- A Tandem Non-Aldol Aldol Mukaiyama Aldol Reaction
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(Equation presented) A new one-pot tandem aldol process is described in which a secondary epoxy silyl ether is converted into the 1,5-bis-silyloxy-3- alkanone in good yield. Thus, treatment of the epoxy silyl ether 8 with TBSOTf and base affords the silyl
- Jung, Michael E.,Van Den Heuvel, Alexandra
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- Reactivity, Selectivity, and Synthesis of 4-C-Silylated Glycosyl Donors and 4-Deoxy Analogues
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A method for introducing dimethylphenylsilyl at the 4-position in carbohydrates has been developed. Two C-silylated glycosyl donors were prepared via levoglucosenone, starting from cellulose. The glycosylation properties were studied using three glucoside
- J?ger Pedersen, Martin,Pedersen, Christian Marcus
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supporting information
p. 2689 - 2693
(2020/12/01)
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- Tuning of α-Silyl Carbocation Reactivity into Enone Transposition: Application to the Synthesis of Peribysin D, E-Volkendousin, and E-Guggulsterone
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A reliable method for enone transposition has been developed with the help of silyl group masking. Enantio-switching, substituent shuffling, and Z-selectivity are the highlights of the method. The developed method was applied for the first total synthesis of peribysin D along with its structural revision. Formal synthesis of E-guggulsterone and E-volkendousin was also claimed using a short sequence.
- Athawale, Paresh R.,Zade, Vishal M.,Rama Krishna, Gamidi,Reddy, D. Srinivasa
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supporting information
p. 6642 - 6647
(2021/09/02)
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- Organocatalyzed Diastereo- and Enantioselective Conjugate Addition of Nitroalkanes to β-Silylmethylene Malonates: Direct Access to Enantioenriched Organosilanes
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Cinchona-alkaloid derived bifunctional thiourea catalyzed conjugate addition reaction of nitroalkanes to β-silylmethylene malonates is reported for direct access of densely functionalized enantioenriched organosilanes in good yields (up to 86 %) with exce
- Chowdhury, Raghunath,Dubey, Akhil K.,Ghosh, Sunil K.
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supporting information
p. 2962 - 2972
(2020/05/16)
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- Synthesis of Alkyl Silanes via Reaction of Unactivated Alkyl Chlorides and Triflates with Silyl Lithium Reagents
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The reaction of unactivated secondary and primary alkyl chlorides as well as primary alkyl triflates with silyl lithium reagents to access tetraorganosilanes is reported. These nucleophilic substitutions proceed in the absence of any transition metal catalyst under mild conditions in moderate to very good yields. The silyl lithium reagents are readily generated from the corresponding commercially available chlorosilanes. Enantioenriched secondary alkyl chlorides react with high stereospecificity under inversion of configuration.
- Mallick, Shubhadip,Würthwein, Ernst-Ulrich,Studer, Armido
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supporting information
p. 6568 - 6572
(2020/09/02)
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- NNB-type tridentate boryl ligands enabling a highly active iridium catalyst for C–H borylation
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Boryl ligands play a very important role in catalysis because of their very high electron-donating property. In this paper, NNB-type boryl anions were designed as tridentate ligands to promote aryl C–H borylation. In combination with [IrCl(COD)]2/su
- Ding, Siyi,Wang, Linghua,Miao, Zongcheng,Li, Pengfei
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- Nickel/copper-cocatalyzed decarbonylative silylation of acyl fluorides
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Ni/Cu-cocatalyzed decarbonylative silylation of acyl fluorides with silylboranes has been developed to afford various arylsilanes with high efficiency and good functional-group compatibility via carbon-fluorine bond cleavage and carbon-silicon bond formation. Such transformation can not only extend the functionalization type of acyl fluorides but complement the synthetic route for arylsilanes.
- Wang, Xiu,Wang, Zhenhua,Nishihara, Yasushi
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supporting information
p. 10507 - 10510
(2019/09/06)
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- Total Synthesis of (-)-Xylogranatopyridine B via a Palladium-Catalyzed Oxidative Stannylation of Enones
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We report a total synthesis of the pyridine-containing limonoid alkaloid (-)-xylogranatopyridine B in 11 steps from commercially available dihydrocarvone. The central pyridine ring was assembled by a late-stage fragment coupling approach employing a modified Liebeskind pyridine synthesis. One fragment was prepared by an allyl-palladium catalyzed oxidative enone β-stannylation, in which the key bimetallic β-stannyl palladium enolate intermediate undergoes a β-hydride elimination. This methodology also allowed introduction of alkyl and silyl groups to the β-position of enones.
- Schuppe, Alexander W.,Huang, David,Chen, Yifeng,Newhouse, Timothy R.
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supporting information
p. 2062 - 2066
(2018/02/19)
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- A mild and ligand-free Ni-catalyzed silylation via C-OMe cleavage
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Metal-catalyzed transformations that forge carbon-heteroatom bonds are of central importance in organic synthesis. Despite the formidable potential of aryl methyl ethers as coupling partners, the scarcity of metal-catalyzed C-heteroatom bond formations via C-OMe cleavage is striking, with isolated precedents requiring specialized, yet expensive, ligands, high temperatures, and π-extended backbones. We report an unprecedented catalytic ipso-silylation of aryl methyl ethers under mild conditions and without recourse to external ligands. The method is distinguished by its wide scope, which includes the use of benzyl methyl ethers, vinyl methyl ethers, and unbiased anisóle derivatives, thus representing a significant step forward for designing new C-heteroatom bond formations via C-OMe scission. Applications of this transformation in orthogonal silylation techniques as well as in further derivatizations are also described. Preliminary mechanistic experiments suggest the intermediacy of Ni(0)-ate complexes, leaving some doubt that a canonical catalytic cycle consisting of an initial oxidative addition of the C-OMe bond to Ni(0) species comes into play.
- Zarate, Cayetana,Nakajima, Masaki,Martin, Ruben
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supporting information
p. 1191 - 1197
(2017/05/16)
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- Transition-Metal-Free Ring-Opening Silylation of Indoles and Benzofurans with (Diphenyl-tert-butylsilyl)lithium
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A practical method is presented for ring opening various indoles and benzofurans with concomitant stereoselective silylation using readily generated (diphenyl-tert-butylsilyl)lithium to afford ortho-β-silylvinylanilines or -phenols. Dearomatization of the heteroarene core proceeds in the absence of any transition-metal catalyst through addition of a silyl anion and a subsequent stereoselective β-elimination. DFT calculations provide insight into the mechanism. Functionalizing C?X bond cleavage of heteroarenes is rare and generally requires transition-metal catalysts.
- Xu, Pan,Würthwein, Ernst-Ulrich,Daniliuc, Constantin G.,Studer, Armido
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supporting information
p. 13872 - 13875
(2017/10/09)
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- 29Si-1H IMPACT HMBC: A suitable tool for analyzing silylated derivatives
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A modified version of the IMPACT heteronuclear multiple bond correlation (HMBC) has allowed the characterization of an organosilane and a tetrasilylated yttrium complex. With the help of this sequence, an average gain in sensitivity close to 2 has been ob
- Farjon, Jonathan,Giros, Audrey,Deloisy, Sandrine,Blanco, Luis,Hannedouche, Jerome,Schulz, Emmanuelle,Merlet, Denis
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p. 230 - 233
(2013/05/21)
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- Efficient synthesis of α-tertiary α-silylamines from aryl sulfonylimidates via one-pot, sequential C-Si/C-C bond formations
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An efficient and flexible route for the synthesis of α-tertiary (α,α-dibranched) α-silylamines via sequential reactions of sulfonylimidates using readily available phenyldimethylsilyllithium and Grignard reagents is described. The procedure allows successive formation of C-Si/C-C bonds in a single flask.
- Han, Xiao-Jun,Yao, Ming,Lu, Chong-Dao
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supporting information; experimental part
p. 2906 - 2909
(2012/07/14)
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- One-pot synthesis of α-amino acids from CO2 using a bismetal reagent with Si-B bond
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In the presence of 1.1 equiv of PhMe2Si-Bpin, 5 equiv of CsF, and 20 mol % of TsOH·H2O, precursors of N-Boc-imines can be converted into the corresponding α-aryl or α-alkenyl glycine derivatives under gaseous CO2 in moderate-to-high yields with a single operation. α-Isobutenyl glycine thus obtained can be further derivatized into various types of α-amino acids including N-Boc-leucine, serine, and glycine derivatives in short steps.
- Mita, Tsuyoshi,Chen, Jianyang,Sugawara, Masumi,Sato, Yoshihiro
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supporting information
p. 6202 - 6205
(2013/02/23)
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- Synthesis of acylsilanes by palladium-catalyzed cross-coupling reaction of thiol esters and silylzinc chlorides
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An acylsilane synthesis by a Pd-catalyzed cross-coupling reaction of thiol esters and silylzinc chlorides was developed. S-Phenyl thiol esters with a variety of functional groups were converted to corresponding acylsilanes.
- Azuma, Hiroki,Okano, Kentaro,Tokuyama, Hidetoshi
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supporting information; experimental part
p. 959 - 961
(2011/12/05)
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- Efficient synthesis of acylsilanes using morpholine amides
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(Chemical Equation Presented) A general synthesis of acylsilanes from the corresponding morpholine amides and silyllithium species is described. The use of morpholine amides is economical and prevents over-addition by the silyl nucleophile. The procedure cleanly affords acylsilanes in good yields and circumvents the use of stoichiometric copper(I) cyanide typically employed to synthesize these compounds from acid chlorides.
- Clark, Christopher T.,Milgram, Benjamin C.,Scheidt, Karl A.
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p. 3977 - 3980
(2007/10/03)
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- Diastereoselective addition of alcohol to diastereotopic silylenes
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The successful example of diastereoselective addition of alcohol to diastereotopic silylenes is reported. Copyright
- Sanji, Takanobu,Fujiyama, Hideyuki,Yoshida, Kaname,Sakurai, Hideki
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p. 3216 - 3217
(2007/10/03)
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- Novel approach to the Zaragozic acids. Enantioselective total synthesis of 6,7-dideoxysqualestatin H5
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The total synthesis of 6,7-dideoxysqualestatin H5 (3) has been completed by a concise approach that features the stereoselective intramolecular vinylogous aldol reaction of the furoic ester 25a to give 30 or its trimethylsilyl ether derivative 34, which possess the requisite absolute stereochemistry at C(3)-C(5) of 3. Compound 34 was reduced to the saturated bislactone 39, and the C(1) side chain subunit 47 was introduced leading to a mixture of the hemiacetals 48 and the corresponding ketone 49. When this mixture was stirred with methanolic acid, transketalization occurred to give a mixture of 50 and the spirocyclic methyl acetals 51a,b. Oxidation of the primary alcohol group in 50 followed by saponification of the two remaining ester groups gave 3. The longest linear sequence in the synthesis commences with commercially available erythronolactone (26) and requires 17 chemical steps with only 10 isolated intermediates.
- Naito, Satoru,Escobar, Maya,Kym, Philip R.,Liras, Spiros,Martin, Stephen F.
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p. 4200 - 4208
(2007/10/03)
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- Boron-metal exchange reaction of silylboranes with organometallic reagents: A new route to arylsilyl anions
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The boron-metal exchange reaction of (arylsilyl)boranes with alkyllithiums, potassium tert-butoxide, and methylmagnesium bromide affords the corresponding silyllithium, silylpotassium, and silylmagnesium compounds, respectively. Especially, the boron-lithium exchange reaction occurs even in hydrocarbon solvents such as toluene and hexane as well as in THF.
- Kawachi, Atsushi,Minamimoto, Takashi,Tamao, Kohei
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p. 1216 - 1217
(2007/10/03)
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- Synthesis of 4,6-dideoxyfuranoses through the regioselective and diastereoselective oxyfunctionalization of a dimethylphenylsilyl-substituted chiral homoallylic alcohol
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The 4,6-dideoxyfuranoses 10a and 10b have been synthesized by starting from the readily available E-5-dimethylphenylsilyl-2-hexene-4-ol (1)and employing successively three versatile oxyfunctionalization methods, namely photooxygenation, metal-catalyzed epoxidation, and oxidative desilylation. Photooxygenation of the hydroxy vinylsilane 1 and subsequent triphenylphosphine reduction of the hydroperoxides 3 afford the like-4a and unlike-4b diols, which have been converted separately to the tetrahydrofurans (2S*,3R*,5R*)-7a and (2S*,3R*,5S*)-7b by a combination of diastereoselective epoxidation and regioselective intramolecular epoxide-ring opening. In the epoxidation reaction, catalyzed by Ti(OiPr)4 or VO(acac)2, only one diastereomer (dr > 95:5) of the epoxide 5 is obtained. Further intramolecular opening of the epoxide ring in erythro-5 occurs regioselectively at the C-α position and diastereoselectively under inversion of the configuration of the silyl-substituted stereogenic center to generate only one diastereomer of the tetrasubstituted tetrahydrofurans 7. Oxidative desilylation of the latter gave the hitherto unknown 4,6-dideoxyfuranoses 10a and 10b. The use of the optically active E-5-dimethylphenylsilyl-2-hexene-4-ol (1) as starting material, which is readily available through lipase-catalyzed kinetic resolution, leads to the D- and L-4,6-dideoxysorbofuranoses 10a and D- and L-4,6-dideoxyfructofuranoses 10b in up to 98% enantiomeric excess.
- Adam,Saha-Moeller,Schmid
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p. 7365 - 7371
(2007/10/03)
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- The preparation and analysis of the phenyldimethylsilyllithium reagent and its reaction with silyl enol ethers
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Phenyldimethylsilyllithium is formed from lithium and phenyldimethylsilyl chloride by slow cleavage of the Si-Si bond of 1,1,2,2-tetramethyl-1,2-diphenyldisilane after the rapid formation of the disilane. 1,1,2,2-Tetramethyl-1,2-diphenyldisiloxane, produced from the silyl chloride by reaction with oxides and hydroxides on the lithium metal surface, is cleaved by dimethyl(phenyl)silyllithium to give lithium dimethyl(phenyl)silanoxide. Dimethyl(phenyl)silyllithium reacts with 1,2-dibromoethane to give dimethyl(phenyl)silyl bromide, which is so rapidly consumed by excess silyllithium reagent that it does not interfere with the double titration used to measure its concentration. Dimethyl(phenyl)silane, produced by protonation of the silyllithium reagent, is also consumed by the silyllithium reagent to give 1,1,2,2-tetramethyl-1,2-diphenyldisilane, which regenerates the silyllithium reagent, as long as lithium is still present. By-products in the preparation of dimethyl(phenyl)silyllithium include 1,3-diphenyl-1,1,2,2,3,3-hexamethyltrisilane, dimethyldiphenylsilane and 1,4-bis[dimethyl(phenyl)-silyl]benzene. Dimethyl(phenyl)silyllithium displaces the silyl group from the tert-butyldimethylsilyl enol ether of cyclohexanone to give the lithium enolate under relatively mild conditions.
- Fleming, Ian,Roberts, Richard S.,Smith, Stephen C.
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p. 1209 - 1214
(2007/10/03)
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- Tridecamethyl-1-phospha-and tridecamethyl-1-arsa-2,3,4,5,6,7,8-heptasilabicyclo[2.2.2]octane
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The octaheterobicyclo[2.2.2]octanes MeSi(SiMe2SiMe2)3E (E = P, As) have been prepared in high yields (up to 50%) from the alkali metal phosphide or arsenide Na3E/K3E and the heptasilane MeSi(SiMe
- Hassler, Karl,Kollegger, Gerlinde M.,Siegl, Harald,Klintschar, Gerd
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- Synthese, Kernresonanzspektren und Schwingungsspektren der Hexamethyltrisilane und Pentamethyltrisilane (XMe2Si)2SiMe2 und (XMe2Si)2SiMeX (X=H, F, Cl, Br, I, Ph, OMe)
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The syntheses, IR, Raman and 29Si spectra of the title compounds are reported.SiSi force constants, calculated with the aid of normal coordinate analyses, are compared with 29Si29Si coupling constants.
- Schenzel, Karla,Hassler, Karl
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p. 127 - 138
(2007/10/02)
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- Composition and Chemistry of the Mixed Higher Order Cuprates (PhMe2Si)m(CH3)nCu(CN)Lim+n
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Low-temperature 29Si, 13C, and 1H NMR spectroscopic techniques were used to probe the nature of THF solutions of cuprates derived from PhMe2SiLi, MeLi, and CuCN in the stoichiometric ratios 1:1:1, 2:1:1, and 1:2:1 (Si:Me:Cu).Unlike the corresponding mixed stannyl systems that yield R3Sn(R)2CuLi2 when the ratio of stannyl anion:alkyl anion:cuprous ion is 1:2:1, these mixed silyl systems only form R3Si(R)Cu(CN)Li2.Solutions wherein the ratio of silyl anion and alkyl anion to cuprous ion is greater than 2:1 contain alkyllithium uncoordinated with cuprous ion.The most striking result is the preferential displacement of RLi when R3SiLi is added to solutions of R3Si(R)Cu(CN)Li2 or R2Cu(CN)Li2.These mixed metallocuprate solutions preferentially transfer the PhMe2Si moiety in reactions with α,β-unsaturated enones and other unsaturated organic substrates.However, the mixed alkylsilylcuprate (PhMe2Si)(CH3)Cu(CN)Li2 reacts with 1,2-epoxyoctane to afford up to 31percent of the methylated alcohol.Frontier orbital analysis of both the predominant cuprates species and preferential ligand transfer provides a rationale for the observed behavior.
- Singer, Robert D.,Oehlschlager, Allan C.
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p. 3510 - 3514
(2007/10/02)
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- CHEMICAL AND SPECTROSCOPIC INVESTIGATIONS OF TRIALKYLSILYLCUPRATES DERIVED FROM CuCN.
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We disclose that in THF addition of increasing amounts of ΦMe2SiLi (with LiCl) to CuCN gives sequentially ΦMe2SiCu(CN)Li (1:1), (ΦMe2Si)2Cu(CN)Li2 (2:1) and (ΦMe2Si)3CuLi2 (3:1).The formation of the latter species is corroborated with chemical tests on bo
- Sharma, Sunaina,Oehlschlager, Allan C.
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p. 557 - 568
(2007/10/02)
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- SILYLCUPRATION OF ACETYLENES
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Several organosilylcuprates have been prepared and their reactions with acetylenes examined.It has been shown that LiCu2 adds to acetylenes in only one manner, i.e. with cis addition and the Si(SiMe3)3 group in the least hindered cite as shown
- Chen, Hsiao-Ming,Oliver, John P.
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p. 255 - 260
(2007/10/02)
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- The Silylcupration of Acetylenes: a Synthesis of Vinylsilanes
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Bis(dimethylphenylsilyl)copper-lithium (1) reacts with hex-1-yne, propyne, acetylene itself, phenylacetylene, and hex-3-yne to give the products of syn addition of the dimethylphenylsilyl group and the copper.The resultant vinylcopper reagents react with a variety of electrophiles, such as the proton, iodine, acyl and alkyl halides, enones, and epoxides, to give vinylsilanes.With the terminal alkynes, the silyl group becomes attached with a high level of regioselectivity to the terminal carbon atom, with the result that the final products are 2,2-disubstituted vinylsilanes.
- Fleming, Ian,Newton, Trevor W.,Roessler, Felix
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p. 2527 - 2532
(2007/10/02)
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- Reaction of a Silyl-Copper Reagent with Acetylenes: a New Synthesis of Vinylsilanes
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A silyl-cuprate reagent adds regioselectively to terminal acetylenes and the intermediate (3) reacts with electrophiles to give 2,2-disubstituted vinylsilanes.
- Fleming, Ian,Roessler, Felix
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p. 276 - 277
(2007/10/02)
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