- Aza-peterson olefinations: Rapid synthesis of (E)-alkenes
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An aza-Peterson olefination methodology to access 1,3-dienes and stilbene derivatives from the corresponding allyl- or benzyltrimethylsilane is described. Silanes can be deprotonated using Schlosser's base and added to N -phenyl imines or ketones to directly give the desired products in high yields.
- Britten, Thomas K.,Basson, Ashley J.,Roberts, Dean D.,McLaughlin, Mark G.
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p. 3535 - 3544
(2021/06/03)
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- Ligand-Free Iron-Catalyzed Carbon(sp2)-Carbon(sp2) Cross-Coupling of Alkenyllithium with Vinyl Halides
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An efficient ligand-free iron-catalyzed cross-coupling reaction involving alkenyllithium and vinyl iodides was developed to form diene species in moderate to good yields. This new iron-catalyzed cross-coupling reaction provides a mild, inexpensive, and environmentally friendly avenue toward synthesis of diversified diene derivatives.
- Liu, Qiang,Wang, Zhi-Yong,Peng, Xiao-Shui,Wong, Henry N. C.
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p. 6325 - 6333
(2018/06/01)
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- Ruthenium-Catalyzed Silylation of 1,3-Butadienes with Vinylsilanes
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A novel method for the synthesis of 1-silyl-substituted 1,3-butadienes, based on [RuHCl(CO)(PCy3)2]-catalyzed silylative coupling of terminal (E)-1,3-dienes with vinylsilanes, is reported. The reaction provides a facile and straightf
- Szudkowska-Fra?tczak, Justyna,Marciniec, Bogdan,Hreczycho, Grzegorz,Kubicki, Maciej,Pawlu?, Piotr
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supporting information
p. 2366 - 2369
(2015/06/02)
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- A synthesis of (1 E,3 E)-TMS dienes from keto-xanthates via Chugaev-type elimination
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An efficient route leading to exclusively (1E,3E)-TMS dienes is described. Radical xanthate addition of keto-xanthates to vinyltrimethylsilane followed by one-pot Chugaev elimination/cyclization and in situ oxidation with m-CPBA afforded the corresponding TMS 2-sulfolenes. Isomerization to 3-sulfolenes by the action of DBU with the extrusion of sulfur dioxide in refluxing toluene gave the titled (1E,3E)-TMS dienes.
- Goh, Kelvin Kau Kiat,Kim, Sunggak,Zard, Samir Z.
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p. 12274 - 12279
(2014/01/06)
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- Heck coupling with nonactivated alkenyl tosylates and phosphates: Examples of effective 1,2-migrations of the alkenyl palladium(II) intermediates
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(Chemical Equation Presented) What the Heck! A catalytic system composed of a Pd complex with a basic, hindered alkyl phosphine ligand is capable of promoting Heck coupling of nonactivated vinyl tosylates and phosphates with electron-deficient olefins. An unexpected 1,2-migration of the alkenyl Pd II intermediates (see Scheme) leads to the isomerized Heck coupling product.
- Hansen, Anders L.,Ebran, Jean-Philippe,Ahlquist, Marten,Norrby, Per-Ola,Skrydstrup, Troels
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p. 3349 - 3353
(2008/02/11)
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- Regioselective alkylation and olefination of allylic carbanion stabilized by two different heteroatoms: Phosphorus and silicon
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Treatment of allylphosphonate with LiHMDS, followed by successive addition of chlorotrimethylsilane and carbonyl reagent, afforded dienylsilanes in good yields. 3-Substituted dienylsilanes were obtained by alkylation and olefination of allylic carbanion of 3-trimethylsilylallylphosphonates.
- Lee, Bum Sung,Gil, Jun Mo,Oh, Dong Young
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p. 2345 - 2347
(2007/10/03)
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- Preparation of silyl-substituted dizinciomethanes and their reactions with electrophiles
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Silyl-substituted bis(bromozincio)methanes (RMe2Si-CH(ZnBr)2; R = Me, Ph, and p-MeO-C6H4), prepared from the corresponding dibromides by Pb catalyzed reaction with zinc, reacted stepwise with two different electrophiles, R1X and E+, yielding R1- CH(SiMe2R)-E.
- Matsubara, Seijiro,Otake, Yasuyuki,Morikawa, Takuya,Utimoto, Kiitiro
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p. 1315 - 1316
(2007/10/03)
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- Alkylidenation of carbonyl compounds with gem-dizincioalkanes mediated with titanium dichloride
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Olefination of carbonyl compounds with gem-dizincio-alkanes, bis(iodozincio)methane, 1,1-bis(iodozincio)ethane, and bis(bromozincio)methyltrimethylsilane, afforded the corresponding olefins in good to excellent yields.
- Matsubara, Seijiro,Mizuno, Tsuyoshi,Otake, Tasuyuiki,Kobata, Masami,Utimoto, Kiitiro,Takai, Kazuhiko
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p. 1369 - 1371
(2007/10/03)
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- A straightforward route to polyenylsilanes by palladium- or nickel-catalyzed cross-coupling reactions
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An efficient conversion of bis-silylated dienes and trienes into polyenylsilanes by cross-coupling reactions is described. The aryl substituted polyenes are synthesized by ipso-borodesilylation with BCl3 followed by Pd-catalyzed coupling reactions of the resulting boron derivative with aryl halides, whereas the synthesis of alkyl substituted polyenes requires the conversion of the boron intermediate into iodo-derivative and the subsequent coupling with alkyl Grignard reagents in the presence of a Ni(II) catalyst.
- Babudri, Francesco,Farinola, Gianluca M.,Fiandanese, Vito,Mazzone, Luigia,Naso, Francesco
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p. 1085 - 1094
(2007/10/03)
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- Highly Regio- and Enantioselective Monoepoxidation of Conjugated Dienes
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This paper describes a highly effective and mild asymmetric monoepoxidation method for conjugated dienes using a fructose-derived chiral ketone 1 as catalyst and Oxone as oxidant. The regioselectivies and enantioslectivies are very high in most cases. For unsymmetrical dienes, the regioselectivity can be regulated by using steric and electronic control. The olefin substrates include trans-disubstituted and trisubstituted olefins that can bear a wide range of functional groups such as hydroxyl groups, TBS ethers, or esters. The enantiomeric excesses for the major monoepoxides range from 89% to 97%. The epoxidation is believed to proceed via a spiro mode.
- Frohn, Michael,Dalkiewicz, Molly,Tu, Yong,Wang, Zhi-Xian,Shi, Yian
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p. 2948 - 2953
(2007/10/03)
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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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- SYNTHESIS OF χ,δ-UNSATURATED α-AMINO ACIDS FROM ALLYLSILANES AND GLYCIDYL CATION EQUIVALENTS
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The synthesis of a series of χ,δ-unsaturated N-protected α-amino acid methylesters from the coupling of different allylsilanes and glycidyl cation equivalents 6 and 7 is described.Reactions with methoxyglycine derivative 6 are induced with BF3*OEt2; in the case of chloroglycine derivative 7 SnCl4 is used as Lewis acid.Reactions are fully regioselective, but show low stereoselectivity.The conversion of the reaction products into unprotected α-amino acids is described for two cases.
- Mooiweer, Hendrik H.,Hiemstra, Henk,Speckamp, W. Nico
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p. 4627 - 4636
(2007/10/02)
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- HIGHLY DIASTEREOSELECTIVE SYNTHESIS OF (E)-1-TRIMETHYLSILYL-1-EN-3-YNES, (1E,3Z)- and (1E,3E)-1-TRIMETHYLSILYL-1,3-DIENES
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In the stereospecific palladium-catalysed cross-coupling reaction of 1-alkynylzinc chlorides or (E)-1-alkenyl diisobutylalanes, (E)-2-bromovinyltrimethylsilane reacts preferentially, in the presence of the corresponding (Z)-stereoisomer to afford good yields of (E)-1-trimethylsilyl-1-en-3-ynes (4) or (1E,3E)-1-trimethylsilyl-1,3-dienes (6),respectively, having very high stereoisomeric purities.Compounds 4 are easily converted into (1E,3Z)-1-trimethylsilyl-1,3-dienes (5) by selective hydrometallation reactions, followed by protonolysis.
- Andreini, Bianca Patrizia,Carpita, Adriano,Rossi, Renzo
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p. 2239 - 2242
(2007/10/02)
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- Regioselective Silylolefination of Allylic Dithioacetals. Stereoselective Synthesis of 1-(Trimethylsilyl)butadienes
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1-(Trimethylsilyl)butadienes are regioselectively and stereoselectively synthesized in good to excellent yields from the reactions of allylic dithioacetals and magnesium chloride in the presence of 5 mol percent of NiCl2(PPh3)2 in
- Ni, Zhi-Jie,Luh, Tien-Yau
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p. 5582 - 5584
(2007/10/02)
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- STEREOSPECIFIC SYNTHESIS OF (1E,3Z)-AND (1E,3E)-1-TRIMETHYLSILYL-1,3-DIENES BY MEANS OF SEQUENTIAL CROSS-COUPLING REACTIONS
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A new synthesis of stereodefined 1-trimethylsilyl-1,3-dienes is described.The method is based on two sequential coupling reactions between Grignard reagents and the readily available (Z)-or (E)-1-bromo-2-phenylthioethene, in the presence of transition met
- Fiandanese, V.,Marchese, G.,Mascolo, G.,Naso, F.,Ronzini, L.
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p. 3705 - 3708
(2007/10/02)
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- Synthesis of 1-Trimethylsilyl 1,3-Dienes by the Palladium-Catalyzed Reaction of Trimethylvinylsilane with Vinyl Iodides/Silver Nitrate or Vinyl Triflates
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A series of 1-trimethylsilyl 1,3-dienes has been synthesized by a palladium-catalyzed coupling of trimethylvinylsilane (1) either with vinyl halides in the presence of silver salts or alternatively with vinyl triflates.Apart from enhancing the rate of the
- Karabelas, Kostas,Hallberg, Anders
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p. 4909 - 4914
(2007/10/02)
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- STEREOSELECTIVE SYNTHESIS OF (E)-ALKENYLSILANES FROM ALDEHYDES WITH A REAGENT PREPARED BY CHROMIUM(II) REDUCTION OF Me3SiCHBr2
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Aldehydes are converted to the corresponding (E)-alkenylsilanes with one carbon homologation by means of a gemdichromium reagent prepared by CrCl2 reduction of Me3SiCHBr2 in THF.Transformation of aldehydes into alkenyl sulfides is also achieved with a com
- Takai, Kazuhiko,Kataoka, Yasutaka,Okazoe, Takashi,Utimoto, Kiitiro
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p. 1443 - 1446
(2007/10/02)
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- The Synthesis of Alkenes from Carbonyl Compounds and Carbanions α to Silicon. Stereoselective Synthesis of 1-Trimethylsilylbuta-1,3-dienes
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Reactions of aldehydes with the 1,3-bis(trimethylsilyl)propenyl anion in the presence of magnesium bromide or trimethyl borate give stereoselectively the alcohols (2) which can be transformed stereospecifically to either (1E,3E)- or (1E,3Z)-1-trimethylsilylbuta-1,3-dienes.
- Chan, Tak-Hang,Li, Ji-Sheng
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p. 969 - 970
(2007/10/02)
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- The Diels-Alder Route to Allylsilanes from 1-Trimethylsilylbutadienes
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The synthesis and Diels-Alder reactions of 1-trimethylsilylbutadiene (3) and its 3-methyl (17), 3-trimethylsilyloxy (20), 4-methyl (4), and 4-trimethylsilyl (6) derivatives are reported.The silyl group reduces somewhat the rate of the Diels-Alder reactions, and has, if anything, a small 'ortho'-directing effect on the regioselectivity in the reactions of (3) with methyl acylate, methyl propiolate, citraconic anhydride, and 2,6-dimethylbenzoquinone.The other substituent in the dienes (17), (20), and (4) is therefore the major influence on the regioselectivity in the reactions of these dienes with methyl acrylate and methyl propiolate.The products of the Diels-Alder reactions of (3), (17), and (4) are allylsilanes, which undergo clean protodesilylation with acid, and, with the acid and ester derived from the maleic anhydride adduct of (3), undergo epoxidation and sulphenylation reactions giving an allyl alcohol (33) and an allyl sulphide (37), respectively.The adducts from (20) can be hydrolysed to β-silylketones, which can be converted into enones by bromination. 1-Pentamethyldisilylbutadiene (15) is no more reactive and no more regioselective than (3).The 'ortho'-adduct (42) from the reaction of (3) and methyl propiolate aromatises with DDQ to give methyl m-trimethylsilylbenzoate (53) in high yield, in a reaction involving rearrangement of the silyl group, even though a direct dehydrogenation is an available pathway.
- Carter, Martin J.,Fleming, Ian,Percival, Alan
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p. 2415 - 2434
(2007/10/02)
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