- Combined Experimental and Theoretical Studies on the Radical Nucleophile Addition Reaction for Sulfide- and Selenide-Centered Anions
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The reactivity of sulfur- and selenium-centered nucleophiles toward 1-naphthyl radicals was studied in dimethylsulfoxide. The photostimulated reaction of sulfide anions, -SC(NH)C6H5 (1), -SC(NH)NH2 (2), and -SC(NH)CH3 (3), renders, after the addition of MeI, methyl 1-naphthylsulfide as a main product together with bis(1-naphthyl) sulfide and naphthalene under irradiation. Concordantly, the reaction of selenide anions, -SeC(NH)C6H5 (4), -SeC(NH)NH2 (5), and -SeCN (6), produces methyl 1-naphthyl selenide, bis(1-naphthyl) selenide, and naphthalene in the presence of potassium tert-butoxide anion (entrainment conditions). Absolute rate constants for the coupling of ions 1-6 to 1-naphthyl radicals were determined; as a general trend, the selenide-centered nucleophiles enhance in 2 times the reactivity of their sulfide analogues. From the mechanistic study, it is proposed that the unstable radical anion produced by the addition of the nucleophile to 1-naphthyl radical affords, after fragmentation, 1-naphthylsulfide/selenide anion. In addition, experimental results are discussed in terms of density functional theory calculations. There is a generally good agreement between the experimental and the calculated reactivities, the spin density being the main parameter to describe the difference found among the anions under study. Moreover, the calculations predict that anion -SeC(NH)CH3 (7) would be a good candidate for the synthesis of selenide derivatives.
- Bouchet, Lydia M.,Pe?é?ory, Alicia B.,Pierini, Adriana B.,Argüello, Juan E.
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p. 5035 - 5042
(2019/06/17)
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- Nature of the chain propagation in the photostimulated reaction of 1-bromonaphthalene with sulfur-centered nucleophiles
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(Chemical Equation Presented) The reactivity of -SC(NH)NH 2 (1), MeCOS- (2), and PhCOS- (3) toward 1-naphthyl radicals was studied in DMSO. The photostimulated reaction of anions 1, 2, and 3 with 1-bromonaphthalene (4) after quenching with MeI renders 1-(methylthio)naphthalene (6) as a main product together with bis(1-naphthyl) sulfide (7) and naphthalene (5). The thioacetate ion (2) and thiobenzoate ion (3) were unreactive toward 4 as electron-donor under photostimulation; however, in the presence of potassium tert-butoxide anion (entrainment conditions), they gave the mentioned products 5, 6, and 7, after the addition of MeI. Quenching of the triplet state of 4 was assigned as the photoinduced initiation step, with a rate constant value of (4.6 ± 0.5) × 108 M-1 s-1 for tert-butoxide anion and a rough estimated value of (8 ± 7) × 107 M-1 s-1 for anion 1. By using hydrogen abstraction from DMSO as the competitive reaction, the absolute rate constants for the addition of anions 1, 2, and 3 to 1-naphthyl radicals have been determined to be 1.0 × 109, 1.2 × 10 9, and 3.5 × 109 M-1 s-1, respectively. This reactivity order is in agreement with the stability of the resulting radical anions (ArNu)?- (10-12)?-. The inhibition experiments of the photoinduced substitution reaction in the presence of radical scavengers and the global quantum yield higher than the unity are evidence of a radical chain mechanism for these substitution reactions by anions 1 and 2. Anion 3 adds to the 1-naphthyl radical, but is neither able to initiate nor to keep the propagation cycle. Evaluation of the electron-transfer driving forces for the reaction between (ArNu) ?- and 4 together with the absence of a chain reaction for the anion 3 indicate that the propagation in the proposed mechanism is given by an acid-base reaction between the radical .C(O)Me or .C(NH)NH2 (13) and a base.
- Schmidt, Luciana C.,Argueello, Juan E.,Penenory, Alicia B.
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p. 2936 - 2944
(2008/02/01)
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- Photoinduced nucleophilic substitution of aryl halides with potassium thioacetate - A one-pot approach to aryl methyl and diaryl sulfides
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Aryl methyl sulfides and diaryl sulfides were prepared by photoinduced reactions of potassium thioacetate with aryl halides under entrainment conditions. Without isolation, the arene thiolates obtained by the aromatic substitution were quenched with methyl iodide to afford the aryl methyl sulfides in 26-59% yields in a "one-pot" procedure together with the diaryl sulfides in variable yields (3-31 %). By optimization of the reaction conditions it was possible to improve the formation of the Ar2S, going from moderate to good yields (64-83%). Wiley-VCH Verlag GmbH & Co. KGaA, 2006.
- Schmidt, Luciana C.,Rey, Valentina,Penenory, Alicia B.
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p. 2210 - 2214
(2007/10/03)
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- Highly efficient and functional-group-tolerant catalysts for the palladium-catalyzed coupling of aryl chlorides with thiols
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The cross-coupling reaction of aryl chlorides with aliphatic and aromatic thiols catalyzed by palladium complexes of the strongly binding bisphosphine CyPF-tBu ligand (1) is reported. Most of the reactions catalyzed by complexes of ligand 1 occur with turnover numbers that exceed those of previous catalysts by two orders of magnitude. The reactions occur with excellent yields, broad scope and high tolerance of functional groups. Coupling of aryl halides with thiols in the presence of low loadings of catalysts derived from other Josiphos type ligands, as well as ligands of other structural types, are also described.
- Fernandez-Rodriguez, Manuel A.,Shen, Qilong,Hartwig, John F.
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p. 7782 - 7796
(2007/10/03)
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- One-Pot Two-Step Synthesis of Aryl Sulfur Compounds by Photoinduced Reactions of Thiourea Anion with Aryl Halides
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(Equation presented) The photoinduced reactions of aryl halides with the thiourea anion afford arene thiolate ions in DMSO. These species without isolation, and by a subsequent aliphatic nucleophilic substitution, S RN1 reaction, oxidation, or protonation, yield aryl methyl sulfides, diaryl sulfides, diaryl disulfides, and aryl thiols with good yields (50-80%). This is a simple and convenient approach which involves the use of the commercially available and inexpensive thiourea in a one-pot two-step process for the synthesis of aromatic sulfur compounds.
- Argueello, Juan E.,Schmidt, Luciana C.,Penenory, Alicia B.
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p. 4133 - 4136
(2007/10/03)
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- HIGH-TEMPERATURE ORGANIC SYNTHESIS. XLI. REACTIONS OF AROMATIC HALOGEN COMPOUNDS WITH HYDROGEN SULFIDE IN THE PRESENCE OF SULFUR
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The reactions of halogenoarenes containing a sufficiently mobile halogen atom with hydrogen sulfide in the presence of elemental sulfur at 90-230 deg C lead to the corresponding sulfides (with yields of up to 87percent).The disulfides, thiols, and arenes are formed at the same time.In the reactions of bromophenols with hydrogen sulfide in the presence of sulfur migration of the halogen atom is observed, and this leads to the formation of isomeric bis(hydroxyphenyl) sulfides and disulfides and 2,4-dibromophenol.It was established that the yield of the reaction products depends on the time, temperature, halogenophenol-sulfur ratio, and delivery rate of hydrogen sulfide.The radical mechanism of the formation of these substances is discussed.
- Papernaya, L. K.,Panova, G. M.,Deryagina, E. N.,Voronkov, M. G.
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p. 1856 - 1862
(2007/10/02)
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- REACTIONS SRN1: PARTIE no 18. ACTION DE SULFANIONS DERIVES DE HS(CH2)nSH VIS-A-VIS DES HALO-1 ET -2 NAPHTALENES
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A double SRN1 reaction was shown to occur between HS(CH2)nSH and 1 or 2 halonaphtalene to give the corresponding double sulfides Napht1(2)-S-(CH2)n-S-Napht1(2) (n=2,3,4)
- Beugelmans, Rene,Ginsburg, Helene
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p. 413 - 414
(2007/10/02)
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- NEW SYNTHESIS OF 1,2,5-SELENADIAZOLES
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A new synthesis of 1,2,5-selenadiazoles which starts from unsubstituted or monosubstituted 1,2,5-thiadiazoles and Grignard reagents is described and the mechanism of the reaction discussed.
- Bertini, Vincenzo,Munno, Angela De,Picci, Nevio,Lucchesini, Francesco,Pocci, Marco
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p. 2153 - 2158
(2007/10/02)
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- HIGH-TEMPERATURE ORGANIC SYNTHESIS. XXVIII. LIQUID-PHASE REACTIONS OF THIOLS WITH AROMATIC BROMINE COMPOUNDS
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In the liquid phase at 125-215 deg C thiophenol only reacts effectively with 2- and 4-bromophenol, 1-bromo-2-napthol, 1-bromonapthalene, and 9-bromoanthracene, forming the corresponding phenyl aryl sulfides. 2-Thiophenethiol and 1-thionapthol reduce the same bromine derivatives to the corresponding arenes.The disulfides formed here undergo secondary transformations.The reactions of thiophenol with 2- and 4-bromophenol and 1-bromo-2-napthol are convenient preparative methods for the synthesis of the previously difficulty obtainable phenyl hydroxyaryl sulfides.
- Papernaya, L. K.,Panova, G. M.,Deryagina, E. N.,Voronkov, M. G.
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p. 1774 - 1777
(2007/10/02)
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- HIGH-TEMPERATURE ORGANIC SYNTHESIS. XVII. REACTION OF CHLOROBENZENE AND ITS DERIVATIVES WITH DIALKYL DISULFIDES
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The products from the reaction of chlorobenzene with dialkyl disulfides in the gas phase at 550-650 deg C are benzene, thiophenol, diphenyl sulfide, and also toluene, thiophene, and benzothiophene.Diethyl disulfide is most reactive.Its copyrolysis with chlorobenzene is distinguished by high selectivity for the formation of thiophenol, the yield of which amounts to 60percent.In the reaction of substituted chlorobenzenes and also 2-chlorothiophene and 1-chloronaphthalene with diethyl disulfide the corresponding thiols were obtained with high yields.Two paths for the formation of thiophene during the pyrolysis of dialkyl disulfide were established, i.e., from vinyl hydrosulfide and S-butyl radical.The last reaction is realized at a high rate.
- Voronkov, M. G.,Deryagina, E. N.,Sukhomazova, E. N.
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p. 1516 - 1522
(2007/10/02)
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