- 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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- 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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- POLYFLUOROALKYLATION OF BROMOAROMATIC COMPOUNDS VIA PERFLUOROALKYLCOPPER INTERMEDIATES
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Cross coupling reactions between various perfluoroalkyl iodides, copper and mono and dibromobenzenes, as well as mono and dibromobenzenes containing functional groups e.g., OH, CO2H, CO2R, NO2, NH2, OCH3 and C(O)CH3 have produced perfluoroalkyl substituted aromatic compounds in good to excellent yields.From certain bromo arenes, by-products were obtained, indicating competing reactions.These reactions may be due to the slower rate of cross coupling between a carbon-bromine bond and the perfluoroalkylcopper intermediate as compared to the cross coupling reaction involving a carbon-iodine bond with the perfluoroalkylcopper intermediate.
- Chen, Grace J.,Tamborski, Christ
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- Nickel-Catalyzed Reversible Functional Group Metathesis between Aryl Nitriles and Aryl Thioethers
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We describe a new functional group metathesis between aryl nitriles and aryl thioethers. The catalytic system nickel/dcype is essential to achieve this fully reversible transformation in good to excellent yields. Furthermore, the cyanide- and thiol-free reaction shows high functional group tolerance and great efficiency for the late-stage derivatization of commercial molecules. Finally, synthetic applications demonstrate its versatility and utility in multistep synthesis.
- Delcaillau, Tristan,Boehm, Philip,Morandi, Bill
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supporting information
p. 3723 - 3728
(2021/04/07)
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- Organocatalytic visible light mediated synthesis of aryl sulfides
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Photo-sensitized synthesis of arylsulfides from arenediazonium salts in the presence of eosin Y has been developed. This protocol exhibits high functional group tolerance and a wide substrate scope and is an attractive alternative to the thermal reaction that involves explosive intermediates.
- Majek, Michal,Von Wangelin, Axel Jacobi
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supporting information
p. 5507 - 5509
(2013/06/27)
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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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- 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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- Photochemical Conversion of Sulfonium Salts via a 1,3-Sigmatropic Rearrangement. Photogeneration of Broensted Acids
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A series of 1-naphthyl methyl-substituted alkylsulfonium salts underwent 1,3-sigmatropic rearrangements to form 1-(methylthio)-2-substituted alkylnaphthalenes and the corresponding acid with quantum yields between 0.24 and 0.10.In competition with rearrangement was a bond-cleavage reaction forming 1-naphthyl methyl sulfide.The quantum yield for bond cleavage was ca. 0.15 for all the compounds studied.
- Saeva, Franklin D.,Morgan, Bradley P.,Luss, Henry R.
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p. 4360 - 4362
(2007/10/02)
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