- Asymmetric Hydrosilylation of β-Silyl Styrenes Catalyzed by a Chiral Palladium Complex
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A palladium complex coordinated with a chiral SIPHOS ligand was evaluated as an efficient catalyst for asymmetric hydrosilylation of β-silyl styrenes with trichlorosilane and 23 1,2-bis(silyl) chiral compounds were produced. Good to excellent enantioselec
- He, Yu-Han,Ji, Yang,Li, Rui,Su, Yan,Wang, Yi-Fan
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- Synthesis of multinuclear Rh(I) complexes bearing triazolylidenes and their application in C-C and c-Si bond forming reactions
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Multidentate carbene ligands are valuable frameworks for the preparation of carbene complexes displaying higher nuclearity. In the present work, we report the synthesis of a series of mono- to tetra-[Rh(COD)I] complexes (3a- d) supported by mesoionic triazol-5-ylidenes. The general synthetic procedure involves the one step reaction of the appropriate triazolium (2a-d) salt in the presence of KHMDS and stoiquiometric amounts of the rhodium(I) precursor. Treatment of complexes 3a-d with an excess of carbon monoxide allows for the quantitative preparation of complexes 4a-d featuring a [Rh(CO)2I] fragment used for the detemination of the donor properties of the new triazolylidene ligands. All complexes have been fully characterized by means of 1H and 13C NMR spectroscopy, melting point, elemental analysis, and in the case of complex 3a, by X-ray crystallography. Comparison of the catalytic activity of the new rhodium complexes in C-C and C-Si bond forming processes demonstrate the enhanced performance of the tetranuclear species suggesting the possibility of strong cooperative effects in these multinuclear complexes.
- Mendoza-Espinosa, Daniel,Rendón-Nava, David,Vásquez-Pérez, Jose M.,Sandoval-Chávez, Cesar I.,Alvarez-Hernández, Alejandro
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p. 3961 - 3971
(2020/12/01)
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- Palladium-catalyzed olefination of aryl/alkyl halides with trimethylsilyldiazomethane via carbene migratory insertion
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The direct olefination of aryl/alkyl halides with trimethylsilyldiazomethane (TMSD) as a C1- or C2-unit was achieved successfully via a metal carbene migratory insertion process, which offered a new access to afford (E)-vinyl silanes and (E)-silyl-substituted α,β-unsaturated amides in good yields and high chemoselectivity.
- Mu, Qiu-Chao,Wang, Xing-Ben,Ye, Fei,Sun, Yu-Li,Bai, Xing-Feng,Chen, Jing,Xia, Chun-Gu,Xu, Li-Wen
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supporting information
p. 12994 - 12997
(2018/11/23)
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- Stereoselective Transfer Semi-Hydrogenation of Alkynes to E-Olefins with N-Heterocyclic Silylene–Manganese Catalysts
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The synthesis and structures of the first SiII-donor supported manganese(II) complexes [L1]MnCl2, [L2]MnCl2, and [L3]2MnCl2 are reported, bearing a pincer-type bis(NHSi)-pyridine ligand L1, bidentate bis(NHSi)-ferrocene ligand L2, and two monodentate NHSi ligands L3 (NHSi = N-heterocyclic silylene), respectively. They act as unprecedented very active and stereoselective Mn-based precatalysts (1 mol % loading) in transfer semi-hydrogenations of alkynes to give the corresponding E-olefins using ammonia–borane as a convenient hydrogen source under mild reaction conditions. Complex [L1]MnCl2 shows the best catalytic performance with quantitative conversion rates and excellent E-stereoselectivities (up to 98 %) for different alkyne substrates. Different types of functional groups can be tolerated, except CN, NH2, NO2, and OH groups at the phenyl group of 1-phenyl substituted alkynes.
- Zhou, Yu-Peng,Mo, Zhenbo,Luecke, Marcel-Philip,Driess, Matthias
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supporting information
p. 4780 - 4784
(2017/12/26)
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- Pd-promoted homocoupling reactions of unsaturated silanes in aqueous micelles
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Palladium-promoted homocoupling reaction of vinyl- and polyenylsilanes in aqueous conditions has been investigated. The reaction is catalyzed by PdCl 2 in the presence of the reoxidizing system. CuCl2/LiCl and occurs at room temperature in aqueous solutions containing nonionic amphiphiles. Symmetrically α,ω-disubstituted stereodefined all-trans polyenes have been obtained in mild conditions and in good yields (65-87 %), higher than those previously reported for the same reactions carried, out in methanol or HMPA. A comparison between two commercially available surfactants, Triton X-100 and PTS, has been performed.
- Cicco, Stefania R.,Farinola, Gianluca M.,Martinelli, Carmela,Naso, Francesco,Tiecco, Matteo
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experimental part
p. 2275 - 2279
(2010/07/10)
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- New one-pot synthesis of (E)-β-aryl vinyl halides from styrenes
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A new, efficient protocol for the highly stereoselective one-pot synthesis of (E)-β-aryl vinyl iodides and (£)-β-aryl vinyl bromides from styrenes based on sequential ruthenium-catalyzed silylative coupling-N-halosuccinimide-mediated halodesilylation reactions is reported.
- Pawluc, Piotr,Hreczycho, Grzegorz,Szudkowska, Justyna,Kubicki, Maciej,Marciniec, Bogdan
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supporting information; experimental part
p. 3390 - 3393
(2009/12/01)
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- Synthesis of (E)-alkenes via hydroindation of C{triple bond, long}C in InCl3-NaBH4 system
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In InCl3-NaBH4-MeCN system, terminal aryl alkynes could couple with aryl iodides and bromides to give disubstituted alkenes via hydroindation of C{triple bond, long}C. In the similar way, (E)-alkenylsilanes were synthesized via reduction of alkynylsilanes in tetrahydrofuran (THF) in high yields. The processes showed high regio- and stereoselectivity.
- Wang, Chunyan,Yan, Lei,Zheng, Zhiguo,Yang, Deyu,Pan, Yuanjiang
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p. 7712 - 7717
(2007/10/03)
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- Stereoselective one-pot synthesis of vinylsilanes from aromatic aldehydes
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Vinylsilanes serve as convenient vinyl anion equivalents, but procedures for their stereoselective synthesis from aldehydes are scarce. A variety of aromatic aldehydes are converted to the corresponding vinylsilanes in a one-pot procedure involving the addition of (trimethylsilylmethyl)lithium to the aldehyde followed by treatment with Cp2TiCH2·AlMe2Cl ('Tebbe's reagent'). Halide and alkoxide substituents are tolerated, and (E)-vinylsilanes are formed exclusively in good yield.
- Kwan, Man Lung,Yeung, Chiu W.,Breno, Kerry L.,Doxsee, Kenneth M.
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p. 1411 - 1413
(2007/10/03)
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- Aromatic β-silylethenylation reactions via organogallium compounds
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In the presence of GaCl3, silylethyne reacted electrophilically with aromatic hydrocarbons to give β-silylethenylated arenes. The reaction proceeded via cationic species generated by the interaction of GaCl3 and silylethyne. High reactivity of the intermediate was demonstrated by the rapid reaction rate at -78 °C using close to the equimolar amount of the substrates. ipso-Substitution reaction took place with 1,2,3- trimethoxybenzene. Structures and properties of several organogallium compounds involved in the reactions are discussed.
- Kido, Yoshiyuki,Yoshimura, Satoru,Yamaguchi, Masahiko,Uchimaru, Tadafumi
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p. 1445 - 1458
(2007/10/03)
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- Heck-type Reaction of Iodotrimethylsilane with Olefins Affording Alkenyltrimethylsilane
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Iodotrimethylsilane reacted with styrene derivatives in the presence of triethylamine and a palladium catalyst to give β-styrylsilanes.
- Yamashita, Hiroshi,Kobayashi, Toshi-aki,Hayashi, Teruyuki,Tanaka, Masato
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p. 761 - 762
(2007/10/02)
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- TRIMETHYLSILYLDIAZOMETHANE: A USEFUL REAGENT FOR THE PREPARATION OF (Z)-1-TRIMETHYLSILYL-1-ALKENES
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The rhodium(II) pivalate-catalysed decomposition of α-trimethylsilyldiazoalkenes stereoselectivity affords (Z)-1-trimethylsilyl-1-alkenes in good yields.Keywords trimethylsilyldiazomethane; α-trimethylsilyldiazoalkane; (Z)-1-trimethylsilyl-1-alkene; rhodium(II) pivalate; catalytic decomposition
- Aoyama, Toyohiko,Shioiri, Takayuki
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p. 2261 - 2262
(2007/10/02)
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- Stereospecific Arylation of Alkenylsilanes with Arylpalladium Acetates
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Alkenyltrimethylsilanes ((E)- and (Z)-RCH=CHSiMe3: R = H, Ph, n-C6H13 and CH3OCH2) stereospecifically reacted at 40 deg C or room temperature with in situ generated phenylpalladium acetate to produce R(Ph)C=CSiMe3 and RCH=C(Ph)SiMe3 with inversion of their geometry.The arylation of CH2=CHSiMe3 with arylpalladium acetates gave (E)-ArCH=CHSiMe3 (Ar = XPH; X = H, 4-Me, 4-MeO, 4-Br, 4-I, 4-EtOCO, and 4-NO2) in good yields.
- Ikenaga, Kazutoshi,Kikukawa, Kiyoshi,Matsuda, Tsutomu
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p. 1276 - 1280
(2007/10/02)
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- Synthesis of (E)-(2-Arylethenyl)silanes by Palladium-Catalyzed Arylation of Vinylsilanes in the Presence of Silver Nitrate
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A series of (E)-trimethyl(2-arylethenyl)silanes 1-16 and (E)-triethoxy(2-arylethenyl)silanes 17 and 18 has been synthesized by palladium-catalyzed arylation of the corresponding vinylsilanes, in the presence of silver nitrate.Apart from enhancing the rate of the reaction, silver nitrate also completely suppresses the desilylation.In the absence of silver salt, under ordinary Heck arylation conditions, styrene derivatives are formed in good yields.A possible mechanistic rationale for the formation of styrenes is discussed.
- Karabelas, Kostas,Hallberg, Anders
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p. 5286 - 5290
(2007/10/02)
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- Reaction of Diazonium Salts with Transition Metals. Part 11. Palladium-catalyzed Aryldesilylation of Alkenylsilanes by Arenediazonium Salts
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Under palladium(0) catalysis, both (E)- and (Z)-RCH=CHSiMe3(R=Rh, 4-MeC6H4, 4-NO2C6H4, n-C6H13, and MeOCH2) were easily aryldesilylated by ArN2X(Ar=Ph, 4-MeC6H4, 4-BrC6H4 and 4-NO2C6H4; X=BF4, PF6, and Cl) to give (E)-RCH=CHAr and RC(Ar)=CH2 as the main products at 25 deg C in acetonitrile. anti- and syn-1,2-Elimination of Pd(0) and Me3Si from the adducts, threo- and erythro-RCH(PdX)CHSiMe3, generated from ArPdX and (E) and (Z)-RCH=CHSiMe3, respectively, are proposed for the formation of (E)-RCH=CHAr from either isomer of RCH=CHSiMe3.
- Ikenaga, Kazutoshi,Kikukawa, Kiyoshi,Matsuda, Tsutomu
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p. 1959 - 1964
(2007/10/02)
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- PALLADIUM-CATALYSED ARYLATION OF VINYLTRIMETHYLSILANE IN THE PRESENCE OF SILVER NITRATE
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A series of arylated vinyltrimethylsilanes have been prepared by means of Heck Arylation in the presence of silver nitrate, which serves to suppress the elimination of the silicon group and enhance the reaction rate.
- Karabelas, Kostas,Hallberg, Anders
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p. 3131 - 3132
(2007/10/02)
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- REACTION OF DIAZONIUM SALTS WITH TRANSITION METALS IX. REACTION OF VINYLTRIMETHYLSILANE WITH ARENEDIAZONIUM TETRAFLUOROBORATES UNDER PALLADIUM(0) CATALYSIS
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Arenediazonium tetrafluoroborates (ArN2BF4 where Ar = Ph, 4-MeC6H4, 4-BrC6H4, 4-IC6H4 and 4-NO2C6H4) reacted easily with CH2=CHSiMe3 at 25 deg C to give ArCH=CH2, (E)-ArCH=CHSiMe3 and Ar(Me3Si)C=CH2 in excellent yields under palladium(0) catalysis. (E)-ArCH=CHSiMe3 compounds were obtained predominantly and isolated in good yields by using an excess of CH2=CHSiMe3 over ArN2BF4.Protodesilylation of the reaction mixture afforded styrene derivatives.
- Kikukawa, Kiyoshi,Ikenaga, Kazutoshi,Kono, Kiyoshi,Toritani, Koji,Wada, Fumio,Matsuda, Tsutomu
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p. 277 - 282
(2007/10/02)
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- NEW METHODS AND REAGENTS IN ORGANIC SYNTHESIS. 37. TRIMETHYLSILYLDIAZOMETHANE. A CONVENIENT REAGENT FOR THE PREPARATION OF VINYLSILANES FROM ALKANESULFONYL CHLORIDES
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Trimethylsilyldiazomethane reacts smoothly with alkanesulfonyl chlorides in the presence of triethylamine to give vinylsilanes.KEYWORDS - trimethylsilyldiazomethane; vinylsilane; alkanesulfonyl chloride; thermal isomerization; sulfene; episulfone
- Aoyama, Toyohiko,Toyama, Sachio,Tamaki, Naoko,Shioiri, Takayuki
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p. 2957 - 2959
(2007/10/02)
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- Silanes in Organic Synthesis. 8. Preparation of Vinylsilanes from Ketones and Their Regiospecific Cyclopentenone Annulation
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A general method is described for the formation of vinylsilanes from ketones.Thus, conversion to the benzene- or p-toluenesulfonylhydrazone and sequential treatment with n-butyllithium and chlorotrimethylsilane in anhydrous tetramethylethylenediamine proceeds regiospecifically to afford the less substituted vinylsilane (in unsymmetrical cases).Friedel-Crafts acylation with acryloyl chlorides and aluminium chloride and subsequent Nazarov cyclization with Lewis acid catalysis results in cyclopentenone annulation.Numerous examples that reveal the scope of this processare described.Due to accompanying polymerization, annulation with acryloyl chloride itself is least efficient.This complication can, however, be averted through use of β-chloropropionyl chloride and dehydrochlorination with 1,5-diazabicycloundec-5-ene prior to ring closure.
- Paquette, Leo A.,Fristad, William E.,Dime, David S.,Bailey, Thomas R.
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p. 3017 - 3028
(2007/10/02)
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