- 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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- Nickel-Catalyzed Enantioselective α-Alkenylation of N-Sulfonyl Amines: Modular Access to Chiral α-Branched Amines
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Chiral α-branched amines are common structural motifs in functional materials, pharmaceuticals, and chiral catalysts. Therefore, developing efficient methods for preparing compounds with these privileged scaffolds is an important endeavor in synthetic chemistry. Herein, we describe an atom-economical, modular method for a nickel-catalyzed enantioselective α-Alkenylation of readily available linear N-sulfonyl amines with alkynes to afford a wide variety of allylic amines without the need for exogenous oxidants, reductants, or activating reagents. The method provides a platform for constructing chiral α-branched amines as well as derivatives such as α-Amino amides and β-Amino alcohols, which can be conveniently accessed from the newly introduced alkene. Given the generality, versatility, and high atom economy of this method, we anticipate that it will have broad synthetic utility.
- Li, Lun,Liu, Yu-Cheng,Shi, Hang
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supporting information
p. 4154 - 4161
(2021/04/06)
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- Build-up of double carbohelicenes using nitroarenes: Dual role of the nitro functionality as an activating and leaving group
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The construction of double carbohelicenes is highly fascinating yet challenging work. Disclosed herein is a streamlined and simplified synthetic route to double carbohelicenes starting from nitroarenes through sequential nitro-activated ortho-C-H arylation, denitrative alkenylation and intramolecular cyclodehydrogenation. In this synthetic strategy, the nitro group plays a dual role namely as a leaving group for the denitrative alkenylation and as an activating group for ortho-C-H arylation, which is distinct from those of aryl halides in a conventional coupling reaction. In this work, the palladium-catalyzed Heck-type alkenylation of nitroarenes has been presented, in which the conventionally inert Ar-NO2 bond is cleaved. This work provides a novel synthetic strategy for polycyclic aromatic hydrocarbons (PAHs). This journal is
- Su, Rongchuan,Yang, Yudong,You, Jingsong,Zhou, Fujian,Zhou, Fulin
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p. 7424 - 7428
(2020/09/09)
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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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- Iron-Catalyzed Cross-Coupling of Bis-(aryl)manganese Nucleophiles with Alkenyl Halides: Optimization and mechanistic investigations
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Various substituted bis-(aryl)manganese species were prepared from aryl bromides by one-pot insertion of magnesium turnings in the presence of LiCl and in situ trans-metalation with MnCl2 in THF at ?5 ?C within 2 h. These bis-(aryl)manganese reagents undergo smooth iron-catalyzed cross-couplings using 10 mol% Fe(acac)3 with various functionalized alkenyl iodides and bromides in 1 h at 25 ?C. The aryl-alkenyl cross-coupling reaction mechanism was thoroughly investigated through paramagnetic 1H-NMR, which identified the key role of tris-coordinated ate-iron(II) species in the catalytic process.
- Rousseau, Lidie,Desaintjean, Alexandre,Knochel, Paul,Lefèvre, Guillaume
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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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- A Bench-Stable, Single-Component Precatalyst for Silyl-Heck Reactions
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Studies of the silyl-Heck reaction aimed at identifying active palladium complexes have revealed a new species that is formed in situ. This complex has been identified as the palladium iodide dimer, [(JessePhos)PdI2]2, which has been
- Krause, Sarah B.,McAtee, Jesse R.,Yap, Glenn P. A.,Watson, Donald A.
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supporting information
p. 5641 - 5644
(2017/10/25)
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- Stereoselective peterson olefinations from bench-stable reagents and N-phenyl imines
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The synthesis of bench-stable α,α-bis(trimethylsilyl)toluenes and tris(trimethylsilyl)methane is described and their use in stereoselective Peterson olefinations has been achieved with a wide substrate scope. Product stereoselectivity was poor with carbonyl electrophiles (E/Z ~1:1 to 4:1) though this was significantly improved by employing the corresponding substituted N-benzylideneaniline (up to 99:1) as an alternative electrophile. The olefination byproduct was identified as N,N-bis(trimethylsilyl)aniline and could be easily separated from product by aqueous acid extraction. Evidence for an autocatalytic cycle has been obtained.
- Das, Manas,Manvar, Atul,Jacolot, Ma?wenn,Blangetti, Marco,Jones, Roderick C.,O'Shea, Donal F.
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p. 8737 - 8740
(2015/06/08)
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- Simplified Preparation of Trialkylvinylsilanes via the Silyl-Heck Reaction Utilizing a Second Generation Catalyst
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Recently we reported a second generation ligand, bis(3,5-di-tert-butylphenyl)(tert-butyl)phosphine, for the preparation of allylsilanes using the silyl-Heck reaction. We now show that this new ligand also provides superior reactivity in the preparation of vinylsilanes from styrene derivatives. For the first time, this new ligand provides exceptionally high yields of trialkylvinylsilanes using the widely available palladium pre-catalyst, tris(dibenzylideneacetone)dipalladium(0) [Pd2(dba)3]. Finally, we demonstrate that this new catalyst system is able to form more highly decorated all-carbon substituted vinylsilanes that have been shown to possess superior reactivity in oxidation and cross-coupling reactions.
- McAtee, Jesse R.,Krause, Sarah B.,Watson, Donald A.
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supporting information
p. 2317 - 2321
(2015/07/27)
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- The first example of nickel-catalyzed silyl-Heck reactions: Direct activation of silyl triflates without iodide additives
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For the first time, nickel-catalyzed silyl-Heck reactions are reported. Using simple phosphine-supported nickel catalysts, direct activation of silyl triflates has been achieved. These results contrast earlier palladium-catalyzed systems, which require io
- McAtee, Jesse R.,Martin, Sara E.S.,Cinderella, Andrew P.,Reid, William B.,Johnson, Keywan A.,Watson, Donald A.
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p. 4250 - 4256
(2014/06/09)
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- Supported palladium nanoparticles as heterogeneous ligand-free catalysts for the Hiyama C-C coupling of vinylsilanes and halobenzenes leading to styrenes
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The Hiyama C-C coupling reaction of a wide range of aryl iodides and vinylsilanes has been performed using ligand-free solid catalysts based on supported palladium nanoparticles. Among the supports tested (Mg, TiO 2, CeO2 and active carbon), the most active catalysts were those in which palladium is supported on MgO and TiO2. Analogous Pt and Au materials were inefficient to promote this reaction. Leaching tests suggest that there is some contribution of dissolved Pd since Pd in solution has been detected and the scavenging test decreases the initial reaction rate. Although the solid Pd catalysts can be reused, it was, however, observed that they undergo a certain deactivation upon use that can be attributed to several factors including the presence of inorganic compounds on the catalyst, Pd leaching or agglomeration of Pd NPs.
- Grirrane, Abdessamad,Garcia, Hermenegildo,Corma, Avelino
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- Oxidative cross-coupling of vinylsilanes in water
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Palladium-promoted cross-dimerization reaction of alkenylsilanes is reported for the first time, which is also one of the very first studies on oxidative cross-coupling between vinylic organometallic reagents. The reaction occurs at room temperature in aqueous micelles and represents a convenient access to all-trans push-pull butadienes.
- Cicco, Stefania R.,Martinelli, Carmela,Pinto, Vita,Naso, Francesco,Farinola, Gianluca M.
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- Preparation of allyl and vinyl silanes by the palladium-catalyzed silylation of terminal olefins: A silyl-heck reaction
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Installing silicon is easy! A high-yielding protocol for the palladium-catalyzed silylation of terminal alkenes is reported. This method allows facile conversion of styrenes to E-β-silyl styrenes by using iodotrimethylsilane (TMSI) or chlorotrimethylsilane/lithium iodide (see scheme). Terminal allyl silanes with good E/Z ratios are also readily accessed from α-olefins.
- McAtee, Jesse R.,Martin, Sara E. S.,Ahneman, Derek T.,Johnson, Keywan A.,Watson, Donald A.
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supporting information; experimental part
p. 3663 - 3667
(2012/05/20)
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- One-pot synthesis of (E)-styryl ketones from styrenes
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A new, efficient protocol for the highly stereoselective one-pot synthesis of (E)-styryl ketones from styrenes based on sequential ruthenium-catalyzed silylative coupling-rhodium-catalyzed desilylative acylation reactions is reported.
- Pawluc, Piotr,Szudkowska, Justyna,Hreczycho, Grzegorz,Marciniec, Bogdan
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supporting information; experimental part
p. 6438 - 6441
(2011/09/15)
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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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- Rapid and efficient entry to vinyl silanes from aldehydes employing a novel metalation-Peterson sequence
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Bis(trimethylsilyl)chloromethane undergoes a rapid and selective metalation with s-BuLi, yielding the nucleophilic bis(trimethylsilyl)methyl anion and providing a straightforward general entry to vinyl silanes from aromatic, aliphatic and vinyl aldehydes. The Royal Society of Chemistry.
- McNulty, James,Das, Priyabrata
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p. 1244 - 1245
(2008/12/21)
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- One-pot palladium-catalyzed highly chemo-, regio-, and stereoselective synthesis of trans-stilbene derivatives. A concise and convenient synthesis of resveratrol
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A convenient, efficient and highly chemo-, regio-, and stereoselective one-flask synthetic method is reported for the construction of unsymmetrical (or symmetrical) trans-stilbene derivatives based on two sequential Heck-type reactions using tetraalkylammonium salt-based catalyst systems and vinyltrimethylsilane as double bond equivalents. Resveratrol has thus been concisely synthesized.
- Jeffery, Tuyet,Ferber, Beno?t
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p. 193 - 197
(2007/10/03)
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- Synthesis of (Z)-vinylsilanes with high diastereoselectivity by using samarium diiodide
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matrix presented β-Elimination of O-acetyl 1-chloro-1-trimethylsilylalkan-2-ols 1 was achieved by using samarium diiodide as a metaling reagent and afforded the corresponding (Z)-vinylsilanes with high stereoselectivity. The starting compounds 1 were easi
- Concelloen, Jose M.,Bernad, Pablo L.,Bardales, Eva
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p. 937 - 939
(2007/10/03)
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- Tetraalkylammonium salt-based catalyst systems for directing the arylation of vinyltrimethylsilane
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A suitable choice of [Pd/MZ/QX] catalyst systems can allow to direct at will the arylation of vinyltrimethylsilane towards the formation of either (E)-trimethyl (2-arylethenyl) silanes or styrene derivatives.
- Jeffery, Tuyet
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p. 1673 - 1676
(2007/10/03)
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- Mechanism of Thermal Eliminations. Part 30. Pyrolysis of 2-Trimethylsilylethanol and 1-Aryl Derivatives
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The Arrhenius parameters (Eact = 45.57 kcal mol-1, log A/s-1 = 12.865) and rate coefficient at 600 K (1.84 * 10-4 s-1) for the cis β-thermal elimination of trimethylsilanol from 2-trimethylsilylethanol are identical (within experimental error) with those reported in the literature for elimination of methyl trimethylsilyl ether from 1-methoxy-2-(trimethylsilyl)ethane.This indicates that the driving force for the reaction, formation of the Si-O bond, is such that alteration of the nucleophilicity of oxygen has little effect on the reaction rate.A series of 1-aryl-2-trimethylsilylethanols have been prepared and their rates of elimination determined.The activating effect of the 1-aryl substituent (5.2-fold) is much less than the corresponding effect in the pyrolysis of ethyl acetates (63-fold) and 2-trimethylsilylethyl acetates (87-fold).Breaking of the α-C-O bond is thus kinetically less important than in the other reactions, and this conclusion is confirmed by a correlation of the rate data with the Yukawa-Tsuno equation which gives ρ = -0.4, r = 0.3.Si-O bond formation in the reaction is thereby shown to be of over-riding kinetic importance.For the 4-methylphenyl- and 4-methoxyphenyl compounds a minor competing reaction was the elimination of water to give the corresponding 1-aryl-2-trimethylsilylethene, and this has a higher activation energy than for the elimination of trimethylsilanol.NMR spectra for the 1-aryl-2-trimethylsilylethanols show that interaction between the OH and SiMe3 groups inhibits free rotation about the C(1)-C(2) bond.Preparation of 1-aryl-2-trimethylsilylethanols gave 1,3-diaryl-4-trimethylsilylbutyl trimethylsilyl ethers as byproducts arising from elimination of water from two molecules of the alcohols in a process believed to be two-step.
- Taylor, Roger
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p. 1703 - 1706
(2007/10/02)
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- Unified synthesis of vinylsilanes and silylated butadienes. Nickel-catalyzed olefination and silylolefination of dithioacetals
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A simple unified reaction has been developed in the syntheses of various vinylsilanes and silylated butadienes by the nickel-catalyzed coupling of dithioacetals with appropriate Grignard reagents. Reactions of 2-aryl-2-(trimethylsilyl)dithianes with MeMgI
- Ni, Zhi-Jie,Yang, Pin-Fan,Ng, Dennis K. P.,Tzeng, Yih-Ling,Luh, Tien-Yau
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p. 9356 - 9364
(2007/10/02)
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- A New Version of the Peterson Olefination Using Bis(trimethylsilyl)methyl Derivatives and Fluoride Ion as Catalyst
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Reaction between a variety of bis(trimethylsilyl)methyl derivatives and carbonyl compounds under fluoride ion as catalyst is described.The reaction works especially well with nonenolizable carbonyl compounds to give the expected alkenes in high yields and, in some cases, with high stereoselectivity.Application of this methodology to an intramolecular alkenation providing a tricyclic benzocarbacephem ring system is also described.
- Palomo, Claudio,Aizpurua, Jesus M.,Garcia, Jesus M.,Ganboa, Inaki,Cossio, F. P.,et al.
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p. 2498 - 2503
(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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- Nickel-Catalyzed Silylolefination of Dithioacetals. A Stereoselective Way to Vinylsilanes
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(E)-Vinylsilanes are synthesized stereoselectively in good yields from dithioacetals and Me3SiCH2MgCl in the presence of a catalytic amount of NiCl2(PPh3)2.
- Ni, Zhi-Jie,Luh, Tien-Yau
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p. 2129 - 2131
(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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- 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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- SYN-ADDITION VON TRIS(TRIMETHYLSILYL)ALUMINIUM AN ALKINE: EINE NEUE SYNTHESE FUER VINYLSILANE
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A new method for the synthesis of vinylsilanes by syn-addition of tris(trimethylsilyl)aluminium to alkynes is described.
- Altnau, G.,Roesch, L.,Bohlmann, F.,Lonitz, M.
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p. 4069 - 4072
(2007/10/02)
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