- Transition metal triflate catalyzed conversion of alcohols, ethers and esters to olefins
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Herein, we report an efficient transition metal triflate catalyzed approach to convert biomass-based compounds, such as monoterpene alcohols, sugar alcohols, octyl acetate and tea tree oil, to their corresponding olefins in high yields. The reaction proceeds through C-O bond cleavage under solvent-free conditions, where the catalytic activity is determined by the oxophilicity and the Lewis acidity of the metal catalyst. In addition, we demonstrate how the oxygen containing functionality affects the formation of the olefins. Furthermore, the robustness of the used metal triflate catalysts, Fe(OTf)3 and Hf(OTf)4, is highlighted by their ability to convert an over 2400-fold excess of 2-octanol to octenes in high isolated yields.
- Keskiv?li,Parviainen,Lagerblom,Repo
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p. 15111 - 15118
(2018/05/04)
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- Photocatalytic Transfer Hydrogenolysis of Allylic Alcohols on Pd/TiO2: A Shortcut to (S)-(+)-Lavandulol
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We report herein a regio- and stereoselective photocatalytic hydrogenolysis of allylic alcohols to form unsaturated hydrocarbons employing a palladium(II)-loaded titanium oxide; the reaction proceeds at room temperature under light irradiation without stoichiometric generation of salt wastes. Olefin and saturated alcohol moieties tolerated the reaction conditions. Hydrogen atoms were selectively incorporated into less sterically congested carbons of the allylic functionalities. This protocol allowed a short-step synthesis of (S)-(+)-lavandulol from (R)-(?)-carvone by avoiding otherwise necessary protection/deprotection steps.
- Takada, Yuki,Caner, Joaquim,Kaliyamoorthy, Selvam,Naka, Hiroshi,Saito, Susumu
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supporting information
p. 18025 - 18032
(2017/12/08)
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- Taking advantage of a terpyridine ligand for the deposition of Pd nanoparticles onto a magnetic material for selective hydrogenation reactions
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A hybrid terpyridine ligand was designed to functionalize a magnetic support constituted of magnetite cores surrounded by a silica shell with the aim of improving the stabilization of supported-palladium nanoparticles for the later application of the obtained composite nanomaterial in hydrogenation catalysis. The preparation of the nanomaterial was performed by direct decomposition of the organometallic complex [Pd2(dba)3] on the terpyridine-modified magnetic support providing well-dispersed Pd NPs of 2.5 ± 0.6 nm mean size. This new nanomaterial is a highly active catalyst for the hydrogenation of cyclohexene under mild conditions reaching turnover frequencies up to ca. 58000 h-1 or 129000 h-1 when corrected for surface Pd atoms. Furthermore, in the hydrogenation of β-myrcene, this nanocatalyst is highly selective for the formation of monohydrogenated compounds. When compared to a similar nanocatalyst consisting of palladium nanoparticles supported on an amino-modified magnetic support or on Pd/C, the activity and selectivity of the nanocatalyst are largely increased. These results show how the design of an appropriate hybrid ligand used to functionalize the support can strongly influence the catalytic properties of supported metal nanoparticles. The Royal Society of Chemistry 2013.
- Guerrero, Miguel,Costa, Natalia J. S.,Vono, Lucas L. R.,Rossi, Liane M.,Gusevskaya, Elena V.,Philippot, Karine
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p. 1441 - 1449
(2013/07/05)
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- Unique catalysis of gold nanoparticles in the chemoselective hydrogenolysis with H2: Cooperative effect between small gold nanoparticles and a basic support
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Gold nanoparticles on hydrotalcite act as a heterogeneous catalyst for the chemoselective hydrogenolysis of various allylic carbonates to the corresponding terminal alkenes using H2 as a clean reductant. The combination of gold nanoparticles and basic supports elicited significantly unique and selective catalysis in the hydrogenolysis.
- Noujima, Akifumi,Mitsudome, Takato,Mizugaki, Tomoo,Jitsukawa, Koichiro,Kaneda, Kiyotomi
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p. 6723 - 6725
(2012/07/28)
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- Study on selectivity of β-myrcene hydrogenation in high-pressure carbon dioxide catalysed by noble metal catalysts
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Hydrogenation of monoterpenes, such as β-myrcene, in high-density carbon dioxide over 0.5 wt.% Pd, or Rh, or Ru supported on alumina was investigated. Hydrogenation catalysed by Rh and Ru is generally faster in a single supercritical (sc) phase (gaseous reagents and solid catalyst) than in a biphasic system (liquid + gas reactants + solid catalyst). The reaction catalysed by Pd occurs faster in two phases. The final composition of the reaction mixture is strongly dependent on the noble metal catalyst used for the reaction. Palladium gives mainly 2,6-dimethyloctane (≈95%), rhodium produces 2,6-dimethyloctane with a yield higher than 40%, and around 40% of 2,6-dimethyloct-2-ene, while ruthenium gives around 10% of 2,6-dimethyloctane and 50% of 2,6-dimethyloct-2-ene leaving the highest amount of unreacted β-myrcene. The Pd catalyst is highly active with an excellent selectivity in enabling the one-pot synthesis of 2,6-dimethyloctane through β-myrcene hydrogenation in the presence of scCO2. The overall activity of the noble metal catalysts decreased in the order Pd > Rh > Ru. The problem of leaching of the active metal from the catalyst rod was also investigated. The Royal Society of Chemistry 2009.
- Bogel-Lukasik,Gomes Da Silva,Nogueira,Bogel-Lukasik,Nunes Da Ponte
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experimental part
p. 1847 - 1856
(2011/03/19)
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- Selective reduction of carbon-carbon double and triple bonds in conjugated olefins mediated by SmI2/H2O/amine in THF
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Conjugated double and triple bonds are reduced into alkenes using non-hazardous SmI2/H2O/amine mixtures as reducing agents in THF. Isolated alkenes are not reduced during these reductions. All the reactions studied are quantitative and are completed in less than five minutes.
- Dahlén, Anders,Hilmersson, G?ran
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p. 2661 - 2664
(2007/10/03)
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- Regiodivergent reduction of allylic esters with Samarium(II) iodide by tuning ester groups and proton sources
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Samarium(II) iodide reduced allylic esters in the presence or the absence of palladium(0) catalyst to give α- and γ-protonated products in a regiodivergent fashion by tuning ester functionality and proton sources.
- Yoshida, Akihiro,Hanamoto, Takeshi,Inanaga, Junji,Mikami, Koichi
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p. 1777 - 1780
(2007/10/03)
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- Allylbarium reagents: Unprecedented regio- and stereoselective allylation reactions of carbonyl compounds
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The first direct preparation of allylbarium reagents by reaction of in situ generated reactive barium with various allylic chlorides and their new and unexpected selective allylation reactions with carbonyl compounds are disclosed. Highly reactive barium was readily prepared by the reduction of barium iodide with 2 equiv of lithium biphenylide in dry THF at room temperature. A variety of carbonyl compounds reacted with barium reagents generated from (E)- or (Z)-allylic chlorides in THF at -78 °C. All reactions resulted in high yields with remarkable α-selectivities not only with aldehydes but also with ketones. The double bond geometry of the starting allylic chloride was completely retained in each case. Stereochemically homogeneous (E)- and (Z)-β,γ-unsaturated carboxylic acids were easily prepared in good yields by highly α-selective carboxylation of allylic barium reagents with carbon dioxide. A selective Michael addition reaction with α,β-unsaturated cycloalkanone was also achieved using an allylbarium reagent. Treatment of 2-cyclopentenone (1 equiv) with allylbarium chloride (2 equiv) in THF at -78 °C for 20 min afforded 3-allylcyclopentanone in 94% yield with a 1,4/1,2 ratio of >99/1. Furthermore, the in situ generated barium enolate was efficiently trapped with various kinds of electrophiles (Me2C=CHCH2Br, nC5H11CHO, and CH3COCl).
- Yanagisawa, Akira,Habaue, Shigeki,Yasue, Katsutaka,Yamamoto, Hisashi
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p. 6130 - 6141
(2007/10/02)
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- Use of high pressure in the reduction of organic chlorides with tri-n-butyltin hydride
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The use of the high pressure technique enables reduction of organic halides by tri-n-butyltin hydride to be carried out in the absence of a catalyst or free radical initiator.It leads to a better conservation of the structure of the starting material during the reduction.In the case of some unsaturated halides, a new chemoselectivity has been observed in favour of the addition of the hydride on the carbon-carbon double bond.
- Rahm, A.,Amardeil, R.,Degueil-Castaing, M.
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- REDUCTION OF ALLYLIC ACETATES BY USING A NOVEL Pd(O)-SmI2 SYSTEM
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Allylic acetates were reduced to alkenes in high yields with SmI2 and 2-propanol in the presence of a catalytic amount of palladium(O) complex.
- Tabuchi, Takanori,Inanaga, Junji,Yamaguchi, Masaru
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p. 601 - 602
(2007/10/02)
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- Preparation of 1-Alkenes by the Palladium-Catalyzed Hydrogenolysis of Terminal Allylic Carbonates and Acetates with Formic Acid-Triethylamine
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A useful method for the preparation of 1-alkenes from terminal allylic carbonates and acetates by the palladium-catalyzed reaction with formates is described.Formic acid-triethylamine is a suitable reductant.As catalyst, Pd2(dba)3CHCl3-P(n-Bu)3 gave the best result, 0.05-0.2 molpercent being sufficient (turnover 500-2000).Using this method, various 1-alkenes were prepared in good yields with high selectivity.
- Tsuji, Jiro,Minami, Ichiro,Shimizu, Isao
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p. 623 - 627
(2007/10/02)
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- SELECTIVE HYDROGENATION OF CONJUGATED DIENES CATALYZED BY THIOCYANATOTRIS(TRIPHENYLPHOSPHINE)COBALT(I).
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Thiocyanatotris(triphenylphosphine)cobalt(I) prepared in situ from bis(thiocyanato)bis(triphenylphosphine)cobalt(II), triphenylphosphine, zinc bromide, selectively hydrogenated conjugated dienes to the corresponding cis-monomenes. The C//2-or/ and C//3-methyl substituted 1,3-butadienes enhance the reactivity by a factor of 2. 3 per one methyl group, while C//1- or/and C//4-methyl substituted 1,3-butadienes lower the reactivity by a factor of 1/23 per one methyl group. In the hydrogenation of cyclic conjugated dienes alpha -angle is closely related to the hydrogenation rate. The rates of hydrogenation in cyclic ethers are greater than those in acyclic ethers, but the cis-selectivity in acyclic ethers is much higher.
- Nakayama,Kanai
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- FORMATION OF 1,3-DIENETRICARBONYLIRON COMPLEXES FROM THE REACTION OF DIPOTASSIUM TETRACARBONYLFERRATE WITH ALLYLIC COMPOUNDS
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The reaction of dipotassium tetracarbonylferrate with various allylic phosphates and halides gives 1,3-dienetricarbonyliron complexes.The formation of the complexes is highly stereoselective depending on the geometry of the allylic compounds used.
- Butsugan, Yasuo,Yamashita, Akihiko,Araki, Shuki
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p. 103 - 108
(2007/10/02)
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- REGIOSELECTIVE SYNTHESIS OF 1-OLEFINS BY PALLADIUM-CATALYZED HYDROGENOLYSIS OF TERMINAL ALLYLIC COMPOUNDS WITH AMMONIUM FORMATE
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Various terminal allylic compounds such as allylic esters, phenyl esters, carbonates, chlorides, and vinyl epoxides react with ammonium or sodium formate to give 1-olefins with high regioselectivity by using palladium-tributylphosphine complex as a catalyst.The reaction offers a useful synthetic method for 1-olefins.
- Tsuji, Jiro,Shimizu, Isao,Minami, Ichiro
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p. 1017 - 1020
(2007/10/02)
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- Reductive displacement of allylic acetates by hydride transfer via catalytic activation by palladium(0) complexes
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Allylic acetates are reduced to alkenes by reductive displacement by hydride reagents via catalytic activation with Pd(0) complexes. In the absence of hydrides, allylic acetates afford conjugated dienes in DMSO solvent.
- Hutchins, Robert O.,Learn, Keith,Fulton, Robert P.
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