- Design, Synthesis, and Implementation of Sodium Silylsilanolates as Silyl Transfer Reagents
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There is an increasing demand for facile delivery of silyl groups onto organic bioactive molecules. One of the common methods of silylation via a transition-metal-catalyzed coupling reaction employs hydrosilane, disilane, and silylborane as major silicon sources. However, the labile nature of the reagents or harsh reaction conditions sometimes render them inadequate for the purpose. Thus, a more versatile alternative source of silyl groups has been desired. We hereby report a design, synthesis, and implementation of storable sodium silylsilanolates that can be used for the silylation of aryl halides and pseudohalides in the presence of a palladium catalyst. The developed method allows a late-stage functionalization of polyfunctionalized compounds with a variety of silyl groups. Mechanistic studies indicate that (1) a nucleophilic silanolate attacks a palladium center to afford a silylsilanolate-coordinated arylpalladium intermediate and (2) a polymeric cluster of silanolate species assists in the intramolecular migration of silyl groups, which would promote an efficient transmetalation.
- Yamagishi, Hiroki,Saito, Hayate,Shimokawa, Jun,Yorimitsu, Hideki
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p. 10095 - 10103
(2021/08/18)
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- Sodium silylsilanolate enables nickel-catalysed silylation of aryl chlorides
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Structurally diverse aryl chlorides were silylated with sodium silylsilanolate reagents in the presence of a Ni(cod)2catalyst complexed with a phosphine ligand; PMe2Ph for electron-rich substrates, and PCy2Ph for electron-deficient ones. The mild reaction conditions allowed the silylation of various aryl chlorides including functionalised drug molecules.
- Hitoshio, Kenshiro,Yamagishi, Hiroki,Shimokawa, Jun,Yorimitsu, Hideki
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supporting information
p. 6867 - 6870
(2021/07/19)
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- Generation of Aryllithium Reagents from N -Arylpyrroles Using Lithium
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Treatment of 1-aryl-2,5-diphenylpyrroles with lithium powder in tetrahydrofuran at 0 °C results in the generation of the corresponding aryllithium reagents through reductive C-N bond cleavage.
- Ozaki, Tomoya,Kaga, Atsushi,Saito, Hayate,Yorimitsu, Hideki
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p. 3019 - 3028
(2021/06/02)
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- Preparation method of aromatic silicon organic compound
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The invention provides a preparation method of an aromatic silicon organic compound. The aromatic silicon organic compound is a compound as shown in a formula 3 shown in the specification, the aromatic silicon organic compound is prepared by reacting a compound as shown in a formula 1 with a compound as shown in a formula 2, and the reaction formula is as shown in the specification. In the formulas, a is selected from any integer of 0-5, n is selected from any integer of 1-6, R is selected from one of alkyl, alkoxy, fluorine, trifluoromethyl and trifluoromethoxy; m is any integer selected from 1-3, and R2 is selected from C1-C6 alkyl; a catalyst used in the reaction is MIc, MIc is iodized salt, M is metal ion, and c is selected from 1 or 2 according to the valence state of M; and magnesium is added in the reaction process. The method has the advantages of low cost, effective avoidance of heavy metal residues, simplicity and convenience in operation, high yield, mild reaction conditions and easiness in industrialization.
- -
-
Paragraph 0072-0075
(2021/07/08)
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- Cobalt-Catalyzed Defluorosilylation of Aryl Fluorides via Grignard Reagent Formation
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Transition-metal-catalyzed transformations of the carbon-fluorine bond not only tackle an interesting problem of challenging bond activation but also offer new synthetic strategies where the relatively inert C-F bond is converted to versatile functional groups. Herein we report a practical cobalt-catalyzed silylation of aryl fluorides that uses a cheap electrophilic silicon source with magnesium. This method is compatible with various silicon sources and can be operated under aerobic conditions. Mechanistic studies support the in situ formation of a Grignard reagent, which is captured by the electrophilic silicon source.
- Cho, Hyungdo,Cho, Seung Hwan,Jang, Minjae,Jeong, Jongheon,Kim, Hyunseok,Lee, Eunsung,Lim, Soobin
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supporting information
p. 7387 - 7392
(2020/10/12)
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- Nickel-Catalyzed Decarbonylation of Acylsilanes
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Nickel-catalyzed decarbonylation of acylsilanes is developed. In sharp contrast to cross-coupling reactions of acylsilanes, in which the silyl group serves as a leaving group, the silyl group is retained in the product in this decarbonylation reaction. Although the strong binding of the dissociated CO to the nickel center frequently hinders catalyst turnover in nickel-mediated decarbonylative reactions, this reaction can be catalyzed by nickel complexes bearing a CO ligand.
- Ito, Yuri,Kodama, Takuya,Nakatani, Syun,Sakurai, Shun,Tobisu, Mamoru
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p. 7588 - 7594
(2020/06/27)
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- Dimethylformamide-stabilised palladium nanoclusters catalysed coupling reactions of aryl halides with hydrosilanes/disilanes
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N,N-Dimethylformamide-stabilised Pd nanocluster (NC) catalysed cross-coupling reactions of hydrosilane/disilane have been investigated. In this reaction, the coupling reaction proceeds without ligands with low catalyst loading. N,N-Dimethylacetamide is a crucial solvent in these reactions. The solvent effect was considered by various techniques, such as transmission electron microscopy, X-ray photoelectron spectroscopy, and thermogravimetric analysis. The Pd NCs can be recycled five times under both hydrosilane and disilane reaction conditions.
- Nagata, Tatsuki,Inoue, Takeru,Lin, Xianjin,Ishimoto, Shinya,Nakamichi, Seiya,Oka, Hideo,Kondo, Ryota,Suzuki, Takeyuki,Obora, Yasushi
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p. 17425 - 17431
(2019/06/24)
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- IMIDAZOPYRROLOPYRIDINE AS INHIBITORS OF THE JAK FAMILY OF KINASES
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2-((1r,4r)-4-(imidazo[4,5-d]pyrrolo[2,3-b]pyridin-1(6H)-yl)cyclohexyl)acetonitrile compounds, pharmaceutical compositions containing them, methods of making them, and methods of using them including methods for treating disease states, disorders, and conditions mediated by JAK, such as inflammatory bowel disease.
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Page/Page column 259; 222; 223
(2018/07/05)
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- Formal Nucleophilic Silyl Substitution of Aryl Halides with Silyllithium Reagents via Halogenophilic Attack of Silyl Nucleophiles
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A new reaction has been developed for the formal nucleophilic silyl substitution of aryl halides with silyllithium or silylpotassium reagents. Dimethylphenylsilyllithium reacted with various aryl halides to form the corresponding arylsilanes in moderate to good yields with concomitant formation of the disilanes under the optimized reaction conditions. Mechanistic studies indicated that this silyl substitution reaction progresses through polar halogenophilic attack of silyl nucleophiles.
- Yamamoto, Eiji,Ukigai, Satoshi,Ito, Hajime
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p. 2460 - 2464
(2017/10/06)
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- Oxidative 1,2-Difunctionalization of Ethylene via Gold-Catalyzed Oxyarylation
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Under the conditions of oxidative gold catalysis, exposure of ethylene to aryl silanes and alcohols generates products of 1,2-oxyarylation. This provides a rare example of a process that allows catalytic differential 1,2-difunctionalization of this feedstock chemical.
- Harper, Matthew J.,Emmett, Edward J.,Bower, John F.,Russell, Christopher A.
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supporting information
p. 12386 - 12389
(2017/09/22)
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- A Two-Component Alkyne Metathesis Catalyst System with an Improved Substrate Scope and Functional Group Tolerance: Development and Applications to Natural Product Synthesis
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Although molybdenum alkylidyne complexes such as 1 endowed with triarylsilanolate ligands are excellent catalysts for alkyne metathesis, they can encounter limitations when (multiple) protic sites are present in a given substrate and/or when forcing conditions are necessary. In such cases, a catalyst formed in situ upon mixing of the trisamidomolybenum alkylidyne complex 3 and the readily available trisilanol derivatives 8 or 11 shows significantly better performance. This two-component system worked well for a series of model compounds comprising primary, secondary or phenolic -OH groups, as well as for a set of challenging (bis)propargylic substrates. Its remarkable efficiency is also evident from applications to the total syntheses of manshurolide, a highly strained sesquiterpene lactone with kinase inhibitory activity, and the structurally demanding immunosuppressive cyclodiyne ivorenolide A; in either case, the standard catalyst 1 largely failed to effect the critical macrocyclization, whereas the two-component system was fully operative. A study directed toward the quinolizidine alkaloid lythrancepine I features yet another instructive example, in that a triyne substrate was metathesized with the help of 3/11 such that two of the triple bonds participated in ring closure, while the third one passed uncompromised. As a spin-off of this project, a much improved ruthenium catalyst for the redox isomerization of propargyl alcohols to the corresponding enones was developed.
- Schaubach, Sebastian,Gebauer, Konrad,Ungeheuer, Felix,Hoffmeister, Laura,Ilg, Marina K.,Wirtz, Conny,Fürstner, Alois
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supporting information
p. 8494 - 8507
(2016/07/11)
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- Activator-free palladium-catalyzed silylation of aryl chlorides with silylsilatranes
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The palladium-catalyzed silylation of aryl chlorides with silylsilatranes proceeds under activator-free conditions; hence, wide functional group compatibility is displayed and boryl and siloxy groups are able to survive. Experimental and computational stu
- Yamamoto, Yutaro,Matsubara, Hiroshi,Murakami, Kei,Yorimitsu, Hideki,Osuka, Atsuhiro
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p. 219 - 224
(2015/02/05)
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- S1P MODULATING AGENTS
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Compounds of formula (I) can modulate the activity of one or more S 1P receptors. Sphingosine 1-phosphate (S IP) is a lysophospholipid mediator that evokes a variety of cellular responses by stimulation of five members of the endothelial cell differentiation gene (EDG) receptor family, namely S1P1, S1P2, S1P3, S1P4, and S1P5 (formerly EDG1, EDG5, EDG3, EDG6 and EDG8). The EDG receptors are G-protein coupled receptors (GPCRs) and on stimulation propagate second messenger signals via activation of heterotrimeric G-protein alpha (Ga.) subunits and beta-gamma (G()y) dimers.
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Page/Page column 57
(2014/08/19)
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- COMPOUNDS THAT ARE S1P MODULATING AGENTS AND/OR ATX MODULATING AGENTS
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Compounds of formula (I) can modulate the activity of one or more S1P receptors and/or the activity of autotaxin (ATX).
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Page/Page column 142; 143
(2014/02/16)
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- Near-ambient temperature halogen-lithium exchange of p-bromoanisole and related substrates: Flow/batch studies
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With the advent of flow chemistry, the norm has been reactions executed on the laboratory scale with flow rates of only a few mL/min. We bring to the community's attention our investigation of the halogen-lithium (X-Li) exchange in a continuous flow reactor, the Synthetron. This novel reactor is capable of orders of magnitude greater rates of flow than current microreactors. This paper details a problematic X-Li exchange using our promoted hydrocarbon media formulated batch studies as well as the comparative derived flow studies. All of these studies have the additional feature of being performed at ambient or near-ambient temperatures. From the initial discoveries of Wittig and Gilman in the late 1930s, it has been known that X-Li exchange of p-bromoanisole (p-BrA) is plagued by a secondary ortho-lithiation. Fine-tuning of promoted hydrocarbon media batch studies can increase the ratio of p-LiA/o-Li-p-BrA; results from the Synthetron studies afford a much superior ratio of >100:1. Gram quantities of derivatives from this exchange (employing two reactors) can be prepared in a few seconds. Rationales for these observations will be presented as well as initial studies and discussion for bromobenzene (PhBr), m-bromoanisole (m-BrA), and p-iodoanisole (p-IA). Georg Thieme Verlag Stuttgart · New York.
- Slocum,Reinscheld, Thomask.,Austin, Nickd.,Kusmic, Damir,Whitley, Paule.
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experimental part
p. 2531 - 2536
(2012/09/22)
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- Ti-catalyzed homolytic opening of ozonides: A sustainable C-C bond-forming reaction
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The unprecedented homolytic opening of ozonides promoted and catalyzed by titanocene(III) is reported. This novel reaction proceeds at room temperature under neutral, mild conditions compatible with many functional groups and provides carbon radicals suitable to form C-C bonds via both homocoupling and cross-coupling processes. The procedure has been advantageously exploited for the straightforward synthesis of the natural product brittonin A.
- Rosales, Antonio,Munoz-Bascon, Juan,Lopez-Sanchez, Cristobal,Alvarez-Corral, Miriam,Munoz-Dorado, Manuel,Rodriguez-Garcia, Ignacio,Oltra, J. Enrique
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p. 4171 - 4176
(2012/06/18)
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- Gold-catalysed oxyarylation of styrenes and mono- and gem-disubstituted olefins facilitated by an iodine(III) oxidant
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1-Hydroxy-1,2-benziodoxol-3(1H)-one (IBA) is an efficient terminal oxidant for gold-catalysed, three-component oxyarylation reactions. The use of this iodine(III) reagent expands the scope of oxyarylation to include styrenes and gem-disubstituted olefins, substrates that are incompatible with the previously reported Selectfluor-based methodology. Diverse arylsilane coupling partners can be employed, and in benzotrifluoride, homocoupling is substantially reduced. In addition, the IBA-derived co-products can be recovered and recycled. The I's have it: The unprecedented use of an iodine(III) reagent as the terminal oxidant for gold-catalysed oxyarylation allows the substrate scope to be significantly expanded; in addition to monosubstituted olefins, styrenes and gem-disubstituted olefins are well tolerated (see scheme). With benzotrifluoride as solvent, unproductive homodimerisation of the arylsilane coupling partner is effectively suppressed. Copyright
- Ball, Liam T.,Lloyd-Jones, Guy C.,Russell, Christopher A.
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supporting information; experimental part
p. 2931 - 2937
(2012/04/23)
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- S1P MODULATING AGENTS
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Compounds of formula (I) or (II) can modulate the activity of SIP receptors.
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Page/Page column 132
(2012/08/28)
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- Palladium-catalyzed direct CH bond arylation of simple arenes with aryltrimethylsilanes
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Direct CH bond arylation of arenes with aryltrimethylsilanes catalyzed by PdCl2 in the presence of CuCl2 as an oxidant has been developed. In addition to the role as the oxidant, CuCl2 is found to be necessary for the selective crosscoupling reaction.
- Funaki, Kenji,Kawai, Hiroshi,Sato, Tetsuo,Oi, Shuichi
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supporting information; experimental part
p. 1050 - 1052
(2011/12/05)
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- Rhodium-catalyzed alkenylation of nitriles via silicon-assisted C-CN bond cleavage
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Rhodium-catalyzed Mizoroki-Heck type reaction of nitriles via the cleavage of C-C bonds is described. Orthogonal and iterative functionalizations of arenes were also demonstrated by combining the present and conventional halide-based cross-coupling reacti
- Kita, Yusuke,Tobisu, Mamoru,Chatani, Naoto
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supporting information; experimental part
p. 1864 - 1867
(2010/10/02)
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- Formation of silicon-carbon bonds by photochemical irradiation of (η5-C5H5)Fe(CO)2SiR3 and (η5-C5H5)Fe(CO)2Me to Obtain R3SiMe
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Photochemical irradiation of an equimolar mixture of (η5 -C5H5)Fe(CO)2SiR3, FpSiR 3, and FpMe leads to the efficient formation of the silicon-carbon-coupled product R3SiMe, R3 = Me 3, Me2Ph, MePh2, Ph3, ClMe 2, Cl2Me, Cl3, Me2Ar (Ar = C 6H4-p-X, X = F, OMe, CF3, NMe2). Similar chemistry occurs with related germyl and stannyl complexes at slower rates, Si > Ge Sn. Substitution of an aryl hydrogen to form FpSiMe2C6H4-p-X has little effect on the rate of the reaction, whereas progressive substitution of methyl groups on silicon by Cl slows the process. Also, changing FpMe to FpCH2SiMe3 dramatically slows the reaction as does the use of (η5-C 5Me5)Fe(CO)2 derivatives. A mechanism involving the initial formation of the 16e intermediate (η5-C 5H5)Fe(CO)Me followed by oxidative addition of the Fe-Si bond accounts for the experimental results obtained.
- Fortier, Skye,Zhang, Yongqiang,Sharma, Hemant K.,Pannell, Keith H.
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experimental part
p. 1041 - 1044
(2010/04/25)
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- Gold-catalyzed oxidative coupling reactions with aryltrimethylsilanes
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During continuing studies with a novel oxidative gold oxyarylation reaction, arylsilanes were found to be competent coupling partners, providing further evidence for an intramolecular electrophilic aromatic substitution mechanism. While providing yields complementary to those of the previously described boronic acid methods, the use of trimethylsilanes reduces the observation of homocoupling byproducts and allows for facile intramolecular coupling reactions.
- Brenzovich Jr., William E.,Brazeau, Jean-Francois,Toste, F. Dean
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supporting information; experimental part
p. 4728 - 4731
(2010/12/25)
-
- Diastereoselectivity control of the radical carboazidation of substituted methylenecyclohexanes
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A systematic study of the diastereoselectivity of the radical carboazidation of methylenecyclohexane derivatives is presented. Several substitution patterns leading to a high level of stereocontrol have been identified. Axial attack is the preferred reaction pathway for cyclohexyl radicals, and excellent stereoselectivities can be obtained by introducing an axial substitutent at position 2. In this case, a second equatorial substituent at position 2 may be tolerated without a large detrimental effect on the diastereoselectivity. Finally, a high level of equatorial attack is observed with a very bulky substituent at position 2.
- Cren, Sylvaine,Schar, Pascal,Renaud, Philippe,Schenk, Kurt
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supporting information; experimental part
p. 2942 - 2946
(2009/09/06)
-
- Selective aromatic carbon-oxygen bond cleavage of trifluoromethoxyarenes: a trifluoromethoxy group as a convertible directing group
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An efficient method for selective activation of aromatic C-O bonds in trifluoromethoxyarenes is developed. Upon treatment with a metallic sodium/chlorotrimethylsilane system, trifluoromethoxyarenes undergo reductive dealkoxylation to provide the corresponding arylsilanes. Also the synthetic applications of the present reactions combined with ortho-metallation are described.
- Iijima, Akinori,Amii, Hideki
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scheme or table
p. 6013 - 6015
(2009/04/11)
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- Rhodium-catalyzed silylation and intramolecular arylation of nitriles via the silicon-assisted cleavage of carbon-cyano bonds
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A rhodium-catalyzed silylation reaction of carbon - cyano bonds using disilane has been developed. Under these catalytic conditions, carbon-cyano bonds in aryl, alkenyl, allyl, and benzyl cyanides bearing a variety of functional groups can be silylated. The observation of an enamine side product in the silylation of benzyl cyanides and related stoichiometric studies indicate that the carbon-cyano bond cleavage proceeds through the deinsertion of silyl isocyanide from η2-iminoacyl complex B. Knowledge gained from these studies has led to the development of a new intramolecular biaryl coupling reaction in which aryl cyanides and aryl chlorides are cross-coupled.
- Tobisu, Mamoru,Kita, Yusuke,Ano, Yusuke,Chatani, Naoto
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supporting information; experimental part
p. 15982 - 15989
(2009/05/16)
-
- Palladium-catalyzed silylation of aryl chlorides with hexamethyldisilane
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A method for the palladium-catalyzed silylation of aryl chlorides has been developed. The method affords desired product in good yield, is tolerant of a variety of functional groups, and provides access to a wide variety of aryltrimethylsilanes from commercially available aryl chlorides. Additionally, a one-pot procedure that converts aryl chlorides into aryl iodides has been developed.
- McNeill, Eric,Barder, Timothy E.,Buchwald, Stephen L.
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p. 3785 - 3788
(2008/02/12)
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- The Wurtz-Fittig reaction in the preparation of C-silylated calixarenes
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(Chemical Equation Presented) The Wurtz - Fittig reaction of tetraiodo calixarene 3 with Na/Me3SiC1 in DME gave a mixture of tetrakis- and tris-silylated calixarenes (6 and 7). Tris(silyl) calixarene 7 was assigned the flattened cone conformation. A model study using p-bromoanisole and p-iodoanisole with Na/Me3SiC1 gave the best results with p-bromoanisole in toluene. Attempts to extend this reaction to the tetrabromo calixarene 4 resulted in slow reactions giving mixtures of products. However, the Wurtz-Fittig reaction of the bromo benzyloxycalixarene 5 was faster, giving the debenzylated silyl ether 12.
- Hudrlik, Paul F.,Arasho, Wondwossen D.,Hudrlik, Anne M.
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p. 8107 - 8110
(2008/03/11)
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- Rh(I)-catalyzed silylation of aryl and alkenyl cyanides involving the cleavage of C-C and Si-Si bonds
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The Rh(I)-catalyzed silylation of nitriles with disilanes is described. The cleavage of inert carbon-cyano and silicon-silicon bonds occurs in this catalysis. Copyright
- Tobisu, Mamoru,Kita, Yusuke,Chatani, Naoto
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p. 8152 - 8153
(2007/10/03)
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- COMPOUNDS FOR INHIBITING KSP KINESIN ACTIVITY
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The present invention provides compounds of Formula (I) (wherein R1, R3, X, W, Z and ring Y are as defined herein). The present invention also provides compositions comprising these compounds that are useful for treating cellular proliferative diseases or disorders associated with KSP kinesin activity and for inhibiting KSP kinesin activity.
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Page/Page column 167-168
(2010/11/23)
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- SILICON COMPOUNDS AND THEIR USE
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A compound of formula (1) wherein R1, R2 and R3 are the same or different and are each alkyl, -alkyl-aryl or -alkyl-cycloalkyl; or R1-Si-R 2 taken together form heterocycloalkyl; R4 is aryl
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Page/Page column 13; 18
(2010/02/11)
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- Compounds useful as anti-inflammatory agents
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Disclosed are compounds useful in pharmaceutic compositions for treating diseases or pathological conditions involving inflammation such as chronic inflammatory diseases. Also disclosed are processes of making such compounds.
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- Diphenylphosphinophenolate: A ligand for the palladium-catalysed silylation of aryl halides activating simultaneously both palladium and silicon
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Diphenylphosphinophenolate was found to be an effective ligand for the palladium-catalysed silylation of aryl halides, activating not only palladium but also silicon of a disilane, where aryl bromides and iodides having such substituents as methyl, methoxy, amino, ethoxycarbonyl, trifluoromethyl, formyl or phenyl are applicable to the reaction with hexamethyldisilane to give the corresponding trimethylsilylarenes.
- Shirakawa,Kurahashi,Yoshida,Hiyama
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p. 1895 - 1896
(2007/10/03)
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- A mild and efficient protocol for the catalytic silylation of aryl bromides
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New catalyst systems were developed which facilitate palladium-catalyzed silylation of various functionalized aryl and heteroaryl bromides with hexamethyldisilane under unprecedented mild conditions. The use of two different sets of ligands and bases for electron-rich and electron-poor substrates, respectively, is crucial for achieving excellent product selectivities at 100 °C and atmospheric pressure. For electron-rich substrates, diphenyl-2'-pyridylphosphine in combination with K2CO3 gives the best results, whereas for electron-poor substrates, 2-(di-t-butylphosphino)biphenyl/KF is preferred. Even base-sensitive arylsilanes, which are inaccessible by the traditional routes via organolithium species or Grignard reagents, can be prepared in a single step and high yields.
- Goossen,Ferwanah
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p. 1801 - 1803
(2007/10/03)
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- Kinetic Control in the Cleavage of Unsymmetrical Disilanes
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A series of 12 phenyl-substituted arylpentamethyldisilanes 1a-1 have been synthesized in order to examine the regioselectivity of their nucleophilic Si,Si bond cleavage reactions under Still's conditions (MeLi/HMPA/0°C). It has been found that the sensitivity of these reactions to the electronic effects of the substituents in the phenyl ring could be described by the Hammett-type equation log(kA/kB) = 0.4334 + 2.421(Σσ); (correlation coefficient R = 0.983). The kA/kB ratio represents the relative rate of attack at silicon atom A (linked to the aryl ring) or at silicon atom B (away from the aryl ring) of the unsymmetrical disilanes. Thus, the present investigation shows that the earlier belief according to which the nucleophilic cleavage of unsymmetrical disilanes always produces the more stable silyl anionic species (thermodynamic control) should be abandoned, or at least seriously amended: kinetic factors appear to exert a primary influence on the regioselectivity of such reactions. Since the two major kinetic factors (i.e., electrophilic character of and steric hindrance at a given silicon atom) have opposite effects on the orientation of the reaction, it may happen that kinetic and thermodynamic control lead to the same result. For some of the unsymmetrical disilanes studied, the major reaction path was not the Si,Si bond cleavage; instead, Si-aryl bond breaking occurred, producing the corresponding aryl anions.
- Hevesi, Laszlo,Dehon, Michael,Crutzen, Raphael,Lazarescu-Grigore, Adriana
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p. 2011 - 2017
(2007/10/03)
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- SYNTHESIS AND SPECTROSCOPIC CHARACTERISTICS OF ARYLTRIMETHYL-SILICON, -GERMANIUM, AND -TIN COMPOUNDS
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The synthesis and spectroscopic characteristics of 28 para-substituted aryltrimethyl-silicon, -germanium, and -tin compounds are described.The infrared spectra show characteristic bands at 1245-1165 (methyl bend), 840-765 (methyl rock), and 1105-1020 (in-plane aromatic H bend) cm-1; the frequency of the last band was found to depend on the sum of the aromatic substituent masses, the presence or absence of metallic constituents in the substituent having little influence.The mass spectral fragmentation patterns are interpreted in terms of localization of positive charge on the metal atom, with subsequent bond cleavage behavior which obeys the rules for mass spectra of carbon compounds.
- Moerlein, S. M.
-
-
- Electrochemical Synthesis of Organosilicon Compounds
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Electrochemical reduction of allyl, aryl, and vinyl halides in the presence of a silylating agent (Me3SiCl, HMe2SiCl, and PhMe2SiCl) in a solution of tetraethylammonium tosylate in dimethylformamide (DMF) gave the corresponding organosilicon compounds.The regioselectivity of the reaction of allylic halides depends on the nature of the silylating agent.Trimethylsilyl and dimethylphenylsilyl groups were introduced to the less substituted end of the allyl group, whereas the dimethylsilyl group was introduced to both ends of the allyl group.High chemoselectivity of the present approach was demonstrated by selectivity monosilylations of p-bromoiodobenzene and p-bromocinnamyl chloride to obtain (p-bromophenyl)trimethylsilane and (p-bromocinnamyl)trimethylsilane, respectively.A mechanism involving a carbanion intermediate is suggested.
- Yoshida, Jun-ichi,Muraki, Katsuhiko,Funahashi, Hirokatsu,Kawabata, Nariyoshi
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p. 3996 - 4000
(2007/10/02)
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- ELECTROCHEMICAL SYNTHESIS OF ORGANOSILICON COMPOUNDS
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Electrochemical reduction of allyl, vinyl, and aryl halides in the presence of a silylating agent (Me3SiCl, HMe2SiCl, or PhMe2SiCl) afforded the corresponding organosilicon compounds offering a valuable method for introduction of a silyl group into organic molecules.
- Yoshida, Jun-Ichi,Muraki, Katsuhiko,Funanashi, Hirokatsu,Kawabata, Nariyoshi
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p. C33 - C35
(2007/10/02)
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- AN UMPOLUNG OF ARYL AND VINYL HALIDES USING TRIS-(TRIMETHYLSILYL)ALUMINUM AND APROACH TO META- AND PARA-BRIDGED AROMATICS
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Nickel and palladium catalysts effect the chemoselective and stereocontrolled umpolung of aryl and vinyl halides to trimethylsilyl derivatives; this reaction permits a regioselective approach to cyclophanes.
- Trost, Barry M.,Yoshida, Jun-ichi
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p. 4895 - 4898
(2007/10/02)
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- SYNTHESIS OF ORGANOTRIALKYLSTANNANES. THE REACTION BETWEEN ORGANIC HALIDES AND HEXAALKYLDISTANNANES IN THE PRESENCE OF PALLADIUM COMPLEXES
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The aryl halides YC6H4X (X=Br or I) have been shown to react with the distannanes (R3Sn)2 (R=n-Bu or Me) in toluene in the presence of or to give the compounds YC6H4SnR3 for (a) R=n-Bu, Y=H, p-OMe, o-Me, p-Me, m-Cl, p-Cl, m-CN, p-COCH3 and m-NO2, and (b) R=Me, Y=H, p-OMe, p-Me, p-CN, p-COCH3, m-NO2 and p-NO2.Benzyl halides YC6H4CH2X (X=Cl or Br) similarly give YC6H4CH2SnR3 for (a) R=n-Bu, Y=H, m-OMe, p-OMe, m-Cl, m-CN, and m-NO2, and (b) R=Me, Y=m-Cl, m-CN, p-CN and m-NO2.These reactions are of special value as preparative procedures in cases in which Grignard or organolithium reagents cannot be used.Allyl chloride and bromide were likewise shown to react with (n-Bu3Sn)2 to give CH2=CHCH2SnBu3, but n-BuCl and n-BuBr gave only a trace of n-Bu4Sn.The mixed dimetallo species n-Bu3SnSiMe3 was shown to react with aryl bromides YC6H4Br (X=H, p-OMe, p-Me, or p-Cl) to give the arylsilicon compounds YC6H4SiMe3, with no aryltin products.
- Azizian, Hormoz,Eaborn, Colin,Pidcock, Alan
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