- The synthesis of 3,3,4,4-tetraphenyl-2-butanone from 1,1-diphenylacetone
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The preparation of 3,3,4,4-tetraphenyl-2-butanone by treatment of 1,1-diphenylacetone(1,1-DPA) with potassium-t-butoxide or lithium diisopropyl amide in THF at 0°C followed by heating with a diphenylmethylhalide is described. A single crystal X-ray analys
- Zieger, Herman E.,Tsang, Choi Han,Malik, Mohammed,Todaro, Louis J.
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- Generation of chirality in a two-component molecular crystal of acridine and diphenylacetic acid and its absolute asymmetric photodecarboxylating condensation
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Despite the fact that acridine (1) and diphenylacetic acid (a) are achiral compounds, a chiral two-component molecular crystal (1·a) in which two molecules are self-assembled in a 1:1 molar ratio by hydrogen bonding crystallizes spontaneously from an acet
- Koshima, Hideko,Ding, Kuiling,Chisaka, Yosuke,Matsuura, Teruo
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- Kinetic Properties of Caged Ambident Radicals Formed in the Thermolyses of Nitrones
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Thermal decompositions of N-benzhydryl-α,α-diphenylnitrone (1) and the para-tetradeuterated analogue 1-d4 in several solvents are reported.Mass spectral analyses of recovered nitrones and/or O-benzhydryl ethers were performed.These data are combined with previously reported spectroscopic rate constants for the decomposition of 1 to evaluate the true carbon-nitrogen homolysis rate constant and the relative rate constants for (a) geminate radical recombination at the iminoxy nitrogen, (b) irreversible recombination at oxygen, and (c) diffusion of the solvent-caged radicals.
- Villarreal, Jose A.,Grubbs, Edward J.
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- Photoinduced Decarboxylative Radical Coupling Reaction of Multiply Oxygenated Structures by Catalysis of Pt-Doped TiO2
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A new reaction system was devised for decarboxylative radical coupling reactions by heterogeneous semiconductor photoredox catalysis. When an α-alkoxy carboxylic acid and Pt-doped TiO2 in EtOAc were irradiated with a violet light-emitting diode at room te
- Kuwana, Daiki,Komori, Yuma,Nagatomo, Masanori,Inoue, Masayuki
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p. 730 - 736
(2022/01/12)
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- Molybdenum-Catalyzed Deoxygenation Coupling of Lignin-Derived Alcohols for Functionalized Bibenzyl Chemicals
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With the growing demand for sustainability and reducing CO2 footprint, lignocellulosic biomass has attracted much attention as a renewable, carbon-neutral and low-cost feedstock for the production of chemicals and fuels. To realize efficient utilization of biomass resource, it is essential to selectively alter the high degree of oxygen functionality of biomass-derivates. Herein, we introduced a novel procedure to transform renewable lignin-derived alcohols to various functionalized bibenzyl chemicals. This strategy relied on a short deoxygenation coupling pathway with economical molybdenum catalyst. A well-designed H-donor experiment was performed to investigate the mechanism of this Mo-catalyzed process. It was proven that benzyl carbon-radical was the most possible intermediate to form the bibenzyl products. It was also discovered that the para methoxy and phenolic hydroxyl groups could stabilize the corresponding radical intermediates and then facilitate to selectively obtain bibenzyl products. Our research provides a promising application to produce functionalized aromatics from biomass-derived materials.
- Jiang, Huifang,Lu, Rui,Luo, Xiaolin,Si, Xiaoqin,Xu, Jie,Lu, Fang
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supporting information
p. 1292 - 1296
(2020/12/09)
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- Synthesis of Dibenzyls by Nickel-Catalyzed Homocoupling of Benzyl Alcohols
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Dibenzyls are essential building blocks that are widely used in organic synthesis, and they are typically prepared by the homocoupling of halides, organometallics, and ethers. Herein, we report an approach to this class of compounds using alcohols, which are more stable and readily available. The reaction proceeds via nickel-catalyzed and dimethyl oxalate assisted dynamic kinetic homocoupling of benzyl alcohols. Both primary and secondary alcohols are tolerated.
- Pan, Feng-Feng,Guo, Peng,Huang, Xiaochuang,Shu, Xing-Zhong
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p. 3094 - 3100
(2021/04/23)
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- Use of Isopropyl Alcohol as a Reductant for Catalytic Dehydoxylative Dimerization of Benzylic Alcohols Utilizing Ti?O Bond Photohomolysis
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Photohomolysis of Ti?O bonds is utilized in photocatalytic generation of titanium(III) species for dehydroxylative dimerization of benzylic alcohols under UV-light irradiation by using isopropyl alcohol (IPA) as a stoichiometric reductant. In this reaction, IPA works not as a single-electron donor as in the photo-redox catalyzed reactions but as an H-atom-donor. The reaction also proceeds under visible-light irradiation in the presence of thioglycolic acid as a ligand.
- Iwasawa, Nobuharu,Sumiyama, Keiichi,Toriumi, Naoyuki
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supporting information
p. 2474 - 2478
(2021/06/25)
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- Metallic Barium: A Versatile and Efficient Hydrogenation Catalyst
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Ba metal was activated by evaporation and cocondensation with heptane. This black powder is a highly active hydrogenation catalyst for the reduction of a variety of unactivated (non-conjugated) mono-, di- and tri-substituted alkenes, tetraphenylethylene, benzene, a number of polycyclic aromatic hydrocarbons, aldimines, ketimines and various pyridines. The performance of metallic Ba in hydrogenation catalysis tops that of the hitherto most active molecular group 2 metal catalysts. Depending on the substrate, two different catalytic cycles are proposed. A: a classical metal hydride cycle and B: the Ba metal cycle. The latter is proposed for substrates that are easily reduced by Ba0, that is, conjugated alkenes, alkynes, annulated rings, imines and pyridines. In addition, a mechanism in which Ba0 and BaH2 are both essential is discussed. DFT calculations on benzene hydrogenation with a simple model system (Ba/BaH2) confirm that the presence of metallic Ba has an accelerating effect.
- Stegner, Philipp,F?rber, Christian,Zenneck, Ulrich,Knüpfer, Christian,Eyselein, Jonathan,Wiesinger, Michael,Harder, Sjoerd
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supporting information
p. 4252 - 4258
(2020/12/22)
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- Photodriven Dehydrogenative Homocoupling of Benzylic C-H Bonds Forming Strained C-C Bonds
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A photoinduced dehydrogenative homocoupling reaction of alkylarenes is reported. Gaseous hydrogen is evolved as the sole byproduct and neither oxidants nor hydrogen acceptors are required. The present reaction offers an environmentally benign and atom-economical means for forming sterically strained C-C single bonds. It also gives a remarkable example of photodriven reactions overcoming a considerable rise in energy.
- Ishida, Naoki,Son, Mingon,Kawasaki, Tairin,Ito, Misato,Murakami, Masahiro
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supporting information
p. 2067 - 2070
(2021/10/14)
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- Designed electron-deficient gold nanoparticles for a room-temperature Csp3-Csp3coupling reaction
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Stille cross-coupling reactions catalysed by an ideal catalyst combining the high activity of homogeneous catalysts and the reusability of heterogeneous catalysts are of great interest for C-C bond formation, which is a widely used reaction in fine chemistry. Despite great effort to increase the utilization ratio of surface metal atoms, the activity of heterogeneous catalysts under mild conditions remains unsatisfactory. Herein, we design a proof-of-concept strategy to trigger the room-temperature activity of heterogeneous Au catalysts by decreasing the electron density at the interface of a rationally designed Schottky heterojunction of Au metals and boron-doped carbons. The electron-deficient Au nanoparticles formed as a result of the rectifying contact with boron-doped carbons facilitate the autocleavage of C-Br bonds for highly efficient C-C coupling reactions of alkylbromides and allylstannanes with a TOF value of 5199 h-1 at room temperature, surpassing that of the state-of-the-art homogeneous catalyst. This journal is
- Yu, Qiu-Ying,Su, Hui,Zhai, Guang-Yao,Zhang, Shi-Nan,Sun, Lu-Han,Chen, Jie-Sheng,Li, Xin-Hao
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supporting information
p. 741 - 744
(2021/02/06)
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- Mechanistic insights into the dearomative diborylation of pyrazines: A radical or non-radical process?
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The mechanisms of the dearomative diborylation of pyrazines were investigated via a combination of density functional theory (DFT) calculations and experimental studies. DFT calculations revealed that a non-radical mechanism involving two successive [3,3]-σ-rearrangement-type processes is responsible for the diborylation of pyrazine with bis(pinacolato)diboron (B2pin2). However, this non-radical process is highly unfavorable for the diborylation reaction of sterically hindered pyrazine (2,3-dimethylpyrazine). For the diboration reaction of 2,3-dimethylpyrazine with B2pin2 in the presence of 2,6-dichloro-4,4′-bipyridine as the catalyst, 4,4′-bipyridine-mediated radical pathway proceeding through a B-B homolytic cleavage/boryl radical addition is preferred. Control experiments combined with kinetic studies provided supportive evidence for the proposed mechanism.
- Gao, Liuzhou,Li, Shuhua,Liu, Xueting,Wang, Guoqiang,Zhang, Hanyin
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supporting information
p. 6982 - 6990
(2021/05/31)
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- Vanadium Pyridonate Catalysts: Isolation of Intermediates in the Reductive Coupling of Alcohols
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The reductive coupling of alcohols using vanadium pyridonate catalysts is reported. This attractive approach for C(sp3)-C(sp3) bond formation uses an oxophilic, earth-abundant metal for a catalytic deoxygenation reaction. Several pyridonate complexes of vanadium were synthesized, giving insight into the coordination chemistry of this understudied class of compounds. Isolated intermediates provide experimental mechanistic evidence that complements reported computational mechanistic proposals for the reductive coupling of alcohols. In contrast to previous mononuclear vanadium(V)/vanadium(III)/vanadium(IV) cycles, this pyridonate catalyst system is proposed to proceed by a vanadium(III)/vanadium(IV) cycle involving bimetallic intermediates.
- Griffin, Samuel E.,Schafer, Laurel L.
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supporting information
(2020/04/15)
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- Bidentate NHC-Cobalt Catalysts for the Hydrogenation of Hindered Alkenes
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Herein, we report a series of easily accessible bidentate N-heterocyclic carbene (NHC) cobalt catalysts, which enable the hydrogenation of hindered alkenes under mild conditions. The four-coordinated bidentate NHC-Co(II) complexes were characterized by X-ray diffraction, elemental analysis, ESI-HRMS, and magnetic moment measurements, revealing a distorted-tetrahedral geometry and a high-spin configuration of the metal center. The activity of the in situ formed catalytic system, which was obtained from easily available NHC precursors, CoCl2, and NaHBEt3, was identical with those of well-defined NHC-cobalt catalysts. This highlights the potential utility of this reaction system.
- Wei, Zeyuan,Wang, Yujie,Li, Yibiao,Ferraccioli, Raffaella,Liu, Qiang
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p. 3082 - 3087
(2020/10/02)
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- HIGHLY SELECTIVE ELECTROCHEMICAL HYDROGENATION OF ALKYNES
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Disclosed are electrochemical methods to prepare an alkane or an alkene, such as a cis- alkene, from an alkyne, or an alkane from an alkene. The method utilizes an electrochemical cell having a cathode and an anode and a reactor.
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(2020/10/20)
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- Hydrogenation reaction method
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The invention relates to a hydrogenation reaction method, and belongs to the technical field of organic synthesis. The hydrogenation reaction method provided by the invention comprises the following steps: carrying out a hydrogen transfer reaction on a hydrogen acceptor compound, pinacol borane and a catalyst in a solvent in the presence of proton hydrogen, so that the hydrogen acceptor compound is subjected to a hydrogenation reaction; the catalyst is one or more than two of a palladium catalyst, an iridium catalyst and a rhodium catalyst; the hydrogen acceptor compound comprises one or morethan two functional groups of carbon-carbon double bonds, carbon-carbon triple bonds, carbon-oxygen double bonds, carbon-nitrogen double bonds, nitrogen-nitrogen double bonds, nitryl, carbon-nitrogentriple bonds and epoxy. The method is mild in reaction condition, easy to operate, high in yield, short in reaction time, wide in substrate application range, suitable for carbon-carbon double bonds,carbon-carbon triple bonds, carbon-oxygen double bonds, carbon-nitrogen double bonds, nitrogen-nitrogen double bonds, nitryl, carbon-nitrogen triple bonds and epoxy functional groups, good in selectivity and high in reaction specificity.
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Paragraph 0034; 0205-0208
(2020/05/14)
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- Generalized Chemoselective Transfer Hydrogenation/Hydrodeuteration
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A generalized, simple and efficient transfer hydrogenation of unsaturated bonds has been developed using HBPin and various proton reagents as hydrogen sources. The substrates, including alkenes, alkynes, aromatic heterocycles, aldehydes, ketones, imines, azo, nitro, epoxy and nitrile compounds, are all applied to this catalytic system. Various groups, which cannot survive under the Pd/C/H2 combination, are tolerated. The activity of the reactants was studied and the trends are as follows: styrene'diphenylmethanimine'benzaldehyde'azobenzene'nitrobenzene'quinoline'acetophenone'benzonitrile. Substrates bearing two or more different unsaturated bonds were also investigated and transfer hydrogenation occurred with excellent chemoselectivity. Nano-palladium catalyst in situ generated from Pd(OAc)2 and HBPin extremely improved the TH efficiency. Furthermore, chemoselective anti-Markovnikov hydrodeuteration of terminal aromatic olefins was achieved using D2O and HBPin via in situ HD generation and discrimination. (Figure presented.).
- Wang, Yong,Cao, Xinyi,Zhao, Leyao,Pi, Chao,Ji, Jingfei,Cui, Xiuling,Wu, Yangjie
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supporting information
p. 4119 - 4129
(2020/08/10)
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- Highly Active Superbulky Alkaline Earth Metal Amide Catalysts for Hydrogenation of Challenging Alkenes and Aromatic Rings
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Two series of bulky alkaline earth (Ae) metal amide complexes have been prepared: Ae[N(TRIP)2]2 (1-Ae) and Ae[N(TRIP)(DIPP)]2 (2-Ae) (Ae=Mg, Ca, Sr, Ba; TRIP=SiiPr3, DIPP=2,6-diisopropylphenyl). While monomeric 1-Ca was already known, the new complexes have been structurally characterized. Monomers 1-Ae are highly linear while the monomers 2-Ae are slightly bent. The bulkier amide complexes 1-Ae are by far the most active catalysts in alkene hydrogenation with activities increasing from Mg to Ba. Catalyst 1-Ba can reduce internal alkenes like cyclohexene or 3-hexene and highly challenging substrates like 1-Me-cyclohexene or tetraphenylethylene. It is also active in arene hydrogenation reducing anthracene and naphthalene (even when substituted with an alkyl) as well as biphenyl. Benzene could be reduced to cyclohexane but full conversion was not reached. The first step in catalytic hydrogenation is formation of an (amide)AeH species, which can form larger aggregates. Increasing the bulk of the amide ligand decreases aggregate size but it is unclear what the true catalyst(s) is (are). DFT calculations suggest that amide bulk also has a noticeable influence on the thermodynamics for formation of the (amide)AeH species. Complex 1-Ba is currently the most powerful Ae metal hydrogenation catalyst. Due to tremendously increased activities in comparison to those of previously reported catalysts, the substrate scope in hydrogenation catalysis could be extended to challenging multi-substituted unactivated alkenes and even to arenes among which benzene.
- Eyselein, Jonathan,F?rber, Christian,Grams, Samuel,Harder, Sjoerd,Knüpfer, Christian,Langer, Jens,Martin, Johannes,Thum, Katharina,Wiesinger, Michael
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supporting information
p. 9102 - 9112
(2020/03/30)
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- Synthesis of dimeric molecules via ag-catalyzed electrochemical homocoupling of organic bromides paired with electrooxidation of urea
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We present a sacrificial anode-free approach to reductive homocoupling of organohalides that does not require a co-catalyst. In this approach, a divided electrochemical cell with aprotic and aqueous compartments separated by an anion exchange membrane enables coupling of the cathodic homocoupling reaction with anodic oxidation of urea. We show that, in contrast with traditional one-compartment cells relying on sacrificial anodes, the proposed cell configuration maintains stable cell voltage in the course of galvanostatic electrolysis. A synthetic potential of this method was assessed using a series of 13 organic bromides that demonstrated a strong dependence of the reaction outcome on the structure of the organic substrate, more specifically, the dissociation energy of the C–Br bond and the redox properties of formed radicals, which are discussed in detail. While not being suitable for the synthesis of byarylstructures, this method is excellent for C(sp3)-C(sp3) coupling to corresponding dimeric products with up to quantitative yields. Simultaneous electrochemical treatment of nitrogenous waste in the adjacent half-cell provides an additional incentive for wide adaptation of this sustainable synthetic approach.
- Klinkova, Anna,Krivoshapkina, Elena F.,Medvedev, Jury J.,Medvedeva, Xenia V.,Pivovarova, Yekaterina,Steksova, Yulia P.
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- Oxovanadium(v)-catalyzed deoxygenative homocoupling reaction of alcohols
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Oxovanadium(v)-catalyzed transformation of alcohols in the presence of hydrazine derivatives was demonstrated. The direct hydrazination reaction of 1,3-diphenylprop-2-en-1-ol with 1,1-diphenylhydrazine in the presence of VO(OSiPh3)3 as a catalyst and MS3A as a dehydrating reagent proceeded to afford the corresponding hydrazination product. On the contrary, the utilization of 1,1-dimethylhydrazine instead of 1,1-diphenylhydrazine was found to induce the deoxygenative homocoupling reaction of the allyl alcohol to give the corresponding 1,5-diene as a major product. In addition to the deoxygenative homocoupling product, the allyl amine into which aniline was introduced was also obtained by using 1,2-diphenylhydrazine in the reaction of 1,3-diphenyl-2-methylprop-2-en-1-ol. Oxovanadium(v)-catalyzed deoxygenative homocoupling reaction of benzyl alcohols could also be performed in the presence of 1,1-dimethylhydrazine.
- Sakuramoto, Takashi,Donaka, Yosuke,Tobisu, Mamoru,Moriuchi, Toshiyuki
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p. 17571 - 17576
(2019/11/25)
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- Mechanistic Features of the Oxidation-Reductive Coupling of Alcohols Catalyzed by Oxo-Vanadium Complexes
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The oxo-vanadium-catalyzed redox disproportionation of activated alcohols (oxidation-reductive coupling, Ox-RC) produces carbonyl compounds and hydrocarbon dimers. A mechanistic study of this novel reaction is reported herein. Following our initial disclosure, new findings include the following: (1) The [(salimin)VO2]--catalyzed Ox-RC of Ph2CHOH in the presence of fluorene affords the products of H-atom abstraction and all possible hydrocarbon dimers. (2) Electronic substituent effects on the relative rates of Ox-RC with respect to 4-X-BnOH reactants and Bu4N[(Y-salimin)VO2] catalysts (1a-c) reveal (a) a correlation of the oxidation rate of X-BnOH reactants with the radical σ parameter and (b) correlation of the oxidation rate for (Y-salimin)VO2- with the standard Hammett σ parameter. (3) The ease of electrochemical reduction of 1a-c is Y = NO2 > OMe > H. (4) Ambient 1H NMR studies of the interaction of 1 with alcohols suggest only a weak equilibrium association. (5) Density functional theory computational modeling of the Ox-RC reaction supports a ping-pong-type catalytic pathway, beginning with alcohol oxidation by (salimin)VO2-, preferably by stepwise-H-atom transfer from the alcohol to 1, affording the carbonyl product and the reduced (salimin)V(III)(OH)2-. The reduction half-reaction likely begins with condensation of the latter species with R2CHOH to give the alkoxide complex (salimin)V(OR)OH- homolysis of the R···OV(III)(salimin) bond affords (salimin)V(IV)OH(O)- and the R-radical; the latter dimerizes and the former can disproportionate via H-transfer to reform catalyst (salimin)VO2- (1) and (salimin)V(OH)2-.
- Steffensmeier, Eric,Swann, Matthew T.,Nicholas, Kenneth M.
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p. 844 - 854
(2019/01/04)
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- SN2 Reaction of Diarylmethyl Anions at Secondary Alkyl and Cycloalkyl Carbons
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The substitution reaction of the diethyl allylic and propargylic phosphates with Ar2CH anions was applied to sec-alkyl phosphates to compare reactivity and stereoselectivity. However, the substitution took place on the ethyl carbon of the diethyl phosphate group. We then found that the diphenyl phosphate leaving group ((PhO)2PO2) was suited for the substitution at the sec-alkyl carbon. Enantioenriched diphenyl sec-alkyl phosphates with different substituents (Me, Et, iPr) on the vicinal position underwent the substitution reaction with almost complete inversion (>99% enantiospecificity). The substitution reactions of cyclohexyl phosphates possessing cis or trans substituents (Me and/or tBu) at the C4, C3, and C2 positions of the cyclohexane ring were also studied to observe the difference in reactivity among the cis and trans isomers. A transition-state model with the phosphate leaving group ((PhO)2PO2) in the axial position was proposed to explain the difference. This model was supported by computational calculation of the virtual substitution reaction of the structurally simpler “dimethyl” cyclohexyl phosphates (leaving group = (MeO)2PO2) with MeLi. Furthermore, the calculation unexpectedly indicated higher propensity of (PhO)2PO2 as a leaving reactivity than alkyl phosphate groups such as (MeO)2PO2 and (iPrO)2PO2.
- Shinohara, Riku,Ogawa, Narihito,Kawashima, Hidehisa,Wada, Kyohei,Saito, Shun,Yamazaki, Takashi,Kobayashi, Yuichi
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p. 1461 - 1478
(2019/01/25)
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- Super-Bulky Penta-arylcyclopentadienyl Ligands: Isolation of the Full Range of Half-Sandwich Heavy Alkaline-Earth Metal Hydrides
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Hydrogenolysis of the half-sandwich penta-arylcyclopentadienyl-supported heavy alkaline-earth-metal alkyl complexes (CpAr)Ae[CH(SiMe3)2](S) (CpAr=C5Ar5, Ar=3,5-iPr2-C6H3; S=THF or DABCO) in hexane afforded the calcium, strontium, and barium metal–hydride complexes as the same dimers [(CpAr)Ae(μ-H)(S)]2 (Ae=Ca, S=THF, 2-Ca; Ae=Sr, Ba, S=DABCO, 4-Ae), which were characterized by NMR spectroscopy and single-crystal X-ray analysis. 2-Ca, 4-Sr, and 4-Ba catalyzed alkene hydrogenation under mild conditions (30 °C, 6 atm, 5 mol % cat.), with the activity increasing with the metal size. A variety of activated alkenes including tri- and tetra-substituted olefins, semi-activated alkene (Me3SiCH=CH2), and unactivated terminal alkene (1-hexene) were evaluated.
- Shi, Xianghui,Qin, Guorui,Wang, Yang,Zhao, Lanxiao,Liu, Zhizhou,Cheng, Jianhua
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supporting information
p. 4356 - 4360
(2019/02/25)
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- Decarboxylative Acetoxylation of Aliphatic Carboxylic Acids
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Organic molecules bearing acetoxy moieties are important functionalities in natural products, drugs, and agricultural chemicals. Synthesis of such molecules via transition metal-catalyzed C-O bond formation can be achieved in the presence of a carefully chosen directing group to alleviate the challenges associated with regioselectivity. An alternative approach is to use ubiquitous carboxylic acids as starting materials and perform a decarboxylative coupling. Herein, we report conditions for a photocatalytic decarboxylative C-O bond formation reaction that provides rapid and facile access to the corresponding acetoxylated products. Mechanistic investigations suggest that the reaction operates via oxidation of the carboxylate followed by rapid decarboxylation and oxidation by Cu(OAc)2
- Senaweera, Sameera,Cartwright, Kaitie C.,Tunge, Jon A.
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p. 12553 - 12561
(2019/10/14)
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- 3-Acetoxyquinuclidine as Catalyst in Electron Donor-Acceptor Complex-Mediated Reactions Triggered by Visible Light
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3-Acetoxyquinuclidine was found to act as a catalytic electron donor species in a variety of electron donor-acceptor complex-mediated reactions. Only substoichiometric amounts (10-25 mol %) were needed to trigger the desired reaction. The outcome could be tuned by selecting the nature of the formed radical to perform amino- and hydro-decarboxylation, dimerization, and cyclization reactions. Importantly, no external additives were needed in this reaction.
- Bosque, Irene,Bach, Thorsten
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p. 9103 - 9109
(2019/10/16)
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- Composition and synthesis of aggregation-induced emission materials
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The present subject matter relates to compositions containing and synthesis of fluorescent materials e made from tetraphenylethylene (TPE) derivative compounds exhibiting aggregation induced emission (AIE) properties. Further contemplated herein are applications for TPE derivative compounds such as electroluminescent devices since they have a high efficiency, low turn on voltage, and excellent brightness. Additionally, application of TPE derivatives exhibiting AIE properties in various fields such as OLEDs, fingerprinting and forensic technology, and various other biological and industrial sectors are discussed.
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Page/Page column 34; 35-36
(2018/04/20)
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- Air-Stable α-Diimine Nickel Precatalysts for the Hydrogenation of Hindered, Unactivated Alkenes
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Treatment of a mixture of air-stable nickel(II) bis(octanoate), Ni(O2CC7H15)2, and α-diimine ligand, iPrDI or CyADI (iPrDI = [2,6-iPr2-C6H3N=C(CH3)]2, CyADI = [C6H11N=C(CH3)]2) with pinacolborane (HBPin) generated a highly active catalyst for the hydrogenation of hindered, essentially unfunctionalized alkenes. A range of tri- and tetrasubstituted alkenes was hydrogenated and a benchtop procedure for the hydrogenation of 1-phenyl-1-cyclohexene on a multigram scale was demonstrated and represents an advance in catalyst activity and scope for the nickel-catalyzed hydrogenation of this challenging class of alkenes. Deuteration of 1,2-dimethylindene with the in situ-generated nickel catalyst with iPrDI exclusively furnished the 1,2-syn-d2-dimethylindane. With cyclic trisubstituted alkenes, such as 1-methyl-indene and methylcyclohexene, deuteration with the in situ generated nickel catalyst under 4 atm of D2 produced multiple deuterated isotopologues of the alkanes, signaling chain running processes that are competitive with productive hydrogenation. Stoichiometric studies, titration, and deuterium labeling experiments identified that the borane reagent served the dual role of reducing nickel(II) bis(carboxylate) to the previously reported nickel hydride dimer [(iPrDI)NiH]2 and increasing the observed hydrogenation activity. Performing the catalyst activation procedure with D2 gas and HBPin generated both HD and DBPin, establishing that the borane is involved in H2 activation as judged by 1H and 11B nuclear magnetic resonance spectroscopies.
- Léonard, Nadia G.,Chirik, Paul J.
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p. 342 - 348
(2018/01/17)
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- Catalyst surfaces with tunable hydrophilicity and hydrophobicity: Metal-organic frameworks toward controllable catalytic selectivity
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This report describes a facile strategy that has the capability of adjusting different surface hydrophilicities/hydrophobicities of catalysts by covering metal-organic frameworks with graphene oxide and reduced graphene oxide. The catalysts exhibit remark
- Chen, Xinyi,Qian, Panpan,Zhang, Tao,Xu, Zhiling,Fang, Chuanzhen,Xu, Xiujie,Chen, Wanzheng,Wu, Peng,Shen, Yu,Li, Sheng,Wu, Jiansheng,Zheng, Bing,Zhang, Weina,Huo, Fengwei
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supporting information
p. 3936 - 3939
(2018/04/23)
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- Silver-Catalyzed Decarboxylative Couplings of Acids and Anhydrides: An Entry to 1,2-Diketones and Aryl-Substituted Ethanes
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Silver-catalyzed oxidative decarboxylative couplings of carboxylic acids and anhydrides to produce 1,2-diketones and substituted ethanes were developed. This reaction allows the generation of acyl or alkyl radicals by decarboxylation of the corresponding α-keto acids, alkyl acids and anhydrides, which are sequentially coupled to efficiently construct a new C?C bond. This reaction represents a carboxylic acid decarboxylative alternative that employs a radical termination strategy. (Figure presented.).
- Zou, Hua-Xu,Li, Yang,Yang, Yuan,Li, Jin-Heng,Xiang, Jiannan
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supporting information
p. 1439 - 1443
(2018/02/26)
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- Transient Kinetics and Quantum Yield Studies of Nanocrystalline α-Phenyl-Substituted Ketones: Sorting Out Reactions from Singlet and Triplet Excited States
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Recent work has shown that diarylmethyl radicals generated by pulsed laser excitation in nanocrystalline (NC) suspensions of tetraarylacetones constitute a valuable probe for the detailed mechanistic analysis of the solid-state photodecarbonylation reaction. Using a combination of reaction quantum yields and laser flash photolysis in nanocrystalline suspensions of ketones with different substituents on one of the α-carbons, we are able to suggest with confidence that a significant fraction of the initial α-cleavage reaction takes place from the ketone singlet excited state, that the originally formed diarylmethyl-acyl radical pair loses CO in the crystal with time constants in the sub-nanosecond regime, and that the secondary bis(diarylmethyl) triplet radical pair has a lifetime limited by the rate of intersystem crossing of ca. 70 ns.
- Park, Jin H.,Chung, Tim S.,Hipwell, Vince M.,Rivera, Edris,Garcia-Garibay, Miguel A.
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p. 8192 - 8197
(2018/06/22)
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- Nondirecting Group sp3 C?H Activation for Synthesis of Bibenzyls via Homo-coupling as Catalyzed by Reduced Graphene Oxide Supported PtPd@Pt Porous Nanospheres
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The use of heterogeneous bimetallic Pd-based nanocatalyst for directing the inactivated sp3 C?H coupling has been scarcely explored. This work reported the formation of symmetrical C?C bonds from the inactivated sp3 C?H bonds catalyzed by employing reduced graphene oxide supported PtPd@Pt porous nanospheres. The reaction of sp3 C?H activation proceeded under mild conditions without any solvent, ligand or directing group. It is a higher atom-, step- and cost-effectiveness strategy for developing heterogeneous catalysts in the synthesis of bibenzyls with various functional groups (e. g. aryl, alkyl, methoxyl, halogen, ester, and pyridyl). (Figure presented.).
- Wang, Zheng-Jun,Lv, Jing-Jing,Yi, Rong-Nan,Xiao, Min,Feng, Jiu-Ju,Liang, Zhi-Wu,Wang, Ai-Jun,Xu, Xinhua
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supporting information
p. 932 - 941
(2018/01/05)
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- Mechanistic Insights into the ReIO2(PPh3)2-Promoted Reductive Coupling of Alcohols
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A mechanistic investigation of the reductive coupling of benzylic and allylic alcohols by triphenylphosphine catalyzed by ReIO2(PPh3)2 (1) is disclosed utilizing (1) stoichiometric reaction studies of 1 with alcohols, with PPh3 and with OPPh3; (2) rate law determination of the reaction of benzhydrol with PPh3 catalyzed by 1; (3) substrate structure-dependent reactivity/selectivity studies; and (4) DFT computational analysis of various potential reaction pathways in the benzyl alcohol/PPh3 reaction. In situ NMR monitoring of reactions of 1 with PPh3 and various alcohols demonstrate (a) facile, reversible PPh3 dissociation from 1; (b) association of various alcohols to form Re-alcohol/alkoxide complexes, (Ph3P)IReO2(ROH) and (Ph3P)IReO(OH)(OR); and (c) thermal conversion of these alcohol(ate)-rhenium complexes to Ph2CH-CHPh2 and OPPh3 at >50 °C. Under pseudo-first-order conditions, the initial rate kinetics of reductive coupling of Ph2CHOH/PPh3 catalyzed by 1 shows (a) a reaction rate that is first-order each in ROH, catalyst and first-order (or higher) in PPh3 and (b) the reaction is inhibited by OPPh3. Alcohol structure effects show (a) relative reactivity of sec-, tert-benzylic = allylic > prim-benzylic/allylic sec-, prim-alkyl and (b) low regioselectivity of the dimers from unsymmetrical allylic alcohols. A DFT computational study of the reaction of benzyl alcohol/PPh3 with 1 reveals a preferred pathway involving: (a) formation of rhenium-alcohol and alkoxide intermediates, (Ph3P)IReO2(ROH) and (Ph3P)IReO(OH)(OR); (b) reduction of the latter by PPh3 to form (OPPh3)(Ph3P)IRe(OH)(OBn) (E); (c) association of a second BnOH with E to give (Ph3P)IRe(OBn)2 (K); (d) facile dissociation of a benzyl radical from K by C-O homolysis; and (e) a second rhenium-O-Bn homolysis from (PPh3)IRe(H2O)(OBn) (O), giving bibenzyl via benzyl radical recombination and regenerating (PPh3)ReIO2.
- Boucher-Jacobs, Camille,Liu, Peng,Nicholas, Kenneth M.
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p. 2468 - 2480
(2018/08/21)
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- Why Do Simple Molecules with "isolated" Phenyl Rings Emit Visible Light?
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π-Bonds connected with aromatic rings were generally believed as the standard structures for constructing highly efficient fluorophores. Materials without these typical structures, however, exhibited only low fluorescence quantum yields and emitted in the ultraviolet spectral region. In this work, three molecules, namely bis(2,4,5-trimethylphenyl)methane, 1,1,2,2-tetrakis(2,4,5-trimethylphenyl)ethane, and 1,1,2,2-tetraphenylethane, with nonconjugated structures and isolated phenyl rings were synthesized and their photophysical properties were systematically investigated. Interestingly, the emission spectra of these three molecules could be well extended to 600 nm with high solid-state quantum yields of up to 70%. Experimental and theoretical analyses proved that intramolecular through-space conjugation between the "isolated" phenyl rings played an important role for this abnormal phenomenon.
- Zhang, Haoke,Zheng, Xiaoyan,Xie, Ni,He, Zikai,Liu, Junkai,Leung, Nelson L. C.,Niu, Yingli,Huang, Xuhui,Wong, Kam Sing,Kwok, Ryan T. K.,Sung, Herman H. Y.,Williams, Ian D.,Qin, Anjun,Lam, Jacky W. Y.,Tang, Ben Zhong
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supporting information
p. 16264 - 16272
(2017/11/22)
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- Generation and Reactivity Studies of Diarylmethyl Radical Pairs in Crystalline Tetraarylacetones via Laser Flash Photolysis Using Nanocrystalline Suspensions
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The nanosecond electronic spectra and kinetics of the radical pairs from various crystalline tetraarylacetones were obtained using transmission laser flash photolysis methods by taking advantage of aqueous nanocrystalline suspensions in the presence of su
- Park, Jin H.,Hughs, Melissa,Chung, Tim S.,Ayitou, A. Jean-Luc,Breslin, Vanessa M.,Garcia-Garibay, Miguel A.
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supporting information
p. 13312 - 13317
(2017/10/05)
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- Feedstocks to Pharmacophores: Cu-Catalyzed Oxidative Arylation of Inexpensive Alkylarenes Enabling Direct Access to Diarylalkanes
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A Cu-catalyzed method has been identified for selective oxidative arylation of benzylic C-H bonds with arylboronic esters. The resulting 1,1-diarylalkanes are accessed directly from inexpensive alkylarenes containing primary and secondary benzylic C-H bonds, such as toluene or ethylbenzene. All catalyst components are commercially available at low cost, and the arylboronic esters are either commercially available or easily accessible from the commercially available boronic acids. The potential utility of these methods in medicinal chemistry applications is highlighted.
- Vasilopoulos, Aristidis,Zultanski, Susan L.,Stahl, Shannon S.
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supporting information
p. 7705 - 7708
(2017/06/20)
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- Pd-Catalyzed Desulfonative Cross-Coupling of Benzylic Sulfone Derivatives with 1,3-Oxazoles
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The Pd-catalyzed desulfonative cross-coupling reaction of benzylic sulfone derivatives with 1,3-oxazoles via a deprotonative pathway has been developed. Broad substrate scope for both sulfone and 1,3-oxazole partners is observed, affording a variety of 1,3-oxazole-containing triarylmethanes. Sulfone partners that are primary benzylic, secondary benzylic, and benzhydryl are all effective. Using this method, the straightforward synthesis of multiply arylated structures has been demonstrated.
- Yim, Jacky C.-H.,Nambo, Masakazu,Crudden, Cathleen M.
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supporting information
p. 3715 - 3718
(2017/07/26)
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- Oxo-rhenium catalyzed reductive coupling and deoxygenation of alcohols
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Representative benzylic, allylic and α-keto alcohols are deoxygenated to alkanes and/or reductively coupled to alkane dimers by reaction with PPh3 catalyzed by (PPh3)2ReIO2 (1). The newly discovered catalytic reductive coupling reaction is a rare C-C bond-forming transformation of alcohols.
- Kasner, Gabrielle R.,Boucher-Jacobs, Camille,Michael McClain,Nicholas, Kenneth M.
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supporting information
p. 7257 - 7260
(2016/06/09)
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- Tetrahydroxydiboron-Mediated Palladium-Catalyzed Transfer Hydrogenation and Deuteriation of Alkenes and Alkynes Using Water as the Stoichiometric H or D Atom Donor
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There are few examples of catalytic transfer hydrogenations of simple alkenes and alkynes that use water as a stoichiometric H or D atom donor. We have found that diboron reagents efficiently mediate the transfer of H or D atoms from water directly onto unsaturated C-C bonds using a palladium catalyst. This reaction is conducted on a broad variety of alkenes and alkynes at ambient temperature, and boric acid is the sole byproduct. Mechanistic experiments suggest that this reaction is made possible by a hydrogen atom transfer from water that generates a Pd-hydride intermediate. Importantly, complete deuterium incorporation from stoichiometric D2O has also been achieved.
- Cummings, Steven P.,Le, Thanh-Ngoc,Fernandez, Gilberto E.,Quiambao, Lorenzo G.,Stokes, Benjamin J.
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supporting information
p. 6107 - 6110
(2016/06/09)
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- Polydimethylsiloxane Coating for a Palladium/MOF Composite: Highly Improved Catalytic Performance by Surface Hydrophobization
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Surface wettability of active sites plays a crucial role in the activity and selectivity of catalysts. This report describes modification of surface hydrophobicity of Pd/UiO-66, a composite comprising a metal–organic framework (MOF) and stabilized palladium nanoparticles (NPs), using a simple polydimethylsiloxane (PDMS) coating. The modified catalyst demonstrated significantly improved catalytic efficiency. The approach can be extended to various Pd nanoparticulate catalysts for enhanced activity in reactions involving hydrophobic reactants, as the hydrophobic surface facilitates the enrichment of hydrophobic substrates around the catalytic site. PDMS encapsulation of Pd NPs prevents aggregation of NPs and thus results in superior catalytic recyclability. Additionally, PDMS coating is applicable to a diverse range of catalysts, endowing them with additional selectivity in sieving reactants with different wettability.
- Huang, Gang,Yang, Qihao,Xu, Qiang,Yu, Shu-Hong,Jiang, Hai-Long
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supporting information
p. 7379 - 7383
(2016/07/06)
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- An unprecedented oxidative intermolecular homo coupling reaction between two sp3C–sp3C centers under metal-free condition
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An unprecedented formation of benzylic sp3C–sp3C coupled dibenzylic products has been illustrated. The reactions have been carried out in the presence of three oxidizing reagents, i.e., diacetoxy-iodobenzene (IBDA), N-fluorobenzenesulfonimide (NFSI), and pyridine (Py) using toluene derivatives.
- Sahoo, Santosh K.
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supporting information
p. 3476 - 3480
(2016/07/15)
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- Facile Rearrangement of the 6,11-Diphenyldibenzo[b,f][1,4]diazocine Skeleton into a Substituted 2-(2-Aminophenyl)-1,3-diphenylisoindole via Anomalous Carbolithiation or Hydrolithiation: Corroboration of Operative SET Processes
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The starting 6,11-diphenyldibenzo[b,f][1,4]diazocine has been individually treated with R-Li reagents in THF, where R = AlH4, PhCH2, Ph2CH, Ph3C, CH3, CH3(CH2)3, C6H5 or Ph-C≡C, to learn whether an expected 1,2- or 1,4-addition would cleanly occur. Contrary to such an assumption based on nucleophilic attack, this [1,4]diazocine with PhCH2Li yielded only the enantiomers of (4b,11R)-11-benzyl-4b,11-diphenyl-4b,11-dihydro-5H-benzo[4,5]imidazo[2,1-a]isoindole; with Ph2CHLi yielded 2-[1-(4-benzhydrylphenyl)-phenyl-2H-isoindol-2-yl]analine; and with LiAlH4 2-(2-aminophenyl)-1,3-diphenylisoindole. Finally, individual reactions of the [1,4]diazocine with CH3Li, nBuLi or PhLi gave 4-5 inseparable products, instead of any simple 1,2 or 1,4 adduct. The anomalous carbolithiations and hydrolithiation observed are irreconcilable with a nucleophilic mechanism but in excellent accord with a SET radical-anion pathway.
- Eisch, John J.,Liu, Wei,Zhu, Lisheng,Rheingold, Arnold L.
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p. 7384 - 7394
(2015/11/25)
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- Visible Light Photocatalytic Reduction of O-Thiocarbamates: Development of a Tin-Free Barton-McCombie Deoxygenation Reaction
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The Barton-McCombie deoxygenation is one of the most important transformations in the toolbox of organic chemists which has been the subject of a number of methodological developments. In this study, we report a photocatalyzed redox deoxygenation of secondary and tertiary alcohols from thiocarbamate precursors under visible light activation. The iridium complex Ir(ppy)3 proved to be the most efficient catalyst in the presence of Hünig's base as sacrifial electron donor. A mechanistic investigation is presented based on fluorescence quenching experiments and cyclic voltammetry.
- Chenneberg, Ludwig,Baralle, Alexandre,Daniel, Marion,Fensterbank, Louis,Goddard, Jean-Philippe,Ollivier, Cyril
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p. 2756 - 2762
(2016/02/19)
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- A clean and selective radical homocoupling employing carboxylic acids with titania photoredox catalysis
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A titania photoredox catalysis protocol was developed for the homocoupling of C-centered radicals derived from carboxylic acids. Intermolecular reactions were generally efficient and selective, furnishing the desired dimers in good yields under mild neutral conditions. Selective cross-coupling with two acids proved unsuccessful. An intra-molecular adaptation enabled macrocycles to be prepared, albeit in modest yields. (Chemical Equation Presented).
- Manley, David W.,Walton, John C.
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supporting information
p. 5394 - 5397
(2015/02/19)
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- Csp3-Csp3 homocoupling reaction of benzyl halides catalyzed by rhodium
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A highly reactive alkylrhodium complex was formed from Me2Zn and RhCl(PPh3)3 and effectively catalyzed a Csp 3-Csp3 homocoupling reaction of benzyl halides. A Csp 3-Csp3 coupling reaction using Rh catalyst has not been reported up to now. The reaction proceeded under very mild conditions and gave the corresponding homocoupling products even if they had reactive substituents such as an uncovered formyl or hydroxymethyl group.
- Sato, Kazuyuki,Inoue, Yuichi,Mori, Tomohisa,Sakaue, Atsushi,Tarui, Atsushi,Omote, Masaaki,Kumadaki, Itsumaro,Ando, Akira
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supporting information
p. 3756 - 3759
(2014/08/05)
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- Convenient synthesis of monobenzylated hydrazides via aqueous zinc-mediated addition reactions
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Addition of substituted benzyl bromides to dialkyl azodicarboxylates under aqueous zinc-mediated addition conditions occurs readily to afford monobenzylated hydrazides in good to excellent yields. The reaction is tolerant of a variety of substituents on the benzyl bromide ring. Several dialkyl azodicarboxylates were successfully tested under the reaction conditions. The limitations of the reaction are also addressed.
- Breton, Gary W.
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supporting information
p. 1128 - 1136
(2014/04/03)
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- Ultrasound-promoted dimerization of benzylic halides
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Simple and straightforward coupling of benzylic compounds was achieved by sonicating benzylic halides in the presence of magnesium.
- Gozhina, Olga V.,Thomassen, Ivar K.,Lejon, Tore
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p. 1867 - 1870
(2013/05/21)
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- Ligand-controlled iron-catalyzed cross coupling of benzylic chlorides with aryl Grignard reagents
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The selective cross coupling of benzylic chlorides with aryl Grignard reagents has been achieved by using catalytic amounts of FeCl2 and electronically tuned ortho-phenylenebisphosphine ligands. Although electron-deficient ligands promoted the reductive homocoupling of benzylic halides, electron-rich ligands effectively promoted the desired cross-coupling reaction to afford the corresponding diarylmethanes in good to excellent yields.
- Kawamura, Shintaro,Nakamura, Masaharu
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supporting information
p. 183 - 185
(2013/03/28)
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- Active-alkali metal promoted reductive desulfurization of dibenzothiophene and its hindered analogues
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Dibenzothiophene and some related organosulfur compounds are efficiently reductively desulfurized under mild reaction conditions, with Na and/or Li metal in the presence of a catalytic amount of tetraphenylethylene in THF at room temperature. This simple methodology was applied to the synthesis of several substituted biphenyls, thus realizing a connection between the directing properties of the sulfur atom of dibenzothiophene and the efficiency of 1,2-dianions of tetraphenylethane as homogenous electron transfer reagents.
- Pittalis, Mario,Azzena, Ugo,Pisano, Luisa
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p. 207 - 211
(2013/01/15)
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- Photoreduction of aliphatic and aromatic thioketals: New access to the reduction of carbonyl groups by a desulfurization chain process
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Aromatic and aliphatic ketones can be converted to methylene groups by desulfurization of the corresponding dithioketals in moderate to good yields. The reaction proceeds by photoinduced electron transfer from tert-BuOK in the presence of 1,4-dicyclohexadiene as hydrogen atom donor. The diene is able to trigger and keep a chain process by hydrogen transfer-proton transfer reactions.
- Oksdath-Mansilla, Gabriela,Argüello, Juan E.,Pe?é?ory, Alicia B.
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p. 1515 - 1518
(2013/03/14)
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- 6,12-Diphenyldibenzo[b,f][1,5]diazocine as an electron-capture agent: Efficient mechanistic probe for SET processes and reagent for the oxidative dimerization of benzylic organometallics
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In the present study, 6,12-diphenyldibenzo[b,f][1,5]diazocine, which X-ray diffraction measurements have now shown to possess a tub-shaped, eight-membered central ring, has been treated with sodium or lithium metal at 25 °C in THF, in an attempt to form the planar, Hueckel-aromatic dianion by the addition of two electrons to the central diazocine. Hydrolysis of such an aromatic dianion should have led to the isomeric 5,12- or 5,6-dihydro derivative of the original diazocine. In actuality, the only product obtained quantitatively upon hydrolytic workup was the interesting quadricyclic transannular reduction product, 4b,9b-diphenyl-4b,5,9b,10-tetrahydroindolo[3,2-b]indole, whose 3D structure has now been confirmed by X-ray crystallography and 13C NMR spectroscopy. Preferential SET transannular reduction of the diazocine to yield the quadricyclic indolo[3,2-b]indole dianion, rather than the planar, Hueckel-aromatic anion, is ascribed to the transannular electronic stabilization operative in the tub-shaped diazocine radical-anion. The quantitative generation of the indolo[3,2-b]indole dianion can be employed for the oxidative dimerization of the organic groups in benzylic lithium reagents. Thus treating one equivalent of the diazocine with two equivalents of benzyllithium, benzhydryllithium, or trityllithium yields quantitatively bibenzyl, 1,1,2,2-tetraphenylethane, or (4-benzhydrylphenyl)triphenylmethane, respectively. This oxidative dimerization is potentially of practical preparative scope, since the hydrolysis byproduct, the indolo[3,2-b]indole, is conveniently reconverted into the starting diazocine reagent by oxidation with chromium trioxide in acetic acid. The formation of the indolo[3,2-b]indole as a byproduct in the carbometalation of the diazocine by various RLi and Grignard reagents offers a clue as to the SET mechanism of carbometalation. Copyright
- Eisch, John J.,Yu, Kun,Rheingold, Arnold L.
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experimental part
p. 3165 - 3171
(2012/06/30)
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- A practical microreactor for electrochemistry in flow
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A microreactor for electrochemical synthesis has been designed and fabricated. It has been shown that different reactions can be carried out successfully using simple protocols.
- Watts, Kevin,Gattrell, William,Wirth, Thomas
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experimental part
p. 1108 - 1114
(2011/10/05)
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- Facile and efficient reductive homocoupling of benzyl and aryl halides catalyzed by ionic liquid [C12mim][CuCl2] in the presence of metallic zinc and copper
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A facile and efficient synthesis of bibenzyl and biaryl derivatives by reductive homocoupling reaction is described. Treatment of benzyl and aryl halides with metallic zinc and copper powder in the presence of a catalytic amount of [C12mim][CuCl2] under ligand- and base-free conditions gives the corresponding bibenzyls and biaryls in good to high yields. The product can be isolated by a simple extraction with organic solvent, and the catalytic system can be recycled or reused without any significant loss of catalytic activity.
- Hu, Yu-Lin,Li, Fu,Gu, Guo-Liang,Lu, Ming
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experimental part
p. 467 - 473
(2011/12/05)
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- Reducing the cost, smell, and toxicity of the Barton reductive decarboxylation: Chloroform as the hydrogen atom source
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When used as solvent, chloroform was found to act as a hydrogen atom donor in Barton reductive decarboxylation reactions. Chloroform offers a substantial practical advantage over pre-existing hydrogen atom donors.
- Ko, Eun Jung,Williams, Craig M.,Savage, G. Paul,Tsanaktsidis, John
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p. 1944 - 1947
(2015/02/18)
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- Triplet halocarbene chemistry: P-nitrophenylchlorocarbene and p-nitrophenylbromocarbene
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Reactions of p-nitrophenylchlorocarbene with cumene and of p-nitrophenylbromocarbene with toluene afford C-H abstraction-recombination products that suggest the involvement of triplet arylhalocarbenes.
- Moss, Robert A.,Lu, Zhifeng,Sauers, Ronald R.
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body text
p. 5940 - 5942
(2010/11/21)
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