- Regiospecific hydroselenation of terminal acetylenes using aluminum phenylselenolate anions
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Regiospecific hydroselenation of terminal acetylenes using aluminum phenylselenolates afforded the 1-organyl-1-phenylseleno ethenes in good yields. The first example of exclusive formation of the hydroselenation Markovnikov adducts is described. Copyright
- Dabdoub, Miguel J.,Cassol, Tania M.,Batista, Antonio C. F.
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- Indium(I) iodide-mediated chemio-, regio-, and stereoselective hydroselenation of 2-alkyn-1-ol derivatives
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Indium(I) iodide efficiently promotes the chemio-, regio-, and stereoselective hydroselenation of 2-alkyn-1-ol derivatives with diphenyl diselenide to produce the Markovnikov adducts with stereochemistry corresponding to an anti addition of the selenol co
- Do Rego Barros, Olga Soares,Lang, Ernesto Shulz,De Oliveira, Carlos Alberto Fernandes,Peppe, Clovis,Zeni, Gilson
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- Cerium(III)-mediated efficient and steroselective hydrochalcogenation of terminal alkynes
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Vinylic chalcogenides were synthesized stereospecifically by hydrochalcogenation of propargylic amines or alcohols mediated by cerium(III) chloride. The products were obtained in good yields and with high regio- and stereoselectivities. Georg Thieme Verla
- Silveira, Claudio C.,Mendes, Samuel R.,Rosa, Daniel D.,Zeni, Gilson
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experimental part
p. 4015 - 4021
(2010/03/24)
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- Hydroselenation of alkynes using NaBH4/BMIMBF4: easy access to vinyl selenides
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A general and easy method for the synthesis of several vinyl selenides using NaBH4 and BMIMBF4 as a recyclable solvent is described. This efficient and improved method furnishes the corresponding vinyl chalcogenides preferentially wi
- Lenard?o, Eder J.,Dutra, Luiz G.,Saraiva, Maiara T.,Jacob, Raquel G.,Perin, Gelson
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p. 8011 - 8013
(2008/03/18)
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- Addition of chalcogenolate anions to terminal alkynes using microwave and solvent-free conditions: Easy access to bis-organochalcogen alkenes
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We present here the reaction of diphenyl dichalcogenides (Se and Te) with propargyl alcohols using alumina supported sodium borohydride under solvent-free conditions. This efficient and improved method is general and furnishes the corresponding vinyl chal
- Perin, Gelson,Jacob, Raquel G.,Dutra, Luiz G.,De Azambuja, Francisco,Dos Santos, Greice F. F.,Lenard?o, Eder J.
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p. 935 - 938
(2007/10/03)
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- Palladium(II) acetate in pyridine as an effective catalyst for highly regioselective hydroselenation of alkynes
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(Chemical Equation Presented) A highly regioselective hydroselenation of terminal alkynes with benzeneselenol can be achieved by the combination of palladium acetate and pyridine, providing the corresponding terminal alkenes, (i.e., 2-phenylseleno-1-alkenes) as a sole product. In this hydroselenation, pyridine may act as a suitable ligand for active palladium intermediates.
- Kamiya, Ikuyo,Nishinaka, Etsuyo,Ogawa, Akiya
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p. 696 - 698
(2007/10/03)
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- Palladium and platinum catalyzed hydroselenation of alkynes: Se-H vs Se-Se addition to C≡C bond
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A mechanistic study of the hydroselenation of alkynes catalyzed by Pd(PPh3)4 and Pt(PPh3)4 has shown that the palladium complex gives products of both Se-H and Se-Se bond addition to the triple bond of alkynes, while the platinum complex selectively catalyzes Se-H bond addition. The key intermediate of PhSeH addition to the metal center, namely Pt(H)(SePh)(PPh3)2, was detected by 1H-NMR spectroscopy. The analogous palladium complex rapidly decomposes with evolution of molecular hydrogen. A convenient method was developed for the preparation of Markovnikov hydroselenation products H2C=C(SePh)R, and the scope of this reaction was investigated. The first X-ray structure of the Markovnikov product H2C=C(SePh)CH2N+ HMe2·HOOC=COO- is reported.
- Ananikov, Valentine P.,Malyshev, Denis A.,Beletskaya, Irina P.,Aleksandrov, Grigory G.,Eremenko, Igor L.
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p. 162 - 172
(2007/10/03)
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- Mechanism of catalytic addition of benzeneselenol to alkynes
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Addition of benzeneselenol to terminal alkynes HC≡CR, catalyzed by Pd(0) complexes, leads to formation of mixtures of mono- and bis(phenylseleno)alkenes, depending on the nature of the R substituent. Electron-donor groups (R = Bu, CH2OH, CH2NMe2) give rise to addition according to the Markownikoff rule, whereas from alkynes with electron-acceptor groups (R = Ph, COOMe) mixtures of products are formed as a result of side reactions. A probable reaction mechanism includes oxidative addition of benzeneselenol to the metal, alkyne insertion into the Pd-Se bond, and reductive elimination.
- Ananikov,Malyshev,Beletskaya
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p. 1475 - 1478
(2007/10/03)
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- Synthesis of chalcogenides using indium intermediates in aqueous media
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Selenides and vinylic selenides were synthesized from their corresponding organic halides and alkynes in aqueous media using indium metal.
- Galindo, Andréa C.,Oliveira, Juliana M.,Barboza, Maria A. G.,Gon?alves, Simone M. C.,Menezes, Paulo H.
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p. 129 - 140
(2007/10/03)
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- ORGANOSELENIUM COMPOUNDS. VIII. SYNTHESIS OF α-(ARYLSELENO)PROPIONALDEHYDES
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The reaction of arylselenomagnesium bromides with propargyl alcohol in diethyl ether leads at the first stage to the formation of β-(arylseleno)allyl alcohols, the acid hydrolysis of which gives α-(arylseleno)propionaldehydes.
- Nedugov, A. N.,Pavlova, N. N.,Shalimov, A. V.
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p. 226 - 228
(2007/10/02)
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- Selenium in Organic Synthesis: A Novel Route to 1-Phenylselenobutadienes and 1,4-Dicarbonyl Compounds
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Two approaches to 1-phenylseleno-1,3-butadienes 5 are reported, via phenylselenoalkenylidene phosphoranes and phenylselenoalkenals, respectively. 1,4-Dicarbonyl compounds are prepared from the 1-phenylselenobutadienes or from the phenylselenoalkenals.
- Comasseto, J. V.,Brandt, C. A.
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p. 146 - 149
(2007/10/02)
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- PREPARATION OF 3-HYDROXYL-VINYL SELENIDES AND 1,3-BIS(SELENO)-PROPENES
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Z and E 3-hydroxy-vinyl selenides can be prepared with very high stereoselectivity respectively by nucleophilic addition of selenolates to propargyl alcohols and by selenylation followed by LiAlH4 reduction of the same propargyl alcohols. 1,3-Bis(seleno)-
- Renard, M.,Hevesi, L.
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p. 5939 - 5954
(2007/10/02)
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