- Aryl Radical-Mediated Alkenylation of Alkyl Halides
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The free-radical alkenylation of a range of alkyl iodides with a vinyldisulfones has been carried out, leading to the desired vinylsulfones in moderate to good yields under mild conditions. The process is initiated by an aryl radical which abstracts the iodine atom from the alkyl iodide to form a C-centered radical intermediate, the addition of which onto the vinyldisulfone providing the final vinylsulfone. The aryl radical is generated in situ through a single-electron transfer from an electron donor-acceptor complex (EDA) formed between a diaryliodonium salt (Ph2I+ PF6?) and triethylamine.
- Chaambi, Ahmed,Kurtay, Gülbin,Abderrahim, Raoudha,Robert, Frédéric,Landais, Yannick
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- Electrochemical radical reactions of alkyl iodides: a highly efficient, clean, green alternative to tin reagents
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An electrochemical ‘redox-relay’ system has been developed which allows the generation of C-centered radicals. Intermolecular ‘tin-like’ radical reactions can subsequently be conducted under the most benign of conditions. The yields and efficiency of the processes are competitive and even superior in most cases to comparable conditions with tributyltin hydride. The use of air and electricity as the promotor (instead of a tin or other reagent) combined with the aqueous reaction media make this a clean and ‘green’ alternative to these classic C-C bond forming processes.
- Li, Diyuan,Ma, Tsz-Kan,Scott, Reuben J.,Wilden, Jonathan D.
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p. 5333 - 5338
(2020/06/04)
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- Alkyl radical precursor and application thereof in establishing C-C bond
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The invention provides a precursor for generating an alkyl radical based on the visible light induction and a novel method for generating the radical. The alkyl sulfenamide is used as the radical precursor to generate the alkyl radical by virtue of the C-S bond cracking accelerated by the visible light, and then the alkyl radical is applied to the chemical reaction for establishing a C-C bond. Thereaction system has the characteristic of high efficiency, and has important scientific significance and application value for researching the novel C-C bond formation reaction, organic synthesis, drug synthesis and the like. In general, the invention provides a novel general method having practical application value. The thioalcohol (thioether) with rich resources is converted to a tool for derivating the alkyl radical.
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Paragraph 0145; 0146; 0148
(2018/09/14)
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- A Desulfurative Strategy for the Generation of Alkyl Radicals Enabled by Visible-Light Photoredox Catalysis
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Herein, we present a new desulfurative method for generating primary, secondary, and tertiary alkyl radicals through visible-light photoredox catalysis. A process that involves the generation of N-centered radicals from sulfinamide intermediates, followed by subsequent fragmentation, is critical to forming the corresponding alkyl radical species. This strategy has been successfully applied to conjugate addition reactions that features mild reaction conditions, broad substrate scope (>60 examples), and good functional-group tolerance.
- Xue, Fei,Wang, Falu,Liu, Jiazhen,Di, Jiamei,Liao, Qi,Lu, Huifang,Zhu, Min,He, Liping,He, Huan,Zhang, Dan,Song, Hao,Liu, Xiao-Yu,Qin, Yong
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supporting information
p. 6667 - 6671
(2018/06/11)
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- Schiff base complex of Mo supported on iron oxide magnetic nanoparticles (Fe3O4) as recoverable nanocatalyst for the selective oxidation of sulfides
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In this work, a new tridentate Schiff base dioxo-molybdenum(VI) complex immobilized on silica-coated magnetic nanoparticles (MoO25CML–Fe3O4@SiO2) has been synthesized and characterized using different techniques such as FTIR, TGA, AAS, ICP–AES, XRD, VSM, EDX and SEM analyses. The catalytic activity of synthesized complex was examined in the oxidation of various sulfides in the presence of H2O2 as cheap, green and eco-friendly oxidant. This catalytic system provides high conversion and selectivity toward either sulfoxides or sulfones under different conditions. Also, the nanocatalyst could be easily separated and regenerated from reaction media by external magnet and could be reused for ten times without significant loss of the activity and selectivity.
- Aghajani, Milad,Monadi, Niaz
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p. 963 - 975
(2017/03/11)
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- Synthesis, crystal structure and spectroscopic studies of a cobalt(III) Schiff base complex and its use as a heterogeneous catalyst for the oxidation reaction under mild condition
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A new Schiff base oriented Co(III) complex, (CoL)Cl4H2O (L = Schiff base), has been synthesized by careful design of the Schiff base ligand thorough oxidation of Co(II) to Co(III) during the reaction process. The complex has been characterized by single-crystal X-ray structure analysis and various spectral analyses. Structure analysis reveals that this monomeric complex crystallizes in triclinic P-1 space group. Supramolecular hydrogen bonding interactions among the guest water molecules and counter anion chloride leads to the formation of 1D water-chloride chain. A polymer anchored heterogeneous cobalt complex has been synthesized, characterized by various physicochemical techniques and successfully used for the oxidation of alkenes and sulfides using H2O2 as oxygen source. The influence of the various reaction parameters has been studied. The heterogeneous cobalt complex can be reused seven times without any significant loss in its catalytic activity.
- Islam, S. Manirul,Roy, Anupam Singha,Dalapati, Sasanka,Saha, Rajat,Mondal, Paramita,Ghosh, Kajari,Chatterjee, Saptarshi,Sarkar, Keka,Guchhait, Nikhil,Mitra, Partho
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- Synthesis, catalytic oxidation and oxidative bromination reaction of a reusable polymer anchored oxovanadium(IV) complex
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Polymer anchored oxovanadium catalyst was synthesized and characterized. The solid catalyst was characterized by Fourier transform infrared spectroscopy (FT-IR), UV-vis diffuse reflectance spectroscopy (DRS), thermogravimetric analysis (TGA) and scanning electron microscope (SEM). Its catalytic activity was evaluated for the oxidation of various alkenes, sulfides and aromatic alcohols with 30% H2O2 under mild reaction conditions. This catalyst was also effective for the oxidative bromination reaction of organic substrates with 80-100% selectivity of mono substituted products with H2O2/KBr at room temperature. The above reactions require minimum amount of H2O2, short time period and most importantly all the above reactions occur in aqueous medium. The developed catalyst can be facilely recovered and reused six times without significant decrease in activity and selectivity. This result confirms that the polymer anchored complex was not leached during the reaction, suggesting the true heterogeneous nature of the catalyst.
- Islam, Sk. Manirul,Roy, Anupam Singha,Mondal, Paramita,Salam, Noor
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experimental part
p. 38 - 48
(2012/05/21)
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- Chemoselective sulfoxidation by H2O2 or HNO3 using a phosphate impregnated titania catalyst
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A variety of organosulfur compounds have been selectively oxidized to the corresponding sulfoxides by either H2O2 or HNO3 using a newly developed solid acid catalyst composed of 84.5% of TiO2 and 15.5% of [Ti4H11(PO4)9]·nH2O (n = 1-4). The chemoselective oxidation of sulfides in the presence of vulnerable groups such as -CN, -C{double bond, long}C-, -CHO, or -OH, as well as sulfoxidation of substrates like benzothiazole, glycosyl sulfide, and dibenzothiophenes is some of the important attribute of the protocol. Nitric acid, under the present experimental conditions, brings about relatively better selectivity than hydrogen peroxide.
- Bharadwaj, Saitanya K.,Sharma, Susanda N.,Hussain, Sahid,Chaudhuri, Mihir K.
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experimental part
p. 3767 - 3771
(2009/10/11)
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- Zn/CuI-mediated coupling of alkyl halides with vinyl sulfones, vinyl sulfonates, and vinyl sulfonamides
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A novel high-yielding Zn/CuI-mediated coupling method of alkyl halides with vinyl sulfones, vinyl sulfonates, and vinyl sulfonamides is described. This protocol is applicable for primary, secondary, and tertiary alkyl iodides and bromides. Alkyl chlorides
- Zhao, Matthew M.,Qu, Chuanxing,Lynch, Joseph E.
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p. 6944 - 6947
(2007/10/03)
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- Organic reactions in ionic liquids: A new method for the synthesis of alkyl aryl sulfones by alkylation of sodium arenesulfinates with unactivated alkyl chlorides
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A new method is reported for the synthesis of alkyl aryl sulfones by alkylation of sodium arenesulfinates with unactivated alkyl chlorides using ionic liquid based on 1-butyl-3-methylimidazolium tetrafluoroborate (BmimBF 4) mixed with water (2:1) as reaction media. The ionic liquid can be reused and the procedure gives the sulfones in moderate yields.
- Hu, Yi,Chen, Zhen-Chu,Le, Zhang-Gao,Zheng, Qin-Guo
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p. 4031 - 4035
(2007/10/03)
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- Integrated Chemical Process: One-Pot Double Elimination Method for Acetylenes
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A novel one-pot process for synthesis of acetylenes has been achieved in which the following series of steps are integrated: addition of an α-anion of sulfone to aldehyde; trapping of the resulting adduct to incorporate a leaving group, and double elimination of this intermediate. Consolidation of Peterson elimination renders the process much simpler. This method provides a convenient and high-yielding access to a variety of enynes and polyynes as well as to functionally substituted aryl acetylenes containing halogen(s) or acetal groups, which are useful building blocks for aryl acetylene scaffolds. Iteration of the one-pot generation of acetylenic bonds provides a new metodology for the buildup of aryl acetylene skeletons.
- Orita, Akihiro,Yoshioka, Naonori,Struwe, Petra,Braier, Arnold,Beckmann, Anke,Otera, Junzo
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p. 1355 - 1363
(2007/10/03)
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- Reductive alkylation of electronegatively-substituted alkenes by alkylmercury halides
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Photolysis of alkylmercury halides in the presence of electronegatively-substituted 1-alkenes yields adduct radicals [RCH2CH(EWG).] that in some cases react with RHgX to form RCH2CH(HgX)(EWG), e.g., EWG = (EtO)2PO or PhSO2. When the EWG is carbonyl or cyano, the resonance stabilized adduct radicals fail to react with the alkyl mercury halide. In these cases photolysis with RHgCl/KI in Me2SO leads to the adduct mercurial via reaction of the adduct radicals with RHgI2-. The reactions of tertiary-enolyl adduct radicals are inefficient with RHgX/KI, and disproportionation of the adduct radicals is the major reaction pathway. For secondary- or tertiary-adduct radicals the reductive alkylation products are formed in excellent yield by reaction with RHgCl and silyl hydrides in Me2SO solution in a process postulated to involve RHgH as an intermediate. The relative reactivities of a number of α,β-unsaturated systems toward t-Bu. have been measured by competitive techniques. The results demonstrate a high reactivity of s-cis enones relative to the s-trans conformers.
- Russell, Glen A.,Shi, Bing Zhi,Jiang, Wan,Hu, Shuiesheng,Kim, Byeong H.,Baik, Woonphil
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p. 3952 - 3962
(2007/10/02)
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- Reaction of 4′-nitrobenzenesulfenanilide (NBSA) with Lewis acids. A study of its application in sulfenocyclization of alkenes and alkynes
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Phenylsulfenocyclization of a number of alkenes and alkynes possessing internal hydroxyl, carboxyl or vinyl functionality has been investigated with NBSA. Thioetherification of 4-penten-1-ol 4 as well as thiolactonization of 4-penten-1-oic acid 7 and, to a modest extent, 4-pentyn-1-oic acid 8 can be successfully achieved with NBSA in the presence of boron trifluoride. On the other hand, under analogous conditions 3-buten-1-ol 3 and 3-buten-1-oic acid 6 fail to undergo thiocyclization and give instead oxa- and/or aza-sulfenylation 1,2-adducts. Similar failure is observed with 4-pentyn-1-ol 5, in which case diphenyl disulfide and 4-nitroaniline are the exclusive products. Hexa-1,5-diene 9, to some extent, affords a cyclized arylaminosulfide, i.e. 23, ascribable to formal loss of a methylene unit from the initial (phenylthiomethyl)- cyclopentyl cation 24. The reaction products are discussed in terms of intermediate thiiranium and thiirenium ions whose decomposition mode is strictly dependent upon their structural features. Novel evidence is also presented that aluminium chloride and bromide can promote reaction of NBSA with alkenes and alkynes to afford chloro- and bromo-sulfenylation adducts in varying yields.
- Benati, Luisa,Capella, Laura,Montevecchi, Pier Carlo,Spagnolo, Piero
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p. 12395 - 12406
(2007/10/02)
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- Homolytic Reactions of Ligated Boranes. Part 9. Overall Addition of Alkanes to Electron-deficient Alkenes by a Radical Chain Mechanism
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Methyl bromoacetate and ethyl 2-bromopropanoate are reduced by Bun3P->BH3 or Bun3P->BH2Ph to methyl acetate and ethyl propanoate, respectively, in chlorobenzene at 80-110 deg C in the presence of dibenzoyl peroxide or t-butyl perbenzoate.Amine complexes of borane or phenylborane are much less effective reducing agents.The reductions may also be initiated photochemically and are inhibited by a phenolic radical scavenger.A homolytic chain mechanism is proposed in which the phosphine-boryl radical abstracts halogen from the bromo ester and is subsequently regenerated by reaction of an α-(alkoxycarbonyl)alkyl radical with the phosphine-borane.The latter propagation step, together with halogen abstraction from RI and addition of the derived alkyl radical to the C=C bond, is also involved in the chain reaction between Bun3P->BH2Ph, an alkyl iodide, and ethyl acrylate according to equation (A); Bun3P->BH3 reacts similarly but gives lower yields of ester.Reaction (A) proceeds smoothly at 110 deg C Bun3P->BH2Ph + RI + CH2=CHCO2Et -> RCH2CH2CO2Et + Bun3P->BHIPh (A) when initiated by t-butyl perbenzoate and moderate yields of isolated esters were obtained from n-butyl iodide, cyclohexyl iodide, and 3β-iodocholest-5-ene.This last iodide gives an epimeric mixture of 3α- and 3β-esters in total isolated yield of ca. 50 percent.Similar addition reactions take place between Bun3P->BH2Ph, BunI, and diethyl vinylphosphonate or phenyl vinyl sulphone.It is concluded that Bun3P->BH3 and particularly Bun3P->BH2Ph offer promise as alternatives to tin, mercury, and germanium hydrides in radical chain reactions of synthetic value.
- Baban, Jehan A.,Roberts, Brian P.
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p. 1195 - 1200
(2007/10/02)
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- Determination of Sulfur in Asphalts by Selective Oxidation and Photoelectron Spectroscopy for Chemical Analysis
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The characterization of sulfur in asphalts is investigated by coupling selective reactions and photoelectron spectroscopy for chemical analysis.The specificity of the two following reactions has been studied on test compounds: oxidation of sulfides with tert-butyl hydroperoxide in chloroform (a); reduction by lithium aluminum hydride of sulfones in tetrahydrofuran (b).These reactions have been used with an asphalt, directly for (a) or after a preoxidation with m-chloroperbenzoic acid for (b) to determine, using photoelectron spectroscopy, which kind of sulfur was invol ved.An analytical scheme sums up the different results: cyclic sulfides = 67percent, thiophenic sulfides = 54percent, cyclanic sulfide = 13percent, alkyl and aryl alkyl sulfides = 33percent.
- Ruiz, Jean-Michel,Carden, Brian M.,Lena, Louis J.Vincent, Emile-Jean,Escalier, Jean-Claude
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p. 688 - 691
(2007/10/02)
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- A Two-stage Conversion of Primary-alkyl Primary-amines into Alcohols and Further Examples of Transfunctionalisation of Amines under Mild Conditions
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Phase-transfer catalysts allow the conversion of primary-alkyl primary-amines into primary alcohols, sulphones, sulphides, and ethers at = 100 deg C via the pentacyclic pyridiniums (9).
- Katritzky, Alan R.,Saba, Antonio,Patel, Ranjan C.
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p. 1492 - 1494
(2007/10/02)
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- New Routes to cis-Jasmone and Dihydrojasmone via 1,4-Diketones Exploiting the Mobile Activating Sulfonyl Group
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cis-Jasmone(1a) and dihydrojasmone(1b) are synthesized starting from cis-3-hexen-1-yl phenyl sulfone (6a) and n-hexyl phenyl sulfone (6b), respectively, through 1,4-diketones 3a,b.The key intermediates in these syntheses are the diketo sulfones 7a,b, which are prepared by two methods.The reaction of dilithiosulfones 12a,b with γ-valerolactone in tetrahydrofuran in the presence of hexamethylphosphoramide at -78 deg C gives the hydroxy keto sulfones 13a,b in satisfactory yields and the successive oxidation of these compounds with Jones reagent in acetone affords 7a,b in very good yields.On the other hand, the reaction of 12a,b with ethyl levulinate ethylene ketal gives the partially protected diketo sulfones 17a,b, from which 7a,b are obtained by removal of the protecting group.Cleavage of the carbon-sulfur bond in 7a,b, accomplished by aluminum amalgam in aqueous tetrahydrofuran, affords 3a,b which are then cyclized to 1a,b by heating over basic alumina in benzene.
- Mussatto, Maria Cristina,Savoia, Diego,Trombini, Claudio,Umani-Ronchi, Achille
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p. 4002 - 4005
(2007/10/02)
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