- Comparative activity of aryl, alkyl, and cycloalkyl halides in the suzuki reaction catalyzed with acyclic diaminocarbene complex of palladium
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Relative activity of halogenated arenes, alkanes, and alkanes in the Suzuki reaction catalyzed with acyclic diaminocarbene complex of palladium has been investigated. Under all the investigated conditions, 4-iodoanisole has been more active than the alkyl
- Kras'Ko,Zlotskii,Boyarskii
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- Hydrogenolysis of carbon-carbon σ-bonds using water catalysed by semi-rigid diiridium(iii) porphyrins
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Semi-rigid diiridium(iii) porphyrin alkyls with m-xylyl and p-xylyl diether linkers were synthesized. They were found to be catalysts for the carbon-carbon σ-bond hydrogenolysis of [2.2]paracyclophane under neutral conditions using water as the hydrogen s
- Fong, Ching Wai,Yu, Ho Yin,Gros, Claude P.,Chan, Kin Shing
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- Carbon-Carbon σ-Bond Transfer Hydrogenation with DMF Catalyzed by Cobalt Porphyrins
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Cobalt porphyrins were found to catalyze the transfer hydrogenation of the carbon-carbon σ bond of [2.2]paracyclophane (PCP) with the solvent DMF serving as the hydrogenating agent. Successful trapping experiments with benzene solvent and the kinetic isot
- Tam, Chun Meng,To, Ching Tat,Chan, Kin Shing
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- NMR and computational studies of the chemical reduction of [2.2]paracyclophane: Formation of dianionic p-xylenyl oligomers
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Reaction of [2.2]paracyclophane with K/Na alloy in THF gives a p-xylylenyl dianion together with its dimer and trimer which are relatively stable at low temperatures; at ambient temperatures further polymerization takes place.
- Gridnev, Ilya D.,Pichierri, Fabio
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- Reversible Thermal Carbon-Hydrogen Bond Cleavage in Alkanes and Arenes with Dihalogenobis(triphenylphosphine)palladium(II) Complexes
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Dihalogenobis(triphenylphosphine)palladium(II) complexes 1, PdX2(PPh3)2 (X = Cl, Br, I), reacts reversibly with saturated and aromatic hydrocarbons RH (RH = p-xylene, toluene, benzene, n-hexane, cyclohexane), slowly at ambient temperature and rapidly on h
- Vedernikov, Andrei N.,Kuramshin, Arkadii I.,Solomonov, Boris N.
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- Iridium-catalyzed carbon-Carbon σ-bond hydrogenation with water: Rate enhancement with iridium hydride
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Iridium porphyrins were found to be good catalysts for the carbon-carbon σ-bond hydrogenation of [2.2]paracyclophane using water in neutral conditions. Mechanistic investigations reveal the promoting effects of iridium porphyrin hydride, IrIII(
- To, Ching Tat,Tam, Chun Meng,Chan, Kin Shing
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- Reductive C(sp3)-C(sp3) homo-coupling of benzyl or allyl halides with H2using a water-soluble electron storage catalyst
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This paper reports the first example of a reductive C(sp3)-C(sp3) homo-coupling of benzyl/allyl halides in aqueous solution by using H2as an electron source {turnover numbers (TONs) = 0.5-2.3 for 12 h}. This homo-coupling reaction, promoted by visible light, is catalysed by a water-soluble electron storage catalyst (ESC). The reaction mechanism, and four requirements to make it possible, are also described.
- Futakuchi, Sayaka,Miyazawa, Keishi,Nakai, Hidetaka,Ogo, Seiji,Shimauchi, Daiki,Takahashi, Yukina,Yatabe, Takeshi,Yoon, Ki-Seok
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p. 39450 - 39454
(2021/12/27)
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- Mixed Alkyl/Aryl Diphos Ligands for Iron-Catalyzed Negishi and Kumada Cross Coupling Towards the Synthesis of Diarylmethane
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Mixed alkyl/aryl diphos ligands have been prepared and their application in iron-catalyzed cross coupling of benzylic chlorides with diaryl zinc (Negishi) or aryl Grignard reagents (Kumada) towards the synthesis of diarylmethane has been evaluated. The iron?diphos catalytic system exhibited the enhanced activity and selectivity in the two coupling reactions. The electron-rich mixed PPh2/PCy2 ligands outperformed their symmetrical PPh2 congeners, and led to decreased homocoupling byproduct formation. It indicates that the electronic effect of the ligands plays an important role in the catalytic performance. The Fe catalyst supported by L8 bearing an electron-rich PCy2 substituent and a sterically demanding tert-butyl on ethene backbone exhibited the best catalytic performance and good functional group tolerance in the two cross coupling reactions.
- Ma, Xufeng,Wang, Han,Liu, Yao,Zhao, Xing,Zhang, Jun
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p. 5134 - 5140
(2021/11/16)
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- Aerobic cross-dehydrogenative couplings of N-heteroarenes with toluene derivatives at room temperature
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A set of mild aerobic cross-dehydrogenative couplings of N-heteroarenes with the benzylic C(sp3)-H bond has been achieved by using visible-light-induced photocatalysis. This approach was found to provide a sustainable alternative to Minisci benzylation reactions using readily accessible toluene derivatives as benzylating agents. The unique combination of photocatalysis, bromo radical mediation, and aerobic oxidation proved to be the key for the success of the transformation. Mechanistic studies revealed the feasibility of both oxidative and reductive quenching of the excited photocatalyst in the initial step.
- Chen, Yufeng,Deng, Guo-Jun,Huang, Huawen,Sun, Zhaozhao,Wang, Qiao-Lin
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supporting information
p. 7790 - 7795
(2021/10/12)
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- Reactions of benzyltriphenylphosphonium salts under photoredox catalysis
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The development of benzyltriphenylphosphonium salts as alkyl radical precursors using photoredox catalysis is described. Depending on substituents, the benzylic radicals may couple to form C-C bonds or abstract a hydrogen atom to form C-H bonds. A natural product, brittonin A, was also synthesized using this method.
- Boldt, Andrew M.,Dickinson, Sidney I.,Ramirez, Jonathan R.,Benz-Weeden, Anna M.,Wilson, David S.,Stevenson, Susan M.
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p. 7810 - 7815
(2021/09/28)
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- Dehydrative/decarboxylative coupling of carboxylic acids with allylic alcohols
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Herein reported is a dehydrative/decarboxylative coupling reaction of carboxylic acids with allylic alcohols, which is cocatalyzed by photoredox and palladium catalysts. α-Hetero- or aryl-substituted carboxylic acids and allylic alcohols, which are both readily available, directly participate in CC bond formation without any functional group transformation.
- Masuda, Yusuke,Ito, Misato,Murakami, Masahiro
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supporting information
p. 1030 - 1033
(2021/05/19)
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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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supporting information
p. 3094 - 3100
(2021/04/23)
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- Ligand-enabled and magnesium-activated hydrogenation with earth-abundant cobalt catalysts
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Replacing expensive noble metals like Pt, Pd, Ir, Ru, and Rh with inexpensive earth-abundant metals like cobalt (Co) is attracting wider research interest in catalysis. Cobalt catalysts are now undergoing a renaissance in hydrogenation reactions. Herein, we describe a hydrogenation method for polycyclic aromatic hydrocarbons (PAHs) and olefins with a magnesium-activated earth-abundant Co catalyst. When diketimine was used as a ligand, simple and inexpensive metal salts of CoBr2in combination with magnesium showed high catalytic activity in the site-selective hydrogenation of challenging PAHs under mild conditions. Co-catalyzed hydrogenation enabled the reduction of two side aromatics of PAHs. A wide range of PAHs can be hydrogenated in a site-selective manner, which provides a cost-effective, clean, and selective strategy to prepare partially reduced polycyclic hydrocarbon motifs that are otherwise difficult to prepare by common methods. The use of well-defined diketimine-ligated Co complexes as precatalysts for selective hydrogenation of PAHs and olefins is also demonstrated.
- Han, Bo,Jiao, Hongmei,Ma, Haojie,Wang, Jijiang,Zhang, Miaomiao,Zhang, Yuqi
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p. 39934 - 39939
(2021/12/31)
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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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- A regionally selective hydrogenation method for chromium-catalyzed thick cyclic aromatic hydrocarbons and olefins based on magnesium-activated ligands
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The present invention relates to the field of hydrogenation, specifically to a chromium-activated complex cyclic aromatic hydrocarbons and olefins promoted by magnesium-activated ligands regionally selective hydrogenation method, which is based on the in situ reduction strategy of magnesium, with biimides as ligands, CrCl2 as catalyst precursors, to construct an efficient low-costchromium hydrogenation system, under mild conditions, to achieve unilateral cyclic hydrogenation of thick ring aromatic hydrocarbons and high-selective hydrogenation of olefins. The system of the present invention is suitable for a variety of substrates of fused cyclic aromatic hydrocarbons, such as tetraphenyl, benzoanthracene, pentabenzo and alfalfa and the like. This provides a simple and efficient strategy and pathway for the synthesis of partially saturated thick cyclic aromatic hydrocarbon compounds.
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Paragraph 0020
(2022/01/10)
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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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- Discovery and mechanistic investigation of Pt-catalyzed oxidative homocoupling of benzene with PhI(OAc)2
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We present a Pt-catalyzed direct coupling of benzene to biphenyl. This catalytic reaction employs a cyclometalated platinum(ii) complex [PtMe(bhq)(SMe2)] (bhq = benzo[h]quinolate) with PhI(OAc)2 as an oxidant and does not require an acid, a co-catalyst or a solvent. The reaction kinetics and characterization of potential catalytic species are reported. The reaction is first-order in Pt and second-order in benzene, which implicates the second C-H activation step as rate-determining. A Pt(ii)/Pt(iv) catalytic cycle is suggested. The reaction commences by oxidation of the Pt(ii) complex to give the platinum(iv) species [Pt(bhq)(SMe2)(OAc)2](OAc) followed by C-H activation of benzene to afford the intermediate [PtPh(bhq)(SMe2)(OAc)](OAc) concurrently with the release of HOAc. A second benzene molecule reacts similarly to give the diphenyl intermediate [PtPh2(bhq)(SMe2)](OAc). C-C bond forming reductive elimination ensues to regenerate Pt(ii) and complete the catalytic cycle. The proposed mechanism has been examined by DFT computations, which provide support to experimental findings.
- Abu-Omar, Mahdi M.,Nabavizadeh, S. Masoud,Niroomand Hosseini, Fatemeh,Park, Chan,Wu, Guang
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supporting information
p. 2477 - 2486
(2020/03/05)
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- Photochemical benzylic radical arylation promoted by supported Pd nanostructures
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We report a novel way to promote photochemical benzylic radical arylations using Pd nanostructures. Traditional benzylic radical reaction pathways are challenged by the presence of metal centres that provoke unprecedented regioselectivity towards more synthetically relevant C(sp3)-C(sp2) couplings. This new C-H activation pathway is rationalised by means of a pseudo-persistent radical effect facilitated by metal centres. We show the mechanistic and computational aspects of the heterogeneous photocatalytic processes that are the root of this drastic change in reactivity. This journal is
- Costa, Paolo,Gawargy, Teresa A.,Lanterna, Anabel E.,Scaiano, Juan C.
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supporting information
p. 6047 - 6052
(2020/10/21)
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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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- Chemical Transformations of Tetracyclo[3.3.1.13,7.01,3]decane (1,3-Dehydroadamantane): IX. Noncatalytic Reactions with Alkylarenes
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Abstract: The reaction of 1,3-dehydroadamantane with alkylbenzenes was studied for the first time. It involved the C–H bond of the alkyl substituent in the α-position with respect to the aromatic ring. The proposed radical mechanism of the reaction was co
- Butov, G. M.,Mokhov, V. M.,Zubovich, E. A.
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p. 1041 - 1045
(2020/07/25)
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- The alkylation method of aromatic compound
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The present invention relates to an alkylation method of an aromatic compound. More particularly, according to the present invention, it is possible to provide a method for enabling the alkylation of an aromatic compound with a high reaction yield by using an ionic liquid catalyst having high catalytic activity for Friedel-Crafts alkylation reaction, and for regenerating an ionic liquid catalyst in a non-destructive manner. The alkylation method of an aromatic compound comprises a step of making an aromatic compound react with a halogenated aliphatic compound under an ionic liquid catalyst comprising benzyltrialkylammonium-Lewis acid.COPYRIGHT KIPO 2020
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Paragraph 0094; 0097-0098; 0125-0128
(2020/06/23)
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- Nickel catalyzed deoxygenative cross-coupling of benzyl alcohols with aryl-bromides
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A nickel-catalyzed cross-electrophile coupling of benzyl alcohols with aromatic bromides has been developed. This deoxygenative cross-coupling occurs under mild reaction conditions at ambient temperature affording diarylmethanes, or 1,3-diarylpropenes from benzyl allyl alcohols. The system demonstrated good chemoselectivity tolerating an assortment of reactive functional groups.
- Kumar Chenniappan, Vinoth,Peck, Devin,Rahaim, Ronald
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- Heteroleptic Ni(II) Complexes Bearing a Bulky Yet Flexible IBiox-6 Ligand: Improved Selectivity in Cross-Electrophile Coupling of Benzyl Chlorides with Aryl Chlorides/Fluorides
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A bisoxazoline-derived NHC known as IBiox-6 reacted smoothly with Ni[P(OEt)3]2Br2 and Ni(PPh3)2Br2 to give the respective heteroleptic Ni(II) complexes Ni(IBiox-6)[P(OEt)3]Br2 (1) and Ni(IBiox-6)(PPh3)Br2 (2) in yields of 60% and 71%. Their crystal structures were characterized to reveal a rare cis disposition of the IBiox-6 ligand to the phosphite ligand in 1, while 2 possessed the more common trans configuration. Both complexes catalyzed the cross-electrophile coupling of benzyl chlorides with aryl chlorides and fluorides in the presence of Mg turnings at 50 °C via a "real one-pot"procedure, featuring no requirement for temperature variation or portionwise addition of any coupling partner. In particular, complex 1 showed a better balance between the catalytic activity and selectivity. The scope of the procedure catalyzed by 1 and Mg turnings was investigated, providing a highly selective, simple, and practical approach to the synthesis of diarylmethanes with high steric hindrance and various functional groups, including oligo-diarylmethane with asymmetric structures.
- Shen, Zheng-Wang,Meng, Die-Die,Imran, Sajid,Yan, Chun-Hui,Sun, Hong-Mei
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p. 3540 - 3545
(2020/10/09)
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- "bulky-Yet-Flexible" α-Diimine Palladium-Catalyzed Reductive Heck Cross-Coupling: Highly Anti-Markovnikov-Selective Hydroarylation of Alkene in Air
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To pursue a highly regioselective and efficient reductive Heck reaction, a series of moisture-and air-stable α-diimine palladium precatalysts were rationally designed, readily synthesized, and fully characterized. The relationship between the structures of the palladium complexes and the catalytic properties was investigated. It was revealed that the"bulky-yet-flexible"palladium complexes allowed highly anti-Markovnikov-selective hydroarylation of alkenes with (hetero)aryl bromides under aerobic conditions. Further synthetic application of the present protocol could provide rapid and straightforward access to functional and biologically active molecules.
- Yang, Xu-Wen,Li, Dong-Hui,Song, A-Xiang,Liu, Feng-Shou
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p. 11750 - 11765
(2020/10/23)
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- Method for preparing biaryl hydrocarbon compound from alcohol compound
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The invention provides a method for preparing a biaryl hydrocarbon compound from an alcohol compound. The method comprises the following steps: sequentially adding the alcohol compound, sodium borohydride and iodine (the molar ratio is 1: (2-3): (0.5-1)) into a reaction tube containing acetonitrile solvent, sealing the reaction tube, heating to 100 DEG C, reacting for 10-20 hours, quenching with water after the reaction is completed, drying an organic phase with anhydrous magnesium sulfate, and carrying out rotary evaporation to remove the solvent and obtain a target product. The method has the advantages of convenience in operation, easiness in product separation, high yield, small environmental pollution and the like, is an ideal method for producing the high-energy-density hydrocarbon by utilizing oxygen-enriched biomass raw materials, and has important practical value.
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Paragraph 0015-0017
(2020/02/14)
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- Ni(II)/Al(0) mediated benzylic Csp 3 - Csp 3 coupling in aqueous media
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Abstract : The reaction of benzyl bromides and chlorides with aluminium metal powder or foil (1.2 eqv.) in the presence of catalytic nickel nitrate (10 mol%) in water at room temperature resulted in homocoupling to the corresponding bibenzyl products which were isolated in moderate to good yields. In sharp contrast, the same reaction in organic solvents like dichloromethane, dimethylformamide, acetonitrile, methanol and toluene yielded only a trace amount of the desired product. The scope of the reaction was tested with substituents on the aromatic ring such as Me-, Cl-, CN-, F-, NO 2-, Ph- as well as 2 ° benzyl halides. Graphical abstract: The reagent combination of aluminium metal and catalytic Ni(NO3)2 promotes the homocoupling of benzyl bromides and chlorides giving rise to the corresponding bibenzyl products in good to excellent yields. The reaction is greatly facilitated in water and showed good functional group tolerance. Besides the mild reaction condition and bench-friendliness, the present reaction constitutes the first example of aluminium-mediated homocoupling of a halide in water. [Figure not available: see fulltext.].
- Nayak, Mukesh Kumar,Mukhi, Priyabrata,Mohanty, Anuradha,Rana, Sohel Samim,Arora, Rajat,Narjinari, Himani,Roy, Sujit
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- Novel preparation of N-arylmethyl-N-arylmethyleneamine N-oxides from benzylic bromides with zinc and isobutyl nitrite
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Treatment of benzylic bromides with Zn and LiCl, followed by the reaction with i-butyl nitrite gave N-arylmethyl-N-arylmethyleneamine N-oxides in moderate yields. The present reaction is a novel and simple method for the preparation of nitrones from benzylic bromides, although the yields are moderate.
- Yanai, Kei,Togo, Hideo
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p. 3523 - 3529
(2019/05/24)
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- Iodine-catalysed transfer hydrogenation of a carbon-carbon σ-bond with water
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Iodine catalysed the transfer hydrogenation of a benzylic C-C σ-bond in [2.2]paracyclophane with water to yield 4,4′-dimethylbibenzyl. The C-C σ-bond was first cleaved by homolytic substitution with iodine radicals to produce a 4,4′-diiodomethylbibenzyl i
- Yang, Wu,To, Ching Tat,Chan, Kin Shing
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supporting information
p. 6757 - 6761
(2019/07/22)
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- Method for preparation of bibenzyl compounds by photocatalytic one-step process
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The invention relates to a brand new low-cost method for synthesis of bibenzyl compounds. The method adopts green and clean light energy as the reaction energy, and takes toluene or a toluene derivative as the raw material to prepare bibenzyl compounds under the catalysis of a solid photocatalyst. The method is carried out at room temperature, and can prepare bibenzyl compounds directly by illumination. The reaction process includes: mixing a toluene derivative, a catalyst and a solvent, then putting the mixture into a pressure-resistant quartz container (larger than 1MPa), and performing replacement with inert gas, conducting illumination stirring at room temperature, and carrying out reaction for 1 or more hour. At the end of the reaction, the catalyst can be easily separated from the reaction system and can be recycled repeatedly, the reaction product can be separated by crystallization, and the yield of bibenzyl compounds can reach 3.21g (g catalyst)h. The method can be used for direct preparation of 1, 2-diphenylethane and natural bibenzyl drugs.
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Paragraph 0055-0056
(2019/07/04)
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- Visible-Light-Driven Self-Coupling of Methylarenes Catalyzed by Ni2P?Cd0.5Zn0.5S Nanoparticles
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The Ni2P?Cd0.5Zn0.5S nanoparticles photocatalyzed self-coupling of p-xylene was reported here, and the corresponding coupling product 1,2-di-p-tolylethane was obtained. The reaction could be extended to toluene derivatives with electron-donating and electron-withdrawing substituents. Ni2P?Cd0.5Zn0.5S nanoparticles had already been characterized by XRD, ICP-AES, SEM, TEM, UV/Vis, FL, XPS. The Mott–Schottky curves of Ni2P?Cd0.5Zn0.5S were made through electrochemical methods. An active carbon free-radical was captured through ESR measurement under irradiation. The research demonstrated this photocatalytic system feasible for the self-coupling reaction of toluene derivatives.
- Yang, Dan-Dan,Hu, Jia-Jun,Zhang, Hong,Lv, Xiao-Jun,Chen, Yong,Fu, Wen-Fu
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p. 1384 - 1392
(2020/01/08)
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- Preparation and application of blended nickel (II) complex with bisoxazoline derived azacyclo-carbene ligand and phosphite ester ligand
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The invention discloses a blended nickel (II) complex with a bisoxazoline derived azacyclo-carbene ligand and a phosphite ester ligand and application of the blended nickel (II) complex. The blended nickel (II) complex has a chemical formula of Ni(NHC)[P(OR)3]X2, in the formula, R is one of ethyl or isopropyl; X is one of bromine atoms or helium atoms; and NHC is the bisoxazoline derived azacyclo-carbene ligand. In the presence of magnesium chips, the blended nickel (II) complex with the bisoxazoline derived azacyclo-carbene ligand and the phosphite ester ligand, which is disclosed by the invention, is capable of catalyzing aromatic hydrocarbon or fluoro-aromatic hydrocarbon with low activity to have a reduction cross coupling reaction with a benzyl chloride type compound at a single temperature, then a diarylmethane compound can be generated at one step, and a novel method is provided for synthesizing diarylmethane compounds.
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Paragraph 0083-0084
(2019/10/17)
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- Photoredox-Catalysis-Modulated, Nickel-Catalyzed Divergent Difunctionalization of Ethylene
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Divergent synthesis that enables a catalytic reaction to selectively produce different products from common substrates will allow the charting of wider chemical space and the unveiling of distinct mechanistic paradigms. A common strategy for it employs different ligands to modulate organometallic catalysts. Dramatic developments in photocatalysis have enabled previously inaccessible transformations. In particular, photoredox catalysis modulates the oxidation state of transition-metal complexes, offering enormous opportunities for methodology development. Herein, we developed a photo-mediated divergent ethylene difunctionalization via modulating oxidation states of the nickel catalyst by using different photoredox catalysts. This work will inspire new perspectives for value-added chemical synthesis using ethylene as a feedstock and shed light on photoredox-catalyst-based divergent synthesis, which fundamentally differs from ligand-controlled transition-metal catalysis.Divergent synthesis represents a powerful strategy for directly accessing different molecular scaffolds originating from the same starting materials. Access to different end products via transition-metal catalysis is conventionally achieved by ligand control. We herein demonstrate the use of ethylene feedstock and commercially available aryl halides to accomplish the divergent synthesis of 1,2-diarylethanes, 1,4-diarylbutanes, or 2,3-diarylbutanes in a highly selective fashion through the synergistic combination of nickel and photoredox catalysis. Mechanistic studies suggest that the observed selectivity was due to different active states of Ni(I) and Ni(0) modulated by Ru- and Ir-based photoredox catalysts, respectively. The ability to access different organometallic oxidation states via photoredox catalysis promises to inspire new perspectives for synergistic transition-metal-catalyzed divergent synthesis.Functionalization of ethylene without polymerization is challenging under photo-irradiation conditions. We have demonstrated that the photo-transformation of ethylene can be controllable by merging photoredox and transition-metal catalysis. In our study, the use of different photoredox catalysts was able to modulate the oxidation state of the nickel catalyst. Through different oxidation states, the nickel-catalyzed couplings proceeded via distinct pathways to generate divergent ethylene difunctionalization products selectively from the same feedstock.
- Li, Jiesheng,Luo, Yixin,Cheo, Han Wen,Lan, Yu,Wu, Jie
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supporting information
p. 192 - 203
(2019/01/21)
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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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- Method for synthesizing 1,2-diphenylethane derivative by catalyzing coupling of sp3C-H bond through graphene-loaded palladium/platinum
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The invention provides a novel method for catalyzing activation of an sp3C-H bond to build a 1,2-diphenylethane compound by developing a novel graphene-loaded bimetal palladium/platinum catalyst whichis simple, convenient and efficient, is free of guide groups and free of participation of solvents and can be reused, so as to increase the yield of the target product, simplify operation steps and improve an atom utilization ratio and the recovery of the catalyst. The invention provides an economical, efficient and green method for preparing the compound. The method has the main advantages thatexperiment operation is simple and convenient, guide groups are not needed, the participation of other solvents is not needed, and the catalyst can be repeatedly recycled.
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Paragraph 0027; 0028
(2018/07/15)
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- Pd-Catalyzed reductive heck reaction of olefins with aryl bromides for Csp2-Csp3 bond formation
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We developed a Pd-catalyzed intermolecular reductive Heck reaction to construct Csp2-Csp3 bonds between aryl bromides and olefins. Various styrene derivatives, acyclic and cyclic alkenes, were well tolerated to couple with varied aryl bromides in linear selectivity. Kinetic and deuterium labeling experiments suggested that i-PrOH provides a hydride through β-H elimination.
- Jin, Liqun,Qian, Jiaxia,Sun, Nan,Hu, Baoxiang,Shen, Zhenlu,Hu, Xinquan
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supporting information
p. 5752 - 5755
(2018/06/07)
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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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- Ligand effect on the rhodium porphyrin catalyzed hydrogenation of [2.2]paracyclophane with water: Key bimetallic hydrogenation
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Rhodium porphyrin catalyzed hydrogenation of the aliphatic carbon-carbon σ-bond of [2.2]paracyclophane with water has been examined with a variety of tetraarylporphyrins and axial ligands. Mechanistic investigations show that RhIII(ttp)H, which can be derived from the reaction of [RhII(ttp)]2 with water without a sacrificial reductant, plays an important role in promoting bimetallic reductive elimination to give the hydrogenation product.
- Tam, Chun Meng,To, Ching Tat,Chan, Kin Shing
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supporting information
p. 10057 - 10063
(2017/08/09)
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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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- Rhodium Complexes of 2,6-Bis(dialkylphosphinomethyl)pyridines: Improved C-H Activation, Expanded Reaction Scope, and Catalytic Direct Arylation
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The reactivity of (PNP)Rh(Ph) (PNP = 2,6-bis(dialkylphosphinomethyl)pyridine) toward a variety of electrophiles (Ar-I, ArCH2Cl, O2, I2, B2pin2, and ArSO3H) was explored, and several new modes of oxidative reactivity were observed. Substituting tBu2P for iPr2P provided 100-fold rate enhancement toward C-H bond activation and addressed the previously reported challenge of N2 inhibition. Studying the stoichiometric reactivity of (PNP)Rh complexes toward C-H cleavage and oxidative functionalization led to (PNP)Rh-catalyzed cross-coupling of aryl iodides with sp2 and sp3 C-H bonds.
- Gair, Joseph J.,Qiu, Yehao,Chan, Natalie H.,Filatov, Alexander S.,Lewis, Jared C.
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supporting information
p. 4699 - 4706
(2018/02/07)
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- Preparation method of chlorobenzene Grignard reagent crystal product
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The invention discloses a preparation method of a chlorobenzene Grignard reagent crystal product and belongs to the technical field of Grignard reagent preparation. The preparation method comprises preparing a bromobenzene Grignard reagent and a 1, 2-dibromoethane Grignard reagent, adding chlorobenzene and magnesium chips into anhydrous ether in a nitrogen protective atmosphere, adding bromobenzene Grignard reagent bulk crystals or 1, 2-dibromoethane Grignard reagent bulk crystals as initiators into the mixture, slowly heating the mixture until a backflow state, keeping the state for 2-4h to obtain a chlorobenzene Grignard reagent crude product, filtering the crude product, preparing an ether saturated solution from the chlorobenzene Grignard reagent-containing filtrate, storing the ether saturated solution at a low temperature of -20 to -25 DEG C for 48h so that a lot of bulk chlorobenzene Grignard reagent crystals are precipitated. The preparation method utilizes easily available raw materials, has simple processes, realizes a high utilization rate and a high yield and is suitable for industrial production.
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Paragraph 0027; 0028; 0029; 0030; 0030; 0031
(2017/03/14)
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- Mechanism and Applications of the Photoredox Catalytic Coupling of Benzyl Bromides
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The photoredox catalytic coupling of halomethyl arenes to bibenzyl derivatives has been demonstrated. The catalytic protocol employed the Hantzsch ester, potassium phosphate, and a photoactive cyclometalated IrIIIcomplex catalyst. A photochemical quantum yield as high as 20 % was obtained. The catalytic mechanism was investigated in detail by performing photophysical and electrochemical measurements, as well as by quantum chemical calculations. The results suggest that two-electron mediation might be responsible for the improved photon economy. The reaction protocol was compatible with halomethyl arenes that contain a variety of functional groups. Finally, the synthetic utility of our protocol was demonstrated by the preparation of a natural dihydrostilbenoid, brittonin A.
- Park, Gyurim,Yi, Seung Yeon,Jung, Jaehun,Cho, Eun Jin,You, Youngmin
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p. 17790 - 17799
(2016/11/28)
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- A well-defined low-valent cobalt catalyst Co(PMe3)4 with dimethylzinc: a simple catalytic approach for the reductive dimerization of benzyl halides
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Herein, we report the first catalytic version of a cobalt-catalysed reductive homocoupling of benzyl halides which proceeds with low catalyst loadings (0.5 to 5 mol%). By synthetizing each cobalt intermediate we demonstrate that reaction proceeds through two single electron transfers (SET) and that dimethylzinc is only involved in the regeneration of the catalytic species.
- Fallon, Brendan J.,Corcé, Vincent,Amatore, Muriel,Aubert, Corinne,Chemla, Fabrice,Ferreira, Franck,Perez-Luna, Alejandro,Petit, Marc
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p. 9912 - 9916
(2016/12/07)
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- Cyclopentadienyl nickel(ii) N, C-chelating benzothiazolyl NHC complexes: Synthesis, characterization and application in catalytic C-C bond formation reactions
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Cyclopentadienyl (Cp) Ni(ii) complexes [CpNiL][PF6] containing hybrid N,C chelating benzothiazolyl NHC ligands (L1 = 1-(2-benzothiazolyl)-3-methylimidazol-2-ylidene, 3a; L2 = 1-(2-benzothiazolyl)-3-allylimidazol-2-ylidene, 3b; L3 = 1-(2-benzothiazolyl)-3-benzylimidazol-2-ylidene, 3c) have been synthesized and fully characterized. The catalytic activity of 3a-3c in some C-C bond formation reactions has been examined. They are efficient catalysts for the homo-coupling of benzyl bromide in the presence of MeMgCl at r.t. with good functional group tolerance. Complex 3a is active in the catalytic oxidative homo-coupling of Grignard reagents with 1,2-dichloroethane as an oxidant at r.t.
- Teo, Wei Jie,Wang, Zhe,Xue, Fei,Andy Hor,Zhao, Jin
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p. 7312 - 7319
(2016/06/01)
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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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- Copper Catalyzed sp3 C-H Etherification with Acyl Protected Phenols
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A variety of acyl protected phenols AcOAr participate in sp3 C-H etherification of substrates R-H to give alkyl aryl ethers R-OAr employing tBuOOtBu as oxidant with copper(I) β-diketiminato catalysts [CuI]. Although 1°, 2°, and 3° C-H bonds may be functionalized, selectivity studies reveal a preference for the construction of hindered, 3° C-OAr bonds. Mechanistic studies indicate that β-diketiminato copper(II) phenolates [CuII]-OAr play a key role in this C-O bond forming reaction, formed via transesterification of AcOAr with [CuII]-OtBu intermediates generated upon reaction of [CuI] with tBuOOtBu.
- Salvador, Tolani K.,Arnett, Charles H.,Kundu, Subrata,Sapiezynski, Nicholas G.,Bertke, Jeffery A.,Raghibi Boroujeni, Mahdi,Warren, Timothy H.
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supporting information
p. 16580 - 16583
(2017/01/10)
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- Reversed electron apportionment in mesolytic cleavage: The reduction of benzyl halides by SmI2
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The paradigm that the cleavage of the radical anion of benzyl halides occurs in such a way that the negative charge ends up on the departing halide leaving behind a benzyl radical is well rooted in chemistry. By studying the kinetics of the reaction of substituted benzylbromides and chlorides with SmI2 in THF it was found that substrates para-substituted with electron-withdrawing groups (CN and CO2Me), which are capable of forming hydrogen bonds with a proton donor and coordinating to samarium cation, react in a reversed electron apportionment mode. Namely, the halide departs as a radical. This conclusion is based on the found convex Hammett plots, element effects, proton donor effects, and the effect of tosylate (OTs) as a leaving group. The latter does not tend to tolerate radical character on the oxygen atom. In the presence of a proton donor, the tolyl derivatives were the sole product, whereas in its absence, the coupling dimer was obtained by a SN2 reaction of the benzyl anion on the neutral substrate. The data also suggest that for the para-CN and CO2Me derivatives in the presence of a proton donor, the first electron transfer is coupled with the proton transfer. Reverse breakup: In the mesolytic cleavage of the radical anions of benzyl halides that are para-substituted by CN or CO2Me groups, the halogen departs, counterintuitively, as a radical and the benzyl system carries the negative charge (see figure).
- Yitzhaki, Offir,Hoz, Shmaryahu
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p. 9242 - 9248
(2015/06/16)
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- Heterogeneous photocatalytic C-C coupling: Mechanism of plasmon-mediated reductive dimerization of benzyl bromides by supported gold nanoparticles
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The use of gold nanoparticles supported on TiO2 (Au@TiO2) as photocatalysts was extended to include photoinduced reductive C-C coupling. Surface plasmon excitation of supported AuNPs in the presence of an amine leads to the C-C coupling of a variety of substituted benzyl bromides at room temperature with good yields in a free radical-mediated reaction. The overall efficiency of the C-C coupling is largely dependent on the nature of the amine used.
- Lanterna, Anabel E.,Elhage, Ayda,Scaiano, Juan C.
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p. 4336 - 4340
(2015/09/01)
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- Two dimensional inorganic electride-promoted electron transfer efficiency in transfer hydrogenation of alkynes and alkenes
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A simple and highly efficient transfer hydrogenation of alkynes and alkenes by using a two-dimensional electride, dicalcium nitride ([Ca2N]+·e-), as an electron transfer agent is disclosed. Excellent yields in the transformation are attributed to the remarkable electron transfer efficiency in the electride-mediated reactions. It is clarified that an effective discharge of electrons from the [Ca2N]+·e- electride in alcoholic solvents is achieved by the decomposition of the electride via alcoholysis and the generation of ammonia and Ca(OiPr)2. We found that the choice of solvent was crucial for enhancing the electron transfer efficiency, and a maximum efficiency of 80% was achieved by using a DMF mixed isopropanol co-solvent system. This is the highest value reported to date among single electron transfer agents in the reduction of C-C multiple bonds. The observed reactivity and efficiency establish that electrides with a high density of anionic electrons can readily participate in the reduction of organic functional groups.
- Kim, Ye Ji,Kim, Sun Min,Cho, Eun Jin,Hosono, Hideo,Yang, Jung Woon,Kim, Sung Wng
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p. 3577 - 3581
(2015/05/27)
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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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- 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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- Copper-catalyzed oxidative homo- and cross-coupling of grignard reagents using diaziridinone
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Transition-metal-catalyzed cross-coupling reactions are among the most powerful synthetic transformations. This paper describes an efficient copper-catalyzed homo- and cross-coupling of Grignard reagents with di-tert-butyldiaziridinone as oxidant under mild conditions, giving the coupling products in good to excellent yields. The reaction process has a broad substrate scope and is also effective for the C(sp)-C(sp3) coupling.
- Zhu, Yingguang,Xiong, Tao,Han, Wenyong,Shi, Yian
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supporting information
p. 6144 - 6147
(2015/01/09)
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- Dilithium tetrachlorocuprate(II) catalyzed oxidative homocoupling of functionalized grignard reagents
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An efficient procedure is described for the oxidative homocoupling of functionalized Grignard reagents using a catalytic amount of dilithium tetrachlorocuprate(II) (CuLi2Cl4) in the presence of pure oxygen gas. This method is applied successfully to a variety of aryl, heteroaryl, alkyl, alkenyl and alkynyl halides, which are converted into the corresponding homocoupled products in good to excellent yields. Georg Thieme Verlag Stuttgart · New York.
- Hua, Si-Kai,Hu, Qiu-Peng,Ren, Jiangmeng,Zeng, Bu-Bing
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p. 518 - 526
(2013/03/29)
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