- Well-Defined Silica-Supported Tungsten(IV)-Oxo Complex: Olefin Metathesis Activity, Initiation, and Role of Br?nsted Acid Sites
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Despite the importance of the heterogeneous tungsten-oxo-based olefin metathesis catalyst (WO3/SiO2) in industry, understanding of its initiation mechanism is still very limited. It has been proposed that reduced W(IV)-oxo surface sp
- Chan, Ka Wing,Mance, Deni,Safonova, Olga V.,Copéret, Christophe
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- Syntheses, photophysical properties, and reactivities of novel bichromophoric Pd complexes composed of Ru(ii)-polypyridyl and naphthyl moieties
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A series of novel bichromophoric Ru(ii) complexes bearing a naphthyl chromophore linked with 2,2′-bipyridyl (bpy) and 2,2′-bipyrimidine (bpm) ligands were synthesized. Complexation with a Pd-alkyl unit led to the formation of bichromophoric Ru-Pd catalyst
- Murata, Kei,Araki, Mizuki,Inagaki, Akiko,Akita, Munetaka
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- Reactive separation of β-bromoethylbenzene from α-β-bromoethylbenzene mixtures: a Zn2+-mediated radical polymerization mechanism
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A Zn2+-induced reactive separation method for the purification of β-bromoethylbenzene from α-β-bromoethylbenzene mixtures is discovered, where the selective decomposition of α-bromoethylbenzene follows a radical mechanism. Zn2+ facilitates the homolysis of the C-Br bond of halohydrocarbons with benzyl bromide, enabling the separation of the corresponding isomers with almost identical physical properties.
- Deng, Tianyu,Tian, Jiaming,Yan, Binhang,Zhu, Junqiu
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p. 1219 - 1222
(2022/02/03)
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- Nickel-Catalyzed Arylation of C(sp3)-O Bonds in Allylic Alkyl Ethers with Organoboron Compounds
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A nickel-catalyzed cross-coupling of allylic alkyl ethers with organoboron compounds through the cleavage of the inert C(sp3)-O(alkyl) bonds is described. Several types of allylic alkyl ethers can be coupled with various boronic acids or their derivatives to give the corresponding products in good to excellent yields with wide functional group tolerance and excellent regioselectivity. The gram-scale reaction and late-stage modification of biologically active compounds further prove the practicality of this synthetic method.
- Li, Xiaowei,Li, Yuxiu,Zhang, Zhong,Shi, Xiaolin,Liu, Ruihua,Wang, Zemin,Li, Xiangqian,Shi, Dayong
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p. 6612 - 6616
(2021/09/02)
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- Remote Arylative Substitution of Alkenes Possessing an Acetoxy Group via β-Acetoxy Elimination
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Palladium-catalyzed remote arylative substitution was achieved for the reaction of arylboronic acids with alkenes possessing a distant acetoxy group to provide arylation products having an alkene moiety at the remote position. The use of β-acetoxy elimination as a key step in the catalytic cycle allowed for regioselective formation of unstabilized alkenes after chain walking. This reaction was applicable to various arylboronic acids as well as alkene substrates.
- Kakiuchi, Fumitoshi,Kochi, Takuya,Kumagai, Takaaki,Muto, Kazuma
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p. 24500 - 24504
(2021/10/19)
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- Site-Selective Acceptorless Dehydrogenation of Aliphatics Enabled by Organophotoredox/Cobalt Dual Catalysis
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The value of catalytic dehydrogenation of aliphatics (CDA) in organic synthesis has remained largely underexplored. Known homogeneous CDA systems often require the use of sacrificial hydrogen acceptors (or oxidants), precious metal catalysts, and harsh reaction conditions, thus limiting most existing methods to dehydrogenation of non- or low-functionalized alkanes. Here we describe a visible-light-driven, dual-catalyst system consisting of inexpensive organophotoredox and base-metal catalysts for room-temperature, acceptorless-CDA (Al-CDA). Initiated by photoexited 2-chloroanthraquinone, the process involves H atom transfer (HAT) of aliphatics to form alkyl radicals, which then react with cobaloxime to produce olefins and H2. This operationally simple method enables direct dehydrogenation of readily available chemical feedstocks to diversely functionalized olefins. For example, we demonstrate, for the first time, the oxidant-free desaturation of thioethers and amides to alkenyl sulfides and enamides, respectively. Moreover, the system's exceptional site selectivity and functional group tolerance are illustrated by late-stage dehydrogenation and synthesis of 14 biologically relevant molecules and pharmaceutical ingredients. Mechanistic studies have revealed a dual HAT process and provided insights into the origin of reactivity and site selectivity.
- Zhou, Min-Jie,Zhang, Lei,Liu, Guixia,Xu, Chen,Huang, Zheng
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supporting information
p. 16470 - 16485
(2021/10/20)
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- Cascade Reductive Friedel-Crafts Alkylation Catalyzed by Robust Iridium(III) Hydride Complexes Containing a Protic Triazolylidene Ligand
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The synthesis of complex molecules like active pharmaceutical ingredients typically requires multiple single-step reactions, in series or in a modular fashion, with laborious purification and potentially unstable intermediates. Cascade processes offer attractive synthetic remediation as they reduce time, energy, and waste associated with multistep syntheses. For example, triarylmethanes are traditionally prepared via several synthetic steps, and only a handful of cascade routes are known with limitations due to high catalyst loadings. Here, we present an expedient catalytic cascade process to produce triarylmethanes. For this purpose, we have developed a bifunctional iridium system as the efficient catalyst to build heterotriaryl synthons via reductive Friedel-Crafts alkylation from ketones, arenes, and hydrogen. The catalytically active species were generated in situ from a robust triazolyl iridium(III) hydride complex and acid and is composed of a metal-bound hydride and a proximal ligand-bound proton for reversible dihydrogen release. These complexes catalyze the direct hydrogenation of ketones at slow rates followed by dehydration. Appropriate adjustment of the conditions successfully intercepts this dehydration and leads instead to efficient C-C coupling and Friedel-Crafts alkylation. The scope of this cascade process includes a variety of carbonyl substrates such as aldehydes, (alkyl)(aryl)ketones, and diaryl ketones as precursor electrophiles with arenes and heteroarenes for Friedel-Crafts coupling. The reported method has been validated in a swift one-step synthesis of the core structure of a potent antibacterial agent. Excellent yields and exquisite selectivities were achieved for this cascade process with unprecedentedly low iridium loadings (0.02 mol %). Moreover, the catalytic activity of the protic system is significantly higher than that of an N-methylated analogue, confirming the benefit of the Ir-H/N-H hydride-proton system for high catalytic performance.
- Albrecht, Martin,Alshakova, Iryna D.
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p. 8999 - 9007
(2021/07/31)
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- Enantioselective Hydroalkenylation of Olefins with Enol Sulfonates Enabled by Dual Copper Hydride and Palladium Catalysis
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The catalytic enantioselective synthesis of α-chiral olefins represents a valuable strategy for rapid generation of structural diversity in divergent syntheses of complex targets. Herein, we report a protocol for the dual CuH- and Pd-catalyzed asymmetric Markovnikov hydroalkenylation of vinyl arenes and the anti-Markovnikov hydroalkenylation of unactivated olefins, in which readily available enol triflates can be utilized as alkenyl coupling partners. This method allowed for the synthesis of diverse α-chiral olefins, including tri- and tetrasubstituted olefin products, which are challenging to prepare by existing approaches.
- Schuppe, Alexander W.,Knippel, James Levi,Borrajo-Calleja, Gustavo M.,Buchwald, Stephen L.
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supporting information
p. 5330 - 5335
(2021/05/04)
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- Preparation and application of triphenylphosphine allyl palladium halide compound and derivative thereof
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The invention discloses a synthesis method of a triphenylphosphine allyl palladium halide compound and a derivative thereof. The synthesis method comprises the step of carrying out one-step reaction on a mixture containing a palladium salt, a halogenated allyl compound and a trisubstituted phosphine compound to obtain the triphenylphosphine allyl palladium halide compound and the derivative thereof. The method is low in cost, high in efficiency, easy to operate and high in safety. The prepared triphenylphosphine allyl palladium halide compound and the derivative thereof can be widely applied as catalysts to catalytic cross coupling or homogeneous coupling reactions of various types of organic substrates so as to prepare various organic reaction intermediates.
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Paragraph 0183-0188
(2020/05/30)
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- In Situ Ring-Closing Strategy for Direct Synthesis of N-Heterocyclic Carbene Nickel Complexes and Their Application in Coupling of Allylic Alcohols with Aryl Boronic Acids
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A in situ ring-closing strategy was developed for the synthesis of N-heterocyclic carbene nickel complexes. The process was carried out in air, and did not require solvent purification. The resulting nickel complexes were investigated as catalysts for the coupling of allylic alcohols with aryl boronic acids. A wide range of allylic substrates and aryl acids proved to be applicable to this catalytic system. Control experiments suggest that the Ni(0) may be the true active species in the coupling reactions. (Figure presented.).
- Wang, Yu-Bin,Liu, Bin-Yuan,Bu, Qingqing,Dai, Bin,Liu, Ning
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p. 2930 - 2940
(2020/06/17)
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- Copper-catalyzed oxidative benzylic C(sp3)-H amination: Direct synthesis of benzylic carbamates
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A new efficient strategy to access benzylic carbamates through C-H activation is reported. The use of a catalytic amount of a Cu(i)/diimine ligand in combination with NFSI ((PhSO2)2NF) or F-TEDA-PF6 as oxidants and H2NCO2R as an amine source directly leads to the C-N bond formation at the benzylic position. The mild reaction conditions and the broad substrate scope make this transformation a useful method for the late-stage incorporation of a ubiquitous carbamate fragment onto hydrocarbons. This journal is
- Liu, Shuai,Achou, Rapha?l,Boulanger, Coline,Pawar, Govind,Kumar, Nivesh,Lusseau, Jonathan,Robert, Frédéric,Landais, Yannick
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supporting information
p. 13013 - 13016
(2020/11/05)
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- Oxidation of Alkenes by Water with H2 Liberation
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Oxidation by water with H2 liberation is highly desirable, as it can serve as an environmentally friendly way for the oxidation of organic compounds. Herein, we report the oxidation of alkenes with water as the oxidant by using a catalyst combination of a dearomatized acridine-based PNP-Ru complex and indium(III) triflate. Compared to traditional Wacker-type oxidation, this transformation avoids the use of added chemical oxidants and liberates hydrogen gas as the only byproduct.
- Ben-David, Yehoshoa,Milstein, David,Tang, Shan
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supporting information
p. 5980 - 5984
(2020/04/27)
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- Mechanistic Investigation of the Nickel-Catalyzed Carbonylation of Alcohols
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The carbonylation of alcohols represents a straightforward and atom-efficient methodology for the preparation of carboxylic acids. It is desirable to perform these reactions under precious metal-free and low-pressure conditions, with regioselectivity control. In this work, we present a detailed mechanistic study of a catalytic system based on NiI2, which can carbonylate benzylic alcohols in a highly regioselective manner to the corresponding branched carboxylic acids, core motifs for nonsteroidal drugs. The combination of catalytic amounts of nickel and iodide is crucial for efficient catalytic and regioselective conversion. Quantum-chemical computations were used to evaluate the underlying mechanistic processes. They revealed that a combination of two mechanisms is responsible for the observed reactivity and that the oxidative addition of alkyl halides to the Ni(0) species follows a radical oxidation pathway via two one-electron steps.
- Comba, Peter,Ghosh, Tamal,Hashmi, A. Stephen K.,Krieg, Saskia,Menche, Maximilian,Paciello, Rocco,Rück, Katharina S. L.,Sabater, Sara,Sch?fer, Ansgar,Schaub, Thomas
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supporting information
(2020/03/19)
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- Nickel-Catalyzed Hydroarylation of in Situ Generated 1,3-Dienes with Arylboronic Acids Using a Secondary Homoallyl Carbonate as a Surrogate for the 1,3-Diene and Hydride Source
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The nickel-catalyzed hydroarylation of 1,3-dienes with arylboronic acids using a secondary homoallyl carbonate as a surrogate for the 1,3-diene and hydride source has been developed. The synthetic strategy allowed an efficient access to a wide array of hydroarylation products in high yields with high functional group compatibility without the use of an external hydride source. Mechanistic experiments indicated that the alkene-directed oxidative addition and subsequent β-hydride elimination would be a critical process in this transformation.
- Hamaguchi, Takashi,Kawatsura, Motoi,Takahashi, Yoshiyuki,Tsuji, Hiroaki
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- Dehydrative Coupling of Benzylic Alcohols Catalyzed by Br?nsted Acid/Lewis Base
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Traditional cross-coupling reactions show some disadvantages like the use of organohalides or the production of stoichiometric amounts of waste. The dehydrative homo- or heterocoupling of alcohols therefore arises as an interesting approach for a highly atom-economical formation of carbon–carbon bonds, since water is produced as the only by-product. We herein report a simple and direct, metal-free protocol for the synthesis of olefins by applying catalytic amounts of a sulfonic acid and triphenylphosphane under air. A variety of olefins could be synthesized from benzylic alcohols under relatively mild conditions. Additionally, dehydrative hydroarylation of benzylic alcohols with electron-rich arenes was possible by using only Br?nsted acid under otherwise same reaction conditions. We could show that phosphane additives are essential to overcome oligomerization as main side reaction by the occupancy of the reactive carbocation intermediate.
- B?ldl, Marlene,Fleischer, Ivana
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supporting information
p. 5856 - 5861
(2019/08/07)
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- Silver triflate mediated dehydration of benzylic alcohols and vinyl hydrovinylation of styrene
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The use of silver trifluoromethanesulfonate (silver triflate, AgOTf) as a halide abstraction reagent is pervasive in organometallic chemistry. However, recent reports suggest a “hidden” Br?nsted acid lurks within it that may catalyze purported metal-based catalysis. Presented herein are new reactions that are either catalyzed or promoted by the “hidden” acid, generated upon silver triflate degradation. 1-Phenylethanol dehydrates to styrene (1) upon reaction with AgOTf at 90 °C over 24 h, which slowly coverts to the vinyl hydrovinylation product (E)-1,3-diphenyl-1-butene, (2, 64%) over several days. While dehydration was observed with a number of benzylic alcohols to yield Zaitsev selective olefins, only 1-phenylethanol affords vinyl hydrovinylation products. Dehydration was not observed for primary and secondary alcohols, suggesting an acid catalyzed E1elimination reaction mechanism is at play. The degradation of silver triflate was found to be the source of the “hidden” Br?nsted acid, which demonstrated a dependence on the presence of light and oxygen. In the absence of light and oxygen, dehydration of 1-phenylethanol was severely stunted and 2 is not formed, but instead the ether product, oxy-bis(ethane-1,1-diyl)dibenzene (3), is afforded. The mesitylene internal standard also reacts with the in situ formed styrene to produce 2-(1-phenylethyl)mesitylene (4) through acid catalyzed electrophilic aromatic substitution. These reactions were monitored (products characterized) by GC-MS and/or 1H NMR spectroscopic methods. We present herein the details of these reactions and our characterization methods.
- Quillian, Brandon,Fields, Alexis E.,Chace, Desiree,Murrell Vickery, Amanda,Sharma, Mrinali,Zurwell, Dane,Bazemore, Joseph G.,Phan, Long,Thomas, Dorey,Padgett, Clifford W.
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supporting information
p. 224 - 229
(2019/03/02)
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- Synthesis of internal olefins by direct coupling of alcohols and olefins over MoΒ zeolite
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An efficient and novel Moβ zeolite catalyzed sp2-sp3 C–C bond development reaction over the direct coupling of alcohols and alkenes has been performed in solvent free environment. The current method gives an attractive access to a wide variety of polysubstituted alkenes in good to excellent yields. The Moβ zeolite was effectively reused for up to 5 successive cycles.
- Chevella, Durgaiah,Macharla, Arun Kumar,Kodumuri, Srujana,Banothu, Rammurthy,Gajula, Krishna Sai,Amrutham, Vasu,Grigor'eva, Nellya Gennadievna,Nama, Narender
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p. 114 - 118
(2019/07/02)
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- Non-corrosive heteropolyacid-based recyclable ionic liquid catalyzed direct dehydrative coupling of alcohols with alcohols or alkenes
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A non-corrosive, recyclable and efficient heterogeneous catalyst based on Keggin-type polyoxometalate, i.e., [NMPH]H3[SiW12O40] was developed for the direct dehydrative coupling of alcohols with alcohols (or alkenes) to synthesize various polysubstituted olefins in good to excellent yields. Furthermore, this reaction could be scaled up and the catalyst could be used for seven runs without significant loss of activity. The kinetic competition experiment shows that the C–H bond cleavage might be involved in the rate-determining step.
- Yang, Guo-Ping,Jiang, Nan,Huang, Xian-Qiang,Yu, Bing,Hu, Chang-Wen
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- Nickel-Catalyzed Direct Coupling of Allylic Alcohols with Organoboron Reagents
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The direct coupling of allylic alcohols with arylboronic acids or their derivatives catalyzed by Ni(cod)2 in the presence of a catalytic amount of base has been developed. A wide variety of allylic substrates or arylboronic acids turned out to be applicable to this catalytic system. The present method does not require the use of ligands for stabilizing the nickel catalyst in most cases or additional activators for activation of allylic alcohols.
- Wang, Gaonan,Gan, Yi,Liu, Yuanhong
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supporting information
p. 916 - 920
(2018/09/22)
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- Manganese-Catalyzed Dual-Deoxygenative Coupling of Primary Alcohols with 2-Arylethanols
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Reported herein is a general and efficient dual-deoxygenative coupling of primary alcohols with 2-arylethanols catalyzed by a well-defined Mn/PNP pincer complex. This reaction is the first example of the catalytic dual-deoxygenation of alcohols using a non-noble-metal catalyst. Both deoxygenative homocoupling of 2-arylethanols (17 examples) and their deoxygenative cross-coupling with other primary alcohols (20 examples) proceeded smoothly to form the corresponding alkenes by a dehydrogenation and deformylation reaction sequence.
- Wang, Yujie,Shao, Zhihui,Zhang, Kun,Liu, Qiang
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supporting information
p. 15143 - 15147
(2018/11/01)
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- Transition-Metal-Free Sulfuration/Annulation of Alkenes: Economical Access to Thiophenes Enabled by the Cleavage of Multiple C-H Bonds
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A novel, atom economical, and transition-metal-free strategy for the synthesis of thiophenes from substituted buta-1-enes with potassium sulfide has been presented. The reaction achieves double C-S bond formations via cleavage of multiple C-H bonds and provides an efficient approach to access various functionalized thiophenes. Moreover, the strategy can also be used for the synthesis of thiophenes from 1,4-diaryl-1,3-dienes. Mechanistically, DMSO plays a role of oxidant and S3?- in situ generated from K2S is involved.
- Chen, Liang,Min, Hao,Zeng, Weilan,Zhu, Xiaoming,Liang, Yun,Deng, Guobo,Yang, Yuan
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supporting information
p. 7392 - 7395
(2019/01/03)
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- Cationic R-Substituted-Indenyl Nickel(II) Complexes of Arsine and Stibine Ligands: Synthesis, Characterization, and Catalytic Behavior in the Oligomerization of Styrene
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A series of new cationic Rn-substituted-indenyl nickel(II) complexes containing arsine or stibine ligands were synthesized in moderate to very high yields by the protonation of the corresponding bis(indenyl) nickel derivatives [Ni(η-Rn-Ind)2] with HBF4, in the presence of 2 equiv. of AsPh3 or SbPh3 donor ligands. These complexes, with the general formula [Ni(η-Rn-Ind)(EPh3)2]BF4 (E = As, Sb), were structurally characterized by NMR spectroscopy and X-ray diffraction, and subsequently tested as single-component catalysts for the oligomerization of styrene, leading to the formation of very low molecular weight head-to-tail oligomers (typically consisting of dimers, trimers and tetramers). The new 1- or 2-monosubstituted-indenyl NiII catalyst precursors exhibit extremely high catalytic activities, considerably higher than those observed for the symmetrical unsubstituted- and the 1,3-disubstituted-indenyl nickel analogues (i.e. monosubstituted >> non-substituted > 1,3-disubstituted), their reactivity pattern showing similarities with that of the corresponding allyl derivatives. A simpler and more straightforward experimental procedure for the high yield preparation of [NiBr2(DME)], an important nickel starting material, which was used in the preparation of the bis(indenyl) nickel precursors of this work, is also described.
- Gomes, Clara S. B.,Costa, Sandra I.,Silva, Leonel C.,Jiménez-Tenorio, Manuel,Valerga, Pedro,Puerta, M. Carmen,Gomes, Pedro T.
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p. 597 - 607
(2018/02/06)
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- Nickel(0)-Catalyzed Hydroarylation of Styrenes and 1,3-Dienes with Organoboron Compounds
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A Ni-catalyzed hydroarylation of styrenes and 1,3-dienes with organoboron compounds has been developed. The reaction offers a highly selective approach to diarylalkanes and allylarenes under redox-neutral conditions. In this hydroarylation reaction, a new strategy that uses the proton of methanol to generate the active catalyst species Ni?H was developed. The Ni-catalyzed hydroarylation, combined with a Ir-catalyzed C?H borylation, affords a very efficient and straightforward access to a retinoic acid receptor agonist.
- Xiao, Li-Jun,Cheng, Lei,Feng, Wei-Min,Li, Mao-Lin,Xie, Jian-Hua,Zhou, Qi-Lin
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supporting information
p. 461 - 464
(2018/02/21)
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- Asymmetric synthesis via stereospecific C-N and C-O bond activation of alkyl amine and alcohol derivatives
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This perspective showcases our development of benzylic and allylic amine and alcohol derivatives as electrophiles for stereospecific, nickel-catalyzed cross-coupling reactions, as well as the prior art that inspired our efforts. The success of our effort
- Pound, Sarah M.,Watson, Mary P.
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p. 12286 - 12301
(2018/11/20)
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- [Pd(acac)(L)2][BF4] (L?=?morpholine, diethylamine, dibutylamine, dioctylamine): Synthesis, structure and their catalytic activity
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Cationic acetylacetonate bis(secondary amine) palladium (II) complexes were synthesized by nitrile substitution of [Pd(acac)(MeCN)2][BF4] with L (L?=?morpholine, diethylamine, dibutylamine, dioctylamine) which yielded [Pd(acac)(L)2][BF4] as a mononuclear species with chelating acac ligand. An X-ray diffraction, NMR, IR and DFT study of [Pd(acac){morpholine}2][BF4] establishes the presence of hydrogen bonding between the morpholine ligand and [BF4]? anion. Crystallographic defects in the crystal and presence of pseudocrystalline structure in solution of [Pd(acac){morpholine}2][BF4] were assumed to explain IR spectra features. Preliminary investigations into the polymerization of norbornene, dimerization of styrene, and telomerization of 1,3-butadiene with diethylamine were performed.
- Suslov,Bykov,Ratovskii,Abramov,Pahomova,Ushakov,Voronov,Tkach
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p. 411 - 421
(2016/12/26)
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- Cationic acetylacetonate palladium complexes/boron trifluoride etherate catalyst systems for hydroamination of vinylarenes using arylamines
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A simple and solvent-free protocol using cationic acetylacetonate palladium complexes with mono-/bidentate phosphine ligands activated with BF3·OEt2as in situ-formed catalyst for hydroamination of vinylarenes with arylamines have bee
- Suslov,Bykov,Pakhomova,Abramov,Ushakov,Tkach
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- One-pot synthesis of 1,3-diaryl but-1-enes from 1-arylethanols over Snβ zeolite
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An environmentally benign catalytic protocol has been successfully developed for the one-pot synthesis of 1,3-diaryl but-1-enes from 1-arylethanols via dehydration of 1-arylethanols followed by head-to-tail dimerization of vinylarenes over heterogeneous c
- Mameda, Naresh,Gajula, Krishna Sai,Peraka, Swamy,Kodumuri, Srujana,Chevella, Durgaiah,Banothu, Rammurthy,Amrutham, Vasu,Nama, Narender
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- Br?nsted Acid-Catalyzed Intramolecular Hydroarylation of β-Benzylstyrenes
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Using triphenylmethylium tetrakis(pentafluorophenyl)borate as a convenient Br?nsted acid precatalyst, β-(α,α-dimethylbenzyl)styrenes are shown to cyclize efficiently to afford a variety of new indanes that possess a benzylic quaternary center. The geminal dimethyl-containing quaternary center is proposed to be necessary to arm the substrate for cyclization through steric biasing.
- Cai, Xiao,Keshavarz, Amir,Omaque, Justin D.,Stokes, Benjamin J.
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supporting information
p. 2626 - 2629
(2017/05/24)
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- Silver-catalyzed decarboxylative C(sp2)-C(sp3) coupling reactions: Via a radical mechanism
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A silver catalyzed decarboxylative C(sp2)-C(sp3) coupling of vinylic carboxylic acids with alcohols, alkylbenzenes, cycloalkanes and cyclic ethers was developed by using DTBP as an oxidant. This reaction tolerates a wide range of substrates, and products are obtained in good to excellent yields. The reaction also shows good stereoselectivity, and only trans-isomers are obtained. In addition, a radical pathway would be involved to facilitate this decarboxylative C(sp2)-C(sp3) coupling reaction.
- Fang, Zhongxue,Wei, Chenlong,Lin, Jing,Liu, Zhenhua,Wang, Wei,Xu, Chenshu,Wang, Xuemin,Wang, Yu
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supporting information
p. 9974 - 9978
(2017/12/26)
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- Calcium(II) catalyzed regioselective dehydrative cross-coupling reactions: Practical synthesis of internal alkenes and benzopyrans
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A simple and operationally easy protocol for the regioselective synthesis of internal alkenes through a dehydrative cross-coupling and direct coupling procedure has been described using the environmentally benign Ca(II) catalyst. Several alkenes and alcohols underwent the coupling reaction under solvent-free conditions in a short time to produce the desired alkenes. This method is further extended to show the application in the synthesis of novel benzopyran molecules through a cascade strategy.
- Yaragorla, Srinivasarao,Pareek, Abhishek,Dada, Ravikrishna,Almansour, Abdulrahman I.,Arumugam, Natarajan
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supporting information
p. 5841 - 5845
(2016/12/14)
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- Highly efficient TfOH-catalyzed head-to-tail dimerization of vinylarenes
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A convenient and efficient TfOH-catalyzed head-to-tail dimerization of vinylarenes has been realized under mild conditions. The present protocol provides an attractive approach to a diverse range of higher olefins in good to excellent yields.
- Yue, Hui-Lan,Zhao, Xiao-Hui,Jiang, Lei,Shao, Yun,Mei, Li-Juan
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p. 179 - 186
(2016/02/23)
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- Efficient hydroarylation and hydroalkenylation of vinylarenes by Br?nsted acid catalysis
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Br?nsted acid Tf2NH alone catalyzed Friedel-Crafts-type hydroarylation and head-to-tail hydroalkenylation of vinylarenes under mild reaction conditions have been realized, providing a readily scalable, metal-free, and practical access to the 1,1-diarylalkane scaffolds and trans-1,3-diaryl-1-butenes in high yields and excellent regioselectivities.
- Liu, Muwen,Zhang, Jinlong,Zhou, Hui,Yang, Huameng,Xia, Chungu,Jiang, Gaoxi
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p. 76780 - 76784
(2016/09/03)
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- Iodine-Promoted Metal-Free Head-to-Tail Dimerization of Styrenes Affording 1,3-Diarylbut-1-enes
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A convenient and efficient iodine-mediated head-to-tail dimerization of styrenes to produce the corresponding dimers in the presence of triethyl phosphite is reported. The advantages of the present protocol are metal-free conditions, short reaction time, simplicity, and high efficiency.
- Wang, Dingyi,Fang, Yanjiao,Xie, Qihuang,Yan, Zhaohua,Lin, Sen,Guo, Shengmei
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supporting information
p. 2815 - 2818
(2016/12/16)
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- Bimetallic nanosized solids with acid and redox properties for catalytic activation of C-C and C-H bonds
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A new approach is presented to form self-supported bimetallic nanosized solids with acid and redox catalytic properties. They are water-, air- and H2-stable, and are able to activate demanding C-C and C-H reactions. A detailed mechanistic study on the formation of the Ag-Fe bimetallic system shows that a rapid redox-coupled sequence between Ag+, O2 (air) and Fe2+ occurs, giving monodisperse Ag nanoparticles supported by O-bridged diatomic Fe3+ triflimides. The system can be expanded to Ag nanoparticles embedded within a matrix of Cu2+, Bi3+ and Yb3+ triflimide.
- Cabrero-Antonino, Jose R.,Tejeda-Serrano, María,Quesada, Manuel,Vidal-Moya, Jose A.,Leyva-Pérez, Antonio,Corma, Avelino
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p. 689 - 696
(2016/12/28)
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- Nickel Catalysts for the Dehydrative Decarbonylation of Carboxylic Acids to Alkenes
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Combining high-throughput experimentation with conventional experiments expedited discovery of new first-row nickel catalysts for the dehydrative decarbonylation of the bioderived substrates hydrocinnamic acid and fatty acids to their corresponding alkenes. Conventional experiments using a continuous distillation process (180 °C) revealed that catalysts composed of NiII or Ni0 precursors (NiI2, Ni(PPh3)4) and simple aryl phosphine ligands were the most active. In the reactions with fatty acids, the nature of the added phosphine influenced the selectivity for α-alkene, which reached a maximum value of 94%. Mechanistic studies of the hydrocinnamic reaction using Ni(PPh3)4 as catalyst implicate a facile first turnover to produce styrene at room temperature, but deactivation of the Ni(0) catalyst by CO poisoning occurs subsequently, as evidenced by the formation of Ni(CO)(PPh3)3, which was isolated and structurally characterized. Styrene dimerization is a major side reaction. Analysis of the reaction mechanism using density functional theory supported catalyst regeneration along with alkene formation as the most energetically demanding reaction steps.
- John, Alex,Miranda, Maria O.,Ding, Keying,Dereli, Büsra,Ortuno, Manuel A.,Lapointe, Anne M.,Coates, Geoffrey W.,Cramer, Christopher J.,Tolman, William B.
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supporting information
p. 2391 - 2400
(2016/08/02)
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- Nickel-Catalyzed Denitrated Coupling Reaction of Nitroalkenes with Aliphatic and Aromatic Alkenes
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A simple and practical denitrated coupling reaction of nitroalkenes with various alkenes using a nickel catalyst and triethoxysilane [(EtO)3SiH] as reducing agent was achieved. Under mild reaction conditions, both aliphatic and aromatic alkenes could react with nitroalkenes to obtain a series of olefins with different functional groups in satisfactory yields under an air atmosphere, which were previously difficult or impossible to access. (Figure presented.).
- Zhang, Na,Quan, Zheng-Jun,Wang, Xi-Cun
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supporting information
p. 3179 - 3183
(2016/10/21)
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- Transition-Metal-Free Stereospecific Cross-Coupling with Alkenylboronic Acids as Nucleophiles
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We herein report a transition-metal-free cross-coupling between secondary alkyl halides/mesylates and aryl/alkenylboronic acid, providing expedited access to a series of nonchiral/chiral coupling products in moderate to good yields. Stereospecific SN2-type coupling is developed for the first time with alkenylboronic acids as pure nucleophiles, offering an attractive alternative to the stereospecific transition-metal-catalyzed C(sp2)-C(sp3) cross-coupling.
- Li, Chengxi,Zhang, Yuanyuan,Sun, Qi,Gu, Tongnian,Peng, Henian,Tang, Wenjun
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supporting information
p. 10774 - 10777
(2016/09/09)
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- Chemo- and regioselective head-to-tail heterodimerization of vinylarenes with 1,1-diphenylethene over a heterogeneous catalyst (Snβ zeolite)
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In the presence of Snβ zeolite, vinylarenes undergo the highly chemo- and regioselective head-to-tail heterodimerization with 1,1-diphenylethene to form the corresponding alkenes in good to excellent yields. The scope of the reaction was explored by various vinylarenes with 1,1-diphenylethene. However, the substrates with strong electron-withdrawing groups failed to react with 1,1-diphenylethene under the present catalytic conditions. Moreover, the Snβ zeolite is recyclable and can be reused without significant loss in its catalytic activity.
- Mameda, Naresh,Peraka, Swamy,Kodumuri, Srujana,Chevella, Durgaiah,Marri, Mahender Reddy,Aytam, Hari Padmasri,Nama, Narender
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p. 1296 - 1300
(2016/01/16)
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- [Pd(acac)(MeCN)2]BF4: Air-tolerant, activator-free catalyst for alkene dimerization and polymerization
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[Pd(acac)(MeCN)2]BF4 has been observed to catalyze selective substituted styrene dimerization and addition norbornene polymerization. Theoretical calculations based on BP86 density functional theory have been carried out to clarify the precatalyst activation mechanism.
- Suslov,Bykov,Abramov,Pahomova,Ushakov,Voronov,Tkach
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p. 104467 - 104471
(2015/12/24)
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- A palladium NNC-pincer complex: An efficient catalyst for allylic arylation at parts per billion levels
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Allylic arylation of allylic acetates by sodium tetraarylborates in the presence of ppb to ppm (molar) loadings of a palladium NNC-pincer complex catalyst in methanol at 50°C gave the corresponding arylated products in excellent yields. Total turnover numbers of up to 500 000 000 and turnover frequencies of up to 11 250 000 h-1 were achieved.
- Hamasaka, Go,Sakurai, Fumie,Uozumi, Yasuhiro
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supporting information
p. 3886 - 3888
(2015/03/04)
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- An Eco-friendly Soft Template Synthesis of Mesostructured Silica-Carbon Nanocomposites for Acid Catalysis
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The synthesis of ordered mesoporous silica-carbon composites was explored by employing TEOS and sucrose as the silica and carbon precursor respectively, and the triblock copolymer F127 as a structure-directing agent via an evaporation-induced self-assembly (EISA) process. It is demonstrated that the synthesis procedures allow for control of the textural properties and final composition of these silica-carbon nanocomposites via adjustment of the effective SiO2/C weight ratio. Characterization by SAXS, N2 physisorption, HRTEM, TGA, and 13C and 29Si solid-state MAS NMR show a 2D hexagonal mesostructure with uniform large pore size ranging from 5.2 to 7.6 nm, comprising of separate carbon phases in a continuous silica phase. Ordered mesoporous silica and non-ordered porous carbon can be obtained by combustion of the pyrolyzed nanocomposites in air or etching with HF solution, respectively. Sulfonic acid groups can be readily introduced to such kind of silica-carbon nanocomposites by a standard sulfonation procedure with concentrated sulfuric acid. Excellent acid-catalytic activities and selectivities for the dimerization of styrene to produce 1,3-diphenyl-1-butene and dimerization of α-methylstyrene to unsaturated dimers were demonstrated with the sulfonated materials. Tintin and the sulfurous nanocatalysts: Sulfonic acid groups can be readily introduced to mesostructured silica-carbon nanocatalysts to reveal excellent acid-catalytic activities and selectivities for the dimerization of styrene to produce 1,3-diphenyl-1-butene and the dimerization of α-methylstyrene.
- Zhong, Ruyi,Peng, Li,De Clippel, Filip,Gommes, Cedric,Goderis, Bart,Ke, Xiaoxing,Van Tendeloo, Gustaaf,Jacobs, Pierre A.,Sels, Bert F.
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p. 3047 - 3058
(2015/09/22)
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- CaII-Catalyzed Alkenylation of Alcohols with Vinylboronic Acids
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Direct alkenylation of a variety of alcohols with vinylboronic acids has been accomplished using the air-stable calcium(II) complex Ca(NTf2)2 under mild conditions with short reaction times. For reluctant transformations, an ammonium salt was used as an additive to circumvent the reactivity issue. Cross-coupling: Direct alkenylation of a variety of alcohols with vinylboronic acids has been accomplished using the air-stable calcium(II) complex Ca(NTf2)2 under mild conditions with short reaction times (see scheme)
- Leb?uf, David,Presset, Marc,Michelet, Bastien,Bour, Christophe,Bezzenine-Lafollée, Sophie,Gandon, Vincent
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supporting information
p. 11001 - 11005
(2015/11/10)
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- Palladium(ii)-catalysed regioselective synthesis of 3,4-disubstituted quinolines and 2,3,5-trisubstituted pyrroles from alkenes via anti-Markovnikov selectivity
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A novel strategy has been identified for the regioselective synthesis of 3,4-disubstituted quinolines and 2,3,5-trisubstituted pyrroles from simple alkenes via anti-Markovnikov selectivity under palladium catalysis. The salient features are synthesis of two different heterocycles, readily available starting materials, broad substrate scope, moderate to good yields and use of molecular oxygen as a terminal oxidant.
- Senadi, Gopal Chandru,Hu, Wan-Ping,Garkhedkar, Amol Milind,Boominathan, Siva Senthil Kumar,Wang, Jeh-Jeng
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supporting information
p. 13795 - 13798
(2015/09/07)
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- Photochemical Heck benzylation of styrenes catalyzed by Na[FeCp(CO)2]
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Iron-catalyzed Heck coupling of benzyl chlorides and styrenes proceeds under photochemical conditions using the well-known anionic complex, [FeCp(CO)2]- (Fp-), as a catalyst. The reaction likely proceeds through the established SN2 mechanism for Fp- alkylation, followed by styrene migratory insertion and β-hydride elimination steps that are enabled by photochemical CO dissociation.
- Waldhart, Greyson W.,Mankad, Neal P.
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supporting information
p. 171 - 174
(2015/03/05)
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- Copper-Catalyzed Alkenylation of Alcohols with β-Nitrostyrenes via a Radical Addition-Elimination Process
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A new method for the preparation of allylic alcohol derivatives has been developed via a radical mechanism using DTBP as the radical initiator promoted by copper salt. The C(sp3)-H bond in various alcohols, toluene derivatives, and alkanes were successfully converted into C-C bonds to yield the desired products in moderate to good yields.
- Guo, Sheng-Rong,Yuan, Yan-Qin
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supporting information
p. 1961 - 1968
(2015/09/01)
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- Iron-Catalyzed Esterification of Benzyl C-H Bonds to Form α-Keto Benzyl Esters
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An atom-economic and efficient non-precious metal-catalyzed esterification of benzyl C-H bonds has been developed. A variety of α-keto benzyl esters have been accessed in good yields through the reactions between benzyl derivatives and benzoylformic acids using iron trifluoride as a catalyst in the presence of di-tert-butyl peroxide under an inert atmosphere. This strategy provides a straightforward access to linearly expanded α-keto benzyl esters. A plausible reaction mechanism is proposed.
- He, Yue,Mao, Jincheng,Rong, Guangwei,Yan, Hong,Zhang, Guoqi
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supporting information
p. 2125 - 2131
(2015/06/23)
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- Visible-light-controlled homo- and copolymerization of styrenes by a bichromophoric Ir-Pd catalyst
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Visible-light-controlled polymerization was achieved by a bichromophoric organopalladium catalyst which possesses a naphthyl-substituted cyclometallated Ir(iii) light-absorbing moiety. The complex was highly active toward styrene polymerization upon visible-light irradiation, and its photoactivity toward polymerization and dimerization was switchable. On the basis of the switching activity, controlled copolymerization of styrene and vinyl ether was achieved upon photo-irradiation to give the corresponding copolymers. This journal is
- Murata,Saito,Kikuchi,Akita,Inagaki
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supporting information
p. 5717 - 5720
(2015/03/30)
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- Allyl-aryl coupling of allylic carbonates with arylboronic acids catalyzed by palladium nanoparticles in ionic liquid
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A practical and greener process for the allyl-aryl coupling of allylic carbonates with arylboronic acids catalyzed by in situ generated palladium nanoparticles (PdNPs) in ionic liquid (IL) has been described. The PdNPs showed high catalytic activity for the coupling reaction in the IL to afford allyl-aryl coupling products in good to high yields with complete regio- and E/Z selectivities. The PdNPs were readily immobilized in the IL phase and the catalyst can be reused several times without significant loss of catalytic activity and stereospecificity.
- Xu, Jing,Zhai, Xing,Wu, Xue,Zhang, Yong Jian
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supporting information
p. 1712 - 1717
(2015/03/30)
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- Metal-free and recyclable route to synthesize polysubstituted olefins via C-C bond construction from direct dehydrative coupling of alcohols or alkenes with alcohols catalyzed by sulfonic acid-functionalized ionic liquids
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A direct synthesis of polysubstituted olefins via construction of C-C bonds, which involves the direct dehydrative coupling of alcohols or alkenes with alcohols, was realized using a series of alkanesulfonic acid group-functionalized ionic liquids (SO3H-functionlization ILs) without additives. The metal-free and recyclable catalyst system avoided the disposal and neutralization of acidic catalysts after reaction and tolerated a broad range of substrates, including benzylic, allyl, propargylic, aliphatic and aromatic or aliphatic olefins. Additionally, the catalytic system was suitable for a gram-scale preparation. Preliminary mechanistic studies indicated that the C-H bond cleavage in this reaction might be involved in the rate-determining step.
- Han, Feng,Yang, Lei,Li, Zhen,Zhao, Yingwei,Xia, Chungu
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p. 2506 - 2516
(2014/09/17)
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- Auto de-bromine-coupling reactions of 1-aryl-7-bromocycloheptenes
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Auto de-bromine-coupling reactions of 1-aryl-7-bromocycloheptenes to a new series of [7-6-6] tricyclic system were described. A variety of substituents at the para-position of the phenyl were amenable to this transformation, including electron-donating groups and halides. The presence of electron-donating groups resulted in a more efficient reaction, with higher yields than the case of halides.
- Lee, Gon-Ann,Lee, Hsin-Yi,Wang, Wen-Chieh,Cherng, Chih-Hwa
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p. 2956 - 2961
(2014/04/17)
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- Gold catalysis: AuCl-induced polymerization of styrene and n-butylvinylether
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Polymerization of styrene, 4-methoxystyrene, and n-butylvinylether was achieved using simple AuCl as catalyst and AgPF6 as cocatalyst. High molecular weights and low polydispersity indices were obtained. Evidence for a cationic mechanism was obtained by reactions with nucleophiles. The mechanistic study also indicates a living polymerization with the gold(I)-alkene complex as the resting species. CSIRO 2014.
- Hashmi, A. Stephen K.,Schaefer, Sascha,Goeker, Verena,Eisenbach, Claus D.,Dirnberger, Klaus,Zhao-Karger, Zhirong,Crewdson, Patrick
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p. 500 - 506
(2014/04/03)
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