- A Core–Shell-Structured Silver Nanowire/Nitrogen-Doped Carbon Catalyst for Enhanced and Multifunctional Electrofixation of CO2
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Numerous catalysts have been successfully introduced for CO2 fixation in aqueous or organic systems. However, a single catalyst showing activity in both solvent types is still rare, to the best of our knowledge. We developed a core–shell-structured AgNW/NC700 composite using a Ag nanowire (NW) core encapsulated by a N-doped carbon (NC) shell at 700 °C. Through control experiments and density functional theory calculations, it was confirmed that Ag nanowires acted as the active sites for CO2 fixation and the uniformly coating of N-doped carbon created a CO2-rich environment around the Ag nanowires, which could significantly improve the catalytic activity of Ag nanowires for electrochemical CO2 fixation. Under mild conditions, up to 96 % faradaic efficiency of CO, 95 % yield of Ibuprofen and 92 % yield of propylene carbonate could be obtained in the electrochemical CO2 direct reduction, carboxylation and cycloaddition, respectively, using the same AgNWs/NC700 catalyst. These results might provide an alternative strategy for efficient electrochemical fixation of CO2.
- Yang, Heng-Pan,Zhang, Han-Wen,Wu, Yu,Fan, Liang-Dong,Chai, Xiao-Yan,Zhang, Qian-Ling,Liu, Jian-Hong,He, Chuan-Xin
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Read Online
- Platinum/nitrogen-doped carbon/carbon cloth: A bifunctional catalyst for the electrochemical reduction and carboxylation of CO2 with excellent efficiency
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A novel Pt-NP@NCNF@CC composite was prepared by the electrospinning technique. It is a highly efficient and binder-free catalyst for the direct reduction and carboxylation of CO2 with halides. Formate with 91% Faradaic efficiency and 2-phenylpropionic acid with 99% yield could be obtained, respectively. Moreover, this catalyst has excellent stability and reusability.
- Yang, Heng-Pan,Lin, Qing,Zhang, Han-Wen,Li, Guo-Dong,Fan, Liang-Dong,Chai, Xiao-Yan,Zhang, Qian-Ling,Liu, Jian-Hong,He, Chuan-Xin
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Read Online
- The marked difference in conformational behavior of the two diastereomers of 7-substituted-1,1-dichloro-7b-((Z)-8-chloro-6,7-dihydro-5H-benzo[7]annulen-9- yl)-1a,2,3,7b-tetrahydro-1H-cyclopropa[a]naphthalene, single crystal X-ray, 1H NMR and AM1 studies
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The 7-substituted of 1 and 2 were synthesized and conformational analysis carried out. While 7-substituted of 2 show two conformers in solution, 7-substituted of 1 show only one form in solution. AM1 semi-empirical molecular orbital calculations show that the conformation of cycloheptadiene ring in 1 and 2 is a twist boat form. In this conformation, the C-7 substituents can be oriented in pseudo equatorial (exo) and pseudo axial (endo) positions. The 3J calculation with Haasnoot equation on optimized structure of 2 reproduces the observed 3J coupling constants in exo and endo forms. Ring inversion of cycloheptadiene moiety in substituted 2 interconvert the e′-a′ (exo-endo) positions. The 3J calculation on optimized structure of 1 shows that 7-substitution is in pseudo equatorial (exo) direction, as found in the crystal structure of 1a by single crystal X-ray crystallography. The barrier to ring inversion in 2a is determined by dynamic 1H NMR spectroscopy to be ΔG≠(335K) = 68.0 ± 0.5 kJ/mol.
- Roshan, Hamid,Rashidi-Ranjbar, Parviz
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Read Online
- Mechanochemical Grignard Reactions with Gaseous CO2 and Sodium Methyl Carbonate**
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A one-pot, three-step protocol for the preparation of Grignard reagents from organobromides in a ball mill and their subsequent reactions with gaseous carbon dioxide (CO2) or sodium methyl carbonate providing aryl and alkyl carboxylic acids in up to 82 % yield is reported. Noteworthy are the short reaction times and the significantly reduced solvent amounts [2.0 equiv. for liquid assisted grinding (LAG) conditions]. Unexpectedly, aryl bromides with methoxy substituents lead to symmetric ketones as major products.
- Pfennig, Victoria S.,Villella, Romina C.,Nikodemus, Julia,Bolm, Carsten
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supporting information
(2022/01/22)
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- Pd-Catalyzed Regioselective Branched Hydrocarboxylation of Terminal Olefins with Formic Acid
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A regioselective Pd-catalyzed hydrocarboxylation of terminal olefins with HCOOH is described. A wide variety of branched carboxylic acids can readily be obtained with high regioselectivities under mild reaction conditions. The reaction is operationally simple and requires no handling of toxic CO. The ligand and LiCl are important factors for reaction reactivity and selectivity.
- Chu, Jianxiao,Guo, Jianqiong,Ren, Wenlong,Shi, Yian,Shi, Yuan,Wang, Mingzhou,Zhou, Jintao
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supporting information
p. 886 - 891
(2022/02/07)
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- Palladium-Catalyzed Direct C-H Arylation of 3-Butenoic Acid Derivatives
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We report herein a direct method to synthesize 4-aryl-3-butenoic acid through a carboxylic-acid-directed oxidative Heck reaction. The various 4-aryl-3-butenoic acids are easily prepared in moderate to good yields. In view of the promising bioactivity of 4-phenyl-3-butenoic acid previously reported, its derivatives reported here may be bioactive.
- Yang, Shan,Liu, Lingling,Zhou, Zheng,Huang, Zhibin,Zhao, Yingsheng
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supporting information
p. 296 - 299
(2021/01/13)
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- Suppressing carboxylate nucleophilicity with inorganic salts enables selective electrocarboxylation without sacrificial anodes
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Although electrocarboxylation reactions use CO2as a renewable synthon and can incorporate renewable electricity as a driving force, the overall sustainability and practicality of this process is limited by the use of sacrificial anodes such as magnesium and aluminum. Replacing these anodes for the carboxylation of organic halides is not trivial because the cations produced from their oxidation inhibit a variety of undesired nucleophilic reactions that form esters, carbonates, and alcohols. Herein, a strategy to maintain selectivity without a sacrificial anode is developed by adding a salt with an inorganic cation that blocks nucleophilic reactions. Using anhydrous MgBr2as a low-cost, soluble source of Mg2+cations, carboxylation of a variety of aliphatic, benzylic, and aromatic halides was achieved with moderate to good (34-78%) yields without a sacrificial anode. Moreover, the yields from the sacrificial-anode-free process were often comparable or better than those from a traditional sacrificial-anode process. Examining a wide variety of substrates shows a correlation between known nucleophilic susceptibilities of carbon-halide bonds and selectivity loss in the absence of a Mg2+source. The carboxylate anion product was also discovered to mitigate cathodic passivation by insoluble carbonates produced as byproducts from concomitant CO2reduction to CO, although this protection can eventually become insufficient when sacrificial anodes are used. These results are a key step toward sustainable and practical carboxylation by providing an electrolyte design guideline to obviate the need for sacrificial anodes.
- Corbin, Nathan,Lazouski, Nikifar,Manthiram, Karthish,Steinberg, Katherine,Yang, Deng-Tao
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p. 12365 - 12376
(2021/10/08)
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- Activated charcoal as an effective additive for alkaline and acidic hydrolysis of esters in water
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Activated charcoal largely enhanced the rates of the alkaline hydrolysis of methyl, ethyl, and n-propyl esters in aqueous 1.5 M NaOH solution to give the corresponding carboxylic acids in excellent yields. The acidic hydrolysis of methyl, ethyl, and n-propyl esters in aqueous 3 M H2SO4 solution was accelerated by the addition of activated charcoal to afford the corresponding carboxylic acids in good yields.
- Rohand, Taoufik,Tanemura, Kiyoshi
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supporting information
(2020/10/08)
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- Ligand-Controlled Regiodivergence in Nickel-Catalyzed Hydroarylation and Hydroalkenylation of Alkenyl Carboxylic Acids**
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A nickel-catalyzed regiodivergent hydroarylation and hydroalkenylation of unactivated alkenyl carboxylic acids is reported, whereby the ligand environment around the metal center dictates the regiochemical outcome. Markovnikov hydrofunctionalization products are obtained under mild ligand-free conditions, with up to 99 % yield and >20:1 selectivity. Alternatively, anti-Markovnikov products can be accessed with a novel 4,4-disubstituted Pyrox ligand in excellent yield and >20:1 selectivity. Both electronic and steric effects on the ligand contribute to the high yield and selectivity. Mechanistic studies suggest a change in the turnover-limiting and selectivity-determining step induced by the optimal ligand. DFT calculations reveal that in the anti-Markovnikov pathway, repulsion between the ligand and the alkyl group is minimized (by virtue of it being 1° versus 2°) in the rate- and regioselectivity-determining transmetalation transition state.
- Deng, Ruohan,Engle, Keary M.,Fu, Yue,Gao, Yang,Li, Zi-Qi,Liu, Peng,Tran, Van T.
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supporting information
p. 23306 - 23312
(2020/10/19)
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- Organocatalyzed Birch Reduction Driven by Visible Light
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The Birch reduction is a powerful synthetic methodology that uses solvated electrons to convert inert arenes to 1,4-cyclohexadienes - valuable intermediates for building molecular complexity. Birch reductions traditionally employ alkali metals dissolved in ammonia to produce a solvated electron for the reduction of unactivated arenes such as benzene (Ered -3.42 V vs SCE). Photoredox catalysts have been gaining popularity in highly reducing applications, but none have been reported to demonstrate reduction potentials powerful enough to reduce benzene. Here, we introduce benzo[ghi]perylene imides as new organic photoredox catalysts for Birch reductions performed at ambient temperature and driven by visible light from commercially available LEDs. Using low catalyst loadings (1 mol percent), benzene and other functionalized arenes were selectively transformed to 1,4-cyclohexadienes in moderate to good yields in a completely metal-free reaction. Mechanistic studies support that this unprecedented visible-light-induced reactivity is enabled by the ability of the organic photoredox catalyst to harness the energy from two visible-light photons to affect a single, high-energy chemical transformation.
- Cole, Justin P.,Chen, Dian-Feng,Kudisch, Max,Pearson, Ryan M.,Lim, Chern-Hooi,Miyake, Garret M.
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supporting information
p. 13573 - 13581
(2020/09/03)
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- A recyclable, metal-free mechanochemical approach for the oxidation of alcohols to carboxylic acids
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The oxidation of primary alcohols under mechanochemical conditions in a Spex8000M Mixer/Mill was investigated. To facilitate ease of separation and recyclability, a polystyrene-bound version of a TEMPO catalyst was employed. When paired with Oxone in a stainless-steel vial with a stainless-steel ball, several primary alcohols were successfully oxidized to the corresponding carboxylic acids. The product was isolated using gravity filtration, which also allowed for the polystyrene-bound TEMPO catalyst to be recovered and reused in subsequent oxidation reactions. Furthermore, it was demonstrated that the size and steric hindrance of the primary alcohol does not hinder the rate of the reaction. Finally, the aldehyde was selectively obtained from a primary alcohol under ball milling conditions by using a combination of non-supported TEMPO with a copper vial and copper ball.
- Carr, Preston,Denlinger, Kendra Leahy,Mack, James,Waddell, Daniel C.
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- Carbonylative Transformation of Allylarenes with CO Surrogates: Tunable Synthesis of 4-Arylbutanoic Acids, 2-Arylbutanoic Acids, and 4-Arylbutanals
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In this Communication, procedures for the selective synthesis of 4-arylbutanoic acids, 2-arylbutanoic acids, and 4-arylbutanals from the same allylbenzenes have been developed. With formic acid or TFBen as the CO surrogate, reactions proceed selectively and effectively under carbon monoxide gas-free conditions.
- Wu, Fu-Peng,Li, Da,Peng, Jin-Bao,Wu, Xiao-Feng
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supporting information
p. 5699 - 5703
(2019/08/01)
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- Direct Carbon Isotope Exchange through Decarboxylative Carboxylation
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A two-step degradation-reconstruction approach to the carbon-14 radiolabeling of alkyl carboxylic acids is presented. Simple activation via redox-active ester formation was followed by nickel-mediated decarboxylative carboxylation to afford a range of complex compounds with ample isotopic incorporations for drug metabolism and pharmacokinetic studies. The practicality and operational simplicity of the protocol were demonstrated by its use in an industrial carbon-14 radiolabeling setting.
- Kingston, Cian,Wallace, Michael A.,Allentoff, Alban J.,Degruyter, Justine N.,Chen, Jason S.,Gong, Sharon X.,Bonacorsi, Samuel,Baran, Phil S.
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supporting information
p. 774 - 779
(2019/01/14)
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- Synthesis of Carboxylic Acids by Palladium-Catalyzed Hydroxycarbonylation
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The synthesis of carboxylic acids is of fundamental importance in the chemical industry and the corresponding products find numerous applications for polymers, cosmetics, pharmaceuticals, agrochemicals, and other manufactured chemicals. Although hydroxycarbonylations of olefins have been known for more than 60 years, currently known catalyst systems for this transformation do not fulfill industrial requirements, for example, stability. Presented herein for the first time is an aqueous-phase protocol that allows conversion of various olefins, including sterically hindered and demanding tetra-, tri-, and 1,1-disubstituted systems, as well as terminal alkenes, into the corresponding carboxylic acids in excellent yields. The outstanding stability of the catalyst system (26 recycling runs in 32 days without measurable loss of activity), is showcased in the preparation of an industrially relevant fatty acid. Key-to-success is the use of a built-in-base ligand under acidic aqueous conditions. This catalytic system is expected to provide a basis for new cost-competitive processes for the industrial production of carboxylic acids.
- Sang, Rui,Kucmierczyk, Peter,Dühren, Ricarda,Razzaq, Rauf,Dong, Kaiwu,Liu, Jie,Franke, Robert,Jackstell, Ralf,Beller, Matthias
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supporting information
p. 14365 - 14373
(2019/09/06)
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- Bidentate Ru(ii)-NC complexes as catalysts for the dehydrogenative reaction from primary alcohols to carboxylic acids
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Four Ru(ii)-NC complexes were synthesized by one-step processes from the corresponding NC ligands with RuHCl(CO)(PPh3)3. These complexes were tested as catalysts for alcohol dehydrogenative reactions, and complex {(C5H4N)-(C6H4)}RuCl(CO)(PPh3)2 (1) showed the highest activity. With KOH as the nucleophile and 0.5 mol% catalyst loading, a series of carboxylic acids were synthesized in toluene without any oxidant. Catalyst 1 could be transformed to complex {(C5H4N)-(C6H4)}RuH(CO)(PPh3)2 (6) when treated with KOH and benzyl alcohol. Complex 6 further reacted with PhCHO and H2O to generate product {(C5H4N)-(C6H4)}Ru(OCOPh)(CO)(PPh3)2 (7). Complexes 6 and 7 exhibited similar efficiency to complex 1, suggesting that they can be regarded as the catalytic intermediates of 1.
- Gong, Dawei,Hu, Bowen,Chen, Dafa
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p. 8826 - 8834
(2019/06/24)
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- Strategic Approach to the Metamorphosis of γ-Lactones to NH γ-Lactams via Reductive Cleavage and C-H Amidation
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A new approach has elaborated on the conversion of γ-lactones to the corresponding NH γ-lactams that can serve as γ-lactone bioisosteres. This approach consists of reductive C-O cleavage and an Ir-catalyzed C-H amidation, offering a powerful synthetic tool for accessing a wide range of valuable NH γ-lactam building blocks starting from γ-lactones. The synthetic utility was further demonstrated by the late-stage transformation of complex bioactive molecules and the asymmetric transformation.
- Jung, Hoi-Yun,Chang, Sukbok,Hong, Sungwoo
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supporting information
p. 7099 - 7103
(2019/09/07)
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- Synthesis of plasmodione metabolites and 13C-enriched plasmodione as chemical tools for drug metabolism investigation
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Malaria is a tropical parasitic disease threatening populations in tropical and sub-tropical areas. Resistance to antimalarial drugs has spread all over the world in the past 50 years, thus new drugs are urgently needed. Plasmodione (benzylmenadione series) has been identified as a potent antimalarial early lead drug, acting through a redox bioactivation on asexual and young sexual blood stages. To investigate its metabolism, a series of plasmodione-based tools, including a fully 13C-labelled lead drug and putative metabolites, have been designed and synthesized for drug metabolism investigation. Furthermore, with the help of UHPLC-MS/MS, two of the drug metabolites have been identified from urine of drug-treated mice.
- Feng, Liwen,Lanfranchi, Don Antoine,Cotos, Leandro,Cesar-Rodo, Elena,Ehrhardt, Katharina,Goetz, Alice-Anne,Zimmermann, Herbert,Fenaille, Fran?ois,Blandin, Stephanie A.,Davioud-Charvet, Elisabeth
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supporting information
p. 2647 - 2665
(2018/04/27)
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- An Electrophilic Trifluoromethylthiolation of Silylenol Ethers and β-Naphthols with Diethylaminosulfur Trifluoride and (Trifluoromethyl)trimethylsilane
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An efficient and general trifluoromethylthiolation of silylenol ethers and β-naphthols have been accomplished employing the combination of diethylaminosulfur trifluoride (DAST) and (trifluoromethyl)trimethylsilane (CF3TMS) as source of electrophilic trifluoromethylthio moiety for the synthesis of α-trifluoromethylthiolated carbonyl compounds and β-naphthols in good yields. Important features of this method include wide functional group tolerance and use of readily available DAST/CF3TMS. Potential of the methodology was demonstrated via the synthesis of α-trifluoromethylthiolated (+)-4-cholesten-3-one and naphthoquinone. (Figure presented.).
- Saravanan, Perumal,Anbarasan, Pazhamalai
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supporting information
p. 2894 - 2899
(2018/08/17)
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- Nickel(0)-catalyzed linear-selective hydroarylation of unactivated alkenes and styrenes with aryl boronic acids
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Herein, we describe the first linear-selective hydroarylation reaction of unactivated alkenes and styrenes with aryl boronic acids, which was achieved by introducing a directing group on the alkenes. This efficient, scalable reaction serves as a method for modular assembly of structurally diverse alkyl arenes, including γ-aryl butyric acid derivatives, which are widely utilized as chemical building blocks for the synthesis of various drugs and other biologically active compounds.
- Lv, Honggui,Xiao, Li-Jun,Zhao, Dongbing,Zhou, Qi-Lin
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p. 6839 - 6843
(2018/09/11)
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- Palladium(ii)-catalyzed γ-selective hydroarylation of alkenyl carbonyl compounds with arylboronic acids
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A catalytic γ-selective syn-hydroarylation of alkenyl carbonyl compounds using arylboronic acids has been developed using a substrate directivity approach with a palladium(ii) catalyst. This method tolerates a wide range of functionalized (hetero)arylboronic acids and a variety of substitution patterns on the alkene. Preliminary mechanistic studies suggest that transmetalation is rate-limiting.
- Matsuura, Rei,Jankins, Tanner C.,Hill, David E.,Yang, Kin S.,Gallego, Gary M.,Yang, Shouliang,He, Mingying,Wang, Fen,Marsters, Rohan P.,McAlpine, Indrawan,Engle, Keary M.
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p. 8363 - 8368
(2018/11/24)
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- Regioselectivity inversion tuned by iron(iii) salts in palladium-catalyzed carbonylations
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Impactful regioselectivity control is crucial for cost-effective chemical synthesis. By using cheap and abundant iron(iii) salts, the hydroxycarbonylations of both aromatic and aliphatic alkenes were significantly enhanced in both reactivity and selectivity (iso/n or n/iso up to >99:1). Moreover, Pd-catalyzed carbonylation selectivity can be switched from branched to linear by using different Fe(iii) salts. In addition, similar results were obtained for the carbonylation of secondary alcohols.
- Huang, Zijun,Cheng, Yazhe,Chen, Xipeng,Wang, Hui-Fang,Du, Chen-Xia,Li, Yuehui
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supporting information
p. 3967 - 3970
(2018/04/23)
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- Efficient Water Reduction with sp3-sp3 Diboron(4) Compounds: Application to Hydrogenations, H–D Exchange Reactions, and Carbonyl Reductions
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A series of crystalline sp3-sp3 diboron(4) compounds were synthesized and shown to promote the facile reduction of water with dihydrogen formation. The application of these diborons as simple and effective dihydrogen and dideuterium sources was demonstrated by conducting a series of selective reductions of alkynes and alkenes, and hydrogen–deuterium exchange reactions using two-chamber reactors. Finally, as the water reduction reaction generates an intermediate borohydride species, a range of aldehydes and ketones were reduced by using water as the hydride source.
- Flinker, Mathias,Yin, Hongfei,Juhl, René W.,Eikeland, Espen Z.,Overgaard, Jacob,Nielsen, Dennis U.,Skrydstrup, Troels
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supporting information
p. 15910 - 15915
(2017/11/23)
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- Selective Aerobic Oxidation of Primary Alcohols to Aldehydes
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The 2-azaadamantane- N -oxyl (AZADO)- and 9-azanoradamantane- N -oxyl (nor-AZADO)-catalyzed selective oxidation of primary alcohols to the corresponding aldehydes is described. The use of tert -butyl nitrite as the co-catalyst enables efficient aerobic oxidation in MeCN instead of previously reported AcOH; this is important for the selectivity of the reaction. The addition of a solution of saturated aqueous NaHCO 3 after the completion of the reaction was effective to suppress the overoxidation of the product to the corresponding carboxylic acid during the workup.
- Shibuya, Masatoshi,Furukawa, Keisuke,Yamamoto, Yoshihiko
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p. 1554 - 1557
(2017/08/11)
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- Cobalt-Catalyzed 1,1-Diboration of Terminal Alkynes: Scope, Mechanism, and Synthetic Applications
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A cobalt-catalyzed method for the 1,1-diboration of terminal alkynes with bis(pinacolato)diboron (B2Pin2) is described. The reaction proceeds efficiently at 23 °C with excellent 1,1-selectivity and broad functional group tolerance. With the unsymmetrical diboron reagent PinB-BDan (Dan = naphthalene-1,8-diaminato), stereoselective 1,1-diboration provided products with two boron substituents that exhibit differential reactivity. One example prepared by diboration of 1-octyne was crystallized, and its stereochemistry established by X-ray crystallography. The utility and versatility of the 1,1-diborylalkene products was demonstrated in a number of synthetic applications, including a concise synthesis of the epilepsy medication tiagabine. In addition, a synthesis of 1,1,1-triborylalkanes was accomplished through cobalt-catalyzed hydroboration of 1,1-diborylalkenes with HBPin. Deuterium-labeling and stoichiometric experiments support a mechanism involving selective insertion of an alkynylboronate to a Co-B bond of a cobalt boryl complex to form a vinylcobalt intermediate. The latter was isolated and characterized by NMR spectroscopy and X-ray crystallography. A competition experiment established that the reaction involves formation of free alkynylboronate and the two boryl substituents are not necessarily derived from the same diboron source.
- Krautwald, Simon,Bezdek, Máté J.,Chirik, Paul J.
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supporting information
p. 3868 - 3875
(2017/03/20)
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- PROCEDURE FOR THE PREPARATION OF 4-PHENYL BUTYRATE AND USES THEREOF
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Provided is a process for preparing 4-phenyl-1-butyric acid, comprising: reacting 4-phenyl-1-butanol with sodium chlorite, a nitroxyl radical catalyst and sodium hypochlorite in an organic solvent and a phosphate buffer; and quenching the reaction with so
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Paragraph 0049-0051
(2017/12/29)
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- Preparation method of carboxylic acid compound
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The invention provides a preparation method of a carboxylic acid compound. The preparation method comprises the following step of taking a lactone component to react with hydrogen in the presence of a compound catalyst to obtain the carboxylic acid compound. The compound catalyst comprises a hydrogenation catalyst and Lewis acid. In the presence of the compound catalyst comprising the hydrogenation catalyst and the Lewis acid, the lactone component is subjected to hydrogenation ring-opening reaction to obtain the carboxylic acid compound. The preparation method has the advantages of moderate reaction conditions and high yield; compared with a traditional method, less byproducts are generated, green and chemical requirements are met and the industrial value is better.
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Paragraph 0113; 0176-0178
(2017/08/29)
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- A Comprehensive Study on Metal Triflate-Promoted Hydrogenolysis of Lactones to Carboxylic Acids: From Synthetic and Mechanistic Perspectives
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Direct hydrogenolysis of lactone to carboxylic acid (i.e., hydrogenolysis of the Calkoxy-O bond with the carbonyl group untouched) is generally difficult, as the current strategies employing Br?nsted acids as the catalyst usually require harsh conditions such as a high temperature and a high H2 pressure. Herein, we report a developed solvent-free catalytic transformation, in which W(OTf)6 is believed to promote the hydrogenolysis process. This strategy could efficiently hydrogenate lactones to carboxylic acids under extra mild conditions (e.g., a reaction temperature of 2) and showed a broad substrate scope. In addition, the catalytic protocol can be further applied to the hydrogenolysis of polyhydroxyalkanoate, as a renewable polymer, to the corresponding straight-chain carboxylic acids. An extensive mechanistic study was subsequently performed, and the density functional theory calculations revealed a reaction pattern, including the complete cleavage of the C=O bond with the assistance of the W(OTf)6 catalyst. Moreover, the key intermediate created in the mechanism, as an oxonium with an OTf moiety, was successfully detected by electrospray ionization mass spectra. Through a comparison with the Br?nsted acid-catalyzed system, the study confirmed that the existence of the OTf moiety can significantly lower the barriers associated with the rearrangement and elimination processes. Meanwhile, emphasis was placed on the critical role that the anion plays, as well as the fact that the anion effect is directly related to the chemoselectivity.
- Zhu, Rui,Jiang, Ju-Long,Li, Xing-Long,Deng, Jin,Fu, Yao
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p. 7520 - 7528
(2017/11/10)
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- COMPOUNDS FOR INHIBITING LIPID OXIDATION AND A METHOD FOR PRODUCING THE SAME
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The present invention relates to a compound for inhibiting lipid oxidation, and a producing method thereof. The compound for inhibiting lipid oxidation is synthesized by a transesterification reaction though a vinyl reaction and a lipase-catalyzed reaction. The produced compound for inhibiting lipid oxidation has an excellent effect of inhibiting oxidation according to a total oxidation value (TOTOX) which is a combination of a P-anisidine value (P-AnV) and a peroxide value (PV) and an analysis of a thiobarbituric acid reaction substance (TBARS).COPYRIGHT KIPO 2016
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Paragraph 0135-0136; 0143
(2017/05/03)
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- Purification method of phenylbutyric acid
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The invention discloses a purification method of phenylbutyric acid. The purification method comprises the following steps: (1) under catalysis of a catalyst, industrial grade phenylbutyric acid reacts in an alcohol solvent, and the system after reaction is treated to obtain 4-phenylbutyrate; and (2) in presence of a basic catalyst or acidic catalyst, the 4-phenylbutyrate hydrolyzes in a solvent to obtain purified phenylbutyric acid, so that purification of the industrial grade phenylbutyric acid is realized According to the purification method disclosed by the invention, a commercially available phenylbutyric acid industrial product is taken as a raw material, firstly methyl 4-phenylbutyrate is prepared, and then high-purity phenylbutyric acid is obtained by hydrolysis and acidification to provide a raw material for obtaining high-purity sodium phenylbutyrate. The purification method takes alcohols (methanol and ethanol) as reaction solvents, and compared with synthetic methods of phenylbutyric acid in the prior art, the purification method disclosed by the invention is more environment-friendly and greener, purification of the phenylbutyric acid is realized by two steps of ordinary reaction, the purity of the purified phenylbutyric acid achieves 99.5%, and single impurity is controlled within 0.13%.
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Paragraph 0057-0065
(2017/01/17)
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- Preparation method for sodium phenylbutyrate
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The invention discloses a preparation method for sodium phenylbutyrate. The method comprises the following steps: (1) purification of 4-phenylbutyric acid: 1) under the catalysis of a catalyst, reacting industrial grade phenylbutyric acid in alcoholic solvents, and treating a reacted system to obtain the 4-phenylbutyric acid; 2) in the existence of an alkali catalyst or an acidic catalyst, performing hydrolysis reaction on the 4-phenylbutyric acid in a solvent to obtained purified phenylbutyric acid, namely, the industrial grade phenylbutyric acid is purified; (2) preparation of the sodium phenylbutyrate: enabling the phenylbutyric acid which is purified by the step 1) to react with a sodium reagent to obtain the sodium phenylbutyrate. According to the preparation method disclosed by the invention, alcohols (methyl alcohol and ethyl alcohol) serve as reaction solvents, so that the preparation method is more environmentally -friendly and green compared with a synthesis method in the prior art; the preparation of high-purity methyl alcohol is realized through a three-step conventional reaction; the purity of the sodium phenylbutyrate prepared by the preparation method reaches 99.5 percent or above, and single impurities are controlled to be within 0.1 percent.
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Paragraph 0068; 0073; 0074
(2017/06/29)
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- Cp2TiCl2-Catalyzed Regioselective Hydrocarboxylation of Alkenes with CO2
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Cp2TiCl2-catalyzed regioselective hydrocarboxylation of alkenes with CO2 to give carboxylic acids in high yields has been developed in the presence of iPrMgCl. The reaction proceeds with a wide range of alkenes under mild conditions. Styrene and its derivatives can transform to α-aryl carboxylic acids, and aliphatic alkenes can transform to form alkanoic acids.
- Shao, Peng,Wang, Sheng,Chen, Chao,Xi, Chanjuan
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supporting information
p. 2050 - 2053
(2016/06/01)
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- Ultrasmall Platinum Nanoparticles Supported Inside the Nanospaces of Periodic Mesoporous Organosilica with an Imidazolium Network: An Efficient Catalyst for the Aerobic Oxidation of Unactivated Alcohols in Water
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The imidazolium group inside the wall of a periodic mesoporous organosilica provides an excellent environment for the stabilization of ultrasmall Pt nanoparticles ((NP)@PMO-IL) with significant activity and recyclability in the selective aerobic oxidation of various alcohols in water at ambient pressure of oxygen. In particular, the catalyst exhibited high activity in the oxidation of unactivated primary alcohols and sterically encumbered secondary aliphatic alcohols, which remain challenging substrates for many catalytic aerobic protocols.
- Karimi, Babak,Naderi, Zahra,Khorasani, Mojtaba,Mirzaei, Hamid M.,Vali, Hojatollah
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p. 906 - 910
(2016/03/15)
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- Palladium-Catalyzed Heck-type Domino Cyclization and Carboxylation to Synthesize Carboxylic Acids by Utilizing Chloroform as the Carbon Monoxide Source
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A palladium-catalyzed domino cyclization and carboxylation reaction for synthesis of a variety of carboxylic acids was developed, where chloroform was used as "carbon monoxide" source. The in situ generated neopentylpalladium species by Heck cyclization was efficiently trapped by dichlorocarbene to form a series of carboxylic acids. It was found that in this type of domino reaction CHCl3 is a convenient and safe alternation for CO gas.
- Liu, Xianglei,Li, Bin,Gu, Zhenhua
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p. 7547 - 7554
(2015/08/18)
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- Unexpected dehomologation of primary alcohols to one-carbon shorter carboxylic acids using o-iodoxybenzoic acid (IBX)
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A novel and efficient transformation of primary alcohols to one-carbon shorter carboxylic acids using IBX is reported. Mechanistic studies revealed that the combination of IBX and molecular iodine produces a different active hypervalent iodine species.
- Xu, Shu,Itto, Kaori,Satoh, Masahide,Arimoto, Hirokazu
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supporting information
p. 2758 - 2761
(2014/03/21)
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- Borontribromide-mediated C-C bond formation in cyclic ketones: A transition metal free approach
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Borontribromide (BBr3) is a well-known demethylating agent. The current investigation was focused on a new application of borontribromide as a C-C bond forming agent in cyclic ketones. In this study, borontribromide mediated C-C bond formation reactions of tetralones, chromenone, thiochromenone and indanones were explored. A methoxy group containing ketones showed selective C-C bond formation reaction instead of demethylation of the methoxy group. MM2 steric energy calculations for the final products showed that the reaction favored the formation of exo- or endo-cyclic double bond containing products, depending upon their low MM2 steric energy in a specific frame structure, as observed in X-ray crystallography. A comprehensive crystallographic and pi-stacking analysis of product 10a demonstrated the formation of 10a as an enantiomeric mixture, and its centre of inversion was stabilized by a set of three unique pi-pi interactions.
- Ahmad, Imran,Pathak, Vinay,Vasudev, Prema G.,Maurya, Hardesh K.,Gupta, Atul
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p. 24619 - 24634
(2014/07/07)
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- Mechanism of SmI2/amine/H2O-promoted chemoselective reductions of carboxylic acid derivatives (esters, acids, and amides) to alcohols
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Samarium(II) iodide-water-amine reagents have emerged as some of the most powerful reagents (E° = -2.8 V) for the reduction of unactivated carboxylic acid derivatives to primary alcohols under single electron transfer conditions, a transformation that had been considered to lie outside the scope of the classic SmI2 reductant for more than 30 years. In this article, we present a detailed mechanistic investigation of the reduction of unactivated esters, carboxylic acids, and amides using SmI2-water-amine reagents, in which we compare the reactivity of three functional groups. The mechanism has been studied using the following: (i) kinetic, (ii) reactivity, (iii) radical clock, and (iv) isotopic labeling experiments. The kinetic data indicate that for the three functional groups all reaction components (SmI2, amine, water) are involved in the rate equation and that the rate of electron transfer is facilitated by base assisted deprotonation of water. Notably, the mechanistic details presented herein indicate that complexation between SmI2, water, and amines can result in a new class of structurally diverse, thermodynamically powerful reductants for efficient electron transfer to a variety of carboxylic acid derivatives. These observations will have important implications for the design and optimization of new processes involving Sm(II)-reduction of ketyl radicals. (Chemical Equation Presented).
- Szostak, Michal,Spain, Malcolm,Eberhart, Andrew J.,Procter, David J.
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p. 11988 - 12003
(2015/01/16)
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- Ketyl-type radicals from cyclic and acyclic esters are stabilized by SmI2(H2O)n: the role of SmI2(H 2O)n in post-electron transfer steps
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Mechanistic details pertaining to the SmI2-H2O- mediated reduction and reductive coupling of 6-membered lactones, the first class of simple unactivated carboxylic acid derivatives that had long been thought to lie outside the reducing range of SmI2, have been elucidated. Our results provide new experimental evidence that water enables the productive electron transfer from Sm(II) by stabilization of the radical anion intermediate rather than by solely promoting the first electron transfer as originally proposed. Notably, these studies suggest that all reactions involving the generation of ketyl-type radicals with SmI2 occur under a unified mechanism based on the thermodynamic control of the second electron transfer step, thus providing a blueprint for the development of a broad range of novel chemoselective transformations via open-shell electron pathways.
- Szostak, Michal,Spain, Malcolm,Procter, David J.
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supporting information
p. 8459 - 8466
(2014/06/24)
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- Organocatalytic one-pot oxidative cleavage of terminal diols to dehomologated carboxylic acids
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The organocatalytic one-pot oxidative cleavage of terminal 1,2-diols to one-carbon-unit-shorter carboxylic acids is described. The combination of 1-Me-AZADO (cat.), NaOCl (cat.), and NaClO2 caused smooth one-pot oxidative cleavage under mild conditions. A broad range of substrates including carbohydrates and N-protected amino diols were converted without epimerization. Terminal triols and tetraols respectively underwent cleavage of their C-2 and C-3 moieties to afford their corresponding two- and three-carbon-unit-shorter carboxylic acids.
- Shibuya, Masatoshi,Doi, Ryusuke,Shibuta, Takuro,Uesugi, Shun-Ichiro,Iwabuchi, Yoshiharu
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supporting information
p. 5006 - 5009
(2013/01/15)
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- Nitroxyl radical/PhI(OAc)2: One-pot oxidative cleavage of vicinal diols to (di)carboxylic acids
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A mild and user-friendly one-pot oxidative cleavage of vicinal diols to their corresponding (di)carboxylic acids using AZADOs and PhI(OAc)2 is described. 1,2-Diols and 2,3-diols as well as 1,2,3-triol gave one- or two-carbon-unit-shorter carboxylic acids. Internal vicinal diols also smoothly underwent one-pot oxidative cleavage to afford the corresponding dicarboxylic acids. Cyclic vicinal diols are converted to their corresponding open-form dicarboxylic acids.
- Shibuya, Masatoshi,Shibuta, Takuro,Fukuda, Hayato,Iwabuchi, Yoshiharu
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supporting information
p. 5010 - 5013
(2013/01/15)
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- One-pot synthesis of trichloromethyl carbinols from primary alcohols
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Versatile trichloromethyl carbinols can be prepared in one pot from primary alcohols by treatment with Dess-Martin periodinane (DMP) in CHCl3 followed by introduction of commercially available 1,5,7-triazabicyclo[4.4.0] dec-5-ene (TBD). A modification of the method was used to convert chiral primary alcohol (R)-(-)-2,2-dimethyl-1,3-dioxolane-4-methanol to the corresponding trichloromethyl carbinol with complete stereochemical fidelity, despite the reactant proceeding through a base-sensitive aldehyde intermediate.
- Gupta, Manoj K.,Li, Zhexi,Snowden, Timothy S.
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experimental part
p. 4854 - 4860
(2012/07/30)
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- Synthesis of uniformly 13C-labeled polycyclic aromatic hydrocarbons
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Convergent synthetic pathways were devised for efficient synthesis of a series of uniformly 13C labeled polycyclic aromatic hydrocarbons de novo from U-13C-benzene and other simple commercially-available 13C-starting compounds. All target products were obtained in excellent yields, including the alternant PAH U-13C-naphthalene, U-13C-phenanthrene, U-13C-anthracene, U- 13C-benz[a]anthracene, U-13C-pyrene and the nonalternant PAH U-13C-fluoranthene.
- Zhang, Zhenfa,Sangaiah, Ramiah,Gold, Avram,Ball, Louise M.
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supporting information; experimental part
p. 5431 - 5435
(2011/09/14)
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- Peptide/laccase cocatalyzed asymmetric α-oxyamination of aldehydes
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An asymmetric α-oxyamination could be successfully performed by a peptide catalyst and laccase. The combination of peptide catalysis and enzymatic air oxidation promoted the reaction smoothly in water without employing a metal reagent. The oxyaminated compounds could be obtained as both aldehyde and carboxylic acid products depending on the reaction conditions.
- Akagawa, Kengo,Kudo, Kazuaki
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scheme or table
p. 3498 - 3501
(2011/09/14)
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- Novel aerobic oxidation of primary sulfones to carboxylic acids
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Primary alkyl aryl sulfones are converted to the corresponding carboxylic acids in fair to excellent yield through double deprotonation and exposure to atmospheric oxygen. The methodology allows for the convenient synthesis of 13C labeled carboxylic acids.
- Bonaparte, Amy C.,Betush, Matthew P.,Panseri, Bettina M.,Mastarone, Daniel J.,Murphy, Ryan K.,Murphree, S. Shaun
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supporting information; experimental part
p. 1447 - 1449
(2011/05/08)
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- Highly efficient, organocatalytic aerobic alcohol oxidation
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5-Fluoro-2-azaadamantane N-oxyl (5-F-AZADO) realizes a simple, organocatalytic aerobic alcohol oxidation system that has a wide scope under mild conditions at ambient pressure and temperature and is weakly acidic and halogen- and transition-metal-free. The oxoammonium nitrate (5-F-AZADO +NO3-) works as a bifunctional catalyst of 5-F-AZADO and NOx that enables the catalytic aerobic oxidation of alcohols by itself (a metal-salt-free system).
- Shibuya, Masatoshi,Osada, Yuji,Sasano, Yusuke,Tomizawa, Masaki,Iwabuchi, Yoshiharu
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supporting information; experimental part
p. 6497 - 6500
(2011/06/23)
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- C-O hydrogenolysis catalyzed by Pd-PMHS nanoparticles in the company of chloroarenes
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Catalytic Pd(OAc)2 and polymethylhydrosiloxane (PMHS), in conjunction with aqueous KF, and a catalytic amount of an aromatic chloride, effects the chemo-, regio-, and stereoselective deoxygenation of benzylic oxygenated substrates at room temperature in THF. Preliminary mechanistic experiments suggest the process to involve palladium-nanoparticle-catalyzed hydrosilylation followed by C-O reduction. The chloroarene additive appears to facilitate the hydrogenolysis process through the slow controlled release of HCl.
- Rahaim, Ronald J.,Maleczka, Robert E.
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supporting information; experimental part
p. 584 - 587
(2011/04/23)
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- FLAVAN-3-OL CONTAINING FOODSTUFFS
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The use of a compound for the reduction or elimination of bitterness caused by flavan-3-ols is provided. Compositions having greater than 0.01 wt % flavan-3-ols and that comprise an effective amount of the compound are also provided. The compound conforms to the general formula (I): wherein R1 represents C2-C3 saturated or unsaturated divalent hydrocarbon radical, n is an integer from 0 to 3, and each X is independently selected from C1-C3 alkyloxy and OH; and wherein if n is 0 then R1 is C3 saturated divalent hydrocarbon radical or C2-C3 unsaturated divalent hydrocarbon radical; and wherein if n is greater than 0 then the compound has formula (II)
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- The conformational diastereomers of 7-substituted-(8Z)-8-chloro-6,7- dihydro-9-(1,2-dihydronaphthalen-4-yl)-5H-benzo[7]annulene derivatives, the question of atropisomerism versus ring inversion
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Conformational diastereomers of 7-substituted-(8Z)-8-chloro-6,7-dihydro-9- (1,2-dihydro- naphthalen-4-yl)-5H-benzo[7]annulene 1 are observed at room temperature in solution. Two conformational processes are possible in 1, i.e. atropisomerism around the sp2-sp2 pivot bond and ring inversion of cycloheptadiene moiety which together provide four minima structures. The 3J calculation by Haasnoot equation on optimized structures is accordance with the 7-substituents in pseudo equatorial (exo) position in both forms. The barrier to conformational process is determined by dynamic 1H-NMR spectroscopy to be δG≠(365K)=74.5±0.5 kJ/mol. Solvent dependent populations of the two forms are studied in DMSO-d6 and CDCl3, the population ratio is not sensitive to solvent polarity. ARKAT USA, Inc.
- Ranjbar, Parviz Rashidi,Roshan, Hamid
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scheme or table
p. 40 - 53
(2010/10/03)
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- 2-(Trimethylsilyl)-1,3-dithiane 1-oxide as a convenient reagent for the transformation of aldehydes and ketones into homologous carboxylic acids
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Aldehydes and ketones were converted into the corresponding homologous carboxylic acids in two steps by treatment with 2-(trimethylsilyl)-1,3-dithiane 1-oxide. A modified Peterson olefination of the carbonyl compounds gave ketene thioacetal sulfoxides that were readily cleaved in acidic acetonitrile to give the required carboxylic acids. Georg Thieme Verlag Stuttgart New York.
- Krohn, Karsten,Cludius-Brandt, Stephan
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experimental part
p. 2616 - 2620
(2010/09/10)
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- Unified oxidation protocol for the synthesis of carbonyl compounds using a manganese catalyst
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We have developed a unified protocol for the oxidation of ethers, benzylic compounds, and alcohols to carbonyl compounds. The protocol uses catalytic amounts of manganese(II) chloride tetrahydrate and tri(t-butyl)-2,2':6',2Prime;- terpyridine in combination with a stoichiometric amount of either m-chloroperbenzoic acid (MCPBA) or potassium hydrogen peroxysulfate (KHSO 5). A reagent system consisting of the Mn catalyst and MCPBA permitted the chemoselective sp3 C-H oxidation of alkyl ethers and benzylic compounds to generate the corresponding ketones. Alternatively, the water-soluble inorganic salt KHSO5 in combination with the Mn catalyst was used to oxidize alcohols to ketones or carboxylic acids. Importantly, the Mn catalyst/KHSO5 system eliminates technical difficulties associated with the isolation of carboxylic acid products. All the oxidations presented in this feature article proceed at sup-ambient temperature in an aerobic atmosphere, and can therefore be used in practical syntheses of complex organic molecules. Georg Thieme Verlag Stuttgart · New York.
- Kamijo, Shin,Amaoka, Yuuki,Inoue, Masayuki
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experimental part
p. 2475 - 2489
(2010/09/06)
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