- Breaking bonds with electrons: Stepwise and concerted reductive cleavage of C-S, C-Se and Se-CN bonds in phenacylthiocyanates and phenacylselenocyanates
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The mechanistic aspects of the electrochemical reduction of phenacylthio- and selenocyanates have been studied. With phenacylthiocyanates (1), a change in the reductive cleavage mechanism is observed as a function of the substituent on the phenyl ring. While a stepwise mechanism involving the intermediacy of a radical anion is followed for substrates bearing a strong electron withdrawing group, such as cyano and nitro substituent (1d, 1e), and a concerted mechanism is favoured for compounds bearing an electron-donating or no substituent on the phenyl ring (1a-c). A regioselective bond cleavage leads to the fragmentation of the CH2-S bond with all compounds 1a-e, further yielding the corresponding 1,4-diketone (3) as products. Contrastingly, with phenacylselenocyanates (2), two different reductive cleavages occur involving the breaking of both the CH2-Se and Se-CN bonds. Several products are obtained, all coming from nucleophilic attack at the α (phenacyl) carbon or the selenium atom.
- Bouchet, Lydia M.,Peory, Alicia B.,Robert, Marc,Argüello, Juan E.
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p. 11753 - 11760
(2015/02/19)
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- Synthesis, characterization, and structures of α-substituted selenenyl-acetophenones
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A series of α-substituted selenenyl acetophenone derivatives of the types, [PhC(OCH2CH2O)CH2Se]2, [PhC(OCH2CH2O)CH2SeR], (PhCOCH2Se) 2, and [PhCOCH2/s
- Hodage, Ananda S.,Phadnis, Prasad P.,Wadawale, Amey,Priyadarsini,Jain, Vimal K.
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p. 700 - 710
(2014/06/09)
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- Di(phenylsulfonyl) diselenide (PhSO2Se)2 and phenylsulfonylselenyl chloride (PhSO2SeCl) as new selenium-transfer reagents in the synthesis of functionalised diselenides and selenides
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The title electrophilic selenium reagents have been used to synthesise functionalised diselenides and selenides.
- Chesney,Bryce,Cooke
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p. 1521 - 1524
(2007/10/02)
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- Phenylsulfinylselenyl Chloride (PhSO2SeCl): A New Reagent for the Formation of C-Se and N-Se Bonds. Generation and In Situ Diels-Alder Trapping of Selenonitrosoarene Intermediates (Ar-N=Se)
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The novel electrophilic selenium transfer reagent phenylsulfinylselenyl chloride, PhSO2SeCl, 3 has been prepared and reacted with enolisable carbonyl compounds to yield α-selenoketones and diselenides; reaction of reagent 3 with arylamines in the presence
- Bryce, Martin R.,Chesney, Antony
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p. 195 - 196
(2007/10/02)
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- Convenient Syntheses of N,N-Dialkylselenoamides and N,N,N',N'-Tetraalkylselenoureas by Treating Terminal gem-Dihaloalkanes, Chloroform , or Sodium Trichloroacetate with a Base, Elemental Selenium, and Amines
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Treatment of terminal gem-dihaloalkanes, chloroform or sodium trichloroacetate with elemental selenium in the presence of NaH and an excess amount of primary or secondary amines gave selenoamides and selenoureas in modest yields.
- Takikawa, Yuji,Yamaguchi, Minoru,Sasaki, Tohru,Ohnishi, Kenji,Shimada, Kazuaki
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p. 2105 - 2108
(2007/10/02)
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- Synthesis of organic diselenide using zinc powder
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A new synthetic method of diselenide by reducing element selenium with zinc powder in basic environment, and then reacting with electrophiles is described. Nine diselenides are synthesized with yields between 52-90%.
- Ping,Xunjun
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p. 1721 - 1725
(2007/10/02)
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- ELECTROCHEMICAL SYNTHESIS OF SELENO AND TELLURO DERIVATIVES IN MeCN
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Large-scale electrolysis with concurrent sonication in MeCN allows for the synthesis of a large variety of seleno and telluro derivatives.Aliphatic chalcogenides REER or RER (E = Se, Te) can be prepared by reduction of E powder to E2(2-) or E(2-), followed by addition of an alkyl halide RX.Depending upon R, substitution can compete with homogeneous electron or H+ transfers.RE+ can be prepared by anodic oxidation of REER, and trapped by nucleophiles and olefins.The synthesis of aromatic chalcogenides ArEAr'can be carried out by electrochemically inducedSRN1 substitution.The yields are improved by redox catalysis.Under such conditions, the synthesis of PhEAr (Ar = NCC6H4, PhCOC6H4) proceeds in good yields.ArEEAr and ArEAr can be prepared by cathodic reduction of PhEAr.
- Degrand, Chantal,Prest, Rita,Nour, Mohamed
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p. 201 - 210
(2007/10/02)
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