredox catalyst, a Pd metal catalyst, and a thiophosphoric imide organocatalyst achieved dehydrogenation of tetrahydronaphthalenes. These hybrid catalyst systems allowed for 2 molar equiv of H2 gas release from six-membered N-heterocycles and tetrahydronaphthalenes under mild conditions, i.e., visible light irradiation at rt. The combined use of two or three different catalyst types was essential for the catalytic activity.
- Kato, Shota,Saga, Yutaka,Kojima, Masahiro,Fuse, Hiromu,Matsunaga, Shigeki,Fukatsu, Arisa,Kondo, Mio,Masaoka, Shigeyuki,Kanai, Motomu
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supporting information
p. 2204 - 2207
(2017/02/23)
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- Nickel-catalyzed cross-coupling of aryl or 2-menaphthyl quaternary ammonium triflates with organoaluminum reagents
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The cross-coupling of aryltrimethylammonium triflates with AlMe3 and β-H-containing trialkylaluminums was performed in dioxane at 110 °C under catalysis of (dppp)NiCl2 to afford alkylated arenes. The cross-coupling of 2-menaphthyltri
- He, Fang,Wang, Zhong-Xia
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p. 4450 - 4457
(2017/06/30)
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- Electrochemical behavior of N-oxyphthalimides: Cascades initiating self-sustaining catalytic reductive N―O bond cleavage
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N-oxyphthalimides are stable and easily accessible compounds that can produce oxygen radicals upon 1-electron reduction. We present a systematic study of electrochemical properties of N-oxyphthalimide derivatives (PI-ORs) in DMF by cyclic voltammetry. In all cases, electron transfer to the substrate leads to decomposition of the intermediate radical anion via the N―O bond cleavage. In the case of benzyloxyphthalimide or its derivatives containing electron-donating substituents, reductive electron transfer induces the chain decomposition of the substrate to phthalimide (PI) radical-anion and the corresponding carbonyl compound. The PI radical-anion product is a powerful reductant that can transfer an electron to the reactant PI-OR, thus establishing a catalytic cycle for reductive N―O scission. This self-catalytic process is reflected in a considerable decrease in the reduction current for the substrate (-/molecule). By contrast, reductive fragmentations of benzyl derivatives containing electron-withdrawing substituents in the aromatic ring or at the benzylic position, as well as tosyl and alkyl derivatives, occur via a 1-electron mechanism. A sequence of N―O and C―C scissions was engineered to support the intermediacy of O-centered radicals in these processes.
- Syroeshkin, Mikhail A.,Krylov, Igor B.,Hughes, Audrey M.,Alabugin, Igor V.,Nasybullina, Darya V.,Sharipov, Mikhail Yu.,Gultyai, Vadim P.,Terent'ev, Alexander O.
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- Electron-Transfer and Hydride-Transfer Pathways in the Stoltz–Grubbs Reducing System (KOtBu/Et3SiH)
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Recent studies by Stoltz, Grubbs et al. have shown that triethylsilane and potassium tert-butoxide react to form a highly attractive and versatile system that shows (reversible) silylation of arenes and heteroarenes as well as reductive cleavage of C?O bonds in aryl ethers and C?S bonds in aryl thioethers. Their extensive mechanistic studies indicate a complex network of reactions with a number of possible intermediates and mechanisms, but their reactions likely feature silyl radicals undergoing addition reactions and SH2 reactions. This paper focuses on the same system, but through computational and experimental studies, reports complementary facets of its chemistry based on a) single-electron transfer (SET), and b) hydride delivery reactions to arenes.
- Smith, Andrew J.,Young, Allan,Rohrbach, Simon,O'Connor, Erin F.,Allison, Mark,Wang, Hong-Shuang,Poole, Darren L.,Tuttle, Tell,Murphy, John A.
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supporting information
p. 13747 - 13751
(2017/10/12)
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- Conversion of propionic acid and 3-pentanone to hydrocarbons on ZSM-5 catalysts: Reaction pathway and active site
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Conversion of propionic acid to gasoline-range molecules was investigated at 350?°C on a series of ZSM-5 catalysts with varying density of Br?nsted acid sites (BAS), achieved by ion exchange of proton with Na+. Ketonization of propionic acid to 3-pentanone is the primary reaction, with the sequential aldol condensation to dipentanone alcohol being the secondary. The major reaction pathway for forming the aromatics involves dehydration, cyclization, dehydration and hydride transfer from dipentanone alcohol, leading to the formation of C10 aromatics before being dealkylated to lighter aromatics. Temperature programmed desorption of propionic acid indicates that the reaction initiates with acylium cation formation on BAS through dehydration. Comparing the turnover frequencies of ketonization and aldol condensation on ZSM-5 with varying density of BAS indicates that BAS is the active site for both reactions. The propionic acid feed deactivates the catalyst faster than the 3-pentantone feed due to a stronger adsorption of propionic acid on the acid sites of ZSM-5.
- Wang, Xuefen,Ding, Shuang,Wang, Hua,Liu, Xiao,Han, Jinyu,Ge, Qingfeng,Zhu, Xinli
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- Iron-Catalyzed C(sp2)–C(sp3) Cross-Coupling of Alkyl Grignard Reagents with Polyaromatic Tosylates
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The iron-catalyzed cross-coupling of polyaromatic tosylates with alkyl Grignard reagents controlled by O-coordinating ligand is reported. The reaction operates under very mild, operationally practical conditions to furnish alkylated polyaromatics that are a common motif in a wide range of electronic-material, pharmaceutical and high-performance fluid applications. The challenging C(sp2)–C(sp3) cross-coupling products are obtained in good to excellent yields obviating the problems associated with β-hydride elimination. For the first time the coupling of polyaromatic tosylates can be achieved in the presence of sensitive carboxylic acid derived functional groups. Mechanistic studies suggest that the reaction selectivity can be correlated with the reduction potential of polyaromatic hydrocarbons. The method represents a rare example of sustainable C–O bond alkylation of polyarenes at room temperature.
- Piontek, Aleksandra,Szostak, Michal
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p. 7271 - 7276
(2018/01/02)
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- En Route to a Practical Primary Alcohol Deoxygenation
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A long-standing scientific challenge in the field of alcohol deoxygenation has been direct catalytic sp3 C-O defunctionalization with high selectivity and efficiency, in the presence of other functionalities, such as free hydroxyl groups and amines widely present in biological molecules. Previously, the selectivity issue had been only addressed by classic multistep deoxygenation strategies with stoichiometric reagents. Herein, we propose a catalytic late-transition-metal-catalyzed redox design, on the basis of dehydrogenation/Wolff-Kishner (WK) reduction, to simultaneously tackle the challenges regarding step economy and selectivity. The early development of our hypothesis focuses on an iridium-catalyzed process efficient mainly with activated alcohols, which dictates harsh reaction conditions and thus limits its synthetic utility. Later, a significant advancement has been made on aliphatic primary alcohol deoxygenation by employing a ruthenium complex, with good functional group tolerance and exclusive selectivity under practical reaction conditions. Its synthetic utility is further illustrated by excellent efficiency as well as complete chemo- and regio-selectivity in both simple and complex molecular settings. Mechanistic discussion is also included with experimental supports. Overall, our current method successfully addresses the aforementioned challenges in the pertinent field, providing a practical redox-based approach to the direct sp3 C-O defunctionalization of aliphatic primary alcohols.
- Dai, Xi-Jie,Li, Chao-Jun
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supporting information
p. 5433 - 5440
(2016/05/19)
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- Preparation of a new solid acid and its catalytic performance in di(1-naphthyl)methane hydrocracking
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A new solid acid was prepared by trifluoromethanesulfonic acid (TFMSA) impregnation into an acid-treated attapulgite (ATA). Di(1-naphthyl)methane (DNM) hydrocracking was used as the probe reaction to evaluate the catalytic performance of TFMSA/ATA for cleaving Car–Calk bridged bonds in coals. The results show that DNM was specifically hydrocracked to naphthalene and 1-methylnaphthalene over TFMSA/ATA in methanol in the absence of gaseous hydrogen. In particular, TFMSA/ATA was demonstrated to be stable after four cycles with slight loss in catalytic activity. Furthermore, a proposed H+ transfer mechanism successfully interprets the TFMSA/ATA-catalyzed hydrocracking reaction of DNM.
- Zhao, Meixia,Wei, Xianyong,Zong, Zhimin
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p. 1324 - 1330
(2016/09/07)
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- Alkyl-Aryl Coupling Catalyzed by Tandem Systems of Pincer-Ligated Iridium Complexes and Zeolites
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We report that pincer-ligated iridium catalysts for alkane dehydrogenation can operate in tandem with zeolite catalysts for arene-alkene coupling, to effect the overall intramolecular dehydrocoupling of alkyl-H and aryl-H bonds (i.e., the dehydrocyclization of alkyl benzene). Thus, zeolite and soluble iridium cocatalysts in refluxing pentylbenzene (205 °C) gave high yields of 1-methyl-1,2,3,4-tetrahydronaphthalene. Subsequent dehydrogenation and isomerization affords 1- and 2-methylnaphthalene and 2-methyl-1,2,3,4-tetrahydronaphthalene. Total yields of cyclized product as high as 5.4 M (94%) have been obtained, corresponding to 6800 turnovers per mol Ir. Turnover numbers for the tandem-catalyzed dehydrocyclization are much greater than those obtained for simple dehydrogenation by Ir catalysts (to give olefins) in the absence of zeolite.
- Dinh, Long V.,Li, Bo,Kumar, Akshai,Schinski, William,Field, Kathleen D.,Kuperman, Alexander,Celik, Fuat E.,Goldman, Alan S.
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p. 2836 - 2841
(2016/07/06)
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- Nickel-Catalyzed Borylation of Aryl and Benzyl 2-Pyridyl Ethers: A Method for Converting a Robust ortho-Directing Group
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The nickel-catalyzed borylation of aryl 2-pyridyl ethers via the loss of a 2-pyridyloxy group is described. This method allows a 2-pyridyloxy group to be used as a convertible directing group in C?H bond functionalization reactions. The nickel catalyst can also borylate arylmethyl 2-pyridyl ethers, in which the stereochemistry at the benzylic position is retained in the case of chiral secondary benzylic substrates. (Figure presented.).
- Tobisu, Mamoru,Zhao, Jiangning,Kinuta, Hirotaka,Furukawa, Takayuki,Igarashi, Takuya,Chatani, Naoto
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p. 2417 - 2421
(2016/08/16)
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