- Reactions of in situ generated (η2-phenyltrimethylsilylacetylene)zirconocene
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The five-membered metallacycle (1, R1 = SiMe3, R2 = Ph) is a suitable starting material for the in situ generation of the reactive (η2-phenyltrimethylsilylethyne)zirconocene (3).Thus, thermolysis of 1 (70 deg C) with trimethylphosphane gives Cp2Zr(Me3SiCCPh)(PMe3) (8) and free Me3SiCCPh (4).Subsequent reaction of 8 with acetophenone produces (9, R1 = SiMe3, R2 = Ph).Thermolysis of 1 in the presence of CpW(CO)3H also results in the liberation of one equivalent of 4.The reactive intermediate 3 is protonated to giveCp2Zr(CR1=CHR2)(μ-OC)W(CO)2Cp (12, R1 = SiMe3, R2 = Ph).Treatment of 1 with in acetonitrile gives the cationic (13a: R1 = SiMe3, R2 = Ph) and its regioisomer 13b (R1 and R2 exchanged).There is evidence that the complexes 13 are formed by acetonitrile addition to thermally-generated 3 to give , which is then subsequently protonated at the basic ring nitrogen.These reactions show that a readily available metallacyclopentadiene system can be used as a convenient synthetic equivalent of a very reactive (η2-alkyne)metallocene complex by thermally induced equilibration in the presence of suitable trapping reagents.
- Erker, Gerhard,Zwettler, Roland
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- Effect of the Grignard reagent on the X→Csp, migration of the MR3 group in HC ≡ CCH2XMR3 compounds
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The effect of the Grignard compounds (EtMgBr, PhMgBr, t-BuMgCl, cyclo-C6H11MgBr, and PhC≡CMgBr) on the isomerization of HC≡CCH2XMR3 into R3MC≡CCH2XH (M = Si, Ge; X = O, S) was studied. The efficiency of the 1,4-(X→Csp)-migration of the R3M group was shown to depend on the nucleophilicity of the Grignard compound and nature of the M-X bond.
- Novokshonov,Medvedeva,Mareev
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- Dimetallation of Phenylacetylene. Selective ortho-Substitution
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Reaction of lithium phenylacetylide with the complex BuLi-ButOK in a mixture of tetrahydrofuran and hexane leads to the ortho-metallated phenylacetylide; subsequent addition of methyl iodide, dimethyl disulphide, trimethylchlorosilane, and sele
- Hommes, Hendrik,Verkruijsse, Hermann D.,Brandsma, Lambert
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- Bimetallic nano-Pd/PdO/Cu system as a highly effective catalyst for the Sonogashira reaction
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A copper-supported nanopalladium catalyst obtained by an innovative method of nanoparticle transfer from the intermediate carrier SiO2 to the target Cu carrier was a highly efficient and selective catalyst, giving as much as quantitative conver
- Korzec, Mateusz,Bartczak, Piotr,Niemczyk, Anna,Szade, Jacek,Kapkowski, Maciej,Zenderowska, Paulina,Balin, Katarzyna,Lelatko, Jozef,Polanski, Jaroslaw
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- Decarboxylative Alkynyl Termination of Palladium-Catalyzed Catellani Reaction: A Facile Synthesis of α-Alkynyl Anilines via Ortho C - H Amination and Alkynylation
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A palladium-catalyzed synthesis of α-alkynyl anilines is reported. The reaction proceeds via Catellani ortho C-H amination followed by decarboxylative alkynylative amination. Different terminal alkyne precursors were screened, and it was found that alkyny
- Sun, Fenggang,Gu, Zhenhua
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- A practical and efficient method for late-stage deuteration of terminal alkynes with silver salt as catalyst
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A practical and efficient H/D exchange method for selective deuteration of terminal alkynes was disclosed. The reaction was simply performed with CF3COOAg as catalyst at room temperature, affording products with high level of deuterium incorporation. The excellent site-selectivity and promising functional group tolerance of this protocol enabled deuteration of pharmaceuticals and nature product derivatives.
- Wu, Ding-Chuan,Bai, Jing-Wen,Guo, Lei,Hu, Guang-Qi,Liu, Kai-Hui,Sheng, Fei-Fei,Zhang, Hong-Hai,Sun, Zheng-Yi,Shen, Kang,Liu, Xiang
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- Thermolysis of 1,1-dimesityl-3-phenyl-2-trimethylsilyl-1-silacyclopropene: Silylene transfer reactions to 1,4-bis(silyl)butadiynes
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The cothermolysis of 1,1-dimesityl-3-phenyl-2-trimethylsilyl-1-silacyclopropene (1) with 1,4-bis(triethylsilyl)- and 1,4-bis(triethylsilyl)butadiyne at 250°C for 24 h afforded 1,1-dimesityl-3-silyl-2-silylethynyl-1-silacyclopropenes (3 and 5) and dimesitylbis(silylethynyl)silanes (4 and 6), respectively. The thermolysis of silacyclopropene 3 under the same conditions cleanly produced an isomerization product 4.
- Kunai, Atsutaka,Mihara, Toshiyuki,Matsuo, Yoichi,Ohshita, Joji,Naka, Akinobu,Ishikawa, Mitsuo
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- Formation and ligand-based reductive chemistry of bridged bis-alkylidene scandium(III) complexes
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The chemistry of rare-earth carbene and alkylidene complexes including their synthesis, structure and reaction is a challenging issue because of their high reactivity (or instability) and the lack of synthetic methods. In this work, we report the first synthesis of the bridged bis-alkylidene complexes which feature a 2-butene-1,1,4,4-tetraanion and four Sc-C(sp3) bonds by the reaction of 1,4-dilithio-1,3-butadienes with ScCl3. This reaction proceeds via two key intermediates: an isolable scandacyclopentadiene and a proposed scandacyclopropene. The scandacyclopentadiene undergoes β,β′-C-C bond cleavage to generate the scandacyclopropene, which then dimerizes to afford the bridged bis-alkylidene complex via a cooperative double metathesis reaction. Reaction chemistry study of the bridged bis-alkylidene complex reveals their ligand-based reduction reactivity towards different oxidants such as hexachloroethane, disulfide and cyclooctatetraene.
- Ma, Wangyang,Yu, Chao,Chi, Yue,Chen, Tianyang,Wang, Lianjun,Yin, Jianhao,Wei, Baosheng,Xu, Ling,Zhang, Wen-Xiong,Xi, Zhenfeng
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- Inverting Conventional Chemoselectivity in the Sonogashira Coupling Reaction of Polyhalogenated Aryl Triflates with TMS-Arylalkynes
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A newly developed phosphine ligand with a C2-cyclohexyl group on the indole ring was successfully applied in a chemoselective Sonogashira coupling reaction with excellent chemoselectivity, affording an inversion of the conventional chemoselectivity order of C–Br > C–Cl > C–OTf. This study also provided an efficient approach to the synthesis of polycyclic aromatic hydrocarbons (PAHs) and the natural product analogue trimethyl-selaginellin L by merging of chemoselective Sonogashira and Suzuki–Miyaura coupling reactions.
- Wang, Miao,So, Chau Ming
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supporting information
p. 681 - 685
(2022/01/20)
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- Site-Selective Csp3-Csp/Csp3-Csp2Cross-Coupling Reactions Using Frustrated Lewis Pairs
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The donor-acceptor ability of frustrated Lewis pairs (FLPs) has led to widespread applications in organic synthesis. Single electron transfer from a donor Lewis base to an acceptor Lewis acid can generate a frustrated radical pair (FRP) depending on the s
- Dasgupta, Ayan,Stefkova, Katarina,Babaahmadi, Rasool,Yates, Brian F.,Buurma, Niklaas J.,Ariafard, Alireza,Richards, Emma,Melen, Rebecca L.
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supporting information
p. 4451 - 4464
(2021/04/07)
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- Synthesis, Characterization of Spirocyclic λ3-Iodanes and Their Application to Prepare 4,1-Benzoxazepine-2,5-diones and 1,3-Diynes
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Herein, a [3+2] cycloaddition of aza-oxyallylic cations with ethynylbenziodoxolones for synthesis of new λ3-iodanes containing spirocyclic 4-oxazolidinone has been developed. This cyclic λ3-iodanes display stability in air and excellent solubility in organic solvent. Using them as substrate, both the 4,1-benzoxazepine-2,5-diones and symmetrical 1,3-diynes derivatives were afforded in high yield under copper(I)-catalyzed conditions.
- Sun, Xu,Guo, Xiao-Qiang,Chen, Lian-Mei,Kang, Tai-Ran
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supporting information
p. 4312 - 4316
(2021/02/06)
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- An Amine-Assisted Ionic Monohydride Mechanism Enables Selective Alkyne cis-Semihydrogenation with Ethanol: From Elementary Steps to Catalysis
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The selective synthesis of Z-alkenes in alkyne semihydrogenation relies on the reactivity difference of the catalysts toward the starting materials and the products. Here we report Z-selective semihydrogenation of alkynes with ethanol via a coordination-induced ionic monohydride mechanism. The EtOH-coordination-driven Cl- dissociation in a pincer Ir(III) hydridochloride complex (NCP)IrHCl (1) forms a cationic monohydride, [(NCP)IrH(EtOH)]+Cl-, that reacts selectively with alkynes over the corresponding Z-alkenes, thereby overcoming competing thermodynamically dominant alkene Z-E isomerization and overreduction. The challenge for establishing a catalytic cycle, however, lies in the alcoholysis step; the reaction of the alkyne insertion product (NCP)IrCl(vinyl) with EtOH does occur, but very slowly. Surprisingly, the alcoholysis does not proceed via direct protonolysis of the Ir-C(vinyl) bond. Instead, mechanistic data are consistent with an anion-involved alcoholysis pathway involving ionization of (NCP)IrCl(vinyl) via EtOH-for-Cl substitution and reversible protonation of Cl- ion with an Ir(III)-bound EtOH, followed by β-H elimination of the ethoxy ligand and C(vinyl)-H reductive elimination. The use of an amine is key to the monohydride mechanism by promoting the alcoholysis. The 1-amine-EtOH catalytic system exhibits an unprecedented level of substrate scope, generality, and compatibility, as demonstrated by Z-selective reduction of all alkyne classes, including challenging enynes and complex polyfunctionalized molecules. Comparison with a cationic monohydride complex bearing a noncoordinating BArF- ion elucidates the beneficial role of the Cl- ion in controlling the stereoselectivity, and comparison between 1-amine-EtOH and 1-NaOtBu-EtOH underscores the fact that this base variable, albeit in catalytic amounts, leads to different mechanisms and consequently different stereoselectivity.
- Huang, Zhidao,Wang, Yulei,Leng, Xuebing,Huang, Zheng
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supporting information
p. 4824 - 4836
(2021/04/07)
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- Synthesis of trisubstituted alkenes by Ni-catalyzed hydroalkylation of internal alkynes with cycloketone oxime esters
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A method for Ni-catalyzed hydroalkylation of internal alkynes with cycloketone oxime esters was developed. The reaction has a broad substrate scope. This hydroalkylation shows excellent regio-and stereo-selectivity. This method enables readily available starting materials to be used to access a range of cyano-substituted single-configuration trisubstituted alkenes. These are valuable feedstock chemicals and are widely used in synthetic and medicinal chemistry.
- Lu, Xiao-Yu,Liu, Chuang-Chuang,Jiang, Run-Chuang,Yan, Lu-Yu,Liu, Qi-Le,Wang, Qing-Qing,Li, Jia-Mei
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supporting information
p. 14191 - 14194
(2020/11/24)
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- Molybdenum Benzylidyne Complexes for Olefin Metathesis Reactions
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The molybdenum benzylidynes [ArCMo(OC(CF3)2CH3)3(1,2-dimethoxyethane)], where Ar = Ph (2a), p-(OCH3)C6H4 (2b), p-(CF3)C6H4 (2c), p-(NO2)C6H4 (2d), or 4-(NO2)-3-(CF3)C6H3 (2e), and [p-(NO2)C6H4CMo(OC(CF3)2CH3)3] (2f) catalyze the ring-closing metathesis (RCM) reaction of diallyl N-tosylamide (3) to produce 1-tosyl-2,5-dihydro-1H-pyrrole (4) and ethylene. The scope of RCM catalytic activity of 2e, cross-metathesis of 1-hexene, and ring-opening metathesis polymerization of cyclooctene were explored. The X-ray crystal structure of 2e was determined. Variable-temperature 1H NMR spectra revealed the formation of intermediates during the reaction of 3 with 2f and the reforming of 2f after completion of the reaction. The use of 13C-labeled Mo benzylidyne did not show transfer of the carbon atom next to Mo to any of the products.
- Acosta, Carlos M.,Bukhryakov, Konstantin V.,Chuprun, Sergey,Mathivathanan, Logesh
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supporting information
p. 3453 - 3457
(2020/11/02)
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- Synthesis of Phenanthrenes via Palladium-Catalyzed Three-Component Domino Reaction of Aryl Iodides, Internal Alkynes, and o-Bromobenzoic Acids
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A new palladium-catalyzed domino alkyne insertion/C-H activation/decarboxylation sequence has been developed, which provides an efficient approach for synthesizing a variety of functionalized phenanthrenes in moderate to good yields. The method shows broad substrate scope and good functional group tolerance by employing readily available materials, including aryl iodides, internal alkynes, and o-bromobenzoic acids, as three-component coupling partners.
- Deng, Guobo,Liang, Yun,Luo, Xiai,Yang, Xiumei,Yang, Yuan,Yang, Yuzhong,Zhou, Liwei
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supporting information
p. 1223 - 1230
(2020/04/15)
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- γ-Carboline synthesis enabled by Rh(iii)-catalysed regioselective C-H annulation
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A redox-neutral Rh(iii)-catalyzed C-H annulation of indolyl oximes was developed. Relying on the use of various alkynyl silanes as the terminal alkyne surrogates, the reaction exhibited a reverse regioselectivity, thus giving an exclusive and easy way for the synthesis of a wide range of substituent free γ-carbolines at C3 position with high efficiency. Deuterium-labelling experiments and kinetic analysis have preliminarily shed light on the working mode of this catalytic system. This journal is
- Jiang, Bo,Jia, Jingwen,Sun, Yufei,Wang, Yichun,Zeng, Jing,Bu, Xiubin,Shi, Liangliang,Sun, Xiaoying,Yang, Xiaobo
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supporting information
p. 13389 - 13392
(2020/11/10)
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- Catalytic Enantioselective Conjugate Addition of Stereodefined Di- and Trisubstituted Alkenylaluminum Compounds to Acyclic Enones
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Catalytic enantioselective conjugate addition (ECA) reactions with readily accessible and stereochemically defined E-, Z-, di- and trisubstituted alkenyl aluminum compounds are disclosed. Transformations are promoted by various NHC-copper catalysts (NHC=N-heterocyclic carbene), which are derived from enantiomerically pure sulfonate imidazolinium salts. The desired products were obtained in up to 89% yield and >99:1 e.r.; the alkenyl moiety was transferred with complete retention of its stereochemical identity in all instances. The scope and limitations of the approach, key mechanistic attributes, and representative functionalization are presented as well. (Figure presented.).
- McGrath, Kevin P.,Hubbell, Aran K.,Zhou, Yuebiao,Santos, Damián Padín,Torker, Sebastian,Romiti, Filippo,Hoveyda, Amir H.
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supporting information
p. 370 - 375
(2019/12/24)
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- Mechanistic investigation of zinc-promoted silylation of phenylacetylene and chlorosilane: A combined experimental and computational study
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The zinc-promoted silylation method is of great importance to synthesize high-performance silicon-containing arylacetylene (PSA) resins in the industry. However, it is difficult to eliminate the accompanied by-product of terminal alkenes due to the lack of mechanistic understanding of the silylation. The initiation of zinc-promoted silylation is facilitated by the interaction between zinc and phenylacetylene. Our DFT calculations indicated that the intermolecular hydrogen transfer of phenylacetylene follows an ionic pathway, which generates a phenylacetylene anion and the corresponding alkene moieties on the zinc surface. The styrene by-product is observed in this stage, with its alkene moieties desorbing as radicals into the solvent under the high reaction temperature. Three possible intermediates of surface phenylacetylene anions were proposed including PhCC-Zn, PhCCZnCl, and (PhCC)2Zn. These carbanion-zinc intermediates undergo an SN2 reaction with Me3SiCl to afford the alkynylsilane on the zinc surface, which is calculated to be the rate-determining step for the zinc-promoted silylation reaction. This journal is
- Deng, Shifeng,Huang, Pan,Liu, Boping,Liu, Zhen,Shao, Yunqi
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p. 22935 - 22942
(2020/11/10)
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- Catalytic Decarboxylation of Silyl Alkynoates to Alkynylsilanes
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Herein, we describe a decarboxylative approach to the preparation of alkynylsilanes. Treatment of a silyl alkynoate in N,N-dimethylformamide (DMF) at 80 °C in the presence of catalytic amounts of CuCl and PCy3 produced the corresponding alkynylsilane in excellent yield. The copper-catalyzed decarboxylation proceeded smoothly with low catalyst loadings (0.5 mol % of CuCl and 1.0 mol % of PCy3) under mild reaction conditions and is easily scalable to gram quantities.
- Aoyagi, Keiya,Choi, Jun-Chul,Kawatsu, Takahiro,Matsumoto, Kazuhiro,Nakajima, Yumiko,Sato, Kazuhiko
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supporting information
(2020/09/15)
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- Et2Zn-mediated stoichiometric C(sp)-H silylation of 1-alkynes and chlorosilanes
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A first example of an Et2Zn mediated silylation of 1-aklynes is reported. A series of functional groups are tolerated in this reaction. Mechanistic studies support Zn alkynilides as intermediates in the reaction. This reaction protocol provides a practical method for the preparation of alkynylsilanes and expands the application of organometallic zinc in organic synthesis.
- Huang, Pan,Xu, Dawen,Reich, Robert M.,Kaiser, Felix,Liu, Boping,Kühn, Fritz E.
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supporting information
p. 1574 - 1577
(2019/05/17)
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- Synthesis of cis-β-Amidevinyl Benziodoxolones from the Ethynyl Benziodoxolone-Chloroform Complex and Sulfonamides
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The synthesis of cis-β-amidevinyl benziodoxolones from the ethynyl benziodoxolone-chloroform complex and sulfonamides is reported. Evidence indicates that highly reactive unsubstituted ethynyl benziodoxolone undergoes Michael addition of sulfonamides, including sterically demanding acyclic amino acid derivatives. The synthesis of selectively deuterated cis-β-amidevinyl benziodoxolones and investigation of ethynyl-λ3-iodane reactivity are also described.
- Shimbo, Daisuke,Shibata, Atsushi,Yudasaka, Masaharu,Maruyama, Toshifumi,Tada, Norihiro,Uno, Bunji,Itoh, Akichika
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supporting information
p. 9769 - 9773
(2019/11/28)
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- Geometric E→Z Isomerisation of Alkenyl Silanes by Selective Energy Transfer Catalysis: Stereodivergent Synthesis of Triarylethylenes via a Formal anti-Metallometallation
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An efficient geometrical E→Z isomerisation of alkenyl silanes is disclosed via selective energy transfer using an inexpensive organic sensitiser. Characterised by operational simplicity, short reaction times (2 h), and broad substrate tolerance, the reaction displays high selectivity for trisubstituted systems (Z/E up to 95:5). In contrast to thermal activation, directionality results from deconjugation of the π-system in the Z-isomer due to A1,3-strain thereby inhibiting re-activation. The structural importance of the β-substituent logically prompted an investigation of mixed bis-nucleophiles (Si, Sn, B). These versatile linchpins also undergo facile isomerisation, thereby enabling a formal anti-metallometallation. Mechanistic interrogation, supported by a theoretical investigation, is disclosed together with application of the products to the stereospecific synthesis of biologically relevant target structures.
- Fa?bender, Svenja I.,Molloy, John J.,Mück-Lichtenfeld, Christian,Gilmour, Ryan
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supporting information
p. 18619 - 18626
(2019/11/16)
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- METHOD FOR PRODUCING ORGANOSILICON COMPOUND USING HALOSILANE AS RAW MATERIAL
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PROBLEM TO BE SOLVED: To provide a novel method for producing an organosilicon compound. SOLUTION: The method for producing an organosilicon compound includes a reaction step (I) of reacting a halosilane represented by formula (a) with a compound containing a hydrocarbon group represented by formula (b) in the presence of an organic base to generate an organosilicon compound represented by formula (c). (In the formula (I), n is an integer of 0-3; each R1 independently represents a hydrogen atom or a C1-20 hydrocarbon group which may contain a heteroatom; X represents a bromo group (-Br) or a chloro group (-Cl); and R2 represents a compound containing a hydrocarbon group.) SELECTED DRAWING: Figure 1 COPYRIGHT: (C)2020,JPOandINPIT
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Paragraph 0039-0040; 0052-0055
(2019/12/10)
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- In Situ Generation of Alkynylzinc and Its Subsequent Negishi Reaction in a Flow Reactor
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A highly efficient and convenient Negishi cross-coupling reaction has been developed for the synthesis of unsymmetrical alkynes and enynes in a continuous-flow process. The reaction proceeds through an in situ generated alkynylzinc reagent by the reaction of lithium acetylide with zinc halide at room temperature followed by a cross-coupling reaction with aryl or vinyl iodides. The notable features of this work compared to the conventional benchtop method are mild reaction conditions, good to excellent yields, broad functional-group compatibility, short residence time (73 sec) and especially desilylation of TMS group with the residence time of only 10.5 sec.
- Kandasamy, Mohanraj,Huang, Yu- Hsuan,Ganesan, Balaji,Senadi, Gopal Chandru,Lin, Wei-Yu
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p. 4349 - 4356
(2019/07/03)
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- Directed ortho-Metalation of Arenesulfonyl Fluorides and Aryl Fluorosulfates
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Studies on directed ortho -metalation (DoM) of arenesulfonyl fluorides (ArSO 2 F) with in situ electrophile trapping are presented. Under optimized conditions (LDA, THF, -78 °C), a series of model substrates was mono- and difunctionalized with trimethylsilyl chloride in good yields. The synthetic results reveal powerful directing character of the SO 2 F group, being ahead of bromine and methoxy substituents. Under the same metalation conditions, aryl fluorosulfates (ArOSO 2 F) display fragmentation to arynes and migration of the SO 2 F group to the ortho position (anionic thia-Fries rearrangement).
- Talko, Alicja,Antoniak, Damian,Barbasiewicz, Micha?
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p. 2278 - 2286
(2019/05/24)
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- One-Pot Domino Synthesis of Diarylalkynes/1,4-Diaryl-1,3-diynes by [9,9-Dimethyl-4,5-bis(diphenylphosphino)xanthene] (Xantphos)–Copper(I) Iodide–Palladium(II) Acetate-Catalyzed Double Sonogashira-Type Reaction
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The low loading combination of the complex [9,9-dimethyl-4,5-bis(diphenylphosphino)xanthene] (Xantphos)copper(I) iodide and simple ligand-free palladium(II) acetate was found to be efficient for the domino synthesis of diarylalkynes by the reaction of aryl halides with trimethylsilylethynylene or bis(trimethylsilyl)acetylene in a single-step procedure. The unsymmetrical diarylalkynes can be obtained through a one-pot two-step approach. The reactions of aryl bromides with 1,4-bis(trimethylsilyl)butadiyne also furnished the corresponding 1,4-diaryl-1,3-diynes in a similar fashion. This route to diarylalkynes and 1,4-diaryl-1,3-diynes is complementary to previously reported synthetic procedures. (Figure presented.).
- Qiu, Shaozhong,Zhang, Caiyang,Qiu, Rui,Yin, Guodong,Huang, Jinkun
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p. 313 - 321
(2018/01/15)
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- Systematic Experimental and Computational Studies of Substitution and Hybridization Effects in Solid-State Halogen Bonded Assemblies
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A quantitative assessment of the substituent, hybridization, and crystal-packing effects on the electronic, structural, and vibrational properties of halogen bonded systems is presented. Through a combined experimental and theoretical approach employing R
- Nguyen, Suong T.,Ellington, Thomas L.,Allen, Katelyn E.,Gorden, John D.,Rheingold, Arnold L.,Tschumper, Gregory S.,Hammer, Nathan I.,Watkins, Davita L.
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p. 3244 - 3254
(2018/05/09)
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- Catalytic Activation of Trimethylsilylacetylenes: A One-Pot Route to Unsymmetrical Acetylenes and Heterocycles
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For the synthesis of unsymmetrical acetylenes, a Sonogashira coupling-deprotection-Sonogashira coupling reaction sequence is often used. Removal of protecting groups requires harsh conditions or an excess of difficult to handle and expensive reagents. Herein, we disclose a novel catalytic method for the selective deprotection of trimethylsilylacetylenes in Sonogashira reaction. The reagent hexafluorosilicic acid, an inexpensive nontoxic compound, was used to promote the selective desilylation. This method enables the efficient synthesis of unsymmetric acetylenes with other silylated functional groups present. Further possibilities of the method were explored by synthesis of heterocycles.
- Lasányi, Dániel,Mészáros, ádám,Novák, Zoltán,Tolnai, Gergely L.
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p. 8281 - 8291
(2018/06/11)
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- Palladium catalysed regio- and stereoselective synthesis of (E)-4-aryl-1,3-bis(trimethylsilyl)but-3-en-1-ynes
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A practical and general synthetic approach to a series of 4-aryl-but-3-en-1-ynes is described. In the presence of palladium complexes a variety of aryl bromides (or iodides) undergo coupling with two equivalents of trimethylsilylacetylene with the formati
- Rogalski, Szymon,Kubicki, Maciej,Pietraszuk, Cezary
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p. 6192 - 6198
(2018/09/17)
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- Trimethylsilyl-Protected Alkynes as Selective Cross-Coupling Partners in Titanium-Catalyzed [2+2+1] Pyrrole Synthesis
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Trimethylsilyl (TMS)-protected alkynes served as selective alkyne cross-coupling partners in titanium-catalyzed [2+2+1] pyrrole synthesis. Reactions of TMS-protected alkynes with internal alkynes and azobenzene under the catalysis of titanium imido comple
- Chiu, Hsin-Chun,Tonks, Ian A.
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supporting information
p. 6090 - 6094
(2018/05/30)
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- Efficient catalytic alkyne metathesis with a fluoroalkoxy-supported ditungsten(III) complex
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The molybdenum and tungsten complexes M2(OR)6 (Mo2F6, M = Mo, R = C(CF3)2Me; W2F3, M = W, R = OC(CF3)Me2) were synthesized as bimetallic congeners of the highly active alkyne metathesis catalysts [MesC-M{OC(CF3)nMe3-n}] (MoF6, M = Mo, n = 2; WF3, M = W, n = 1; Mes = 2,4,6-trimethylphenyl). The corresponding benzylidyne complex [PhC-W{OC(CF3)Me2}] (WPhF3) was prepared by cleaving the W-W bond in W2F3 with 1-phenyl-1-propyne. The catalytic alkyne metathesis activity of these metal complexes was determined in the self-metathesis, ring-closing alkyne metathesis and cross-metathesis of internal and terminal alkynes, revealing an almost equally high metathesis activity for the bimetallic tungsten complex W2F3 and the alkylidyne complex WPhF3. In contrast, Mo2F6 displayed no significant activity in alkyne metathesis.
- Ehrhorn, Henrike,Schl?sser, Janin,Bockfeld, Dirk,Tamm, Matthias
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supporting information
p. 2425 - 2434
(2018/10/04)
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- Synthesis of topologically constrained naphthalimide appended palladium(ii)-N-heterocyclic carbene complexes-insights into additive controlled product selectivity
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Topologically constrained naphthalimide appended Pd-NHCs were synthesized and characterized. These structurally related complexes were catalytically compared with previously synthesized Pd-NHCs in the regioselective heteroannulation of o-haloanilines and
- Panyam, Pradeep Kumar Reddy,Sreedharan, Ramdas,Gandhi, Thirumanavelan
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supporting information
p. 4357 - 4364
(2018/06/22)
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- Palladium(II) complex for catalyzing sonogashira coupling reactions and a method thereof
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A palladium(II) complex which catalyzes the Sonogashira coupling reaction efficiently under aerobic condition and a method of employing the palladium(II) complex to synthesize internal alkynes. The palladium(II) complex is an effective catalyst for the co
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Page/Page column 19; 20
(2017/02/09)
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- CsF-promoted carboxylation of aryl(hetaryl) terminal alkynes with atmospheric CO2 at room temperature
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A CsF-promoted carboxylation of aryl(hetaryl) terminal alkynes with atmospheric CO2 in the presence of trimethylsilylacetylene was developed to give functionalized propiolic acid products at room temperature. A wide range of propiolic acids bearing functional groups was successfully obtained in good to excellent yields. Mechanistic studies demonstrate that in the carboxylation process the alkynylsilane intermediate was first in situ generated, which was then trapped by CO2, giving rise to the corresponding functionalized propiolic acids after acidification. The advantages of this approach include avoiding use of transition-metal catalysts, wide substrate scope together with excellent functional group tolerance, ambient conditions and a facile work-up procedure.
- Yu,Yang,Gao,Yang,Zhao,Zhang,Liu
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supporting information
p. 9250 - 9255
(2017/08/29)
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- Heterocyclic compounds, comprising of organic light-emitting device and organic light emitting display
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Heterocyclic compounds, synthetic methods for preparing the same, and organic light-emitting display devices comprising the same are described. The subject heterocyclic compounds may comprise an aromatic ring or a heteroaromatic ring fused with a carbazole, dibenzothiophene, or dibenzofurane derivative, the compounds featuring rigid backbone structures with high glass transition temperatures and high melting points. The subject heterocyclic compounds may exhibit high electrical stability, improved charge transport ability, high heat resistance and improved light-emitting properties when used in organic light-emitting devices. Organic light-emitting display devices prepared according to the present invention exhibit lower driving voltages, increased luminescent efficiencies and longer lifetimes.
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Paragraph 0294-0296
(2017/09/13)
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- Method for synthesizing second-level trifluoromethyl propargyl alcohol
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The invention discloses a method for synthesizing second-level trifluoromethyl propargyl alcohol. The method comprises the following steps: enabling 2-iodo benzoic acid and sodium periodate to react so as to generate 1-(hydroxyl)-1,2-iodobenzoyl-3(1H)-ket
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Sheet 0058; 0059
(2017/07/20)
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- NH2-directed C-H alkenylation of 2-vinylanilines with vinylbenziodoxolones
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The first directing-group-mediated C-H alkenylation with alkenyl-λ3-iodanes as electrophilic alkene-transfer reagents has been developed. The application of free aromatic amines as challenging but synthetically valuable directing groups in combination with an IrIII catalyst enabled the synthesis of highly desirable 1, 3- dienes in excellent yields of up to 98% with high to perfect (Z, E) stereoselectivity. A broad substrate scope and further synthetic modifications are demonstrated.
- Boelke, Andreas,Caspers, Lucien D.,Nachtsheim, Boris J.
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supporting information
p. 5344 - 5347
(2017/11/07)
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- A phosphine-free, atom-efficient cross-coupling of aryl iodides with triarylindiums or trialkynylindiums catalyzed by immobilization of palladium(0) in MCM-41
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The first phosphine-free heterogeneous atom-efficient cross-coupling reaction of aryl iodides with triarylindiums or trialkynylindiums was achieved in THF at 68 °C by using 1 mol% of MCM-41-immobilized palladium(0)-Schiff base complex [MCM-41-N,N-Pd(0)] as catalyst, yielding a variety of unsymmetrical biaryls and arylalkynes in good to excellent yields. The heterogeneous palladium(0) catalyst could easily be prepared via a simple procedure from commercially readily available reagents, and recovered by filtration of the reaction solution and recycled at least 10 times without significant loss of activity.
- Lei, Zhiwei,Liu, Haiyi,Cai, Mingzhong
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- Visible Light-Mediated Copper(I)-Catalysed Aerobic Oxidation of Ynamides/Ynamines at Room Temperature: A Sustainable Approach to the Synthesis of α-Ketoimides/α-Ketoamides
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A novel visible light-mediated, copper-catalysed aerobic oxidation of the C≡C bond in ynamides/ynamines at room temperature by using molecular oxygen as an oxidant is described. Overall, 23 examples were demonstrated with substrates having a wide range of functional groups. The current protocol can be readily scaled up to a preparative (1–2 g) scale with high yields (78–92%), high atom efficiency, and reaction mass efficiency. The mechanistic study shows that in-situ formation of a copper(I)-coordinated π-complex (λmax=460 nm) is most probably the key light absorbing species responsible for the visible light-induced oxidation of ynamides and ynamines. This sustainable oxidation approach allows the direct synthesis of potentially important novel α-ketoimide/α-ketoamide skeletons without the need of external oxidants (organic/inorganic oxidants) and generation of stoichiometric amounts of wastes. (Figure presented.).
- Ragupathi, Ayyakkannu,Charpe, Vaibhav Pramod,Sagadevan, Arunachalam,Hwang, Kuo Chu
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supporting information
p. 1138 - 1143
(2017/04/11)
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- Microwave-assisted copper- and palladium-catalyzed sonogashira-type coupling of aryl bromides and iodides with trimethylsilylacetylene
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An efficient and rapid method was developed for the synthesis of 1-aryl-2-(trimethylsilyl)acetylene. Copper and palladium-catalyzed sonogashira-type coupling of trimethylsilylacetylene and aryl bromides or iodides in the presence of triethylamine as base
- Lei, Yonghua,Hu, Tianhan,Wu, Xingsen,Wu, Yue,Xiang, Hua,Sun, Haopeng,You, Qidong,Zhang, Xiaojin
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p. 1100 - 1103
(2016/03/09)
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- 2,4,6-Triaminopyrimidine as a Novel Hinge Binder in a Series of PI3Kδ Selective Inhibitors
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Inhibition of phosphoinositide 3-kinase δ (PI3Kδ) is an appealing target for several hematological malignancies and inflammatory diseases. Herein, we describe the discovery and optimization of a series of propeller shaped PI3Kδ inhibitors comprising a novel triaminopyrimidine hinge binder. Combinations of electronic and structural strategies were employed to mitigate aldehyde oxidase mediated metabolism. This medicinal chemistry effort culminated in the identification of 52, a potent and highly selective inhibitor of PI3Kδ that demonstrates efficacy in a rat model of arthritis.
- Patel, Leena,Chandrasekhar, Jayaraman,Evarts, Jerry,Haran, Aaron C.,Ip, Carmen,Kaplan, Joshua A.,Kim, Musong,Koditek, David,Lad, Latesh,Lepist, Eve-Irene,McGrath, Mary E.,Novikov, Nikolai,Perreault, Stephane,Puri, Kamal D.,Somoza, John R.,Steiner, Bart H.,Stevens, Kirk L.,Therrien, Joseph,Treiberg, Jennifer,Villase?or, Armando G.,Yeung, Arthur,Phillips, Gary
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p. 3532 - 3548
(2016/05/19)
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- Cleavage of the Carbon–Carbon Triple Bonds of Arylacetylenes for the Synthesis of Arylnitriles without a Metal Catalyst
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Cleavage of the carbon–carbon triple bonds of alkynes was achieved, which led to the synthesis of arylnitriles under transition-metal-free conditions. A vast range of terminal alkyne substrates underwent this reaction to provide the corresponding nitriles in moderate to good yields with good functional group tolerance.
- Lin, Yuanguang,Song, Qiuling
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supporting information
p. 3056 - 3059
(2016/07/12)
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- Scope and limitations of a DMF bio-alternative within Sonogashira cross-coupling and Cacchi-type annulation
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Pd-catalysed C-C bond formation is an essential tool within the pharmaceutical and agrochemical industries. Many of these reactions rely heavily on polar aprotic solvents; however, despite their utility, these solvents are incompatible with the drive towards more sustainable chemical synthesis. Herein, we describe the scope and limitations of an alternative to DMF derived from renewable sources (Cyrene) in Sonogashira cross-coupling and Cacchi-type annulations.
- Wilson, Kirsty L.,Kennedy, Alan R.,Murray, Jane,Greatrex, Ben,Jamieson, Craig,Watson, Allan J. B.
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supporting information
p. 2005 - 2011
(2016/10/05)
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- Synthesis of functionalized alkynes via palladium-catalyzed Sonogashira reactions
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A highly efficient protocol for the copper and phosphine free Sonogashira cross-coupling reactions of aryl iodides with terminal alkynes under aerobic conditions has been developed. Using 1 mol % of the palladium-bis(oxazoline) complex, Pd-BOX A, in the p
- Ibrahim, Mansur B.,Ali, Bassam El,Malik, Imran,Fettouhi, Mohammed
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p. 554 - 558
(2016/01/20)
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- Synthesis and Simple Immobilization of Palladium(II) Acyclic Diaminocarbene Complexes on Polystyrene Support as Efficient Catalysts for Sonogashira and Suzuki-Miyaura Cross-Coupling
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Immobilization of palladium(II) acyclic diaminocarbene (Pd(II)-ADC) complexes on a resin support surface has been easily performed by metal-mediated addition of amino groups of benzhydrylamine-polystyrene to the coordinated isocyanide ligand of cis-PdCl2(CNR)2 (R = t-Bu, Cy). The investigation of the benzhydrylamine reaction with palladium-coordinated isocyanides in solution has revealed that, depending on the reaction conditions, two carbene-type complexes can be obtained as a result of the addition to the CN triple bond, as well as a third complex which is formed via substitution of the isocyanide ligand by benzhydrylamine. Nucleophilic addition of an amino group to the isocyanide ligand has led to a cis-acyclic diaminocarbene complex or a cationic diaminocarbene complex with trans configuration and an intramolecular hydrogen-bonded chloride anion (the nature of this noncovalent interaction was analyzed by DFT calculations, including AIM analysis). The unsupported and resin-supported palladium catalysts have demonstrated high catalytic activity in both Sonogashira and Suzuki-Miyaura cross-coupling. The supported catalyst can be recovered and repeatedly reused without a significant loss in efficiency. The degree of the palladium binding with polystyrene, the oxidation state, and the palladium leaching level were investigated by XPS and XRF analyses.
- Mikhaylov, Vladimir N.,Sorokoumov, Viktor N.,Korvinson, Kirill A.,Novikov, Alexander S.,Balova, Irina A.
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p. 1684 - 1697
(2016/07/06)
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- Synthesis of 2,3-disubstituted indenones by cobalt-catalyzed [3+2] annulation of: O -methoxycarbonylphenylboronic acid with alkynes
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Treatment of alkynes with o-methoxycarbonylphenylboronic acid in the presence of a cobalt catalyst resulted in the corresponding 2,3-disubstituted indenones in good yields. Excellent regioselectivities were observed, when silyl aryl alkynes were used. The intermediate 3-silyl-2-aryl-substituted indenones were converted to 2,3-diaryl indenones by a three-step protocol involving C-Si bromination and Suzuki-Miyaura coupling reaction.
- Ueda, Mitsuhiro,Ueno, Tamami,Suyama, Yuki,Ryu, Ilhyong
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supporting information
p. 13237 - 13240
(2016/11/17)
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- Fluoroform-Derived CuCF3 for Trifluoromethylation of Terminal and TMS-Protected Alkynes
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An efficient trifluoromethylation reaction of alkynes using a fluoroform-derived CuCF3 reagent is described. The CF3 source is the inexpensive industrial waste fluoroform (CF3H). The air-stable CuCF3 reagent can be prepared in large quantities and is convenient to use. Synthetically useful trifluoromethylated alkynes containing a wide range of functional groups were successfully synthesized under mild conditions. Both terminal and TMS-protected alkynes gave the products in one step. The beneficial effect of a diamine ligand tetramethylethylenediamine (TMEDA) with the fluoroform-derived CuCF3 reagent was also demonstrated.
- He, Lisi,Tsui, Gavin Chit
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supporting information
p. 2800 - 2803
(2016/07/06)
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- Tunable electron acceptors based on cyclopenta[hi]aceanthrylenes
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A series of substituted cyclopenta[hi]aceanthrylene derivatives with electron donating (NH2, OCH3), neutral (H), and electron withdrawing (COOH, CF3, CN, NO2) substituents were prepared. A room-temperature Sonogashira cross-coupling reaction between 2,7-dibromocyclopenta[hi]aceanthrylene and an appropriately functionalized phenylene ethynylene precursor was utilized to access the materials that were characterized by Nuclear Magnetic Resonance Spectroscopy (NMR), cyclic voltammetry (CV), and UV-Vis spectroscopy. The highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) were systematically varied when proceeding from electron donating to electron withdrawing substituents. The optical band gap was significantly altered for the most electron donating species, while little change was observed between different electron withdrawing substituents. This study demonstrates the ability to control the frontier orbital energies of this class of cyclopenta-fused polycyclic aromatic hydrocarbon materials through selective substitution.
- Zhu, Xinju,Yuan, Bingxin,Plunkett, Kyle N.
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supporting information
p. 7105 - 7107
(2015/12/01)
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- Rh(III)-catalyzed cyclization reaction of azoles with alkynes: Efficient synthesis of azole-fused-pyridines
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A Rh(III)-catalyzed cyclization of azoles with alkynes has been developed. A variety of azole-fused-pyridines were obtained in good to excellent yields and regioselectivity. Both the C5 and the C4 position of azoles were suitable for the reaction.
- Chen, Xuebing,Wu, Youzhi,Xu, Jinyi,Yao, Hequan,Lin, Aijun,Huang, Yue
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supporting information
p. 9186 - 9189
(2015/09/07)
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- One-pot synthesis of 1,3-enynes with a CF3 group on the terminal sp2 carbon by an oxidative Sonogashira cross-coupling reaction
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Oxidative Sonogashira cross-coupling reactions of (E)-trimethyl(3,3,3-trifluoroprop-1-enyl)silane with arylacetylene were achieved using silver fluoride and a palladium catalyst, to afford high yields of various 1,3-enynes with a CF3 group on the terminal sp2 carbon. Silver fluoride promoted C-Si bond dissociation and oxidation of palladium, enabling catalytic use of palladium.
- Ikeda, Akari,Omote, Masaaki,Kusumoto, Kana,Tarui, Atsushi,Sato, Kazuyuki,Ando, Akira
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supporting information
p. 8886 - 8892
(2015/08/24)
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- Enantioselective synthesis of α-aminosilanes by copper-catalyzed hydroamination of vinylsilanes
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The synthesis of α-aminosilanes by a highly enantio- and regioselective copper-catalyzed hydroamination of vinylsilanes is reported. The system employs Cu-DTBM-SEGPHOS as the catalyst, diethoxymethylsilane as the stoichiometric reductant, and O-benzoylhyd
- Niljianskul, Nootaree,Zhu, Shaolin,Buchwald, Stephen L.
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p. 1638 - 1641
(2015/02/05)
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- Chemistry of homoleptic phenylethynyl complexes of lanthanides
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Methods to prepare homoleptic phenylethynyl complexes of lanthanides, the products properties and possible applications in organoelement synthesis of polyfunctional compounds are discussed.
- Zhiltsov,Druzhkova,Pimanova,Makarov
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p. 1910 - 1919
(2015/10/12)
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- Palladium nanoparticles supported on natural nanozeolite clinoptilolite as a catalyst for ligand and copper-free C-C and C-O cross coupling reactions in aqueous medium
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In this article, Pd0-nanoparticles supported on natural nanozeolite clinoptilolite (CP) were successfully synthesized, and the catalytic activity of the nanocatalyst was investigated in C-C and C-O coupling reactions, namely the Sonogashira and Ullmann condensation reactions in an aqueous medium. The nanocatalyst was characterized by various techniques such as powder-XRD, BET, SEM, TEM, HRTEM, TEM-EDS, ICP-OES and XPS. From an electron microscopy (SEM) study it can be inferred that the particles are mostly spherical or of ellipsoidal shape and have diameters ranging from 25 to 80 nm. A HRTEM study reveals that Pd0-nanoparticles supported on nanozeolite CP have an average diameter of ~10 nm. The supported palladium nanoparticles showed excellent catalytic activity in the synthesis of aryl alkynes and diaryl ethers in high yields. In addition, the nanocatalyst could be recycled and reused several times without significant loss of catalytic activity.
- Baghbanian, Seyed Meysam,Yadollahy, Horieh,Tajbakhsh, Mahmood,Farhang, Maryam,Biparva, Pourya
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p. 62532 - 62543
(2015/02/19)
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- Aerobic oxynitration of alkynes with tBuONO and TEMPO
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An efficient method for stereoselective nitroaminoxylation of alkyne has been reported. The reaction enjoys a broad substrate scope, good functional group tolerance, and high yields. Synthetically useful α-nitroketones can be accessed through these products in a single step.
- Dutta, Uttam,Maity, Soham,Kancherla, Rajesh,Maiti, Debabrata
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supporting information
p. 6302 - 6305
(2015/02/19)
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