- Oxidation by Chemical Manganese Dioxide. Part 3.1 Oxidation of Benzylic and Allylic Alcohols, Hydroxyarenes and Aminoarenes
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The combined use of chemical manganese dioxide (CMD) and molecular sieves in hexane (or in acetone) in general or CMD alone in particular cases enables the convenient and efficient oxidation of benzylic and allylic alcohols, phenols and amines under relatively mild conditions.
- Hirano, Masao,Yakabe, Sigetaka,Chikamori, Hideki,Clark, James H.,Morimoto, Takashi
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- Total Synthesis of (-)-Phorbaketal A
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A convergent asymmetric total synthesis of phorbaketal A was achieved in 10 steps through a Au(I)-catalyzed intramolecular spiroketalization reaction of an alkyne diol intermediate prepared from (R)-carvone and geranial. The spiroketalization reaction was
- Joung, Seewon,Kim, Rira,Lee, Hee-Yoon
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- 3,5-dimethylpyrazolium fluorochromate(VI)-catalysed oxidation of organic substrates by hydrogen peroxide under solvent-free conditions
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3,5-Dimethylpyrazolium fluorochromate (VI), C5H 8N2H[CrO3F], DmpzHFC, serves as an efficient catalyst for oxidation of primary, secondary and allylic alcohols to the corresponding carbonyl compounds using H2O2 at room temperature under solvent-free conditions. Oxidation of methyl phenyl sulfides and triphenylphosphine were also carried out successfully.
- Chaudhuri, Mihir K.,Dehury, Sanjay K.,Hussain, Sahid,Duarah, Ankur,Gogoi, Nayanmoni,Lakshmi Kantam
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- Transition Metal-Substituted Potassium Silicotungstate Salts as Catalysts for Oxidation of Terpene Alcohols with Hydrogen Peroxide
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Abstract: In this work, the catalytic activity of the transition metal-substituted potassium silicotungstate salts (i.e. K8-nSiMn+W11O39 (Mn+ = Cu2+, Co2+, Ni2+, Zn2+ and Fe3+) was investigated on the oxidation reactions of the terpene alcohols with H2O2 aqueous solution. The metal-substituted silicotungstate salts were easily synthesized in one-pot reactions of the precursor metal solutions (i.e. Na2WO4, Na2SiO3 and MCln) with KCl added in stoichiometric amount; after this precipitation step, the solid heteropoly salts were filtered and dried in an oven. This procedure of synthesis avoids multi-step processes that starts from the pristine heteropolyacid. The substituted metal heteropoly salts were characterized by infrared spectroscopy, measurements of the specific surface area (BET) and porosimetry by isotherms of adsorption/desorption of N2, X-rays diffraction, thermal analyses, dispersive X-rays spectroscopy, scanning electronic microscopy. The acidity strength was estimated by potentiometric titration with n-butylamine. All the salts were evaluated as catalysts in terpenic alcohols oxidation reactions with H2O2. The K5SiFeW11O39 was the most active and selective catalyst toward oxidation products. The impacts of the main reaction variables such as catalyst concentration, temperature, oxidant load, and nature of the terpene substrate were assessed. The highest activity of the K5SiFeW11O39 catalyst was assigned to the highest Lewis acidity. Graphic Abstract: [Figure not available: see fulltext.].
- da Silva, Marcio Jose,da Silva Andrade, Pedro Henrique,Sampaio, Vinicius Fernando Coelho
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- Asymmetric total synthesis of ieodomycin B
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Ieodomycin B, which shows in vitro antimicrobial activity, was isolated from a marine Bacillus species. A novel asymmetric total synthetic approach to ieodomycin B using commercially available geraniol was achieved. The approach involves the generation of 1,3-trans-dihydroxyl at C-3 and C-5 positions via a Crimmins-modified Evans aldol reaction and a chelation-controlled Mukaiyama aldol reaction of a p-methoxybenzyl-protected aldehyde, as well as the generation of a lactone ring in a deprotection-lactonization one-pot reaction.
- Lin, Shuangjie,Zhang, Jianting,Zhang, Zhibin,Xu, Tianxiang,Huang, Shuangping,Wang, Xiaoji
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- Remarkable substituent effects on the oxidizing ability of triarylbismuth dichlorides in alcohol oxidation
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Substituent effects on the oxidizing ability of triarylbismuth dichlorides were examined by intermolecular and intramolecular competition experiments on geraniol oxidation in the presence of DBU. It was found that the oxidizing ability of the dichlorides increases with increasing electron-withdrawing ability of the para substituents, and by introduction of a methyl group at the ortho position of the aryl ligands attached to the bismuth. The intermolecular and intramolecular H/D kinetic isotope effects observed for the competitive oxidation of p-bromobenzyl alcohols indicate that the rate-determining step involves C-H bond cleavage. Several primary and secondary alcohols were oxidized efficiently under mild conditions by the combined use of newly developed organobismuth(V) oxidants and DBU.
- Matano, Yoshihiro,Hisanaga, Teppei,Yamada, Hisatsugu,Kusakabe, Shingo,Nomura, Hazumi,Imahori, Hiroshi
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- Highly efficient aerobic oxidation of benzylic and allylic alcohols by a simple catalyst system of [RuCl2(p-cymene)]2/Cs2CO3
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A new catalyst system of [RuCl2(p-cymene)]2/Cs2CO3 has been disclosed for highly efficient aerobic oxidation of activated alcohols to the corresponding carbonyl compounds, which is characterized by its high selectivity and activity, operational simplicity, and low air and moisture sensitivity. (C) 2000 Elsevier Science Ltd.
- Lee,Chang
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- POLYMER-ANCHORED VANADIUM(V) AND MOLYBDENUM(VI) CATALYSTS FOR THE REGIOSELECTIVE EPOXIDATION OF (E)-GERANIOL WITH t-BUTYL HYDROPEROXIDE
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The reaction of (E)-geraniol with t-BuOOH in the presence of polymer-anchored VV or MoVI complexes gave 2,3-epoxygeraniol in high yields.The conversion and the selectivity by the MR-type polymer catalysts containing VV were comparable to those given by homogeneous catalyst based on VO(acac)2.The present catalysts can be used repeatedly without causing significant decrease in catalytic activity.
- Yokoyama, Toshiro,Nishizawa, Masato,Kimura, Tetsuo,Suzuki, Toshishige M.
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- Pt-Catalyzed selective oxidation of alcohols to aldehydes with hydrogen peroxide using continuous flow reactors
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The oxidation of alcohols to aldehydes is a powerful reaction pathway for obtaining valuable fine chemicals used in pharmaceuticals and biologically active compounds. Although many oxidants can oxidize alcohols, only a few hydrogen peroxide oxidations can be employed to continuously synthesize aldehydes in high yields using a liquid-liquid two-phase flow reactor, despite the possibility of the application toward a safe and rapid multi-step synthesis. We herein report the continuous flow synthesis of (E)-cinnamaldehyde from (E)-cinnamyl alcohol in 95%-98% yields with 99% selectivity for over 5 days by the selective oxidation of hydrogen peroxide using a catalyst column in which Pt is dispersed in SiO2. The active species for the developed selective oxidation is found to be zero-valent Pt(0) from the X-ray photoelectron spectroscopy measurements of the Pt surface before and after the oxidation. Using Pt black diluted with SiO2as a catalyst to retain the Pt(0) species with the optimal substrate and H2O2introduction rate not only enhances the catalytic activity but also maintains the activity during the flow reaction. Optimizing the contact time of the substrate with Pt and H2O2using a flow reactor is important to proceed with the selective oxidation to prevent the catalytic H2O2decomposition.
- Kon, Yoshihiro,Nakashima, Takuya,Yada, Akira,Fujitani, Tadahiro,Onozawa, Shun-Ya,Kobayashi, Shū,Sato, Kazuhiko
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supporting information
p. 1115 - 1121
(2021/02/16)
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- An alkenate compound containing an aromatic ring and its preparation and application
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The present invention discloses an enoate compound containing an aromatic ring and its preparation and application. The compound structure of the present invention is simple, easy to synthesize, synthetic raw materials are derived from natural products, pollution-free to the environment, eco-friendly. The compounds provided by the present invention have a good repellent and killing effect on aphids, while having a good inhibitory activity against plant pathogens, can be used as an aphid control agent and fungicide, and have good application prospects in the green prevention and control of pests and plant diseases.
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Paragraph 0049-0052
(2022/01/04)
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- Selective aerobic oxidation of benzylic and allylic alcohols catalyzed by Cu(OAc)2/TEMPO/Et2NH
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Selective oxidation of benzylic and allylic alcohols to their corresponding aldehyde/ketone derivative without affecting saturated alcohols is still a challenging endeavor in organic synthesis. Various metal complexes, especially the copper complexes in the presence of TEMPO are being used very often for such transformations under aerobic conditions, but they are not selective to allylic and benzylic alcohols. The use of copper salt for oxidation of alcohols in the absence of a ligand are very scarcely studied except for the one catalyzed by CuCl/TEMPO where chloride inhibition and lack of selective oxidation have been noted upon use of CuCl2. Herein we report a Cu(OAc)2 catalyzed and TEMPO mediated selective aerobic oxidation of benzylic and allylic alcohols to aldehyde/ketone in the presence of Et2NH. The method avoids pre-synthesis of the catalyst as in the case of Cu(II)/(I) complexes/TEMPO catalyzed oxidation reactions, requires low catalyst loading, employs cheaper copper salt, and gives excellent selectivity for oxidation of benzylic and allylic alcohols.
- Pasupuleti, Bala Gangadhar,Gogoi, Achinta,Bez, Ghanashyam
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p. 589 - 597
(2021/09/28)
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- Dysprosium-doped zinc tungstate nanospheres as highly efficient heterogeneous catalysts in green oxidation of terpenic alcohols with hydrogen peroxide
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A green route to oxidize terpenic alcohols (nerol and geraniol) with H2O2over a solid catalyst was developed. The Dy-doped ZnWO4catalyst was synthesized by coprecipitation and microwave-assisted hydrothermal heating, containing different dysprosium loads. All the catalysts were characterized through infrared spectroscopy, powder X-ray diffraction, surface area and porosimetry, transmission electronic microscopy image, andn-butylamine potentiometric titration analyses. The influence of main reaction parameters such as temperature, the stoichiometry of reactants, loads, and catalyst nature was assessed. ZnWO42.0 mol% Dy was the most active catalyst achieving the highest conversion (98%) and epoxide selectivity (78%) in nerol oxidation. The reaction scope was extended to other terpenic alcohols (i.e., geraniol, borneol, and α-terpineol). The highest activity of ZnWO42.0 mol% Dy was assigned to the lower crystallite size, higher surface area and pore volume, higher acidity strength and the greatest dysprosium load.
- Batalha, Daniel Carreira,Mesquita Borges, Kellen Cristina,de Fátima Gon?alves, Rosana,de Matos Rodrigues, Murillo Henrique,Godinho, Mário Júnior,Fajardo, Humberto Vieira,de Oliveira Bruziquesi, Carlos Giovani,da Silva, Márcio José
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p. 6661 - 6670
(2021/04/22)
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- Saegusa Oxidation of Enol Ethers at Extremely Low Pd-Catalyst Loadings under Ligand-free and Aqueous Conditions: Insight into the Pd(II)/Cu(II)-Catalyst System
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A highly efficient and practical Pd(II)/Cu(OAc)2-catalyst system of Saegusa oxidation, which converts enol ethers to the corresponding enals with a number of diverse substrates at extremely low catalyst loadings (500 mol ppm) under ligand-free and aqueous conditions, is described. Its synthetic utility was demonstrated by large-scale applications of the catalyst system to important nature molecules. This work allows Saegusa oxidation to become a highly practical approach to preparing enals and also suggests new insight into the Pd(II)/Cu(II)-catalyst system for dehydrogenation of carbonyl compounds and decreasing Pd-catalyst loadings.
- Zhu, Quan,Luo, Yunsong,Guo, Yongyan,Zhang, Yushun,Tao, Yunhai
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p. 5463 - 5476
(2021/05/05)
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- Method for preparing olefine aldehyde through catalytic oxidation of enol ether
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The invention relates to the technical field of olefine aldehyde preparation, and provides a method for preparing olefine aldehyde through catalytic oxidation of enol ether. According to the invention, a palladium catalyst, a copper salt, a solvent and enol ether are mixed and subjected to a catalytic oxidation reaction to obtain olefine aldehyde. According to the method, the copper salt is used as the oxidizing agent, the mixed solvent of water and acetonitrile is used as the reaction solvent, and the volume ratio of water to acetonitrile in the mixed solvent is controlled to be (3-7): (3-7), so that the catalytic oxidation reaction can be smoothly carried out in the mixed solvent with a specific ratio, and the generation of palladium black precipitate can be avoided. The method provided by the invention has the advantages of simple steps, low reagent cost, no need of dangerous reagents, wide substrate adaptability and small catalyst dosage. Furthermore, octadecane mercaptan is added to promote the catalytic oxidation reaction, and when the dosage of the palladium catalyst is extremely low, the olefine aldehyde yield can be greatly increased by adding octadecane mercaptan.
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Paragraph 0082-0086; 0089
(2021/06/23)
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- Unraveling the role of the lacunar Na7PW11O39 catalyst in the oxidation of terpene alcohols with hydrogen peroxide at room temperature
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In this work, we have assessed the activity of various Keggin heteropolyacid (HPA) salts in a new one-pot synthesis route of valuable products, which were obtained from the oxidation of terpenic alcohols (i.e., aldehyde, epoxide, and diepoxide), using a green oxidant (i.e., hydrogen peroxide) at mild conditions (i.e., room temperature). Lacunar Keggin HPA sodium salts were the goal catalysts investigated in this reaction. Starting from the HPAs (H3PW12O40, H3PMo12O40, and H4SiW12O40), we synthesized lacunar sodium salts (Na7PW11O39, Na7PW11O39 and Na8SiW11O39) and a saturated salt (Na3PW12O40). All of them were investigated in oxidation reactions in a homogeneous phase with nerol as a model molecule. Na7PW11O39 was the most active and selective towards the oxidation products. All the catalysts were characterized by FT-IR, TG/DSC, BET, XRD, and SEM-EDS analyses and potentiometric titration. The main reaction parameters were assessed. Geraniol, α-terpineol, β-citronellol and borneol were also successfully oxidized. Special attention was dedicated to correlating the composition and properties of the catalysts with their activity.
- Vilanculo, Castelo B.,Da Silva, Márcio J.
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p. 2813 - 2820
(2020/03/03)
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- Oxidation of terpenic alcohols with hydrogen peroxide promoted by Nb2O5 obtained by microwave-assisted hydrothermal method
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The present work describes the synthesis of niobium oxides by microwave-assisted hydrothermal method and their evaluation as a solid catalyst in oxidation reactions of terpenic alcohols with hydrogen peroxide. Effects of main parameters of synthesis were assessed and all the prepared catalysts were characterized by physical adsorption/ desorption analyses of nitrogen, infrared and Raman spectroscopies, scanning electron microscopy and powder X-rays diffraction analyses. The strength and number of acidic sites of the catalysts were determined by potentiometric titration. Morphological and structural characterization corroborate with the activity and selectivity achieved by the niobium oxides. The reusability of the catalyst was evaluated. The impacts of main reaction variables such as temperature, catalyst, and oxidant load were assessed. Niobium oxide demonstrated to be an effective catalyst, selectively converting the nerol (model molecule) to epoxide and aldehyde. Oxidation of various terpenic alcohols was investigated. Only geraniol and nerol were selectively epoxidized, suggesting a hydroxyl group assisted reaction. Although being also allylic alcohol, linalool was unreactive toward epoxidation due to the presence of a methyl group at the same carbon atom than the hydroxy group. The use of an environmentally cheap friendly oxidant (H2O2) and efficient solid catalyst (Nb2O5) are positive aspects of this process.
- Carreira Batalha, Daniel,Hadler Marins, Natália,Lenin Villarreal Carre?o, Neftalí,Marques e Silva, Ricardo,Vieira Fajardo, Humberto,da Silva, Márcio José
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- A Simple, Mild and General Oxidation of Alcohols to Aldehydes or Ketones by SO2F2/K2CO3 Using DMSO as Solvent and Oxidant
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A practical, general and mild oxidation of primary and secondary alcohols to carbonyl compounds proceeds in yields of up to 99% using SO2F2 as electrophile in DMSO as both the oxidant and the solvent at ambient temperature. No moisture- and oxygen-free conditions are required. Stoichiometric amount of inexpensive K2CO3, which generates easy to separate by-products, is used as the base. Thus, 5-gram scale runs proceeded in nearly quantitative yields by a simple filtration as the work-up. The use of a polar solvent such as DMSO, which usually promotes competing Pummerer rearrangement, is also noteworthy. This protocol is compatible with a variety of common N-, O-, and S-functional groups on (hetero)arene, alkene and alkyne substrates (68 examples). The protocol was applied (99% yield) to a formal synthesis of the important cholesterol-lowering drug Rosuvastatin. (Figure presented.).
- Zha, Gao-Feng,Fang, Wan-Yin,Leng, Jing,Qin, Hua-Li
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supporting information
p. 2262 - 2267
(2019/04/17)
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- Copper-Catalyzed One-Pot Borylative Aldolisation β-Fluoride Elimination for the Formal Addition of Acrylates to Carbonyl Moieties
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Herein, we report the copper-catalyzed domino borylation/aldolisation of methyl 2-fluoroacrylate with carbonyl compounds followed by an elimination to give Morita–Baylis–Hillman (MBH) analogues. The optimal conditions described were shown to be compatible
- Rasson, Corentin,Stouse, Adrien,Boreux, Arnaud,Cirriez, Virginie,Riant, Olivier
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supporting information
p. 9234 - 9237
(2018/06/04)
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- ATP3 and MTP3: Easily Prepared Stable Perruthenate Salts for Oxidation Applications in Synthesis
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The Ley–Griffith tetra-n-propylammonium perruthenate (TPAP) catalyst has been widely deployed by the synthesis community, mainly for the oxidation of alcohols to aldehydes and ketones, but also for a variety of other synthetic transformations (e.g. diol cleavage, isomerizations, imine formation and heterocyclic synthesis). Such popularity has been forged on broad reaction scope, functional group tolerance, mild conditions, and commercial catalyst supply. However, the mild instability of TPAP creates preparation, storage, and reaction reproducibility issues, due to unpreventable slow decomposition. In search of attributes conducive to catalyst longevity an extensive range of novel perruthenate salts were prepared. Subsequent evaluation unearthed a set of readily synthesized, bench stable, phosphonium perruthenates (ATP3 and MTP3) that mirror the reactivity of TPAP, but avoid storage decomposition issues.
- Moore, Peter W.,Read, Christopher D. G.,Bernhardt, Paul V.,Williams, Craig M.
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supporting information
p. 4556 - 4561
(2018/03/13)
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- Enantio- A nd regioselective: Ene-reductions using F420H2-dependent enzymes
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In the past decade it has become clear that many microbes harbor enzymes that employ an unusual flavin cofactor, the F420 deazaflavin cofactor. Herein we show that F420-dependent reductases (FDRs) can successfully perform enantio-, regio- A nd chemoselective ene-reductions. For the first time, we have demonstrated that F420H2-driven reductases can be used as biocatalysts for the reduction of α,β-unsaturated ketones and aldehydes with good conversions (>99%) and excellent regioselectivities and enantiomeric excesses (>99% ee). Noteworthily, FDRs typically display an opposite enantioselectivity when compared to the well established FMN-dependent Old Yellow Enzymes (OYEs).
- Mathew, Sam,Trajkovic, Milos,Kumar, Hemant,Nguyen, Quoc-Thai,Fraaije, Marco W.
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supporting information
p. 11208 - 11211
(2018/10/15)
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- Divergent synthesis of four isomers of 6,7-dihydroxy-3,7-dimethyloct-2-enoic acid, esters and evaluation for the antifungal activity
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The four isomers of 6,7-dihydroxy-3,7-dimethyloct-2-enoic acid 2 were synthesized via the selective direct Sharpless asymmetry dihydroxylation of geraniol as the key step in 35.0%-48.0% overall yields with 91.9%-97.7% ee values for esters 4 and 31.3%-36.4% overall yields with 90.3-97.5% ee values for acids 2 using cis- and trans-geraniol as raw materials. Their structures were characterized by 1H, 13C NMR and HR-ESI-MS data. The in vivo bioassay results showed that the chiral acid (Z, S)-2 was a good lead compound with 80%-100% inhibitory rates against P. cubensis, E. graminis, P. sorghi and C. gloeosporioides at the concentration of 400μg/mL.
- Wang, Weiwei,Zhang, Xiaoteng,Zhao, Yu,Liu, Xinlei,Zhang, Zhenhua,Wang, Mingan
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supporting information
(2018/03/12)
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- Monolacunary K8SiW11O39-Catalyzed Terpenic Alcohols Oxidation with Hydrogen Peroxide
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Abstract: Lacunar potassium undecasilicotungstate salt catalyst was highly efficient in oxidation reactions of terpenic alcohols with hydrogen peroxide. Carbonylic products were selectively obtained from alcohols such as borneol, nerol, geraniol and β-citronellol. The K8SiW11O39 catalyst was synthesized in one pot reaction starting from precursor salts (KCl, Na2WO4, and Na2SiO3). The catalyst salt was characterized by FT-IR, TG/DSC, BET, XRD analyses and potentiometric titration. The main reaction parameters were assessed. Based on experimental data, a reaction pathway was proposed. In borneol oxidation, TON of 2720 was achieved, indicating the high catalytic activity. As far we know, it is the first time where the monolacunar catalyst is used without an additional introduction of metal transition into Keggin anion. A comparison of the catalytic performance of different lacunar silicotungstic acid salts exchanged with different cations was performed. The K8SiW11O39 catalyst was used without loss activity.
- da Silva, Márcio José,da Silva Andrade, Pedro Henrique,Ferreira, Sukarno Olavo,Vilanculo, Castelo Bandane,Oliveira, Cesar Macedo
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p. 2516 - 2527
(2018/06/07)
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- A Highly Selective Na2WO4-Catalyzed Oxidation of Terpenic Alcohols by Hydrogen Peroxide
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Sodium tungstate was found to be an active and highly selective catalyst to oxidation of various primary or secondary origin renewable alcohols by hydrogen peroxide as green oxidant. Borneol, nerol, geraniol and β-citronellol were efficiently and selectively converted to respective carbonyl derivatives by hydrogen peroxide. ATR/FT-IR measurements confirmed that Na2W(O2)4 was the specie active catalytically. The role of the main reaction variables, including temperature, reactants and catalyst concentration, solvent, and nature of substrate were also assessed. In addition to use a green oxidant, this simple and environmentally friendly catalyst system did not require additive to control pH, molecular sieves or phase transfer catalyst. Graphical Abstract: [Figure not available: see fulltext.].
- Viana, Luna Andrade Silva,da Silva, Giovanna Rodrigues Nobile,da Silva, Márcio Jose
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p. 374 - 382
(2017/12/04)
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- Preparation method of trans-citral
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The invention relates to a preparation method of trans-citral. The method includes the following steps: a) adding myrcene, N-alkyl-N-trimethylsilylamine and an alkali catalyst into a first reactor, heating the mixture to a first preset temperature, and carrying out a stirring reaction for a first preset time to obtain a first intermediate product; b) at a second preset temperature, adding distilled water, stirring the mixture for a second preset time, after hydrolysis is completed, adding ammonium chloride to obtain a first mixture liquid, performing separation to obtain a first organic layer,and processing the first organic layer to obtain a first compound; c) adding the first compound and a first catalyst to a second reactor, heating the mixture to a third preset temperature, stirring the mixture for a third preset time, cooling the mixture to room temperature to obtain a second compound; d) mixing the second compound with a first acid mixture solution, and stirring the mixture fora fourth preset time at a fourth preset temperature, and cooling the mixture to room temperature to obtain a second mixture liquid; and e) separating the second mixture liquid to obtain a second organic layer, and processing the second organic layer to obtain the trans-citral. The method is reduced in preparation cost and increased in preparation efficiency, and satisfies practical application demands.
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- A bis(pyridyl)-: N -alkylamine/Cu(i) catalyst system for aerobic alcohol oxidation
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Herein a bis(pyridyl)-N-alkylamine/CuI/TEMPO/NMI catalyst system is reported for aerobic oxidation of a variety of primary alcohols to the corresponding aldehydes using readily available reagents, at room temperature and ambient air as the oxidant. ESI-MS analysis of the reaction showed the formation of a [(L1)(NMI)CuII-OOH]+ species, which is a key intermediate in the alcohol oxidation reaction. Evaluation of the effect of reaction parameters on the initial rate of the reaction allowed us to obtain the optimum conditions for catalytic activity. The careful choice of reaction solvent allowed for the oxidation of 4-hydroxybenzyl alcohol, a substrate which proved problematic in previous studies. In the case of 2-pyridinemethanol as substrate, experimental evidence shows that catalytic activity is diminished due to competitive inhibition of the catalyst by the alcohol substrate.
- Marais, Lindie,Burés, Jordi,Jordaan, Johan H. L.,Mapolie, Selwyn,Swarts, Andrew J.
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p. 6926 - 6933
(2017/09/01)
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- Effect of citral and citral related compounds on viability of pancreatic and human B-lymphoma cell lines
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Citral, 3,7-dimethyl-2,6-octadienal, is a key component of the essential oils extracted from several lemon-scented herbal plants. It has been demonstrated to be an effective antifungal agent and in recent years, to have antiproliferative effect in certain tumor cell lines: thus citral could be a potential anticancer drug. In this study, we investigated the effect of citral on the proliferation of pancreatic cell tumor lines (MIA PaCa-2 cells) and human B-lymphoma (DeFew cells). To analyze which part of the molecule is pivotal for the activity, we also studied the effect of several citral related compounds, in particular focusing on some chemical aspects of the terpenic scaffold. The in vitro studies revealed the significant cytotoxic activity of some of the tested compounds.
- Di Mola, Antonia,Massa, Antonio,De Feo, Vincenzo,Basile, Anna,Pascale, Maria,Aquino, Rita Patrizia,De Caprariis, Paolo
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p. 631 - 639
(2017/02/15)
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- 2-Iodoxybenzoic Acid Tosylates: the Alternative to Dess–Martin Periodinane Oxidizing Reagents
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Two powerful hypervalent iodine(V) oxidants, DMP-OTs (1-tosyloxy-1,1-diacetoxy-1H-1λ5-benzo[d][1,2]iodoxol-3-one) and IBX-OTs (1-tosyloxy-1-oxo-1H-1λ5-benzo[d][1,2]iodoxol-3-one) show high reactivity in the oxidation of structurally complex primary and secondary alcohols, which are highly functionalized polyketide or terpene fragments or steroids. The yields of the corresponding carbonyl compounds are even higher for the protocol that uses pyridine as additive. The oxidations proceed very rapidly at room temperature leaving the protective groups and π-systems intact and affording the corresponding carbonyl compounds in good to excellent yields. Moreover, IBX-OTs is an efficient reagent for the oxidative dehydrogenation of steroidal alcohols to the corresponding enones. (Figure presented.).
- Yusubov, Mekhman S.,Postnikov, Pavel S.,Yusubova, Roza Ya.,Yoshimura, Akira,Jürjens, Gerrit,Kirschning, Andreas,Zhdankin, Viktor V.
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p. 3207 - 3216
(2017/09/11)
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- Selective Oxidation of Activated Alcohols by Supported Gold Nanoparticles under an Atmospheric Pressure of O2: Batch and Continuous-Flow Studies
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In the hunt for a simple, mild, and scalable protocol for gold nanoparticle-catalyzed oxidation of benzylic and allylic alcohols under O2, we have used commercially available gold nanoparticles supported on alumina to selectively oxidize a large range of activated alcohols to the corresponding carbonyl compounds in good yields (68–99 %) and with excellent selectivity (ca. 100 %). The true heterogeneous nature of the catalysis by gold was demonstrated, allowing us to further adapt this protocol to continuous-flow reactors by using the tube-in-tube technology, in which higher yields were obtained thanks to an improved oxygenation of the reaction medium.
- Giorgi, Pascal D.,Elizarov, Nelli,Antoniotti, Sylvain
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p. 1830 - 1836
(2017/05/29)
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- Asymmetric Traceless Petasis Borono-Mannich Reactions of Enals: Reductive Transposition of Allylic Diazenes
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The traceless Petasis borono-Mannich reaction of enals, sulfonylhydrazines, and allylboronates, catalyzed by chiral biphenols, results in an asymmetric reductive transposition of the in situ generated allylic diazene. Acyclic 1,4-diene products bearing either alkyl- or aryl-substituted benzylic stereocenters are afforded in excellent yields and enantiomeric ratios of up to 99:1. The use of crotylboronates in the reaction results in concomitant formation of two stereocenters in either a 1,4-syn or anti relationship from the corresponding E- or Z-crotylboronate used in the reaction. The use of β-monosubstituted enals in the asymmetric traceless Petasis borono-Mannich reaction of crotylboronates installs tertiary methyl-bearing stereocenters in good yields and high enantioselectivities.
- Jiang, Yao,Thomson, Regan J.,Schaus, Scott E.
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p. 16631 - 16635
(2017/12/13)
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- Alkyldisulfanium salts: Isolable, electrophilic sulfur reagents competent for polyene cyclizations
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Tools that can effect electrophilic sulfur-promoted cation-π cyclizations are generally lacking, especially using alkylsulfide-based reagents. Herein we report that combining three different 1,2-dithioethers with Cl2 and SbCl5 generates isolable alkyldisulfanium salts that can effect such reactions. These new reagents can install -SMe, -SEt, and -SCH2CH2CF3 in modest, moderate, or good yield on diverse frameworks, including polyenes that terminate with electron-deficient groups. We also show that reagents such as dimethyl(methylthio)sulfonium tetrafluoroborate (DMTSF) can accomplish similar chemistry.
- Schevenels, Florian T.,Shen, Minxing,Snyder, Scott A.
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supporting information
p. 2 - 5
(2017/11/27)
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- Manufacture of Citronellal by the Rhodium-Catalyzed Homogeneous Hydrogenation of Neral
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The highly chemoselective hydrogenation of neral affording citronellal is described. The reaction has been conducted with homogeneous rhodium complexes. Among the set of ancillary diphosphane ligands tested, Xantphos was found to be superior. The relevant precatalyst has been generated from neutral metal sources such as Rh(acac)(CO)2 or the carbon monoxide-free rhodium source Rh(acac)(cod) in the absence of any base. A high activity and chemoselectivity in favor of the desired citronellal is achieved at 0.1 MPa and room temperature. Under the same conditions, geranial is also reduced to citronellal. The addition of carbon monoxide to the hydrogen stream as used in an industrial process is not necessary. (Figure presented.).
- Holz, Jens,Doerfelt, Stephan,B?rner, Armin
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p. 4379 - 4387
(2017/12/26)
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- Method of manufacturing calbonyl compd.
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PROBLEM TO BE SOLVED: To provide a method of manufacturing a carbonyl compound by smoothly performing a dehydrogenation reaction while preventing side reactions.SOLUTION: A method of manufacturing a carbonyl compound includes a process of converting alcohol to aldehyde or ketone by irradiating visible light to a reaction system containing a primary alcohol or a secondary alcohol, SrTiOcarrying a Ru atom and doped with Rh atom, and water.
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Paragraph 0051; 0053
(2018/06/30)
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- Exploration of Aryllithium-Derived Copper Reagents for Quaternary-Stereogenic-Center-Forming Allylic Substitution of γ,γ-Disubstituted Secondary Allylic Picolinates
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The allylic substitution of γ,γ-disubstituted secondary allylic picolinates (esters of 2-PyCO2H) with aryllithium-based copper reagents was carried out in order to construct quaternary carbons. Initially, 2-methyl-7-phenylhept-2-en-4-yl picolinate was reacted with phenyl copper reagents derived from phenyllithium with Cu(acac)2, Cu(OMe)2, CuBr·Me2S, and CuCN in 1-3:1 ratios in the presence of excess magnesium bromide. Although the SN2′ product with a quaternary carbon was formed, the regioselectivity was 90% at most. Instead, phenyllithium/copper(I) thiophene-2-carboxylate/magnesium bromide (Ph/Cu = 1.5-2:1, Mg/Li = >1) was found to produce >98% regioselectivity and sufficient reactivity. This system was successful with eight aryllithium based copper reagents possessing sterically congested, electron-donating, or electron-withdrawing substituents. The anti stereochemical course was established by using an enantiomerically enriched geranaldehyde-derived picolinate.
- Ozaki, Takuri,Kobayashi, Yuichi
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supporting information
p. 611 - 615
(2016/03/12)
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- The Convenient Way for Obtaining Geranial by Acid-Catalyzed Kinetic Resolution of Citral
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A new simple method has been developed for isolation of geranial from citral, which is a mixture of two isomeric aldehydes, geranial and neral. The storage of citral in the presence of K10 montmorillonite clay has been demonstrated to result in an almost complete conversion of neral to dimeric and oligomeric products, with most geranial remaining unconverted. This enables isolation of geranial with the yield of up to 94%, based on the amount of geranial originally present in citral.
- Il'Ina, Irina V.,Volcho, Konstantin P.,Korchagina, Dina V.,Salakhutdinov, Nariman F.
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p. 373 - 377
(2016/06/01)
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- METHOD FOR PRODUCING α,β-UNSATURATED CARBONYL COMPOUNDS
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PROBLEM TO BE SOLVED: To provide a simple and efficient, novel method for producing α,β-unsaturated carbonyl compounds, which can provide α,β-unsaturated carbonyl compounds from allyl alcohols with high yields under a mild reaction condition, and has extremely little influence and toxicity on the environment and the human body. SOLUTION: Provided is a method for producing α,β-unsaturated carbonyl compounds, the method comprising reacting allyl alcohols and hydrogen peroxide to carbonylate alcohol portions to produce corresponding α,β-unsaturated carbonyl compounds. As a reaction catalyst, there are used an Fe(II) or Fe(III) salt soluble in water or an organic solvent, and at least one picolinic acid selected from 2-picolinic acid and 6-C1-4 alkyl-2-picolinic acid in coexistence in a ratio of 1:1 to 1:4. COPYRIGHT: (C)2015,JPOandINPIT
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Paragraph 0037; 0042-0043
(2016/12/26)
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- Formulation, characterization, and antitumor properties of trans- and cis-citral in the 4T1 breast cancer xenograft mouse model
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Purpose Citral is composed of a random mixture of two geometric stereoisomers geranial (trans-citral) and neral (cis-citral) yet few studies have directly compared their in vivo antitumor properties. A micelle formulation was therefore developed. Methods Geranial and neral were synthesized. Commerciallypurchased citral, geranial, and neral were formulated in PEG-b-PCL (block sizes of 5000:10,000, Mw/Mn 1.26) micelles. In vitro degradation, drug release, cytotoxicity, flow cytometry, and western blot studies were conducted. The antitumor properties of drug formulations (40 and 80mg/kg based on MTD studies) were evaluated on the 4T1 xenograft mouse model and tumor tissues were analyzed by western blot. Results Micelles encapsulated drugs with >50% LE at 5-40% drug to polymer (w/w), displayed sustained release (t1/2 of 8-9 h), and improved drug stability at pH 5.0. The IC50 of drug formulations against 4T1 cells ranged from 1.4 to 9.9 μM. Western blot revealed that autophagy was the main cause of cytotoxicity. Geranial at 80 mg/kg was most effective at inhibiting tumor growth. Conclusions Geranial is significantly more potent than neral and citral at 80 mg/kg (p0.001) and western blot of tumor tissues confirms that autophagy and not apoptosis is the major mechanism of tumor growth inhibition in p53-null 4T1 cells.
- Zeng, San,Kapur, Arvinder,Patankar, Manish S.,Xiong, May P.
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p. 2548 - 2558
(2016/09/09)
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- Synthesis and fungicidal activities of (Z/E)-3,7-dimethyl-2,6-octadienamide and its 6,7-epoxy analogues
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In order to find new lead compounds with high fungicidal activity, (Z/E)-3,7-dimethyl- 2,6-octadienoic acids were synthesized via selective two-step oxidation using the commercially available geraniol/nerol as raw materials. Twenty-eight different (Z/E)-3,7-dimethyl-2,6-octadienamide derivatives were prepared by reactions of (Z/E)-carboxylic acid with various aromatic and aliphatic amines, followed by oxidation of peroxyacetic acid to afford their 6,7-epoxy analogues. All of the compounds were characterized by HR-ESI-MS and 1H-NMR spectral data. The preliminary bioassays showed that some of these compounds exhibited good fungicidal activities against Rhizoctonia solani (R. solani) at a concentration of 50 μg/mL. For example, 5C, 5I and 6b had 94.0%, 93.4% and 91.5% inhibition rates against R. solani, respectively. Compound 5f displayed EC50 values of 4.3 and 9.7 μM against Fusahum graminearum and R. Solani, respectively.
- Yang, Mingyan,Dong, Hongbo,Jiang, Jiazhen,Wang, Mingan
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p. 21023 - 21036
(2016/01/25)
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- Highly efficient aerobic oxidation of alcohols by using less-hindered nitroxyl-radical/copper catalysis: Optimum catalyst combinations and their substrate scope
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The oxidation of alcohols into their corresponding carbonyl compounds is one of the most fundamental transformations in organic chemistry. In our recent report, 2-azaadamantane N-oxyl (AZADO)/copper catalysis promoted the highly chemoselective aerobic oxidation of unprotected amino alcohols into amino carbonyl compounds. Herein, we investigated the extension of the promising AZADO/copper-catalyzed aerobic oxidation of alcohols to other types of alcohol. During close optimization of the reaction conditions by using various alcohols, we found that the optimum combination of nitroxyl radical, copper salt, and solution concentration was dependent on the type of substrate. Various alcohols, including highly hindered and heteroatom-rich ones, were efficiently oxidized into their corresponding carbonyl compounds under mild conditions with lower amounts of the catalysts.
- Sasano, Yusuke,Kogure, Naoki,Nishiyama, Tomohiro,Nagasawa, Shota,Iwabuchi, Yoshiharu
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supporting information
p. 1004 - 1009
(2015/03/31)
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- Catalytic activity of molybdenum(II) complexes in homogeneous and heterogeneous conditions
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The new complexes [MoBr(η3-C3H5)(CO)2(L)2] (C1) and [MX2(CO)3(L)2] (M = Mo(II), X = I (C2); M = Mo(II), X = Br (C3); M = W(II), X = I (C4); M = W(II), X = Br (C5)) were synthesized by reaction of 2-amino-1,3,4-thiadiazole (L) with [MoBr(η3-C3H5)(CO)2(NCCH3)2] (1), [MoI2(CO)3(CH3CN)2](M = Mo (2); M = W (4)), or [MoBr2(CO)3(CH3CN)2](M = Mo (3); M = W (5)) in 2:1 ratio. The five complexes were immobilized in MCM-41, yielding the materials MCM-Cn (n = 1-5), and C1 was also immobilized in silica gel (Silica-C1) and in a polyhedral oligomeric silsesquioxane (Cube-C1). Complexes and materials were fully characterized by spectroscopic techniques and elemental analysis. DFT calculations showed that several C1 isomers should coexist. The as synthesized and supported complexes were tested as catalysts on the oxidation of geraniol, cis-hex-3-en-1-ol, trans-hex-3-en-1-ol, (S)-limonene, and 1-octene. The conversions and TOF significantly depend on the complex and the nature of the substrate. The general conclusions are (i) complex C1 has the highest activity; (ii) tungsten complexes C4 and C5 are more active than the molybdenum analogues; (iii) the immobilization of the catalysts improves the performance; and (iv) silica gel and the polyhedral oligomeric silsesquioxane supports modify the selectivity, leading to products different from the one obtained with MCM for specific substrates.
- Vasconcellos Dias, Maria,Saraiva, Marta S.,Ferreira, Paula,Calhorda, Maria José
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p. 1465 - 1478
(2015/05/13)
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- Pore size matters! Helical heterogeneous catalysts in olefin oxidation
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Helical mesoporous materials of the MCM-41 type with different pore sizes were prepared, choosing as templates myristyl (C14) or cetyl (C16) trimethyl ammonium salts, and functionalized with Mo(II) active sites based on MoI2(CO)3 (1) and MoBr(η3-C3H5)(CO)2 (2) fragments, respectively, using a pyridine-2-carbaldehyde ligand as anchor. The new materials were tested as the catalytic precursors in the epoxidation of cis-cyclooctene, styrene, R-(+)-limonene, trans-hex-2-en-1-ol, cis-3-hex-1-ol, and geraniol using tert-butylhydroperoxide (tbhp) as oxidant. All catalysts were moderately to highly selective toward the epoxide products. The materials with larger pores (C16 template) displayed a better catalytic activity, leading in general to higher conversions and selectivities, as well as faster kinetics. For instance, geraniol is epoxidized (more than 90%) with conversions above 90%. The major achievement of these catalysts, however, is the excellent product selectivity control, which is boosted when the allyl complex 1 is used, reaching 100% of the 2S, 3R species in the epoxidation of trans-hex-2-en-1-ol. The catalysts were also found to be stable through recycling experiments and truly heterogeneous with little or no leaching.
- Saraiva, Marta S.,Fernandes, Cristina I.,Nunes, Teresa G.,Calhorda, Maria José,Nunes, Carla D.
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p. 328 - 337
(2015/10/05)
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- Bismuth-substituted "sandwich" type polyoxometalate catalyst for activation of peroxide: Umpolung of the peroxo intermediate and change of chemoselectivity
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The epoxidation of alkenes with peroxides by WVI, MoVI, VV, and TiIV compounds is well established, and it is well accepted that the active intermediate peroxo species are electrophilic toward nucleophilic substrates. Polyoxotungstates, for example, those of the "sandwich" structure, [WZn(TM-L)2(ZnW9O34)2]q- in which TM = transition metal and L = H2O, have in the past been found to be excellent epoxidation catalysts. It has now been found that substituting the Lewis basic BiIII into the terminal position of the "sandwich" polyoxometalate structure to yield [Zn2BiIII2(ZnW9O34)2]14- leads to an apparent umpolung of the peroxo species and formation of a nucleophilic peroxo intermediate. There are two lines of evidence that support the formation of a reactive nucleophilic peroxo intermediate: (1) More electrophilic sulfoxides are more reactive than more nucleophilic sulfides, and (2) nonfunctionalized aliphatic alkenes and dienes showed ene type reactivity rather than epoxidation pointing toward "dark" formation of singlet oxygen from the nucleophilic intermediate peroxo species. Allylic alcohols reacted much faster than alkenes but showed chemoselectivity toward C-H bond activation of the alcohol and formation of aldehydes or ketones rather than epoxidation. This explained via alkoxide formation at the BiIII center followed by oxidative β-elimination.
- Amanchi, Srinivasa Rao,Khenkin, Alexander M.,Diskin-Posner, Yael,Neumann, Ronny
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p. 3336 - 3341
(2015/06/16)
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- Enzyme-inspired functional surfactant for aerobic oxidation of activated alcohols to aldehydes in water
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We describe an enzyme-inspired catalytic system based on a rationally designed multifunctional amphiphile. The resulting micelles feature metal-binding sites and stable free radical moieties as well as fluorous pockets that attract and preconcentrate molecular oxygen. In the presence of copper ions, the micelles effect chemoselective aerobic alcohol oxidation under ambient conditions in water, a transformation that is challenging to achieve nonenzymatically.
- Chen, Ba-Tian,Bukhryakov, Konstantin V.,Sougrat, Rachid,Rodionov, Valentin O.
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p. 1313 - 1317
(2015/02/19)
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- Efficient conversion of primary azides to aldehydes catalyzed by active site variants of myoglobin
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The oxidation of primary azides to aldehydes constitutes a convenient but underdeveloped transformation for which no efficient methods are available. Here, we demonstrate that engineered variants of the hemoprotein myoglobin can catalyze this transformation with high efficiency (up to 8500 turnovers) and selectivity across a range of structurally diverse aryl-substituted primary azides. Mutagenesis of the 'distal' histidine residue was particularly effective in enhancing the azide oxidation reactivity of myoglobin, enabling these reactions to proceed in good to excellent yields (37-89%) and to be carried out at a synthetically useful scale. Kinetic isotope effect, isotope labeling, and substrate binding experiments support a mechanism involving heme-catalyzed decomposition of the organic azide followed by alpha hydrogen deprotonation to generate an aldimine which, upon hydrolysis, releases the aldehyde product. This work provides the first example of a biocatalytic azide-to-aldehyde conversion and expands the range of non-native chemical transformations accessible through hemoprotein-mediated catalysis.
- Giovani, Simone,Singh, Ritesh,Fasan, Rudi
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p. 234 - 239
(2015/12/30)
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- Selective oxidations of activated alcohols in water at room temperature
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Allylic and benzylic alcohols can be selectively oxidized to their corresponding aldehydes or ketones in water containing nanoreactors composed of the designer surfactant TPGS-750-M. The oxidation relies on catalytic amounts of CuBr, bpy, and TEMPO, with N-methyl-imidazole; air is the stoichiometric oxidant. the Partner Organisations 2014.
- Lipshutz,Hageman,Fennewald,Linstadt,Slack,Voigtritter
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supporting information
p. 11378 - 11381
(2014/11/08)
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- Ruthenium-catalyzed oxidation of allyl alcohols with intermolecular hydrogen transfer: Synthesis of α,β-unsaturated carbonyl compounds
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Ruthenium-catalyzed oxidation of multisubstituted allyl alcohols in the presence of benzaldehyde gives enals or enones in good yields. Unlike the commonly reported ruthenium-catalyzed isomerization reaction of allyl alcohols to give saturated ketones, an intermolecular rather than intramolecular hydrogen transfer is involved in this transformation. This reaction offers an efficient, mild, and high-yielding method for the preparation of substituted α,β-unsaturated compounds.
- Ren, Kai,Hu, Bei,Zhao, Mengmeng,Tu, Yahui,Xie, Xiaomin,Zhang, Zhaoguo
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p. 2170 - 2177
(2014/04/03)
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- First evidence for the use of polyamines as nucleophiles in a regioselective palladium-catalyzed allylic amination reaction
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Palladium-catalyzed reaction of unsymmetrical allylic electrophiles with polyamines gives rise to regioisomeric allylic polyamines. An original catalytic procedure providing an efficient method for the regioselective synthesis of new classes of polyamino derivatives of biological interest is reported. Based on experimental considerations, a mechanistic rationale involving a thermodynamically controlled isomerization of the initially formed branched product is proposed to account for the total regioselectivity observed.
- Pieri, Cyril,Combes, Sébastien,Brunel, Jean Michel
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p. 9718 - 9725
(2015/01/09)
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- Synthesis of α-hydroxy(polyprenyl) bisphosphonates
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Bisphosphonates derived from natural terpenes were synthesized by phosphonylation of corresponding aldehydes. The general strategy of introduction of the phosphonate groups into the polyprenol molecule involves successive treatment of a hydroxyl compound by Swern reagent to oxidize the C-OH group into C=O and a (EtO)3P/[PyH]+ClO - 4 mixture to phosphylate the resulting carbonyl compound.
- Kolodyazhnaya,Kolodyazhnyi,Cherkasov,Garifzyanov,Davletshina,Koshkin
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p. 647 - 653
(2014/06/09)
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- Practical organic solvent-free Cu(OAc)2/DMAP/TEMPO-catalyzed aldehyde and imine formation from alcohols under air atmosphere
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A highly efficient and practical organic solvent-free Cu(OAc)2/DMAP/TEMPO catalyst system for the selective aerobic oxidation of benzylic and allylic alcohols to aldehydes and phenones under an ambient air atmosphere was reported. A wide range of functional groups such as phenolic hydroxyl, amino, and methylthio are compatible with the catalyst system. The organic solvent-free aerobic oxidative imine synthesis from benzyl alcohol and amines was also achieved via the newly developed Cu(OAc)2/DMAP/TEMPO catalyst. 100 g-scale reactions for aldehyde and imine formation were achieved with over 90% yield using 0.5 mol% catalyst loading in 36 hours, presenting a potential valuable protocol for both economical and environmental considerations. This journal is
- Guan, Mingyu,Wang, Chao,Zhang, Jingyu,Zhao, Yingsheng
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p. 48777 - 48782
(2014/12/10)
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- METHOD FOR OXIDIZING ALCOHOLS
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A method for oxidizing an alcohol, wherein oxidation is performed in the presence of a compound represented by the following formula (I) and a bulk oxidant, which enables efficient oxidation of secondary alcohols as well as primary alcohols, and can attain high reaction efficiency even when air is used as a bulk oxidant.
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Paragraph 0131; 0132
(2013/06/05)
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- Various oxidative reactions with novel ion-supported (diacetoxyiodo) benzenes
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The oxidation of secondary alcohols and primary alcohols with two novel ion-supported (diacetoxyiodo)benzenes (IS-DIBs) A and B in the presence of a catalytic amount of 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO) in dichloromethane at room temperature proceeded efficiently to provide the corresponding ketones and aldehydes, respectively, in good yields. The oxidative reaction of N,N-diisopropylbenzylamines with those IS-DIBs was also carried out to generate the corresponding aromatic aldehydes in good yields. In addition, the Hofmann rearrangement of primary amides in methanol under basic conditions and the oxidative 1,2-rearrangement of propiophenones in trimethyl orthoformate under acidic conditions with those IS-DIBs provided the corresponding methyl carbamates and methyl 2-arylpropanoates, respectively, in good yields. Moreover, treatment of acetophenones with those IS-DIBs in the presence of trifluoromethanesulfonic acid in acetonitrile generated the corresponding 5-aryl-2-methyloxazoles in good yields. In those five reactions, the desired products were obtained in good yields with high purity by simple extraction of the reaction mixture with diethyl ether and subsequent removal of the solvent from the extract. Moreover, ion-supported iodobenzenes, which were the co-products derived from IS-DIBs in the present oxidative reactions, were recovered in good yields and could be re-oxidized to IS-DIBs A and B for reuse in the same oxidative reactions.
- Iinuma, Masataka,Moriyama, Katsuhiko,Togo, Hideo
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p. 2961 - 2970
(2013/04/10)
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- A conjunctive diiodoheptaene for the synthesis of C2-symmetric carotenoids
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(2E,4E,6E,8E,10E,12E,14E)-2,15-Diiodo-6,11-dimethylhexadeca-2,4,6,8,10,12, 14-heptaene, prepared by homometathesis, has been used in palladium-catalyzed Suzuki and Stille cross-coupling reactions with the appropriate partners to construct the C2-symmetric carotenoids β,β-carotene, lycopene, synechoxanthin and 4,4′-diapo-ψ,ψ-carotene-4,4′- dial. The Royal Society of Chemistry 2013.
- Fontán, Noelia,Vaz, Belén,álvarez, Rosana,De Lera, ángel R.
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p. 2694 - 2696
(2013/04/10)
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- Copper(I)/ABNO-catalyzed aerobic alcohol oxidation: Alleviating steric and electronic constraints of Cu/TEMPO catalyst systems
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Cu/TEMPO catalyst systems promote efficient aerobic oxidation of sterically unhindered primary alcohols and electronically activated substrates, but they show reduced reactivity with aliphatic and secondary alcohols. Here, we report a catalyst system, consisting of (MeObpy)CuI(OTf) and ABNO (MeObpy =4,4′-dimethoxy-2,2′-bipyridine; ABNO = 9-azabicyclo[3.3.1]nonane N-oxyl), that mediates aerobic oxidation of all classes of alcohols, including primary and secondary allylic, benzylic, and aliphatic alcohols with nearly equal efficiency. The catalyst exhibits broad functional group compatibility, and most reactions are complete within 1 h at room temperature using ambient air as the source of oxidant.
- Steves, Janelle E.,Stahl, Shannon S.
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supporting information
p. 15742 - 15745
(2013/11/06)
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- Redox-selective generation of aldehydes and H2 from alcohols under visible light
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Photosynthetic dehydrogenation: Potential usefulness of visible-light-induced dehydrogenation of alcohols in organic synthesis was demonstrated, in which aldehydes and H2 were afforded by using Ru/SrTiO3:Rh and water (see scheme). Water was essential for the reaction. High efficiency (TON: up to 15 400 based on Rh; H2 and aldehyde evenly generated) and high selectivity were achieved. Copyright
- Liu, Zijun,Caner, Joaquim,Kudo, Akihiko,Naka, Hiroshi,Saito, Susumu
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supporting information
p. 9452 - 9456
(2013/07/26)
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- Stereocontrol in palladium-catalyzed propargylic substitutions: Kinetic resolution to give enantioenriched 1,5-enynes and propargyl acetates
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Kinetic resolution during the catalytic allyl-propargyl cross-coupling with chiral starting materials can be accomplished with a chiral palladium catalyst. These reactions offer ready access to enantiomerically enriched enyne products from simple, readily
- Ardolino, Michael J.,Eno, Meredith S.,Morken, James P.
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supporting information
p. 3413 - 3419
(2013/12/04)
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