- MIXTURE OF 3-HEXEN-1-OL ISOMERS AND A PROCESS OF PREPARING SAME
-
Compositions comprising 3-hexen-l-ol are described herein, as well as odor-imparting formulations comprising same and articles-of-manufacturing comprising such compositions or odor-imparting formulations. The compositions comprise trans- 3-hexen-l-ol in a range of from 67 % to 82 % by weight and cA-3-hexen-l-ol in a range of from 18 % to 33 % by weight, wherein a total concentration of trans- 3-hexen-l-ol and cA-3-hexen-l-ol is at least 97 % by weight. Further described herein is a process for preparing a composition comprising 3-hexen-l-ol, the process comprising: contacting 1-pentene with a formaldehyde in the presence of a Lewis acid to thereby obtain a crude mixture comprising 3-hexen-l-ol; and contacting the mixture comprising 3-hexen- l-ol with a base.
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Page/Page column 21-22
(2021/08/14)
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- Accelerated Semihydrogenation of Alkynes over a Copper/Palladium/Titanium (IV) Oxide Photocatalyst Free from Poison and H2 Gas
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Selective hydrogenation of alkynes to alkenes (semihydrogenation) without the use of a poison and H2 is challenging because alkenes are easily hydrogenated to alkanes. In this study, a titanium (IV) oxide photocatalyst having Pd core-Cu shell nanoparticles (Pd@Cu/TiO2) was prepared by using the two-step photodeposition method, and Pd@Cu/TiO2 samples having various Cu contents were characterized by electron transmission microscopy, X-ray photoelectron spectroscopy and UV-vis spectroscopy. Thus-prepared Pd@Cu/TiO2 samples were used for photocatalytic hydrogenation of 4-octyne in alcohol and the catalytic properties were compared with those of Pd/TiO2 and Cu/TiO2. 4-Octyne was fully hydrogenated to octane over Pd/TiO2 at a high rate and 4-octyne was semihydrogenated to cis-4-octene over Cu/TiO2 at a low rate. Rapid semihydrogenation of 4-octyne was achieved over Pd(0.2 mol%)@Cu(1.0 mol%)/TiO2, indicating that the Pd core greatly activated the Cu shell that acted as reaction sites. A slight increase in the reaction temperature greatly increased the rate with a suppressed rate of H2 evolution as the side reaction. Changes in the reaction rates of the main and side reactions are discussed on the basis of results of kinetic studies. Reusability and expandability of Pd@Cu/TiO2 in semihydrogenation are also discussed.
- Imai, Shota,Nakanishi, Kousuke,Tanaka, Atsuhiro,Kominami, Hiroshi
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p. 1609 - 1616
(2020/02/15)
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- Method for synthesizing geraniol from piperylene (by machine translation)
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The method comprises the following steps: reacting piperylene with carbon monoxide and hydrogen to prepare an intermediate cis -3 -hexene -1 - aldehyde; and preparing the geraniol through hydrogenation. The yield of the leaf alcohol is 81.56-92 .73percent, the yield of the cis -3 - hexenyl -1 - aldehyde is 80.69-88 .13percent, the yield of the leaf alcohol is -3 - 54.94-80 .35percent (calculated by pentadiene), the yield of the leaf alcohol is 99.2-99 .50percent.1 - percent, and the yield fluctuation range of the leaf alcohol is 10 within 55.53-80 .97percent percent of the yield of the leaf 0.4 alcohol in 98.36-99 .60percent percent. (by machine translation)
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Paragraph 0040; 0042-0043
(2020/07/12)
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- Visible light-induced diastereoselective semihydrogenation of alkynes to cis-alkenes over an organically modified titanium(IV) oxide photocatalyst having a metal co-catalyst
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Hydrogen (H2)-free and poison (lead and quinoline)-free semihydrogenation of alkynes to cis-alkenes under gentle conditions is one of the challenges to be solved. In this study, a titanium(IV) oxide photocatalyst having two functions (visible light responsiveness and semihydrogenation activity) was prepared by modification with 2,3-dihydroxynaphthalene (DHN) and a copper (Cu) co-catalyst, respectively. The photocatalyst (DHN/TiO2-Cu) showed high performance for diastereoselective semihydrogenation of alkynes to cis-alkenes in water-acetonitrile solution under visible light irradiation without the use of H2 and poisons. Alkynes having reducible functional groups were converted to the corresponding alkenes with the functional groups being preserved. The addition of water to acetonitrile changed the amount of alkynes adsorbed on the photocatalyst, which was a decisive factor determining the rate of hydrogenation. A relatively large apparent activation energy, 27 kJ mol?1, was obtained by a kinetic study, indicating that the rate-determining step of this reaction was not an electron production process but a thermal catalytic semihydrogenation process over the Cu co-catalyst. Semihydrogenation and hydrogen evolution occurred competitively on Cu metals and the former became predominant at slightly elevated temperatures, which is discussed on the basis of the kinetic parameters of two reactions.
- Fukui, Makoto,Omori, Yuya,Kitagawa, Shin-ya,Tanaka, Atsuhiro,Hashimoto, Keiji,Kominami, Hiroshi
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- Water as a Hydrogenating Agent: Stereodivergent Pd-Catalyzed Semihydrogenation of Alkynes
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Palladium-catalyzed transfer semihydrogenation of alkynes using H2O as the hydrogen source and Mn as the reducing reagent is developed, affording cis- and trans-alkenes selectively under mild conditions. In addition, this method provides an efficient way to access various cis-1,2-dideuterioalkenes and trans-1,2-dideuterioalkenes by using D2O instead of H2O.
- Zhao, Chuan-Qi,Chen, Yue-Gang,Qiu, Hui,Wei, Lei,Fang, Ping,Mei, Tian-Sheng
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supporting information
p. 1412 - 1416
(2019/03/07)
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- A General One-Pot Methodology for the Preparation of Mono- and Bimetallic Nanoparticles Supported on Carbon Nanotubes: Application in the Semi-hydrogenation of Alkynes and Acetylene
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A facile and straightforward methodology for the preparation of monometallic (copper and palladium) and bimetallic nanocatalysts (NiCu and PdCu) stabilized by a N-heterocyclic carbene ligand is reported. Both colloidal and supported nanoparticles (NPs) on carbon nanotubes (CNTs) were prepared in a one-pot synthesis with outstanding control on their size, morphology and composition. These catalysts were evaluated in the selective hydrogenation of alkynes and alkynols. PdCu/CNTs revealed an efficient catalytic system providing high selectivity in the hydrogenation of terminal and internal alkynes. Moreover, this catalyst was tested in the semi-hydrogenation of acetylene in industrially relevant acetylene/ethylene-rich model gas feeds and showed excellent stability even after 40 h of reaction.
- Lomelí-Rosales, Diego A.,Delgado, Jorge A.,Díaz de los Bernardos, Miriam,Pérez-Rodríguez, Sara,Gual, Aitor,Claver, Carmen,Godard, Cyril
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supporting information
p. 8321 - 8331
(2019/06/04)
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- A Supramolecular Strategy for Selective Catalytic Hydrogenation Independent of Remote Chain Length
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Performing selective transformations on complex substrates remains a challenge in synthetic chemistry. These difficulties often arise due to cross-reactivity, particularly in the presence of similar functional groups at multiple sites. Therefore, there is a premium on the ability to perform selective activation of these functional groups. We report here a supramolecular strategy where encapsulation of a hydrogenation catalyst enables selective olefin hydrogenation, even in the presence of multiple sites of unsaturation. While the reaction requires at least one sterically nondemanding alkene substituent, the rate of hydrogenation is not sensitive to the distance between the alkene and the functional group, including a carboxylate, on the other substituent. This observation indicates that only the double bond has to be encapsulated to effect hydrogenation. Going further, we demonstrate that this supramolecular strategy can overcome the inherent allylic alcohol selectivity of the free catalyst, achieving supramolecular catalyst-directed regioselectivity as opposed to directing-group selectivity.
- Bender, Trandon A.,Bergman, Robert G.,Raymond, Kenneth N.,Toste, F. Dean
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supporting information
p. 11806 - 11810
(2019/08/22)
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- Stable Zero-Valent Nickel Nanoparticles in Glycerol: Synthesis and Applications in Selective Hydrogenations
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Small (mean diameter, ca. 1.2 nm) and well-dispersed zero-valent nickel nanoparticles (NiNPs) stabilized by cinchona-based alkaloids and TPPTS (tris(3-sulfophenyl)phosphine trisodium salt), were synthesized from the organometallic precursor [Ni(cod)2] in neat glycerol under hydrogen pressure. NiNPs were fully characterized ((HR)-TEM, EDX, XPS, XRD, IR, magnetization), both at solid state and directly from the corresponding colloidal solutions in glycerol due to its negligible vapour pressure. NiNPs dispersed in glycerol were applied in hydrogenation reactions, in particular in semihydrogenation of alkynes to give (Z)-alkenes under satisfactory conditions (3 bar H2, 1 mol% Ni, 100 °C), showing remarkable activity and selectivity. The catalytic phase was recycled at least ten times without loss of activity, affording in each case metal-free organic products. Other functional groups such as nitro, nitrile and formyl groups were efficiently hydrogenated to the corresponding anilines, benzylamines and benzylalcohols respectively (77–95% yields). (Figure presented.).
- Reina, Antonio,Favier, Isabelle,Pradel, Christian,Gómez, Montserrat
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supporting information
p. 3544 - 3552
(2018/08/01)
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- Z-Selective alkyne semi-hydrogenation catalysed by piano-stool N-heterocyclic carbene iron complexes
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NHC iron(ii) piano-stool complexes catalyse the selective semi-hydrogenation of alkynes to alkenes using silanes as reducing agents. Aromatic terminal alkynes are converted to styrenes without over-reduction to ethylbenzene derivatives. Furthermore, internal aryl alkynes afford cis-alkenes with excellent Z-selectivity.
- Johnson, Chloe,Albrecht, Martin
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p. 2779 - 2783
(2018/06/14)
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- Selective hydrogenation of 3-Hexyn-1-ol with Pd nanoparticles synthesized via microemulsions
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In the study at hand we present a design strategy for novel catalysts which can be used for the selective hydrogenation of alkynes to alkenes. The design of the novel catalysts is based on two main ideas, namely (1) the synthesis of Pd nanoparticles via microemulsions and (2) the use of highly-ordered mesoporous silica with a 3-D pore network (FDU-12) serving as support. The nanoparticles are deposited on FDU-12 in two different ways. Firstly, we simply impregnated the support with a dispersion of the nanoparticles. The resulting catalyst was not selective at all; on the contrary, it fully hydrogenated our model alkyne, namely 3-hexyn-1-ol. Secondly, we synthesized the FDU-12 in the presence of the nanoparticles (in-situ synthesis). In this case, we obtained one catalyst which performed as well as the Lindlar catalyst although the metal content was slightly lower and our catalyst contained no Pb. Another catalyst of the same series, prepared in the presence of another stabilizer, performed as well as the NanoSelect catalyst but at a 7 times higher metal content. For the sake of comparison we also impregnated FDU-12 via classical incipient wetness impregnation and again obtained a completely nonselective catalyst. Our results demonstrate that the in-situ synthesis has great potential as regards the development of novel catalysts.
- Montsch, Thomas,Heuchel, Moritz,Traa, Yvonne,Klemm, Elias,Stubenrauch, Cosima
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- Unconventional Pd@Sulfonated Silica Monoliths Catalysts for Selective Partial Hydrogenation Reactions under Continuous Flow
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Doubly functionalized, hierarchical-porosity silica monoliths were synthesized by postgrafting of sulfonic groups and in situ growth of Pd nanoparticles in that order. PdNP of 3.1 nm size located in the mesopores of the material showed to be evenly distributed within 4.6 % wt Pd monoliths. The system was explored in the continuous-flow, catalytic partial hydrogenation reaction of 3-halogeno-nitrobenzenes and 3-hexyn-1-ol in the liquid phase, showing remarkable conversion, selectivity, and resistance under very mild conditions.
- Liguori, Francesca,Barbaro, Pierluigi,Said, Bilel,Galarneau, Anne,Santo, Vladimiro Dal,Passaglia, Elisa,Feis, Alessandro
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p. 3245 - 3258
(2017/08/29)
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- Design of Core-Pd/Shell-Ag Nanocomposite Catalyst for Selective Semihydrogenation of Alkynes
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We designed core-Pd/shell-Ag nanocomposite catalyst (Pd@Ag) for highly selective semihydrogenation of alkynes. The construction of the core-shell nanocomposite enables a significant improvement in the low activity of Ag NPs for the selective semihydrogenation of alkynes because hydrogen is supplied from the core-Pd NPs to the shell-Ag NPs in a synergistic manner. Simultaneously, coating the core-Pd NPs with shell-Ag NPs results in efficient suppression of overhydrogenation of alkenes by the Pd NPs. This complementary action of core-Pd and shell-Ag provides high chemoselectivity toward a wide range of alkenes with high Z-selectivity under mild reaction conditions (room temperature and 1 atm H2). Moreover, Pd@Ag can be easily separated from the reaction mixture and is reusable without loss of catalytic activity or selectivity.
- Mitsudome, Takato,Urayama, Teppei,Yamazaki, Kenji,Maehara, Yosuke,Yamasaki, Jun,Gohara, Kazutoshi,Maeno, Zen,Mizugaki, Tomoo,Jitsukawa, Koichiro,Kaneda, Kiyotomi
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supporting information
p. 666 - 670
(2016/02/18)
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- Heterogeneous Gold-Catalyzed Selective Semireduction of Alkynes using Formic Acid as Hydrogen Source
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A convenient and robust protocol for the selective transfer semireduction of alkynes was developed, using bio-renewable formic acid as the hydrogen source and easily handled supported gold nanoparticles as the catalyst. The catalytic system showed several attractive features such as high activity and selectivity, recyclability, scalability and adaptability to continuous operation under mild reaction conditions, thus providing a practical alternative to current methods for alkyne semireduction.
- Li, Shu-Shuang,Tao, Lei,Wang, Fu-Ze-Rong,Liu, Yong-Mei,Cao, Yong
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supporting information
p. 1410 - 1416
(2016/05/19)
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- Ligand ordering determines the catalytic response of hybrid palladium nanoparticles in hydrogenation
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Supported palladium nanoparticles, prepared by reducing the active metal in the presence of the hexadecyl(2-hydroxyethyl)dimethylammonium dihydrogen-phosphate (HHDMA) ligand and depositing the resulting colloids on titanium silicate (TiSi2O6), represent a proven alternative to the archetypal poisoned catalysts in industrially-relevant selective hydrogenations. To date, a key aspect in the design of these hybrid nanocatalysts remains unaddressed, namely the impact of the ligand content on the catalytic behaviour. In order to assess the structural and associated catalytic implications of this variable, we have prepared a series of Pd-HHDMA/TiSi2O6 catalysts with different HHDMA content (0.3-16.8 wt%), keeping the average particle size (5 nm) and Pd content (0.3 wt%) constant. The materials are characterised with a toolbox of methods, including advanced microscopy and solid-state nuclear magnetic resonance, in order to assess the structure metal-ligand interface and the mobility of the alkyl chain. Continuous-flow three-phase hydrogenations of short-chain acetylenic compounds, nitriles, and carbonyls reveal an increase in the catalytic activity with the ligand content. Density Functional Theory indicates that the ligand behaves as a self-assembled monolayer, changing its adsorption configuration as a function of the HHDMA concentration. At low coverage, the organic layer lies almost flat on the surface of the metal nanoparticle blocking a large number of metal sites and resembling a two-dimensional catalyst; high HHDMA coverages favour an extended three-dimensional configuration of the alkyl chain, and consequently a lower fraction of Pd sites are poisoned. These results provide new fundamental insights into the role of the ligand on the catalytic activity and can enable the design of hybrid nanocatalysts with optimised performance.
- Albani, Davide,Vilé, Gianvito,Mitchell, Sharon,Witte, Peter T.,Almora-Barrios, Neyvis,Verel, René,López, Núria,Pérez-Ramírez, Javier
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p. 1621 - 1631
(2016/04/05)
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- Identification of (Z)-3:(E)-2-Hexenal isomerases essential to the production of the leaf aldehyde in plants
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The green odor of plants is characterized by green leaf volatiles (GLVs) composed of C6 compounds. GLVs are biosynthesized from polyunsaturated fatty acids in thylakoid membranes by a series of enzymes. A representative member of GLVs (E)-2-hexenal, known as the leaf aldehyde, has been assumed to be produced by isomerization from (Z)-3-hexenal in the biosynthesis pathway; however, the enzyme has not yet been identified. In this study, we purified the (Z)-3:(E)-2-hexenal isomerase (HI) from paprika fruits and showed that various plant species have homologous HIs. Purified HI is a homotrimeric protein of 110 kDa composed of 35-kDa subunits and shows high activity at acidic and neutral pH values. Phylogenetic analysis showed that HIs belong to the cupin superfamily, and at least three catalytic amino acids (His, Lys, Tyr) are conserved in HIs of various plant species. Enzymatic isomerization of (Z)-3-hexenal in the presence of deuterium oxide resulted in the introduction of deuterium at the C4 position of (E)-2-hexenal, and a suicide substrate 3-hexyn-1-al inhibited HI irreversibly, suggesting that the catalytic mode of HI is a keto-enol tautomerism reaction mode mediated by a catalytic His residue. The gene expression of HIs in Solanaceae plants was enhanced in specific developmental stages and by wounding treatment. Transgenic tomato plants overexpressing paprika HI accumulated (E)-2-hexenal in contrast to wild-type tomato plants mainly accumulating (Z)-3-hexenal, suggesting that HI plays a key role in the production of (E)-2-hexenal in planta.
- Kunishima, Mikiko,Yamauchi, Yasuo,Mizutani, Masaharu,Kuse, Masaki,Takikawa, Hirosato,Sugimoto, Yukihiro
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p. 14023 - 14033
(2016/07/11)
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- PdNP@Titanate Nanotubes as Effective Catalyst for Continuous-Flow Partial Hydrogenation Reactions
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Pd nanoparticles were easily immobilized onto titanate nanotubes by a straightforward procedure. The material (0.50 wt % Pd) was used as catalyst in the continuous-flow, liquid-phase hydrogenation reaction of unsaturated C-C bonds and it showed excellent performance and durability under very mild conditions (room temperature, 1-2 bar H2, residence time 13-36 s). In particular, very high productivity was obtained in the synthesis of the perfumery component cis-3-hexen-1-ol (40.6 mol gPd-1 h-1) without additives or metal contamination, with clear benefits in terms of process economy and environmental impact compared with conventional catalysts. The catalyst performance is discussed in the light of comparable systems.
- Linares, Noemi,Moreno-Marrodan, Carmen,Barbaro, Pierluigi
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p. 1001 - 1011
(2016/03/15)
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- SYNTHESIS OF OLEFINIC ALCOHOLS VIA ENZYMATIC TERMINAL HYDROXYLATION
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In certain aspects, the present invention provides methods for producing terminally hydroxylated alkenes and alkynes by contacting an unsaturated or saturated hydrocarbon substrate with a hydroxylase enzyme. Exemplary terminal hydroxylases useful for carrying out the methods of the invention exhibit strong selectivity towards one terminal carbon of a hydrocarbon substrate and include, but are not limited to, non-heme diiron alkane monooxygenases, cytochromes P450 (e.g., cytochromes P450 of the CYP52 and CYP153 family), as well as long chain alkane hydroxylases. In some embodiments, the terminally hydroxylated alkene or alkyne is further converted to a terminal alkenal. In certain embodiments, terminally hydroxylated alkenes and alkynes are useful as insect pheromones which modify insect behavior. In other embodiments, terminally hydroxylated alkenes and alkynes are useful intermediates for producing pheromones via acetylation or oxidation of the alcohol moiety.
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Paragraph 0277
(2016/01/30)
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- Convenient transfer semihydrogenation methodology for alkynes using a PdII-NHC precatalyst
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A convenient and easy-to-use protocol for the Z-selective transfer semihydrogenation of alkynes was developed, using ammonium formate as the hydrogen source and the easily prepared and commercially available, highly stable complex PdCl(η3-C3H5)(IMes) (1) as the (pre)catalyst. Combined with triphenyl posphine as an additional ligand, this system provides a robust catalytic synthetic method that shows little to no over-reduction or isomerization after full substrate conversion. The system allows the direct use of solvents and reagents, as received from the supplier without drying or purification, thus providing a practical method for semihydrogenation of a broad range of alkynes. The mechanism behind these high and enhanced selectivities was determined through a set of kinetic experiments.
- Drost, Ruben M.,Bouwens, Tessel,Van Leest, Nicolaas P.,De Bruin, Bas,Elsevier, Cornelis J.
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p. 1349 - 1357
(2014/05/20)
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- Continuous flow hydrogenation reactions by Pd catalysts onto hybrid ZrO2/PVA materials
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Palladium nanoparticles of 3.2?±?0.9?nm size were generated within 12–18 mesh pellets of hybrid zirconia/polyvinyl alcohol matrix, to afford a 0.03–0.1% Pd loading (w/w). The material was used in the catalytic, continuous flow hydrogenation reaction of multiple C[dbnd]C and C[tbnd]C bonds and nitrobenzene, showing good selectivity at full conversion and excellent resistance over prolonged time-on-stream under room temperature and 1–2?bar H2gas. No metal leaching in solution was detected as well as no additives nor regeneration steps were needed for use in hydrophilic solvents.
- Liguori, Francesca,Barbaro, Pierluigi,Sawa, Haruo
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- Green semi-hydrogenation of alkynes by Pd@borate monolith catalysts under continuous flow
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Palladium nanoparticles were immobilized onto an unconventional polymeric borate macroporous monolith and the resulting mesoreactor (i.d. 3 mm, length 25 mm) used in liquid-phase catalytic semi-hydrogenation reaction of substituted alkynes under continuous flow. The catalytic system showed excellent efficiency, both in terms of activity and selectivity, and long-term stability under mild reaction conditions (methanol, room temperature, 1.5 bar H2 max), with no need of additives. Particularly, the leaf alcohol cis-3-hexen-1-ol was for the first time obtained with selectivity comparable to that of the industrial batch process. The performance of the catalyst is discussed and compared with those of the analogous batch and industrial processes.
- Liguori, Francesca,Barbaro, Pierluigi
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p. 212 - 220
(2014/01/17)
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- SUPPORTED METAL CATALYSTS
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The present invention relates to supported metal catalysts, wherein the catalysts are modified by at least one amine, a method for the preparation thereof and hydrogenation processes utilising the supported metal catalysts.
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Paragraph 0280
(2013/03/28)
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- A well-defined Pd hybrid material for the Z-selective semihydrogenation of alkynes characterized at the molecular level by DNP SENS
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Direct evidence of the conformation of a Pd-N heterocyclic carbene (NHC) moiety imbedded in a hybrid material and of the Pd-NHC bond were obtained by dynamic nuclear polarization surface-enhanced NMR spectroscopy (DNP SENS) at natural abundance in short experimental times (hours). Overall, this silica-based hybrid material containing well-defined Pd-NHC sites in a uniform environment displays high activity and selectivity in the semihydrogenation of alkynes into Z-alkenes (see figure). Copyright
- Conley, Matthew P.,Drost, Ruben M.,Baffert, Mathieu,Gajan, David,Elsevier, Cornelis,Franks, W. Trent,Oschkinat, Hartmut,Veyre, Laurent,Zagdoun, Alexandre,Rossini, Aaron,Lelli, Moreno,Lesage, Anne,Casano, Gilles,Ouari, Olivier,Tordo, Paul,Emsley, Lyndon,Coperet, Christophe,Thieuleux, Chloe
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supporting information
p. 12234 - 12238
(2013/09/23)
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- Metal-ligand core-shell nanocomposite catalysts for the selective semihydrogenation of alkynes
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Catalysts with a sheltered upbringing: Novel core-shell nanocomposite catalysts consisting of active metal nanoparticles encapsulated by macroligands have been prepared. They have Pd nanoparticles (PdNPs) as an active core and shell ligands having sulfoxide moieties coordinated to the PdNPs. The shell protects the catalyst from coordination by alkenes and allows the lead-free selective semihydrogenation of a wide range of alkynes without any additives (see scheme). Copyright
- Mitsudome, Takato,Takahashi, Yusuke,Ichikawa, Satoshi,Mizugaki, Tomoo,Jitsukawa, Koichiro,Kaneda, Kiyotomi
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supporting information
p. 1481 - 1485
(2013/04/10)
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- Enantiodivergent and γ-selective asymmetric allylic amination
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Double agent: The title reaction using the guanidine catalyst 1 can deliver both enantiomers of the product with excellent enantioselectivity by judicious choice of the double bond geometry of the the β,γ-unsaturated carbonyl compound. Computational studies reveal the possible origin of the inversed enantioselectivity, and the potential for enantiodivergent synthesis chiral amine-containing substrates is attractive. Copyright
- Wang, Jianmin,Chen, Jie,Kee, Choon Wee,Tan, Choon-Hong
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supporting information; experimental part
p. 2382 - 2386
(2012/05/19)
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- Green production of polymer-supported PdNPs: Application to the environmentally benign catalyzed synthesis of cis-3-hexen-1-ol under flow conditions
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Pd nanoparticles generated on gel type ion-exchange resins under catalytic conditions show high activity, selectivity and durability in partial hydrogenation reactions under mild conditions, thus providing a green, low-cost option for fine-chemicals production. The application to the continuous-flow synthesis of the leaf alcohol fragrance cis-3-hexen-1-ol is demonstrated.
- Moreno-Marrodan, Carmen,Barbaro, Pierluigi,Catalano, Massimo,Taurino, Antonietta
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supporting information
p. 12666 - 12669
(2013/01/15)
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- PROCESS FOR THE PREPARATION OF AN AQUEOUS COLLOIDAL PRECIOUS METAL SUSPENSION
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The invention is directed to a process for the preparation of an aqueous colloidal precious metal suspension, which process comprises reducing a precious metal salt in aqueous solution using a functionalised, water soluble quaternary ammonium salt in the absence of organic solvents, to form elementary nanoparticles.
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Page/Page column 2
(2011/02/18)
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- Highly efficient Pd/SiO2-dimethyl sulfoxide catalyst system for selective semihydrogenation of alkynes
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Silica-supported Pd nanoparticles (Pd/SiO2) with dimethyl sulfoxide (DMSO) show excellent catalytic activity and selectivity for the semihydrogenation of alkynes. Small amounts of DMSO drastically suppress the overhydrogenation and isomerization of alkenes. This catalyst system is also applicable to both internal and terminal alkynes. Furthermore, the Pd/SiO 2 catalyst was separable from the reaction mixture after the hydrogenation and reusable without loss of its high catalytic activity or selectivity.
- Takahashi, Yusuke,Hashimoto, Norifumi,Hara, Takayoshi,Shimazu, Shogo,Mitsudome, Takato,Mizugaki, Tomoo,Jitsukawa, Koichiro,Kaneda, Kiyotomi
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p. 405 - 407
(2012/10/29)
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- New environmentally friendly catalysts containing Pd-interstitial carbon made from Pd-glucose precursors for ultraselective hydrogenations in the liquid phase
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We report a novel preparation of a Pd nanocatalyst modified with subsurface C via blending a glucose precursor at the molecular level: the catalyst is demonstrated for the first time to be stereoselective in the hydrogenation of alkynes to cis-alkenes in the liquid phase.
- Chan, Chun Wong Aaron,Xie, Yaling,Cailuo, Nick,Yu, Kai Man Kerry,Cookson, James,Bishop, Peter,Tsang, Shik Chi
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supporting information; scheme or table
p. 7971 - 7973
(2011/08/07)
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- New monodispersed palladium nanoparticles stabilized by poly-(N-vinyl-2-pyrrolidone): Preparation, structural study and catalytic properties
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Mesitylene/1-hexene solvated palladium nanoparticles, obtained by metal vapour synthesis (MVS) technique, were stabilized in solution at room temperature with poly-(N-vinyl-2-pyrrolidone) (PVP) and isolated by precipitation with a diethyl ether or THF as brown powder. HRTEM and FT-IR analyses on samples with different Pd/PVP ratio (1%, 5%, 10%, 15%, 20 w/w%) showed palladium nanoparticles with mean diameters limited in the range 1.5-2.5 nm and the presence of competitive intermolecular interactions between CO groups and palladium atoms on nanoparticle surface. The Pd-PVP systems, dissolved in EtOH solvent, showed excellent catalytic activity and selectivity in the hydrogenation of aliphatic alkynes (1-hexyne, 2-hexyne, 3-hexyne, 3-hexyne-1-ol) to the corresponding (Z)-alkenes. The catalytic activity of Pd-PVP samples, dissolved in 1-methyl-2-pyrrolidinone (NMP), has been also evaluated in the Mizoroki-Heck C-C coupling reaction of iodobenzene and bromo-arenes with butyl acrylate showing high efficiency. Moreover, the catalyst can be quantitatively recovered at the end of the reaction by precipitation with diethyl ether and reused without significant loss of catalytic activity.
- Evangelisti, Claudio,Panziera, Nicoletta,D'Alessio, Aldo,Bertinetti, Luca,Botavina, Maria,Vitulli, Giovanni
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experimental part
p. 246 - 252
(2010/09/17)
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- Highly active and selective semihydrogenation of alkynes with the palladium nanoparticles-tetrabutylammonium borohydride catalyst system
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Palladium nanoparticles are prepared from palladium(II) acetate and 2 equivalents of potassium tert-butoxide in the presence of 4-octyne. The palladium nanoparticles-tetrabutylammonium borohydride system shows excellent catalytic activity and selectivity in the semihydrogenation of alkynes to the [(Z)-]alkenes. The hydrogenation of 4-octyne is conducted with the catalyst system at a substrate-to-palladium molar ratio of 10,000-200,000 under 8 atm of hydrogen to give (Z)-4-octene in > 99% yield. Isomerization and over-reduction of the Z-alkene are very slow even after consumption of the alkyne.
- Hori, Junichi,Murata, Kunihiko,Sugai, Toshiki,Shinohara, Hisanori,Noyori, Ryoji,Arai, Noriyoshi,Kurono, Nobuhito,Ohkuma, Takeshi
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supporting information; experimental part
p. 3143 - 3149
(2010/04/06)
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- Stereoselective hydrogenation of olefins using rhodium-substituted carbonic anhydrase - A new reductase
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One useful synthetic reaction missing from nature's toolbox is the direct hydrogenation of substrates using hydrogen. Instead nature uses co-factors like NADH to reduce organic substrates, which adds complexity and cost to these reductions. To create an enzyme that can directly reduce organic substrates with hydrogen, researchers have combined metal hydrogenation catalysts with proteins. One approach is an indirect link where a ligand is linked to a protein and the metal binds to the ligand. Another approach is direct linking of the metal to protein, but nonspecific binding of the metal limits this approach. Herein, we report a direct hydrogenation of olefins catalyzed by rhodium(I) bound to carbonic anhydrase (CA-[Rh]). We minimized nonspecific binding of rhodium by replacing histidine residues on the protein surface using site-directed mutagenesis or by chemically modifying the histidine residues. Hydrogenation catalyzed by CA-[Rh] is slightly slower than for uncomplexed rhodium(I), but the protein environment induces stereoselectivity favoring cis- over transstilbene by about 20:1. This enzyme is the first cofactor-independent reductase that reduces organic molecules using hydrogen. This catalyst is a good starting point to create variants with tailored reactivity and selectivity. This strategy to insert transition metals in the active site of metalloenzymes opens opportunities to a wider range of enzyme-catalyzed reactions.
- Jing, Qing,Okrasa, Krzysztof,Kazlauskas, Romas J.
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supporting information; scheme or table
p. 1370 - 1376
(2009/09/04)
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- Transfer semihydrogenation of alkynes catalyzed by a zero-valent palladium N-heterocyclic carbene complex
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(Chemical Equation Presented) Beyond Lindlar and without hydrogen: Transfer hydrogenation of internal alkynes catalyzed by a palladium(0) catalyst containing an N-heterocyclic carbene ligand gives Z alkenes without over-reduction to alkanes (see scheme). Contrary to most transfer hydrogenations, ketones are not reduced. As such, this is the first catalyst that shows excellent stereo- and chemo-selectivity for the semihydrogenation of alkynes without the need for hydrogen gas.
- Hauwert, Peter,Maestri, Giovanni,Sprengers, Jeroen W.,Catellani, Marta,Elsevier, Cornelis J.
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p. 3223 - 3226
(2008/12/23)
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- 1,4-HYDROGENATION OF DIENES WITH RU COMPLEXES
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The present invention relates to the use of Ru complexes, having a cyclopentadienyl derivatives and a diene as ligands, together with some acidic additives for improving the selectivity in the 1,4-hydrogenation of conjugated dienes into the corresponding "cis "-alkene as major product, i.e. wherein the two substituents in position 2,3 of said diene are in a cis configuration in the corresponding alkene.
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Page/Page column 19; 23-24
(2008/12/04)
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- 1,4-HYDROGENATION OF SORBOL WITH RU COMPLEXES
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The present invention relates to the use of Ru complexes, having a pentamethyl- cyclopentadienyl and a cyclooctadine as ligands, together with some acidic additives for improving the selectivity in the 1,4-hydrogenation of sorbol into the corresponding Z-alkene as major product.
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Page/Page column 7-9
(2008/12/04)
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- Highly selective hydrogenation of multiple carbon-carbon bonds promoted by nickel(0) nanoparticles
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A new method for the highly stereoselective cis semihydrogenation of internal alkynes, semihydrogenation of terminal alkynes, reduction of dienes to alkenes, and reduction of alkynes and alkenes to alkanes is described based on in situ generated both Ni(0) nanoparticles and molecular hydrogen.
- Alonso, Francisco,Osante, I?aki,Yus, Miguel
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- Highly stereoselective semihydrogenation of alkynes promoted by nickel(0) nanoparticles
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A new method for the highly stereoselective cis-semihydrogenation of internal alkynes is described based on in situ generated Ni(0) nanoparticles and molecular hydrogen. This reduction system also allows the semihydrogenation of terminal alkynes.
- Alonso, Francisco,Osante, Inaki,Yus, Miguel
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p. 305 - 308
(2007/10/03)
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- Process for preparing cis alkenes and new catalysts therefor
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In a method for preparation of cis-alkenes (I) by hydrogenating conjugated, non-cyclic dienes (II) in presence of homogeneously soluble transition metal catalyst (III), the new feature is that (III) is prepared in situ. In a method for preparation of cis-alkenes (I) by hydrogenating conjugated, non-cyclic dienes (II) in presence of homogeneously soluble transition metal catalyst (III), the new feature is that (III) is prepared in situ. (III) are of formulae (IIIa) or (IIIb). M = in (IIIa), a transition metal of Group VI in zero oxidation state, or in (IIIb) a metal of Group VIII in +2 oxidation state, Group IX in +1 oxidation state or Group X in +2 oxidation state; L1 = polydentate neutral or anionic ligand; L2 and L3 = together a conjugated, non-cyclic diene ligand; L4 = monodentate neutral ligand; L5 = polydentate neutral ligand; X = anion; and n = 1 or 2. Independent claims are also included for the following: (1) transition metal complex (C) for stereoselective hydrogenation of conjugated dienes to cisoid compounds that comprises a central ruthenium(II), an eta5 ligand, a bidentate, non-cyclic conjugated diene ligand and optionally a non-coordinating counterion for electrical neutrality, provided that when the ligand is pentamethylcyclopentadienyl (CpMe5) and the diene is sorbic acid, then the counterion is not triflate (trifluoromethylsulfonate) nor the BARF anion; and (2) methods for preparing specific (C).
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Page/Page column 10
(2010/02/05)
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- First example of high loaded polymer-stabilized nanoclusters immobilized on hydrotalcite: Effects in alkyne hydrogenation
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Poly(N-vinyl-2-pyrrolidone)-stabilized Pd-nanoclusters, for the first time exclusively supported on the hydrotalcite lateral surface, showed a remarkable catalytic performance in the selective hydrogenation of 3-hexyn-1-ol, which can be ascribed to both the influence of the protecting polymer PVP as well as the nature of the support.
- Roelofs, Jules C. A. A.,Berben, Peter H.
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p. 970 - 971
(2007/10/03)
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- Selective liquid-phase semihydrogenation of functionalized acetylenes and propargylic alcohols with silica-supported bimetallic palladium-copper catalysts
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Silica-supported, bimetallic palladium-copper catalysts were prepared in solution under mild conditions by reacting lithium di(4-tolyl)cuprate with palladium acetate in the presence of silica particles. Small bimetallic palladium-copper particles were deposited on the silica surface as confirmed with TEM-EDAX and EXAFS. The new material has been applied as catalyst in the liquid-phase semihydrogenation of mono- and disubstituted alkynes and showed high selectivity toward the cis-alkenes. The influence of addition of quinoline or potassium hydroxide to the semihydrogenation reaction mixture and the effects of exposure of the catalyst to air before use have been investigated. Silica-supported, bimetallic palladium-copper catalysts were prepared in solution under mild conditions by reacting lithium di(4-tolyl)cuprate with palladium acetate in the presence of silica particles. Small bimetallic palladium-copper particles were deposited on the silica surface as confirmed with TEM-EDAX and EXAFS. The new material has been applied as catalyst in the liquid-phase semihydrogenation of mono- and disubstituted alkynes and showed high selectivity toward the cis-alkenes. The influence of addition of quinoline or potassium hydroxide to the semihydrogenation reaction mixture and the effects of exposure of the catalyst to air before use have been investigated.
- Spee,Boersma,Meijer,Slagt,Van Koten,Geus
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p. 1647 - 1656
(2007/10/03)
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- Stereoselective catalytic hydrogenation of sorbic acid and sorbic alcohol with new Cp*Ru complexes
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The new Cp*Ru complexes [Cp*Ru(η4-MeCH=CHCH=CHCO2H)]+X- (X- = CF3SO3- or [B{C6H3(CF3)2-3,5}4]-) are very effective catalysts for the hydrogenation of sorbic acid to cis-hex-3-enoic acid and of sorbic alcohol to cis-hex-3-en-1-ol (leaf alcohol) under mild conditions in liquid two-phase systems.
- Steines, Stephan,Englert, Ulli,Driessen-Hoelscher, Birgit
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p. 217 - 218
(2007/10/03)
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- Selective homogeneous palladium(0)-catalyzed hydrogenation of alkynes to (Z)-alkenes
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Zero-valent palladium precatalysts containing rigid bidentate bis(arylimino)acenaphthene ligands (shown schematically) facilitate the highly stereoselective homogeneous catalytic hydrogenation of alkynes to (Z)- alkenes. Internal, terminal, aryl-substituted, and cyclic alkynes are suitable substrates, as are some enynes, which are chemoselectively hydrogenated to dienes. E=CO2Me; R1, R2 = 4-OCH3, 4-CH3, 2,6-(CH3)2.
- Van Laren, Martijn W.,Elsevier, Cornelis J.
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p. 3715 - 3717
(2007/10/03)
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- A new, highly stereoselective approach to pyrrolidines via overall 5-endo-trig cyclisations of homoallylic tosylamides
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Iodocyclisations of E-homoallylic tosylamides 7 lead to excellent yields of either 2,5-trans- or 2,5-cis-3-iodopyrrolidines (10 or 11), depending upon the reaction conditions.
- Jones, Andrew D.,Knight, David W.
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p. 915 - 916
(2007/10/03)
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- Selective reduction of alkynes to Z-alkenes using hydrosilane functions immobilized on silica gel
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A solid reagent consisting of hydrosilane functions immobilized on the surface of silica gel was used in conjunction with acetic acid and tetrakis(triphenylphosphine)palladium(0) catalyst to effect the reduction of alkynes to Z-olefins. Simple filtration provides a convenient means for the reaction workup and isolation of products.
- Kini, Abhay D.,Nadkarni, Durgesh V.,Fry, James L.
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p. 1507 - 1510
(2007/10/02)
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- Preparation of E-alkenes using lithium and 1,3-diaminopropane
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A new selective reducing system, lithium in 1,3-diaminopropane, is described, which enables the preparation of E-olefins from acetylenes in high purity.
- Kovarova,Streinz
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p. 2397 - 2404
(2007/10/02)
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- COMPOUNDS WITH A HERBAL ODOR 1. CIS-2-PENTENYLCARBINOLS
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cis-2-Pentenylcarbinols were synthesized by selective hydrogenation of 1,3-pentadienylcarbinols at chromium hexacarbonyl.The obtained compounds have a herbal odor.
- Vasil'ev, A.A.,Cherkaev, G.V.,Soldatenko, L.I.,Kolomeer, G.G.
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p. 269 - 272
(2007/10/02)
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- Stereoselective synthesis of alkenyl alcohols using dissolving metal(Ca,Na) reduction
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Use of the calcium-ethylenediamine and sodium-liquid ammonia reduction systems for the ring opening of dihydropyran derivatives was studied. (Z)-Alkenyl alcohols and (E)-alkenyl alcohols were stereoselectively synthesized respectively.
- Zhou,Lu,Huang,Wu
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p. 435 - 441
(2007/10/02)
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- A Quick Procedure for the Partial Reduction of Triple Bonds
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Regio- as well as stereospecific cis-reductions of a wide variety of acetylenic derivatives can be carried out in absolute ethanol with zinc powder activated with 1,2-dibromoethane and with zinc power treated successively with dibromoethane and lithium bromocuprate, the first reagent being less powerful and more selective than the second one.
- Aerssens, M.H.P.J.,Heiden, R. van der,Heus, M.,Brandsma, L.
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p. 3421 - 3425
(2007/10/02)
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- SELECTIVE HYDROGENATION BY A NOVEL PALLADIUM(II) COMPLEX
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A novel insoluble green complex of palladium(II) and salicylidene ethylene diamine (salen) has been prepared and found to be an active and selective heterogeneous hydrogenation catalyst especially for the reduction of alkynes in the presence of alkenes and of alkenes in the presence of other functional groups.
- Kerr, James M.,Suckling, Colin J.
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p. 5545 - 5548
(2007/10/02)
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- Ring Scission Of Cyclic β-Halogeno-ethers with Samarium Di-iodide: A Synthesis of (E)- and (Z)-Enynols
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The use of samarium di-iodide in place of sodium metal for the ring scission of cyclic β-halogeno-ethers drastically alters the stereochemistry of the resulting olefinic alcohols: using the method, highly stereoselective syntheses of enynols in (Z)- and (E)-forms are reported.
- Crombie, Leslie,Rainbow, Linda J.
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p. 6517 - 6520
(2007/10/02)
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