- Palladium on carbon-catalyzed Α-alkylation of ketones with alcohols as electrophiles: Scope and mechanism
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The α-alkylation of ketones with alcohols represents a green strategy for the formation of crucial carbon–carbon bonds since it only produces water as byproduct. In terms of reaction mechanism, the evidence for homogeneous catalysis supports a catalytic hydrogen-borrowing pathway; however, the reaction mechanism has not been investigated for heterogeneous Pd/C catalysts. Here, we report an improved method for α-alkylation of ketones with alcohols using commercially available Pd/C, ubiquitous in organic synthesis labs, as catalyst. The reaction conditions are mild compared to state-of-the-art for both homo- and heterogeneous catalysts, and the developed conditions produces quantitative yields for most ketones and alcohols. A hot filtration experiment and recycling of the catalyst supports the heterogeneous nature of catalysis. Importantly, the reaction mechanism is studied for the first time by a combination of stoichiometric experiments and kinetic analyses by in-situ IR (React-IR).
- Bennedsen, Niklas R.,Mortensen, Rasmus L.,Kramer, S?ren,Kegn?s, S?ren
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- A simple synthesis of ketone from carboxylic acid using tosyl chloride as an activator
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An effective process for the conversion of carboxylic acid to ketone has been discovered. In this process, carboxylic acid has been activated using p-toluene sulphonyl group. Under the optimized condition, aromatic, aliphatic heteroaromatic carboxylic acids have been proved to be good substrates for this methodology. The byproduct of this reaction can be removed very easily during work up process. Also, one equivalent of organometallic reagent is sufficient to complete this transformation.
- Jana, Samaresh,Sahoo, Debasis,Sarkar, Sohini
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- Reaction of Lithium Dialkylcuprates with S-2-Pyridiyl Thioates in the Presence of Oxygen. A Carboxylic Ester Synthesis
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Reaction of lithium dialkylcuprates with S-2-pyridyl thioates in the presence of oxygen affords carboxylic esters in high yields, whereas under nitrogen it affords ketones.
- Kim, Sunggak,Lee, Jae In,Chung, Bong Young
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- Ready Coupling of Acid Chlorides with Tetra-alkyl-lead Derivatives Catalysed by Palladium
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Palladium-catalysed coupling of acid chlorides with tetra-alkyl-lead derivatives gives the corresponding ketones in high yields under mild conditions.
- Yamada, Jun-ichi,Yamamoto, Yoshinori
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- A FACILE PREPARATION OF TELLUROL ESTERS FROM PHENYLTELLUROTRIMETHYLSIANE AND ACYL CHLORIDES
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Phenyltellurotrimethylsilane cleanly reacted with acyl chloride, giving tellurol ester in an excellent yield.The high rectivity of tellurol ester toward lithium organocuprate was demonstrated.
- Sasaki, Kazuaki,Aso, Yoshio,Otsubo, Tetsuo,Ogura, Fumio
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- Palladium-Catalyzed Cross-Coupling Reactions of Carboxylic Anhydrides with Organozinc Reagents
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(Matrix presented) Negishi-type cross-coupling reaction was effected by employing organozincs and anhydrides or mixed anhydrides that formed in situ from sodium salts of the corresponding acids and ethyl chloroformate under the catalysis of palladium(0). A general method for preparing symmetrical/ unsymmetrical ketones was developed.
- Wang, Donghui,Zhang, Zhaoguo
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- A Palladium Bipyridyl Complex Grafted onto Nanosized MCM-41 as a Heterogeneous Catalyst for Negishi Coupling
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The Negishi coupling of aryl bromides or acyl chlorides with organozinc chlorides catalyzed by a palladium bipyridyl complex anchored on nanosized mobile crystalline material 41 (MCM-41) were investigated. The reactions proceeded smoothly with a very low catalyst loading in THF at 70°C for electron-deficient aryl bromides, which gave good to high yields of the Negishi coupling products. However, reactions in toluene at 110°C were required if electron-rich aryl bromides were employed. For acyl chlorides, the reactions could be performed in THF at 50°C and the corresponding ketones and ynones were obtained in high yields. After centrifugation, it was possible to easily recover the supported catalyst from the reaction mixture, and this could be reused several times without any retreatment or regeneration with only a slight decrease in activity.
- Wu, Wei-Yi,Lin, Tze-Chiao,Takahashi, Tamotsu,Tsai, Fu-Yu,Mou, Chung-Yuan
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- ANWENDUNG NICHTSTABILISIERTER EISEN(II)-ALKYLE ALS HOCHSELEKTIVE NUCLEOPHILE ALKYLIERUNGSREAGENZIEN
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Nonstabilized Fe(II) alkyls (RFeCl, R2Fe, R3FeM, R4FeM2; R=Me, n-Bu, M=Li, MgBr) are readily accessible in solution (THF, Et2O, CH2Cl2) by reaction of MeLi, MeMgBr, n-BuLi or n-BuMgBr, respectively, with FeCl2 at -78 to -50 deg C.The needed FeCl2 can be made by in-situ-reduction with RLi or RMgBr.For checking the transmetallation process the "β-bromostyrene-ketone-test" is especially favorable in case of the methyl derivatives.The prepared Fe compounds are alkylating reagents of high selectivity.
- Kauffmann, Thomas,Laarmann, Barbara,Menges, Detlef,Voss, Karl-Uwe,Wingbermuehle, Dorothea
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- Nickel N-heterocyclic carbene-catalyzed cross-coupling reaction of aryl aldehydes with organozinc reagents to produce aryl ketones
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The transformation of aromatic aldehydes into aryl ketones by nickel-catalyzed cross-coupling has been developed. This transformation represents an efficient and attractive synthetic utilization of organozinc reagents. The reaction provides a mild, practical method toward the synthesis of aryl ketones which are versatile intermediates and building blocks in organic synthesis.
- Jin, Cheng,Gu, Lijun,Yuan, Minglong
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- Polystyrene resins containing 1,3-propanedithiol functions for solid-phase organic syntheses
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A completely odourless reliable synthesis of styrenic resins containing 1,3-propanedithiol functions able to form 1,3-dithiane derivatives with carbonyl compounds and back up the chemistry of thioacetals and thioketals is reported. The degree of functionalisation of the resin can be easily determined through the composition of the copolymerising mixture and confirmed by titration. The resins show good accessibility to various reagents and are effective for solid-phase synthesis being exploitable in the field of combinatorial chemistry.
- Bertini, Vincenzo,Pocci, Marco,Lucchesini, Francesco,Alfei, Silvana,De Munno, Angela
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- Alcohols for the α-alkylation of methyl ketones and indirect aza-wittig reaction promoted by nickel nanoparticles
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Nickel nanoparticles have been found to activate primary alcohols used for the α-alkylation of ketones or in indirect aza-Wittig reactions. These processes involve hydrogen transfer from the alcohol to the intermediate α,β-unsaturated ketone or imine, respectively. All these reactions are carried out in the absence of any ligand, hydrogen acceptor or base under mild reaction conditions. For the first time nickel is employed as a potential alternative to noble-metal-based catalysts in both reactions. A reaction mechanism is proposed on the basis of some deuteration experiments. Wiley-VCH Verlag GmbH & Co. KGaA, 2008.
- Alonso, Francisco,Riente, Paola,Yus, Miguel
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- Regioselective ring-opening of cyclopropyl ketones with organometallic reagents
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Regioselective ring-opening reaction of cyclopropyl ketones was conducted successfully, in which the reaction of cyclopropyl phenyl ketone with trimethylaluminum catalyzed by nickel acetyl-acetonate gave the ring-opening product in up to 76% yield.
- Ichiyanagi, Tsuyoshi,Kuniyama, Satoru,Shimizu, Makoto,Fujisawa, Tamotsu
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- Chemiluminescence of Imino-1,2-dioxetan Formed from Ketenimine and Singlet Oxygen
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The chemiluminescent properties of several imino-1,2-dioxetans prepared by the photosensitized oxygenation of ketenimines at -78 degC, indicate that the energy level of the transition state for their decomposition to the corresponding ketones and isocyanates is low and that the decomposition proceeds via a biradical mechanism.
- Ito, Yoshikatsu,Yokoya, Hiroaki,Kyono, Kazuaki,Yamamura, Soichiro,Yamada, Yutaka,Matsuura, Teruo
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- A Novel Ru(VII)/Ru(IV) Mediatory System for Electrooxidation of Primary and Secondary Alcohols, Leading to Aldehydes and Ketones
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A soluble Ru(VII)/Ru(IV) redox system in MeCN/H2O(9/1 v/v)-Bu4NOH-(Pt/Pt) was found to be a mild oxidizing method for the electrochemical conversion of primary and secondary alcohols into their corresponding aldehydes and ketones under basic conditions.
- Torii, Sigeru,Yoshida, Akihito
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- Suzuki-Miyaura coupling of simple ketones via activation of unstrained carbon-carbon bonds
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Here, we describe that simple ketones can be efficiently employed as electrophiles in Suzuki-Miyaura coupling reactions via catalytic activation of unstrained C-C bonds. A range of common ketones, such as cyclopentanones, acetophenones, acetone and 1-indanones, could be directly coupled with various arylboronates in high site-selectivity, which offers a distinct entry to more functionalized aromatic ketones. Preliminary mechanistic study suggests that the ketone α-C-C bond was cleaved via oxidative addition.
- Xia, Ying,Wang, Jianchun,Dong, Guangbin
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- A New Oxidizing Reagent: Triethylsilyl Hydrotrioxide
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Triethylsilyl hydrotrioxide (Et3SiOOOH) is a new, short-lived oxidizing agent that can react at -78 deg C directly and rapidly with olefins to form 1,2-dioxetanes and oxidatively cleaved carbonyl products.
- Posner, Gary H.,Webb, Kevin S.,Nelson, William M.,Kishimoto, Takashi,Seliger, Howard H.
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- Nickel catalyzed cross-coupling of modified alkyl and alkenyl Grignard reagents with aryl- and heteroaryl nitriles: Activation of the C-CN bond
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The nickel catalyzed cross-coupling of alkyl and alkenyl Grignard reagents with aryl nitrile derivatives affords good yields of the corresponding aryl alkanes or aryl alkenes via activation of the C-CN bond. To prevent direct addition of the nucleophile to the nitrile group, the reactivity of the Grignard reagent was modulated by reaction with either LiOt-Bu or PhSLi prior to cross-coupling. The optimum catalyst was determined to be NiCl2(PMe3)2, which is a convenient air stable commercially available complex.
- Miller, Joseph A.,Dankwardt, John W.
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- Reactivities of mixed organozinc and mixed organocopper reagents. Part 13 Kinetic study for phosphine-catalyzed acylation of alkylarylzincs and effect of residual group on the transfer rate of alkyl group
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Kinetics of reactions of di-n-butylzinc, n-Bu2Zn, and mixed n-butyl(substituted phenyl)zinc reagents and n-Bu(functional group (FG)-C6H4)Zn with benzoyl chloride in the presence of tri-n-butylphosphine have been investigated. Reaction rates of transferable n-butyl group have been determined in tetrahydrofuran at 0 °C to compare the transfer rate of n-butyl group in homo and mixed diorganozincs. Rate law is consistent with a third-order reaction, which is first order in diorganozinc, benzoyl chloride, and n-Bu3P, and a mechanism was proposed. The lower reaction rate of n-BuPhZn than that of n-Bu2Zn and negative reaction constant in Hammett plot are in accordance with the carbanionic charge of transferable n-butyl group in the acylation reaction. These findings support the hypothesis that the reaction rate of transferable group, RT, changes depending upon the residual group, RR, in RRRTZn reagents.
- ?mür Pekel, ?zgen
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- Direct and efficient one-pot preparation of ketones from aldehydes using N-tert-butylphenylsulfinimidoyl chloride
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(Chemical Equation Presented) A general, one-pot process has been established to prepare ketones from aldehydes using N-tert- butylphenylsulfinimidoyl chloride. By employing the developed protocol, a range of unsymmetrical ketones has been prepared in good yields from aldehydes in one simple synthetic operation.
- Crawford, James J.,Henderson, Kenneth W.,Kerr, William J.
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- Nucleophilic properties of butyllithium versus free carboxylic acids
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In opposition to the generally accepted idea, butyl lithium is not only a deprotonating agent for free carboxylic acids, but can also act as a nucleophile on the carbon oxygen double bond.
- Einhorn,Einhorn,Luche
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- Reactivities of mixed organozinc and mixed organocopper reagents, 2. Selective n-alkyl transfer in tri-n-butylphosphine-catalyzed acylation of n-alkyl phenylzincs; an atom economic synthesis of n-alkyl aryl ketones
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Tri-n-butylphosphine-catalyzed acylation of mixed n-alkyl phenylzincs with aromatic acyl halides in THF is efficient in selective transfer of n-alkyl groups to produce n-alkyl aryl ketones in good yields. This route provides an atom economic organocatalyzed alternative to transition metal-catalyzed acylation of di-n-alkylzincs.
- Erdik, Ender,Pekel, ?zgen ?mür
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- H2-Generation from Alcohols by the MOF-Based Noble Metal-Free Photocatalyst Ni/CdS/TiO2@MIL-101
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The synthesis of important classes of chemical compounds from alcohols helps to conserve Earth's fossil carbon resources, since alcohols can be obtained from indigestible and abundantly available biomass. The utilisation of visible light for the activation of alcohols permits alcohol-based C-N and C-C bond formation under mild conditions inaccessible with thermally operating hydrogen liberation catalysts. Herein, we report on a noble metal-free photocatalyst able to split alcohols into hydrogen and carbonyl compounds under inert gas atmosphere without the requirement of electron donors, additives, or aqueous reaction media. The reusable photocatalyst mediates C-N multiple bond formation using the oxidation of alcohols and subsequent coupling with amines. The photocatalyst consists of a CdS/TiO2 heterojunction decorated with co-catalytic Ni nanoparticles and is prepared on size-optimised colloidal metal-organic framework (MOF) crystallites.
- Tilgner, Dominic,Klarner, Mara,Hammon, Sebastian,Friedrich, Martin,Verch, Andreas,De Jonge, Niels,Kümmel, Stephan,Kempe, Rhett
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- Oxidative rearrangement of internal alkynes to give one-carbon-shorter ketones via manganese porphyrins catalysis
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Oxidative rearrangement of internal alkynes catalyzed by manganese(III) porphyrin is described, which opens a new access to one-carbon-shorter ketones using molecular oxygen. Under the standard conditions, a variety of alkynes including diarylalkynes and arylalkylalkynes rearranged smoothly to the corresponding ketones in high yields. Based upon experimental observations, a plausible reaction mechanism is proposed.
- Sheng, Wen-Bing,Jiang, Qing,Luo, Wei-Ping,Guo, Can-Cheng
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- Synthesis of Functionalized Ketones from Acid Chlorides and Organolithiums by Extremely Fast Micromixing
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Synthesis of ketones containing various functional groups from acid chlorides bearing electrophilic functional groups and functionalized organolithiums was achieved using a flow microreactor system. Extremely fast mixing is important for high chemoselectivity.
- Nagaki, Aiichiro,Sasatsuki, Kengo,Ishiuchi, Satoshi,Miuchi, Nobuyuki,Takumi, Masahiro,Yoshida, Jun-ichi
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- IRON CATALYZED CROSS-COUPLING REACTIONS OF ACYL CHLORIDES WITH GRIGNARD REAGENTS. A MILD, GENERAL, AND CONVENIENT SYNTHESIS OF ALIPHATIC AND AROMATIC KETONES.
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Acyl chlorides couple with Grignard reagents at room temperature in the presence of catalytic amounts of tris(acetylacetonate)iron(III), Fe(acac)3.The reaction is general with respect to both reactants and provides a very mild and convenient method for the synthesis of aliphatic and aromatic ketones.
- Fiandanese, V.,Marchese, G.,Martina, V.,Ronzini, L.
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- Reactivities of mixed organozinc and mixed organocopper reagents: 1 - Solvent controlled organic group transfer from mixed diorganozincs
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The selectivity of organyl group transfer in the copper catalyzed benzoylation of n-butyl phenylzinc in THF depends on N-, O- or P-donor cosolvents and additives as well as copper salts and Lewis acids. In THF:NMP (3:1) and in THF:diglyme (2:1), n-butyl group/ phenyl group transfer ratio is 9:1 whereas only n-butyl group transfer is observed in THF:n-Bu3P (1 equiv.) and only phenyl group transfer is observed in THF:TMEDA (2:1).
- Erdik, Ender,Pekel, ?zgen ?mür
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- Carbon-carbon bond formation via oxidative-addition processes of titanium(II) reagents with π-bonded organic substrates. Reactivity modifications by Lewis acids and Lewis bases Part 22. Organic chemistry of subvalent transition metal complexes
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A series of titanium(II) derivatives, TiE2, was prepared by alkylative reduction of TiE4 by two equivalents of n-butyllithium in THF at -78 to 25°C (E = Cl, F, OBun, OPri and 0.5 NPh-CH2-CH2-NPh). The LiE by-product could usually be removed by THF evaporation and dissolution of the TiE2 into toluene. All such TiE2 derivatives were shown to effect the epimetallation and oligomerization of olefins, acetylenes and carbonyl derivatives in varying degrees. Particularly pertinent were the isolation and chemical reactions of titanium(II) isoproxide, the postulated intermediate in the Kulinkovich synthesis of cyclopropanols from ethyl Grignard reagents and organic esters, as well as an intermediate in many allied reactions developed by the Sato group. The findings of the present study corroborate completely the foregoing hypothesis that titanium(II) isopropoxide is the key intermediate in such novel reactions in organic synthesis. Furthermore, Ti(OPrl)2 can be prepared readily in a relatively pure state and has been found to react with 1-alkenes, alkynes and ketones by epimetallation at 25°C to form three-membered titanacycles, which can be utilized in organic synthesis. Finally, the ease with which such TiE2 derivatives epimetallate unsaturated organic substrates has been shown to be decreased by the steric demands of E and by the coordination of Lewis bases or donor solvent to the titanium(II) center. Lewis acids, on the other hand, greatly increase the rate of epimetallation by TiE2. A dramatic illustration of this effect is in the action of TiCl2·Me2AlCl on unsaturated hydrocarbons, wherein the polymerization of ethylene and of 1-alkene and the cyclotrimerization of alkynes are found to occur at room temperature.
- Eisch, John J.,Gitua, John N.,Otieno, Peter O.,Shi, Xian
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- Catalytic and chemoselective oxidation of activated alcohols and direct conversion of diols to lactones with in situ-generated bis-IBX catalyst
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The twisted 3,3′-diiodo-2,2′,6,6′-tetramethoxybiphenyl-4, 4′-dicarboxylic acid (DIDA) was designed and synthesized for the in situ generation of Bis-IBX and catalytic oxidations. The seemingly better solubility of the in situ-generated Bis-IBX and the attenuated reactivity arising from its unique structural features and methoxy substituents allowed the catalytic oxidation of activated alcohols selectively using DIDA/oxone. Chemoselective oxidations were demonstrated for substrates containing two different hydroxy groups. Furthermore, the unique reactivity of DIDA was demonstrated for sequential oxidation reactions of 1,4- and 1,6-diols to give lactones catalytically in respectable yields.
- Seth, Saona,Jhulki, Samik,Moorthy, Jarugu Narasimha
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- Preparation of ketones via the palladium-catalyzed cross-coupling of acid chlorides with trialkylboranes
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Trialkylboranes react with acid chlorides in the presence of palladium to generate alkyl and aryl ketones in good yields. (C) 2000 Elsevier Science Ltd.
- Kabalka, George W.,Malladi, Rama R.,Tejedor, David,Kelley, Shane
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- A remarkable effect of ionic liquids in transition-metal-free aerobic oxidation of benzylic alcohols
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The transition-metal-free aerobic oxidation of benzylic alcohols is uniquely accelerated by a 1-butyl-3-methylimidazolium hexafluorophosphate (BMI-PF6)/PhCF3 biphasic system and Cs2CO 3 to afford the corresponding ketones in good yields. The reaction system is also applicable to an oxidative cross-esterification of primary benzyl alcohols with a higher aliphatic alcohol.
- Oda, Yoshiro,Hirano, Koji,Satoh, Tetsuya,Kuwabata, Susumu,Miura, Masahiro
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- Simple one pot synthesis of ketone from carboxylic acid using DCC as an activator
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Simple one pot procedure for the conversion of carboxylic acid to ketone is described. Various carboxylic acids were converted to the corresponding ketones in excellent manner in presence of N,N′-dicyclohexylcarbodiimide (DCC) and organometallic reagents. Aromatic, heteroaromatic and aliphatic acids were converted to the corresponding ketones smoothly under the optimum conditions using organolithium reagents. In this process, desired products have been isolated from the crude reaction mixtures in moderate yields during the purification process.
- Mekonnen, Habtamu Gelaw,Jana, Samaresh
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- Ring Expansion and Contraction of a Two-Carbon Bridged Spiropentane
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The reactions of tricyclo[4.1.0.01,3]heptan-4-one (5) and two related systems with diazomethane and m-CPBA were examined in order to determine the relative reactivity and migratory aptitudes for the three compounds. The reactions of 5 with diazomethane and m-CPBA yielded new derivatives of the tricyclo[5.1.0.01,3]octane ring system that showed that migration of cyclopropylcarbinyl is favored over cyclopropyl migration in this system. Photolysis of 5-diazotricyclo[4.1.0.01,3]heptan-4-one (23) in methanol and dimethylamine did not lead to ring contraction to the tricyclo[3.1.0.01,3]hexane ring system, but an interesting product was derived from an unusual rearrangement process in the photolysis in dimethylamine. Matrix photolysis of 23 at 15 K gave a decrease in the diazo band at 2085 cm-1 and the appearance of a new band at 2117 cm-1, which is a normal position expected for a small-ring ketene such as cyclopropylketene. Thus, matrix photolysis appears to have yielded a derivative of the previously unknown tricyclo[3.1.0.01,3]hexane ring system. The lithium enolate of 5 was characterized by NMR spectroscopy at -80 °C and was found to rearrange to m-cresol at -65 °C. The geometries of the bridged spiropentanes of this work were optimized at the MP2(frozen core)/6-31G* level of theory, and group equivalent values were derived in order to calculate the heats of formation for these compounds using the calculated energies.
- Wiberg, Kenneth B.,Snoonian, John R.
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- Palladium-catalyzed carboacylation of alkenes by using acylchromates as acyl donors
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Palladium-catalyzed arylacylation of alkenes proceeds by employing acylchromates as acyl donors. When active alkenes such as norbornene and methoxyallene are treated with an aryl iodide, an acylchromate, and a catalytic amount of Pd(OAc)2/2P(o-Tol)3, arylacylation of these alkenes proceeds at room temperature. From aryl iodides having an intramolecular alkene moiety, cyclization-acylation products are obtained via intramolecular arylpalladation followed by acylation with acylchromates.
- Yamane, Motoki,Kubota, Yuko,Narasaka, Koichi
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- Crystal structures and photoreactivity of transand cis-valerophenone diperoxides
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The crystal structures of valerophenone diperoxides trans-1 and cis-1 were elucidated by X-ray crystallographic analysis. The 1,2,4,5-tetraoxane rings of both compounds adopt chair conformations. Intermolecular CH...O hydrogen bond, π-π, and CH/π interactions exist in cis-1, whereas only CH/π interactions exist in trans-1. In the asymmetric unit of the crystal, a half molecule exists for trans-1, while one molecule for cis-1 which shows wholemolecule disorder. Solid-state photolysis (at 254 nm) or solution-state thermolysis (at 150 °C) of trans-1 and cis-1 produced valerophenone (2) and butyl benzoate (3). Rationalization of the solid-state photoreactivity of the diperoxides by their crystal structures was attempted. Springer Science+Business Media, LLC 2011.
- Takahashi, Hiroki,Ito, Yoshikatsu
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- A new method for the synthesis of ketones: The palladium-catalyzed cross-coupling of acid chlorides with arylboronic acids
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The cross-coupling reaction of acid chlorides with arylboronic acids, using catalytic amounts of Pd(PPh3)4 and five equivalents Cs2CO3, under anhydrous conditions provides a new method for the synthesis of ketones in good to moderate yields.
- Haddach, Mustapha,McCarthy, James R.
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- Contra-Thermodynamic Positional Isomerization of Olefins
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A light-driven method for the contra-thermodynamic positional isomerization of olefins is described. In this work, stepwise PCET activation of a more substituted and more thermodynamically stable olefin substrate is mediated by an excited-state oxidant an
- Zhao, Kuo,Knowles, Robert R.
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supporting information
p. 137 - 144
(2022/01/19)
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- Selective Activation of Unstrained C(O)-C Bond in Ketone Suzuki-Miyaura Coupling Reaction Enabled by Hydride-Transfer Strategy
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A Rh(I)-catalyzed ketone Suzuki-Miyaura coupling reaction of benzylacetone with arylboronic acid is developed. Selective C(O)-C bond activation, which employs aminopyridine as a temporary directing group and ethyl vinyl ketone as a hydride acceptor, occurs on the alkyl chain containing a β-position hydrogen. A series of acetophenone products were obtained in yields up to 75%.
- Zhong, Jing,Zhou, Wuxin,Yan, Xufei,Xia, Ying,Xiang, Haifeng,Zhou, Xiangge
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supporting information
p. 1372 - 1377
(2022/02/23)
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- Nickel-Catalyzed Reductive Acylation of Carboxylic Acids with Alkyl Halides and N-Hydroxyphthalimide Esters Enabled by Electrochemical Process
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A sustainable Ni-catalyzed reductive acylation reaction of carboxylic acids via an electrochemical pathway is presented, affording a variety of ketones as major products. The reaction proceeds at ambient temperature using unactivated alkyl halides and N-hydroxyphthalimide (NHP) esters as coupling partners, which exhibits several synthetic advantages, including mild conditions and convenience of amplification (58% yield for 6 mmol scale reaction). (Figure presented.).
- Guo, Lin,Xia, Raymond Yang,Xia, Wujiong,Yang, Chao,Zhang, Haoxiang,Zhou, Xiao
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supporting information
(2022/03/31)
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- Combined Theoretical and Experimental Studies Unravel Multiple Pathways to Convergent Asymmetric Hydrogenation of Enamides
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We present a highly efficient convergent asymmetric hydrogenation of E/Z mixtures of enamides catalyzed by N,P-iridium complexes supported by mechanistic studies. It was found that reduction of the olefinic isomers (E and Z geometries) produces chiral amides with the same absolute configuration (enantioconvergent hydrogenation). This allowed the hydrogenation of a wide range of E/Z mixtures of trisubstituted enamides with excellent enantioselectivity (up to 99% ee). A detailed mechanistic study using deuterium labeling and kinetic experiments revealed two different pathways for the observed enantioconvergence. For α-aryl enamides, fast isomerization of the double bond takes place, and the overall process results in kinetic resolution of the two isomers. For α-alkyl enamides, no double bond isomerization is detected, and competition experiments suggested that substrate chelation is responsible for the enantioconvergent stereochemical outcome. DFT calculations were performed to predict the correct absolute configuration of the products and strengthen the proposed mechanism of the iridium-catalyzed isomerization pathway.
- Yang, Jianping,Massaro, Luca,Krajangsri, Suppachai,Singh, Thishana,Su, Hao,Silvi, Emanuele,Ponra, Sudipta,Eriksson, Lars,Ahlquist, M?rten S. G.,Andersson, Pher G.
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supporting information
p. 21594 - 21603
(2021/12/27)
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- Ruthenium-on-Carbon-Catalyzed Facile Solvent-Free Oxidation of Alcohols: Efficient Progress under Solid-Solid (Liquid)-Gas Conditions
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A protocol for the ruthenium-on-carbon (Ru/C)-catalyzed solvent-free oxidation of alcohols, which proceeds efficiently under solid-solid (liquid)-gas conditions, was developed. Various primary and secondary alcohols were transformed to corresponding aldehydes and ketones in moderate to excellent isolated yields by simply stirring in the presence of 10% Ru/C under air or oxygen conditions. The solvent-free oxidation reactions proceeded efficiently regardless of the solid or liquid state of the substrates and reagents and could be applied to gram-scale synthesis without loss of the reaction efficiency. Furthermore, the catalytic activity of Ru/C was maintained after five reuse cycles.
- Park, Kwihwan,Jiang, Jing,Yamada, Tsuyoshi,Sajiki, Hironao
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p. 1200 - 1205
(2021/12/29)
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- Selective Electrochemical Oxygenation of Alkylarenes to Carbonyls
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An efficient electrochemical method for benzylic C(sp3)-H bond oxidation has been developed. A variety of methylarenes, methylheteroarenes, and benzylic (hetero)methylenes could be converted into the desired aryl aldehydes and aryl ketones in moderate to excellent yields in an undivided cell, using O2 as the oxygen source and lutidinium perchlorate as an electrolyte. On the basis of cyclic voltammetry studies, 18O labeling experiments, and radical trapping experiments, a possible single-electron transfer mechanism has been proposed for the electrooxidation reaction.
- Li, Xue,Bai, Fang,Liu, Chaogan,Ma, Xiaowei,Gu, Chengzhi,Dai, Bin
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supporting information
p. 7445 - 7449
(2021/10/02)
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- Cu2O-CuO/Chitosan Composites as Heterogeneous Catalysts for Benzylic C?H Oxidation at Room Temperature
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Recently, in catalysis, chitosan has been exploited as a macrochelating ligand for metal active species due to the presence of various functional groups in its structure. Moreover, copper-based catalysts are classified as one of the most environmentally friendly catalytic systems and their use for the oxidation of alkylarene has not been established much. Therefore, in this work, the hydrothermal synthesis of copper oxide-chitosan composites as heterogeneous catalysts for the benzylic C?H oxidation of alkylarene was investigated. Characterization results reveal mixed phases of CuO and Cu2O, inferring the ability of chitosan to act as a reducing sugar under the hydrothermal condition. The pre-existing interaction between copper species and chitosan as well as the co-existence of the Cu2O and CuO structures give rise to the efficient performance of the catalysts. The synthesized composites exhibit high activity for the oxidation of fluorene to 9-fluorenone at room temperature and small catalyst loading (1 mol % of Cu, >90 % conversion and 100 % selectivity). Superior TOF was observed, and a good scope of substrates can be converted to corresponding ketones in 48–97 % yields with these copper oxide-chitosan catalysts. In addition, the catalysts can be used for up to nine cycles without significant decrease of the activity.
- Kanarat, Jurin,Bunchuay, Thanthapatra,Klysubun, Wantana,Tantirungrotechai, Jonggol
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p. 4833 - 4840
(2021/10/07)
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- Metal- And additive-free C-H oxygenation of alkylarenes by visible-light photoredox catalysis
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A metal- and additive-free methodology for the highly selective, photocatalyzed C-H oxygenation of alkylarenes under air to the corresponding carbonyls is presented. The process is catalyzed by an imide-acridinium that forms an extremely strong photooxidant upon visible light irradiation, which is able to activate inert alkylarenes such as toluene. Hence, this is an easy to perform, sustainable and environmentally friendly oxidation that provides valuable carbonyls from abundant, readily available compounds.
- García Manche?o, Olga,Kuhlmann, Jan H.,Pérez-Aguilar, María Carmen,Piekarski, Dariusz G.,Uygur, Mustafa
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supporting information
p. 3392 - 3399
(2021/05/21)
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- Visible-Light-Driven Oxidative Cleavage of Alkenes Using Water-Soluble CdSe Quantum Dots
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The oxidative cleavage of C=C bonds is an important chemical reaction, which is a popular reaction in the photocatalytic field. However, high catalyst-loading and low turnover number (TON) are general shortcomings in reported visible-light-driven reactions. Herein, the direct oxidative cleavage of C=C bonds through water-soluble CdSe quantum dots (QDs) is described under visible-light irradiation at room temperature with high TON (up to 3.7×104). Under the same conditions, water-soluble CdSe QDs could also oxidize sulfides to sulfoxides with 51–84 % yields and TONs up to 3.4×104. The key features of this photocatalytic protocol include high TONs, wide substrates scope, low catalyst loadings, simple and mild reaction conditions, and molecular O2 as the oxidant.
- Li, Jianing,Zhao, Jingnan,Ma, Cunfei,Yu, Zongyi,Zhu, Hongfei,Yun, Lei,Meng, Qingwei
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p. 4985 - 4992
(2021/10/16)
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- PhSe(O)OH/NHPI-catalyzed oxidative deoximation reaction using air as oxidant
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A novel oxidative deoximation method was developed in this article. Compared with the reported organoselenium-catalyzed oxidative deoximation reaction, this reaction employed N-hydroxyphthalimide (NHPI) as the co-catalyst, so that the oxidative deoximation reaction could utilize air as oxidant in the green DMC solvent under mild reaction conditions. Control experiments and X-ray photoelectron spectroscopy (XPS) analysis results indicated that NHPI was essential for activating the catalytic organoselenium species. It could accelerate the activation of molecular oxygen in air to promote the reaction process. The reaction can avoid metal residues in product and is of potential application values in pharmaceutical industry due to the transition metal-free process.
- Shi, Yaocheng,Wang, Feng,Yang, Chenggen,Yu, Lei
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- A Fast and General Route to Ketones from Amides and Organolithium Compounds under Aerobic Conditions: Synthetic and Mechanistic Aspects
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We report that the nucleophilic acyl substitution reaction of aliphatic and (hetero)aromatic amides by organolithium reagents proceeds quickly (20 s reaction time), efficiently, and chemoselectively with a broad substrate scope in the environmentally responsible cyclopentyl methyl ether, at ambient temperature and under air, to provide ketones in up to 93 % yield with an effective suppression of the notorious over-addition reaction. Detailed DFT calculations and NMR investigations support the experimental results. The described methodology was proven to be amenable to scale-up and recyclability protocols. Contrasting classical procedures carried out under inert atmospheres, this work lays the foundation for a profound paradigm shift of the reactivity of carboxylic acid amides with organolithiums, with ketones being straightforwardly obtained by simply combining the reagents under aerobic conditions and with no need of using previously modified or pre-activated amides, as recommended.
- Ghinato, Simone,Territo, Davide,Maranzana, Andrea,Capriati, Vito,Blangetti, Marco,Prandi, Cristina
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supporting information
p. 2868 - 2874
(2021/01/21)
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- Iridium Complexes as Efficient Catalysts for Construction of α-Substituted Ketones via Hydrogen Borrowing of Alcohols in Water
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Ketones are of great importance in synthesis, biology, and pharmaceuticals. This paper reports an iridium complexes-catalyzed cross-coupling of alcohols via hydrogen borrowing, affording a series of α-alkylated ketones in high yield (86 %–95 %) and chemoselectivities (>99 : 1). This methodology has the advantages of low catalyst loading (0.1 mol%) and environmentally benign water as the solvent. Studies have shown the amount of base has a great impact on chemoselectivities. Meanwhile, deuteration experiments show water plays an important role in accelerating the reduction of the unsaturated ketones intermediates. Remarkably, a gram-scale experiment demonstrates this methodology of iridium-catalyzed cross-coupling of alcohols has potential application in the practical synthesis of α-alkylated ketones.
- Luo, Nianhua,Zhong, Yuhong,Wen, Huiling,Shui, Hongling,Luo, Renshi
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p. 1355 - 1364
(2021/03/03)
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- Selective catalytic synthesis of α-alkylated ketones and β-disubstituted ketones via acceptorless dehydrogenative cross-coupling of alcohols
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Herein, a phosphine-free pincer ruthenium(III) catalyzed β-alkylation of secondary alcohols with primary alcohols to α-alkylated ketones and two different secondary alcohols to β-branched ketones are reported. Notably, this transformation is environmentally benign and atom efficient with H2O and H2 gas as the only byproducts. The protocol is extended to gram-scale reaction and for functionalization of complex vitamin E and cholesterol derivatives.
- Bhattacharyya, Dipanjan,Sarmah, Bikash Kumar,Nandi, Sekhar,Srivastava, Hemant Kumar,Das, Animesh
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supporting information
p. 869 - 875
(2021/02/06)
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- Nickel-Mediated Photoreductive Cross Coupling of Carboxylic Acid Derivatives for Ketone Synthesis**
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A simple visible light photochemical, nickel-catalyzed synthesis of ketones from carboxylic acid-derived precursors is presented. Hantzsch ester (HE) functions as a cheap, green and strong photoreductant to facilitate radical generation and also engages in the Ni-catalytic cycle to restore the reactive species. With this dual role, HE allows for the coupling of a large variety of radicals (1°,2°, benzylic, α-oxy & α-amino) with aroyl and alkanoyl moieties, a new feature in reactions of this type. With both precursors deriving from abundant carboxylic acids, this protocol is a welcome addition to the organic chemistry toolbox. The reaction proceeds under mild conditions without the need for toxic metal reagents or bases and shows a wide scope, including pharmaceuticals and complex molecular architectures.
- Brauer, Jan,Quraishi, Elisabeth,Kammer, Lisa Marie,Opatz, Till
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p. 18168 - 18174
(2021/11/30)
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- Using the Thiyl Radical for Aliphatic Hydrogen-Atom Transfer: Thiolation of Unactivated C?H Bonds
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A metal- and catalyst-free thiyl-radical-mediated activation of alkanes is described. Tetrafluoropyridinyl disulfide is used to perform thiolation of the C?H bonds under irradiation with 400 nm light-emitting diodes. The key C?H activation step is believed to proceed via hydrogen-atom abstraction effected by the fluorinated thiyl radical. Secondary, tertiary, and heteroatom-substituted C?H bonds can be involved in the thiolation reaction. The resulting sulfides have wide potential as photoredox-active radical precursors in reactions with alkenes and heteroarenes.
- Panferova, Liubov I.,Zubkov, Mikhail O.,Kokorekin, Vladimir A.,Levin, Vitalij V.,Dilman, Alexander D.
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supporting information
p. 2849 - 2854
(2020/12/17)
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- Selective Synthesis of Z-Silyl Enol Ethers via Ni-Catalyzed Remote Functionalization of Ketones
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We report a remote functionalization strategy, which allows the Z-selective synthesis of silyl enol ethers of (hetero)aromatic and aliphatic ketones via Ni-catalyzed chain walking from a distant olefin site. The positional selectivity is controlled by the directionality of the chain walk and is independent of thermodynamic preferences of the resulting silyl enol ether. Our mechanistic data indicate that a Ni(I) dimer is formed under these conditions, which serves as a catalyst resting state and, upon reaction with an alkyl bromide, is converted to [Ni(II)-H] as an active chain-walking/functionalization catalyst, ultimately generating a stabilized η3-bound Ni(II) enolate as the key selectivity-controlling intermediate.
- Guven, Sinem,Kundu, Gourab,Rissanen, Kari,Schoenebeck, Franziska,Ward, Jas S.,We?els, Andrea
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supporting information
p. 8375 - 8380
(2021/06/27)
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- Nickel-Catalyzed Isomerization/Allylic Cyanation of Alkenyl Alcohols
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Herein reported is a nickel-catalyzed isomerization/allylic cyanation of alkenyl alcohols, which complements current methods for the allylic substitution reactions. The specific diphosphite ligand and methanol as the solvent are crucial for the success for this transformation. A gram-scale regioconvergent experiment and formal synthesis of quebrachamine demonstrate the high potential of this methodology.
- Ding, Ying,Long, Jinguo,Sun, Feilong,Fang, Xianjie
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p. 6073 - 6078
(2021/08/16)
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- Metal-free, visible-light driven C-H ketoalkylation of glycine derivatives and peptides
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A metal-free, visible-light driven C-H ketoalkylation of glycine derivatives and peptides with cycloalkyl hydroperoxides is presented. This protocol provides a straightforward route to unnatural amino acids bearing a distal carbonyl group with moderate to good yields. Preliminary mechanistic studies revealed that both a SET event and radical chain propagation were involved in this transformation. This journal is
- Duan, Xin-Hua,Guo, Li-Na,Wang, Ming-Hua,Xin, Hong,Yang, Mingyu,Yuan, Zi-Hang
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supporting information
p. 9549 - 9553
(2021/12/09)
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- The Application of 1,2-Oxazinanes as Chiral Cyclic Weinreb Amide-Type Auxiliaries Leading to a Three-Component, One-Pot Reaction
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1,2-Oxazines were synthesised via a copper-catalysed aerobic acyl nitroso Diels-Alder reaction from 1,4-disubstituted 1,3-dienes and N-Boc-hydroxylamine. From this, 1,2-oxazinanes were obtained in a novel follow-up reaction path. The stability of several 1,2-oxazines and 1,2-oxazinanes towards organometallic compounds was tested to rate their operability as cyclic chiral Weinreb amide auxiliaries. 3,6-Di-tertbutyl-1,2-oxazinane gave the best results and was introduced as a chiral Weinreb amide-type auxiliary to yield chiral α-substituted ketones in a diastereomeric ratio of up to 98:2. The removal of the auxiliary can be performed with BuLi to form unsymmetrical α-chiral ketones. Thereafter, the chiral auxiliary can be re-isolated and purified by sublimation under vacuum.
- F?hrmann, Jan,Hermann, Ludmila,Hilt, Gerhard
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- Nickel-Catalyzed Allylic Defluorinative Cross-Electrophile Coupling with Cycloalkyl Silyl Peroxides as the Alkyl Source
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Herein we demonstrate the first successful application of cycloalkyl silyl peroxides (CSP) as an electrophilic coupling partner in the cross-electrophile coupling reaction. Diverse CSP are efficiently cross-coupled with an array of α-trifluoromethyl alkenes under the catalysis of nickel with the assistance of zinc as the reducing agent. This method allows the use of unstrained CSP as the carbonyl-containing alkyl source in the allylic defluorinative reaction, to access a variety of gem-difluoroalkenes bearing a pendent ketone moiety with high functionality tolerance.
- Dong, Haiyan,Lin, Zhiyang,Wang, Chuan
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- Base-free oxidation of alcohols enabled by nickel(ii)-catalyzed transfer dehydrogenation
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An efficient nickel(ii)-catalyzed transfer dehydrogenation oxidation of alcohols is reported that relies on cyclohexanone as the formal oxidant and does not require the use of an external base. The synthetic utility of this protocol is demonstratedviathe facile oxidation of structurally complicated natural products.
- Ye, Danfeng,Liu, Zhiyuan,Sessler, Jonathan L.,Lei, Chuanhu
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supporting information
p. 11811 - 11814
(2020/10/13)
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- Method for synthesizing aryl ketone compound by taking TBADT as photocatalyst
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The invention provides a method for synthesizing an aryl ketone compound by taking TBADT as a photocatalyst. The method comprises the following steps: with TBADT as a photocatalyst, under the conditions of a palladium catalyst, a phosphine ligand, weak base and an organic solvent, irradiating the reactants under a 380-400 nm photocatalysis lamp at the room temperature under the inert protective atmosphere, so that an aldehyde group-containing compound reacts with Ar-X, wherein the Ar-X is aryl halide or aryl trifluoromethanesulfonate, and the aryl halide is aryl bromide or aryl iodide; the aldehyde group-containing compound is one of aryl aldehyde, alkyl aldehyde, linear primary aldehyde, acyclic secondary aldehyde and N-methylformamide. According to the invention, the tetrabutylammonium sebacate (TBADT)HAT photocatalyst and palladium catalysis are combined for use, and aldehyde C-H arylation and alkenylation reactions can be directly carried out to synthesize ketone. The method has the advantages of mild reaction conditions, high yield and wide substrate application range, and can be used for synthesizing natural products in medicinal plants.
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Paragraph 0040-0044; 0060-0067
(2020/09/21)
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- Method for synthesizing aryl ketone compound by taking AQ as photocatalyst
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The invention provides a method for synthesizing an aryl ketone compound by taking AQ as a photocatalyst. The method comprises the following steps that AQ serves as a photocatalyst; under the conditions of a palladium catalyst, a phosphine ligand, weak base and an organic solvent, a 390-to-430-nm photocatalysis lamp is used for irradiation at room temperature in an inert protective atmosphere, soan aldehyde group-containing compound reacts with Ar-X, wherein Ar-X is aryl halide or aryl trifluoromethanesulfonic acid, the aryl halide is aryl bromide or aryl iodide, and the aldehyde group-containing compound is one selected from aryl aldehyde, alkyl aldehyde, linear primary aldehyde and acyclic secondary aldehyde. According to the invention, the anthraquinone (AQ) HAT photocatalyst and palladium catalyst are combined for use, C-H arylation and alkenylation reactions of aldehyde can be directly carried out to synthesize ketone, and reaction efficiency is high. The method has the advantages of mild reaction conditions, high yield and a wide substrate application range, and can be used for synthesizing natural products in medicinal plants.
- -
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Paragraph 0039-0043; 0068-0075
(2020/09/16)
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- A metal-free heterogeneous photocatalyst for the selective oxidative cleavage of CC bonds in aryl olefins: via harvesting direct solar energy
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Selective cleavage of CC bonds is highly important for the synthesis of carbonyl containing fine chemicals and pharmaceuticals. Novel methodologies such as ozonolysis reactions, Lemieux-Johnson oxidation reaction etc. already exist. Parallel to these, catalytic methods using homogeneous catalysts also have been discovered. Considering the various advantages of heterogeneous catalysts such as recyclability and stability, couple of transition metal-based heterogeneous catalysts have been applied for this reaction. However, the pharmaceutical industries prefer to use metal-free catalysts (especially transition metal-free) to avoid further leaching in the final products. This is for sure a big challenge to an organic chemist and to the pharmaceutical industries. To make this feasible, a mild and efficient protocol has been developed using polymeric carbon nitrides (PCN) as metal-free heterogeneous photocatalysts to convert various olefins into the corresponding carbonyls. Later, this catalyst has been applied in the gram scale synthesis of pharmaceutical drugs using direct solar energy. Detailed mechanistic studies revealed the actual role of oxygen, the catalyst, and the light source.
- Das, Shoubhik,Hatami, Nareh,Jooss, Christian,Lange, Niklas Simon,Ronge, Emanuel,Schilling, Waldemar,Zhang, Yu
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supporting information
p. 4516 - 4522
(2020/08/10)
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- Direct C-H Arylation of Aldehydes by Merging Photocatalyzed Hydrogen Atom Transfer with Palladium Catalysis
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Herein, we report that merging palladium catalysis with hydrogen atom transfer (HAT) photocatalysis enabled direct arylations and alkenylations of aldehyde C-H bonds, facilitating visible light-catalyzed construction of a variety of ketones. Tetrabutylammonium decatungstate and anthraquinone were found to act as synergistic HAT photocatalysts. Density functional theory calculations suggested a Pd0-PdII-PdIII-PdI-Pd0 pathway and revealed that regeneration of the Pd0 catalyst and the photocatalyst occurs simultaneously in the presence of KHCO3. This regeneration features a low energy barrier, promoting efficient coupling of the palladium catalytic cycle with the photocatalytic cycle. The work reported herein suggests great promise for further applications of HAT photocatalysis in palladium-catalyzed cross-coupling and C-H functionalization reactions to be successful.
- Chen, Guangying,Cheng, Gui-Juan,Guo, Bin,Li, Xiaobao,Ran, Chongzhao,Wang, Lu,Wang, Ting,Wei, Jun-Jie,Zheng, Caijuan,Zheng, Chao
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p. 7543 - 7551
(2020/08/21)
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- Redox-triggered ruthenium-catalyzed remote C?H acylation with primary alcohols
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Redox-triggered metal-catalyzed cross-coupling reactions from readily available alcohols provide a step economical means to synthesize ketones and related compounds. Prior examples for hydrogenative remote C(sp3)?H functionalization of olefins via a metal walking process featured external reducing agents. Here, we report a strategy for redox-triggered hydrogenative remote C(sp3)?H acylation of olefins with primary alcohols both as an acylating agent and a reductant, which is validated by the base-free 1,3-diketone synthesis. Mechanistic studies have confirmed that the reaction takes place via an aldehyde intermediate and a metal walking process.
- Li, Gongqiang,Xia, Ji-Bao,Guo, Xiao,Wu, Yang
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p. 12987 - 12995
(2020/11/16)
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- Method for preparing alpha-alkyl substituted ketone compound
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The invention relates to a method for preparing an alpha-alkyl substituted ketone compound, which comprises the following steps: preparing a primary alcohol compound and a secondary alcohol compound as raw materials, adding alkali; with a cyclic iridium complex as a catalyst and water as a reaction medium, heating and stirring the mixture and reacting for 10 to 24 hours under the protection of inert gas, and cooling a reaction product to room temperature after the reaction is finished; carrying out reduced pressure distillation and concentration to obtain a crude product, and carrying out column chromatography purification to obtain a series of alpha alkyl substituted ketone compounds. The method is simple to operate, available in raw materials, low in price, high in reaction efficiency and selectivity, good in adaptability to various functional groups and wide in substrate universality; since water is used as a reaction medium to meet the green and environment-friendly requirements, the method is environmentally friendly and is carried out at gram level, so that the potential of industrially synthesizing the alpha alkyl substituted ketone compound is achieved; therefore, The method has expanded application in the fields of medicines, organic synthesis and the like.
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Paragraph 0181-0188
(2020/12/29)
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- Copper-Catalyzed Oxidative Fragmentation of Alkynes with NFSI Provides Aryl Ketones
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A copper-catalyzed oxidative cleavage reaction of alkynes using NFSI and TBHP was described. Various terminal and internal alkyne substrates were employed to render quick access to aryl ketone products in moderate to good yields. NFSI not only functioned as N-centered radical precursors but also engaged in the aryl group migration. Mechanistic studies also suggested the important role of water in the title reactions.
- Chen, Hanfei,Cheng, Hao,Huang, Yifan,Jin, Chaochao,Song, Weihan,Tan, Chen,Tan, Jiajing,Tang, Lin,Yang, Fang,Zhang, Shuaifei
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supporting information
(2020/11/03)
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- Palladium-Catalyzed Amide N-C Hiyama Cross-Coupling: Synthesis of Ketones
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N-Acylglutarimides and arylsiloxanes reacted in the presence of Pd(OAc)2/PCy3, Et3N·3HF, and LiOAc to provide the corresponding arylketones in good yields. Aryl-, vinyl-, and alkyl-substituted N-acylglutarimides showed good activity in the coupling reactions of arylsiloxanes. The reaction had a broad substrate scope and showed good functional group tolerance. N-Benzoylsuccinimide and N-protected N-phenylbenzamides showed good activities in coupling reactions with phenylsiloxane. The employment of CuF2 as an activor afforded the decarbonylative products at 160 °C.
- Idris, Muhammad Aliyu,Lee, Sunwoo
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supporting information
p. 9190 - 9195
(2020/11/18)
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- Carbonylation of tertiary carbon radicals: synthesis of lactams
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Herein, we disclose an interesting iron-catalyzed approach for the carbonylation of a tertiary carbon radical. The tertiary carbon radical generated from a 1,5-hydrogen atom transfer can be captured by CO gas smoothly. Various six-membered lactams were constructed chemo-selectively in high yields.
- Yin, Zhiping,Zhang, Zhuan,Zhang, Youcan,Dixneuf, Pierre H.,Wu, Xiao-Feng
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supporting information
p. 4655 - 4658
(2019/05/09)
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- Table salt as a catalyst for the oxidation of aromatic alcohols and amines to acids and imines in aqueous medium: Effectively carrying out oxidation reactions in sea water
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A simple, efficient, sustainable and economical method for the oxidation of alcohols and amines has been developed based on chloride, a sea abundant anionic catalyst for the practical synthesis of a wide range of carboxylic acids, ketones and imines. Oxidation of aromatic alcohols was carried out using NaCl (20 mol%) as the catalyst, NaOH (50 mol%) and aq. TBHP (4 equiv.) as the oxidant in 55-92% isolated yields. Oxidation of aromatic amines to imines was achieved by using only 20 mol% of NaCl and aq. TBHP (4 equiv.) in 32-93% isolated yields. The chlorine species formed during the reaction as the active oxidation catalyst has been identified as ClO2- for alcohols and ClO-/ClO2- for amines by control experiments. This method is mostly free from chromatographic purification, which makes it suitable for large-scale synthesis. We have scaled up to 30 gram scale the synthesis of carboxylic acids and imines in good yields and have also carried out efficiently this new method using filtered sea water as the solvent and catalyst.
- Hazra, Susanta,Kushawaha, Ajay Kishor,Yadav, Deepak,Dolui, Pritam,Deb, Mayukh,Elias, Anil J.
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supporting information
p. 1929 - 1934
(2019/04/29)
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- Regioselective Vinylation of Remote Unactivated C(sp3)?H Bonds: Access to Complex Fluoroalkylated Alkenes
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Regioselective incorporation of a particular functional group into aliphatic sites by direct activation of unreactive C?H bonds is of great synthetic value. Despite advances in radical-mediated functionalization of C(sp3)?H bonds by a hydrogen-atom transfer process, the site-selective vinylation of remote C(sp3)?H bonds still remains underexplored. Reported herein is a new protocol for the regioselective vinylation of unactivated C(sp3)?H bonds. The remote C(sp3)?H activation is promoted by a C-centered radical instead of the commonly used N and O radicals. The reaction possesses high product diversity and synthetic efficiency, furnishing a plethora of synthetically valuable E alkenes bearing tri-/di-/mono-fluoromethyl and perfluoroalkyl groups.
- Wu, Shuo,Wu, Xinxin,Wang, Dongping,Zhu, Chen
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supporting information
p. 1499 - 1503
(2019/01/04)
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- Nonclassical Mechanism in the Cyclodehydration of Diols Catalyzed by a Bifunctional Iridium Complex
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1,4- and 1,5-diols undergo cyclodehydration upon treatment with cationic N-heterocyclic carbene (NHC)–IrIII complexes to give tetrahydrofurans and tetrahydropyrans, respectively. The mechanism was investigated, and a metal-hydride-driven pathway was proposed for all substrates, except for very electron-rich ones. This contrasts with the well-established classical pathways that involve nucleophilic substitution.
- González Miera, Greco,Bermejo López, Aitor,Martínez-Castro, Elisa,Norrby, Per-Ola,Martín-Matute, Belén
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p. 2631 - 2636
(2019/02/01)
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- 3. 5 - Dihydroxy fifth heavenly stem benzene synthetic method
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The invention provides a 3, 5 - dihydroxy fifth heavenly stem benzene synthetic method, through under the acid catalysis of benzene with a Friedel - crafts acylation reaction to obtain the [...], the acid is a Lewis acid; the obtained [...] nitration to obtain 3, 5 - dinitrobenzene pentanone; then into methylene carbonyl reduction after reduction of nitro, to obtain 3, 5 - diamino [...]; diazotisations 3, 5 - diamino [...] variable hydroxy obtain 3, 5 - dihydroxy fifth heavenly stem benzene. The invention raw materials used are cheap and easily obtained bulk chemical raw materials, every one-step reaction conditions are relatively mild, which belongs to the chemical industry a large number of applied to the conventional reaction. In accordance with the technique to obtain the final product 3, 5 - dihydroxy fifth heavenly stem benzene (Olivetol) high purity, can reach 98.5% or more, the single hetero in 0.3% to the inner.
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Paragraph 0031; 0032
(2019/07/04)
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- Novel benzene-based carbamates for ache/bche inhibition: Synthesis and ligand/structure-oriented sar study
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A series of new benzene-based derivatives was designed, synthesized and comprehensively characterized. All of the tested compounds were evaluated for their in vitro ability to potentially inhibit the acetyl-and butyrylcholinesterase enzymes. The selectivity index of individual molecules to cholinesterases was also determined. Generally, the inhibitory potency was stronger against butyryl-compared to acetylcholinesterase; however, some of the compounds showed a promising inhibition of both enzymes. In fact, two compounds (23, benzyl ethyl(1-oxo-1-phenylpropan-2-yl)carbamate and 28, benzyl (1-(3-chlorophenyl)-1-oxopropan-2-yl) (methyl)carbamate) had a very high selectivity index, while the second one (28) reached the lowest inhibitory concentration IC50 value, which corresponds quite well with galanthamine. Moreover, comparative receptor-independent and receptor-dependent structure–activity studies were conducted to explain the observed variations in inhibiting the potential of the investigated carbamate series. The principal objective of the ligand-based study was to comparatively analyze the molecular surface to gain insight into the electronic and/or steric factors that govern the ability to inhibit enzyme activities. The spatial distribution of potentially important steric and electrostatic factors was determined using the probability-guided pharmacophore mapping procedure, which is based on the iterative variable elimination method. Additionally, planar and spatial maps of the host–target interactions were created for all of the active compounds and compared with the drug molecules using the docking methodology.
- Bak, Andrzej,Kozik, Violetta,Kozakiewicz, Dariusz,Gajcy, Kamila,Strub, Daniel Jan,Swietlicka, Aleksandra,Stepankova, Sarka,Imramovsky, Ales,Polanski, Jaroslaw,Smolinski, Adam,Jampilek, Josef
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- Dehalogenative Deuteration of Unactivated Alkyl Halides Using D2O as the Deuterium Source
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The general dehalogenation of alkyl halides with zinc using D2O or H2O as a deuterium or hydrogen donor has been developed. The method provides an efficient and economic protocol for deuterium-labeled derivatives with a wide substrate scope under mild reaction conditions. Mechanistic studies indicated that a radical process is involved for the formation of organozinc intermediates. The facile hydrolysis of the organozinc intermediates provides the driving force for this transformation.
- Xia, Aiyou,Xie, Xin,Hu, Xiaoping,Xu, Wei,Liu, Yuanhong
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p. 13841 - 13857
(2019/10/17)
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- Iron-Enabled Utilization of Air as the Terminal Oxidant Leading to Aerobic Oxidative Deoximation by Organoselenium Catalysis
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In contrast to conventional organoselenium-catalyzed oxidation reactions that require peroxide oxidants such as hydrogen peroxide, in this work we found that, addition of a low loading of iron (II) could enable the successful utilization of air as the terminal oxidant in organoselenium-catalyzed oxidative deoximation reaction of ketoximes. This led to a new mild and relatively green aerobic oxidative deoximation method. Control reactions and X-ray photoelectron spectroscopy (XPS) analysis suggest that iron is crucial in the catalytic cycle, working to prohibit the deactivation of selenium catalyst through an iron-catalyzed aerobic oxidation of low valent selenium species by air to the active high valent selenium species. Since air can be utilized as the terminal oxidant, this work may contribute to the advance of organoselenium catalysis. (Figure presented.).
- Chen, Chao,Zhang, Xu,Cao, Hongen,Wang, Fang,Yu, Lei,Xu, Qing
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p. 603 - 610
(2018/12/14)
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- Assessing the effectiveness of oxidative approaches for the synthesis of aldehydes and ketones from oxidation of iodomethyl group
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Owing to excellent selectivity, high yield and stability towards over-reduction and over-oxidation, one of the impressive approaches to synthesize aldehydes and ketones is the oxidation of halomethyl groups. Numerous halomethyl oxidation-based methodologies to afford aldehydes and ketones are disclosed in the literature. Mostly, chloromethyl or bromomethyl group containing substrates have been used in the literature for performing oxidation. There are negligible data available in the literature that addresses the use of iodomethyl group containing substrates for transformation to aldehydes and ketones. In this research work, 110 reactions have been carried out to construct aldehydes and ketones from oxidation of iodomethyl group in benzylic iodides and allylic iodides using numerous well-known approaches reported in the literature. The classical approaches under observation include Sommelet oxidation, Kr?hnke oxidation, sodium periodate-mediated oxidative protocol, manganese dioxide-based oxidative approach, Kornblum oxidation and Hass–Bender oxidation. The eco-friendly approaches under observation include periodic acid-based IL protocol, periodic acid in vanadium pentoxide-mediated IL method, hydrogen peroxide in vanadium pentoxide-based approach and bismuth nitrate-promoted IL technique. In this investigation, yield, recyclability, cost-effectiveness, eco-friendliness and over-oxidation are the main parameters which are under observation. Among all these investigated techniques, periodic acid-based IL protocol, periodic acid in vanadium pentoxide-mediated IL method and hydrogen peroxide in vanadium pentoxide-based approach (aka. Chunbao oxidation protocol) were found to be highly efficient due to the following reasons: these approaches (1) provide excellent yields, (2) do not lead towards over-oxidation, (3) show good recyclability, (4) demonstrate high thermal stability and negligible flammability, and (5) require no special handling.
- Faisal, Muhammad,Hussain, Sarwat,Haider, Azeem,Saeed, Aamer,Larik, Fayaz Ali
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p. 1053 - 1067
(2019/04/25)
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- Directed: Ortho-metalation-nucleophilic acyl substitution strategies in deep eutectic solvents: The organolithium base dictates the chemoselectivity
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Directed ortho metalation (DoM) or nucleophilic acyl substitution (SNAc) can be efficiently programmed on the same aromatic carboxylic acid amide, in a choline chloride-based eutectic mixture, by simply switching the nature of the organolithium reagent. Telescoped, one-pot ortho-lithiation/Suzuki-Miyaura cross-couplings have also been demonstrated for the first time in Deep Eutectic Solvents.
- Ghinato, Simone,Dilauro, Giuseppe,Perna, Filippo Maria,Capriati, Vito,Blangetti, Marco,Prandi, Cristina
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p. 7741 - 7744
(2019/07/12)
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- Mn-Enabled Radical-Based Alkyl-Alkyl Cross-Coupling Reaction from 4-Alkyl-1,4-dihydropyridines
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Highly efficient alkylation of β-chloro ketones and their derivatives was achieved by means of domino dehydrochlorination/Mn-enabled radical-based alkyl-alkyl cross-coupling reaction. In situ-generated α,β-unsaturated ketones and their analogues were identified as the reaction intermediates. Known bioactive compounds, such as melperone and azaperone, could be easily prepared from β-chloropropiophenone in two steps.
- Wang, Jie,Pang, Yu-Bo,Tao, Na,Zeng, Run-Sheng,Zhao, Yingsheng
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p. 15315 - 15322
(2019/11/19)
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- Direct transformation of aryl 2-pyridyl esters to secondary benzylic alcohols by nickel relay catalysis
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A direct transformation of aryl esters to secondary benzylic alcohols via tandem Ni-catalyzed cross-coupling reactions of aromatic 2-pyridyl esters with alkyl zinc reagents and carbonyl group reduction by Ni-H species is achieved. Preliminary mechanistic studies reveal that the Ni-H species is generated in situ via β-hydride elimination of the Negishi reagents. The reaction is catalyzed by bench-stable nickel salts under mild conditions with wide functional group tolerance.
- Wu, Xianqing,Li, Xiaobin,Huang, Wenyi,Wang, Yun,Xu, Hui,Cai, Liangzhen,Qu, Jingping,Chen, Yifeng
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p. 2453 - 2458
(2019/03/29)
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- Sodium Hypochlorite Pentahydrate as a Reagent for the Cleavage of trans-Cyclic Glycols
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Sodium hypochlorite pentahydrate (NaOCl·5H2O) can be used toward the efficient glycol cleavage of trans-cyclic glycols, which are generally resistant to this transformation. Interestingly, the reaction of cis-cyclic glycols with NaOCl·5H2O is slower than that observed for the corresponding trans-isomer. This trans selectivity is in sharp contrast to traditional oxidants used for glycol cleavage. Acyclic glycols can also react efficiently with NaOCl·5H2O to form their corresponding carbonyl compounds in high yield.
- Kirihara, Masayuki,Osugi, Rie,Saito, Katsuya,Adachi, Kouta,Yamazaki, Kento,Matsushima, Ryoji,Kimura, Yoshikazu
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p. 8330 - 8336
(2019/06/24)
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- Efficient aerobic oxidation of alcohols catalyzed by NiGa hydrotalcites in the absence of any additives
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The aerobic oxidation of alcohol catalyzed by NiGa hydrotalcites in the absence of any additives has been studied in detail. The research results revealed that the surface basicity significantly affected the catalytic performance. Moreover, the Br?nsted OH basic site on Ni-containing hydrotalcites was suggested to be the key active site and accelerated the oxidation. The catalytic system had good tolerance for various alcohols, and an excellent selectivity of aldehyde could be obtained for the oxidation of primary alcohol. A probable non-radical reaction path for the transformation has been proposed according to the catalytic results, isotope labelling experiments and Hammett experiments.
- Sun, Fuan,Zhou, Jiacheng,Zhou, Weiyou,Pan, Jiugao,Qian, Junfeng,He, Mingyang,Chen, Qun
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p. 4029 - 4035
(2018/03/21)
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- Preparation method of aromatic ketone
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The invention discloses a preparation method of aromatic ketone. Under the effects of a palladium catalyst and a nitrogen-containing ligand, nitrile compounds and arylsulfonylhydrazide take desulfurization addition reaction in an organic solvent; after the reaction is completed, post treatment is performed to obtain aromatic ketone. The reaction is applicable to aromatic nitrile compounds, and isalso applicable to aliphatic nitrile compounds; the reaction realizes the wide substrate applicability and functional group tolerance; the potential application value is realized in the aspect of aryl-carbonyl building.
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Paragraph 0051; 0052; 0053; 0055
(2018/09/11)
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- Synthesis of some ketones via nano-nickel oxide catalyzed acylation of arylzinc reagents; strategy involving the use of mixed (methyl)(aryl)zincs
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Nano-NiO catalyzed acylation of mixed (methyl)(aryl)zincs with aromatic acyl halides in THF at room temperature provides a new facile route for aryl–aroyl coupling. Among NiCl2 .L2 and NiCl2 .L (L = monodentate and bidentate phosphine ligand) catalysts, the lower catalyst loading of NiCl2 (dppf) may seem attractive; however, nano-NiO, being the lowest cost catalyst, is more favorable for aroylation of (methyl)(aryl)zincs. This procedure also provides a supplement to Cu and Pd catalyzed acylation of diorganozincs.
- Pekel, ?zgen ?MüR,Erdik, Ender,Kalkan, Melike
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p. 759 - 767
(2018/06/07)
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