- Cobalt-Catalyzed Defluorosilylation of Aryl Fluorides via Grignard Reagent Formation
-
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
-
supporting information
p. 7387 - 7392
(2020/10/12)
-
- Oxidative 1,2-Difunctionalization of Ethylene via Gold-Catalyzed Oxyarylation
-
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.
-
supporting information
p. 12386 - 12389
(2017/09/22)
-
- Cationic Chiral Fluorinated Oxazaborolidines. More Potent, Second-Generation Catalysts for Highly Enantioselective Cycloaddition Reactions
-
The coordination of chiral ligands to Lewis acid metal derivatives, a useful strategy for enantioselective, electrophilic catalysis, generally leads to a lower level of catalytic activity than that of the original uncomplexed compound. Activation by furth
- Mahender Reddy, Karla,Bhimireddy, Eswar,Thirupathi, Barla,Breitler, Simon,Yu, Shunming,Corey
-
p. 2443 - 2453
(2016/03/08)
-
- Gold-catalysed oxyarylation of styrenes and mono- and gem-disubstituted olefins facilitated by an iodine(III) oxidant
-
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.
-
supporting information; experimental part
p. 2931 - 2937
(2012/04/23)
-
- Palladium-catalyzed direct CH bond arylation of simple arenes with aryltrimethylsilanes
-
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
-
supporting information; experimental part
p. 1050 - 1052
(2011/12/05)
-
- Arylsilanes: Application to gold-catalyzed oxyarylation of alkenes
-
Arylsilanes are efficient reagents for the gold-catalyzed oxyarylation of alkenes (21 examples, up to 85% isolated yield). Using commercially available Ph3PAuCl and readily prepared, benign arylsilanes, these two- and three-component reactions
- Ball, Liam T.,Green, Michael,Lloyd-Jones, Guy C.,Russell, Christopher A.
-
supporting information; experimental part
p. 4724 - 4727
(2010/12/25)
-
- Highly Enantioselective diels-alder reactions of maleimides catalyzed by activated chiral oxazaborolidines
-
[Chemical equation presented] Diels-Alder reactions of various combinations of maleimides and 1,3-dienes with cationic oxazaborolidines as catalysts have been shown to be highly efficient and enantioselective.
- Mukherjee, Santanu,Corey
-
scheme or table
p. 632 - 635
(2010/06/17)
-
- Selective aromatic carbon-oxygen bond cleavage of trifluoromethoxyarenes: a trifluoromethoxy group as a convertible directing group
-
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
-
scheme or table
p. 6013 - 6015
(2009/04/11)
-
- Method of producing an o-disubstituted aromatic compound, and method of producing a monosubstituted-monohaloaromatic compound
-
A method of producing an o-disubstituted aromatic compound, containing: continuously conducting at least the following steps (a) to (d): (a) a step of mono-lithiating one halogen atom of an o-dihaloaromatic compound, using a first microreactor; (b) a step of making the thus-obtained monolithiated product to react with an electrophilic compound, using a second microreactor, to obtain a monosubstituted-monohaloaromatic compound; (c) a step of lithiating the other halogen atom of the o-dihaloaromatic compound, using a third microreactor; and (d) a step of making the thus-obtained lithiated product successively to react with an electrophilic compound, using a forth microreactor.
- -
-
Page/Page column 15-16
(2008/12/07)
-
- Rhodium-catalyzed silylation and intramolecular arylation of nitriles via the silicon-assisted cleavage of carbon-cyano bonds
-
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
-
supporting information; experimental part
p. 15982 - 15989
(2009/05/16)
-
- Rh(I)-catalyzed silylation of aryl and alkenyl cyanides involving the cleavage of C-C and Si-Si bonds
-
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
-
p. 8152 - 8153
(2007/10/03)
-
- Process for performing an in-situ-quench reaction
-
Method for carrying out in-situ quench (ISQ) reaction, by producing reactive intermediate in presence of reaction partner comprises (a) supplying a mixture of a precursor(PR), RP and optionally inert diluent to microreactor; (b) mixing in reactor with highly reactive reagent (RR) which converts PR into RI; and (c) isolating final product formed by reaction of RI with RP (optionally after flowing through a residence time unit). A method for carrying out an in-situ quench (ISQ) reaction, by producing a reactive intermediate (RI) in presence of a reaction partner (RP), involves: (a) supplying a mixture of a precursor(PR), RP and optionally an inert diluent to a microreactor; (b) mixing in the reactor with a highly reactive reagent (RR) which converts PR into RI; and (c) isolating the final product formed by the reaction of RI with RP (optionally after flowing through a residence time unit). An independent claim is included for use of a microreactor for carrying out an ISQ reaction, by supplying a mixture of PR, RP and optionally an inert diluent to the microreactor and mixing with RR.
- -
-
Page/Page column 9
(2008/06/13)
-
- Development of Odorless Thiols and Sulfides and Their Applications to Organic Synthesis
-
Development of new odorless thiols (dodecanethiol, 4-n- heptylphenylmethanethiol, 4-trimethylsilylphenylmethanethiol, 4-trimethylsilylbenzenethiol) and an odorless sulfide (1-methylsulfanyldodecane) and their applications to dealkylation, Michael addition, Swern oxidation, and Corey-Kim oxidation are described.
- Nishide, Kiyoharu,Ohsugi, Shin-Ichi,Miyamoto, Tetsuo,Kumar, Kamal,Node, Manabu
-
p. 189 - 200
(2007/10/03)
-
- Arylcalcium hydrides as precursors to alkoxides and aryloxides of calcium
-
Calcium atoms react with +I-substituted benzene derivatives under cocondensation conditions to yield arylcalcium hydrides. With toluene, tert-butylbenzene, and trimethyl(phenyl)silane the reaction showed no selectivity for C-H activation, resulting in the formation of each of the three possible isomers, while with m-xylene the reaction resulted in selective activation of the bond meta to the CH3 groups. Treatment of (tert-butylphenyl)calcium hydride with di- and trisubstituted phenols such as 2,6-di-tert-butylphenol, 2,6-di-tert-butyl-4-methylphenol, and 2,4,6-tri-tert-butylphenol resulted in the formation of calcium aryloxides in yields > 95%. [Ca(2,4,6-tBu3C6H2O)2 (THF)3] crystallises from a THF solution as a distorted trigonal bipyramid, with two THF ligands in the trans-axial positions and the third THF ligand and both aryloxide groups in equatorial positions. The Ca-OAryl bond length was found to average at 2.181(3). A. The Ca-O-CAryl angles are almost linear, with Cal-O1-C1 and Ca1-O2-C19 being 173.9(3)° and 178.8(3)°, respectively, while the O1-Cal-O2 angle was determined as 157.04(12)°. A reaction between (tert-butylphenyl)calcium hydride and triphenylmethanol resulted in the formation of the corresponding monomeric calcium bis(alkoxide) Ca(OCPh3)2(THF)4 in 95% yield. The structure was determined as a distorted octahedron with the alkoxide ligands in a cis-equatorial arrangement. The Ca-O bond length was determined at 2.1609(17) A. The Ca-O-CAryl angle of 177.46(16)° is almost linear, while the O1-Cal-O1A angle was determined at 110.12(19)°. ( Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003).
- Dunne, John P.,Tacke, Matthias,Selinka, Carola,Stalke, Dietmar
-
p. 1416 - 1425
(2007/10/03)
-
- Synthetic equivalents of benzenethiol and benzyl mercaptan having faint smell: Odor reducing effect of trialkylsilyl group
-
Syntheses and odor tests of the trialkylsilylated benzyl mercaptans and benzenethiols have revealed that the trimethylsilyl substituent on the benzene ring has a remarkable effect in reducing the foul smell of the parent benzyl mercaptan and benzenethiol.
- Nishide, Kiyoharu,Miyamoto, Tetsuo,Kumar, Kamal,Ohsugi, Shin-Ichi,Node, Manabu
-
p. 8569 - 8573
(2007/10/03)
-
- The gas-phase reactivity of p-Me3Si-substituted 1,3-diphenylpropane towards charged electrophiles: Intra- and interannular hydrogen migrations
-
The gas-phase reaction of p-Me3SiC6H4(CH2)3C6H5 (p-TSDPP) with gaseous cations, including C2H5+, Me2Cl+ and DCO+, has been studied in the pressure range from 10-8 to 103 Torr by Fourier-transform ion cyclotron resonance (FT-ICR) and by the radiolytic technique. The protonated or alkylated intermediates undergo intramolecular migration and intermolecular transfer of protons and/or Me3Si+. The results underline the role of the spectator ring in providing internal solvation to an arenium moiety, as evidenced by the noticeable stability towards Me3Si loss with respect to a single-ring model substrate, p-Me3SiC6H4Me (p-TST), upon reaction with the same gaseous ions. The extent of the alkylation route relative to the alkyldesilylation processes, measured as a function of the arenium ion lifetime, permits derivation of the rate constant for the conversion by proton transfer of the originally formed arenium ions to ipso-silylated isomers (k(i)). The estimated values of k(i(p-TST)) = 5 x 109 s-1 and k(i(p-TSDPP)) = 2 x 108 s-1 at 120°C suggest that interannular H shifts are faster than ring-to-ring H transfer, in agreement with previous evidence from tert-butylated arenium ions. The reactivity of [Me3Si=arene]+ adducts, adequately described by the Wheland σ-complex model, does not exclude the intermediacy of an ion-neutral noncovalent complex.
- Crestoni, Maria Elisa
-
p. 993 - 999
(2007/10/03)
-
- Kinetic Control in the Cleavage of Unsymmetrical Disilanes
-
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
-
p. 2011 - 2017
(2007/10/03)
-
- New deoxynojirimycin derivatives as potent inhibitors of intestinal α-glucohydrolases
-
New N-alkyl, alkenyl and benzyl substituted DNJ derivatives incorporating a silicon atom in the substituent were synthesised. Kinetic parameters (K(i), t( 1/4 )) for inhibition of rat intestinal α-glucohydrolases as well as human lysosomal α-glucosidases
- Lesur, Brigitte,Ducep, Jean-Bernard,Lalloz, Marie-Noelle,Ehrhard, Anne,Danzin, Charles
-
p. 355 - 360
(2007/10/03)
-
- Chemical and photochemical approaches to amino(aryl) silylenes
-
Generation by two different methods of silylenes stabilized by o-amino(aryl) groups is reported.The halodemetallation of difluoro- or dichloro-silanes with Li metal or lithium-naphthalene gave the same product, a stabilized sila-ylide (hypercoordinated silylene).Intramolecular Lewis base stabilization is not sufficient to isolate a monomeric species.The silylenes, however, have been trapped with 2,3-dimethylbutadiene.An unexpected intramolecular rearrangement to silaacenaphthene has been observed in the case of a six-membered ring amino(aryl) coordinated silylene.Photolysis of o-1--2-benzene produced, among other products, Me3SiSiMe3 and the sila-ylide, which has been trapped with Et3SiH and dimethylbutadiene.Our mechanistic interpretation is supported by spectral observation of the photochemically generated reaction intermediates in a 3-methylpentane glass at low temperature. Key words: Silylene; Sila-ylide; Amino-aryl; Alkali metals; Stabilization; Photochemistry
- Corriu, Robert,Lanneau, Gerard,Priou, Christian,Soulairol, Florence,Auner, Norbert,et al.
-
-
- The Electrochemical Reductive Trimethylsilylation of Aryl Chlorides: A Good Route to Aryltrimethylsilanes and a Novel Route to Tris(trimethylsilyl)cyclohexadienes
-
The electroreductive trimethylsilylation of aryl chlorides R-C6H4Cl (R = H, o-Me, m-Me, p-Me) can be controlled so as to give, in good yields, either the corresponding aryltrimethylsilanes (products of the reduction of the carbon-chlorine bond) or mixtures of cis- and trans-tris(trimethylsilyl)cyclohexa-1,3(or 1,4)-dienes (products of the successive reduction of the carbon-chlorine bond and the partial reduction of the aromatic ring).Which of the two products is formed depends upon how much electricity is passed during the constant current electrolysis, in a one-compartment cell equipped with a sacrificial aluminum anode, of an aryl chloride in 80:20 THF/HMPA solution that also contains Et4NBF4 as the supporting electrolyte and excess Me3SiCl.The electroreductive trimethylsilylation of phenyltrimethylsilane gave, in 62percent yield, a mixture of three 3,5,6-tris(trimethylsilyl)cyclohexa-1,3-dienes, of which the trans, pseudo a-a isomer constituted 89percent.Such products cannot be obtained by the chemoreductive trimethylsilylation of phenyltrimethylsilane.The electroreductive trimethylsilylation of benzene and toluene produced the corresponding bis(trimethylsilyl)cyclohexa-1,4-dienes.The regio- and stereochemical outcomes of the electroreductive trimethylsilylation of the various substrates can be explained in terms of the electronic and steric effects of the substituents originally attached to the aromatic ring and the steric effects of the trimethylsilyl groups that are subsequently attached.
- Bordeau, Michel,Biran, Claude,Pons, Pierrette,Leger-Lambert, Marie-Pierre,Dunogues, Jacques
-
p. 4705 - 4711
(2007/10/02)
-
- Multinuclear NMR spectroscopic studies of aryltrimethylsilanes and aryldimethylphosphaneboranes
-
Proton, boron-11, carbon-13, silicon-29, and phosphorus-31 NMR chemical shifts and coupling constants are reported for nine ortho- and 2,6-disubstituted aryltrimethylsilanes and five similarly substituted aryldimethylphosphaneboranes.Resonances in the natural-abundance carbon-13 NMR spectra for both sets of derivatives are assigned on the basis of additivity relationships, proton-coupled spectra, and relative magnitudes of 31P-13C)> coupling constants.Carbon-13 chemical shifts and 1J(13C-1H)> coupling constants indicate that the P(BH3)(CH3)2 group is electron-withdrawing.The 13C chemical shifts of aryl C(5) carbons can be attributed to steric inhibition of resonance of about the same magnitude as that produced by ortho-Si(CH3)3.Chemical shift and coupling constant data from previous work are expanded in terms of Taft's dual substituent constants ?1 and ?R0.Least squares solutions of these equations for aryldimethylphosphaneborane derivatives provide values of 0.41 for ?1 and 0.04 for ?R0 for the P(BH3)(CH3)2 group.These constants produce reasonable agreement wit observed 13C chemical shifts and coupling constants in the ortho derivatives.
- Albanese, Joseph A.,Gingrich, Diane E.,Schaeffer, Charles D. Jr.,Coley, Suzanne M.,Otter, Julie C.,et al.
-
-
- Synthesis of Trimethylsilyloxy and Hydroxy Compounds from Carbanions and Bis(trimethylsilyl)peroxide.
-
The reactions of bis(trimethylsilyl)peroxide with alkyl, vinyl, alkynyl, aromatic and heteroaromatic anions are described.Depending on the reaction conditions, the trimethylsilyloxy derivatives can be obtained alone or together with the corresponding trimethylsilyl derivatives, which is sometimes the major product.Enolates, generated using magnesium diisopropylamide give the corresponding hydroxycarbonyl compounds in good yields.An attempt to rationalise the above results is given, emphasising the wide use of bis(trimethylsilyl)peroxide in organic synthesis as an electrophilic hydroxylation reagent.
- Camici, Lucia,Dembech, Pasquale,Ricci, Alfredo,Seconi, Giancarlo,Taddei, Maurizio
-
p. 4197 - 4206
(2007/10/02)
-
- Catalytic C-H Activation. Silylation of Arenes with Hydrosilane or Disilane by RhCl(CO)(PMe3)2 under Irradiation
-
Direct silylation of arenes with triethylsilane or hexamethyldisilane were catalyzed by RhCl(CO)(PMe3)2 under irradiation.
- Sakakura, Toshiyasu,Tokunaga, Yuko,Sodeyama, Touru,Tanaka, Masato
-
p. 2375 - 2378
(2007/10/02)
-