2609-23-6Relevant articles and documents
Transition metal triflate catalyzed conversion of alcohols, ethers and esters to olefins
Keskiv?li,Parviainen,Lagerblom,Repo
, p. 15111 - 15118 (2018/05/04)
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.
Photocatalytic Transfer Hydrogenolysis of Allylic Alcohols on Pd/TiO2: A Shortcut to (S)-(+)-Lavandulol
Takada, Yuki,Caner, Joaquim,Kaliyamoorthy, Selvam,Naka, Hiroshi,Saito, Susumu
supporting information, p. 18025 - 18032 (2017/12/08)
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.
Taking advantage of a terpyridine ligand for the deposition of Pd nanoparticles onto a magnetic material for selective hydrogenation reactions
Guerrero, Miguel,Costa, Natalia J. S.,Vono, Lucas L. R.,Rossi, Liane M.,Gusevskaya, Elena V.,Philippot, Karine
, p. 1441 - 1449 (2013/07/05)
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.
Unique catalysis of gold nanoparticles in the chemoselective hydrogenolysis with H2: Cooperative effect between small gold nanoparticles and a basic support
Noujima, Akifumi,Mitsudome, Takato,Mizugaki, Tomoo,Jitsukawa, Koichiro,Kaneda, Kiyotomi
, p. 6723 - 6725 (2012/07/28)
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.
Study on selectivity of β-myrcene hydrogenation in high-pressure carbon dioxide catalysed by noble metal catalysts
Bogel-Lukasik,Gomes Da Silva,Nogueira,Bogel-Lukasik,Nunes Da Ponte
experimental part, p. 1847 - 1856 (2011/03/19)
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.
Selective reduction of carbon-carbon double and triple bonds in conjugated olefins mediated by SmI2/H2O/amine in THF
Dahlén, Anders,Hilmersson, G?ran
, p. 2661 - 2664 (2007/10/03)
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.
Semiochemicals of the scarabaeinae. VII: Identification and synthesis of ead-active constituents of abdominal sex attracting secretion of the male dung beetle, Kheper subaeneus
Burger,Petersen,Weber,Munro
, p. 2527 - 2539 (2007/10/03)
Using gas chromatography with flame ionization detection (FID) and electroantennographic detection (EAD) in parallel, butanoic acid, skatole, and (E)-2,6-dimethyl-6-octen-2-ol were identified as constituents of the abdominal sex-attracting secretion of the male dung beetle, Kheper subaeneus, which reproducibly elicited EAD responses in male and female antennae. This is the first report of the occurrence of (E)-2,6-dimethyl-6-octen-2-ol as a natural product, for which the name (E)-subaeneol is proposed. In some experiments, a few other constituents of the secretion also gave reproducible responses in specific male and female antennae but did not elicit responses when the analyses were repeated with other antennae. The major volatile constituent of the secretion, identified as (S)-(+)-2,6-dimethyl-5-heptenoic acid, is one of these EAD-active compounds. Both this compound and (E)-2,6-dimethyl-6-octen-2-ol were synthesized from authentic starting materials for comparison with the natural products.
Revisit to the reduction of allylic chlorides to less substituted olefins by a low-valent chromium species in the presence of a proton source
Omoto, Mineko,Kato, Nobuo,Sogon, Tetsuya,Mori, Akira
, p. 939 - 941 (2007/10/03)
Allylic chlorides have been reduced to afford less substituted olefins by a low-valent chromium species in the presence of an alcoholic proton source. This process certainly has synthetic benefits since the regio-selectivity of the reduction is high and the reaction conditions are mild and nearly neutral.
Regiodivergent reduction of allylic esters with Samarium(II) iodide by tuning ester groups and proton sources
Yoshida, Akihiro,Hanamoto, Takeshi,Inanaga, Junji,Mikami, Koichi
, p. 1777 - 1780 (2007/10/03)
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.
Chemical and electrochemical reductions of some allyl type halides catalyzed by vitamin B12
Petrovic, Zorica D.,Konstantinovic,Scheffold,Milosavljevic
, p. 765 - 768 (2007/10/03)
Chemical and electrochemical reductions of some attyl type halides catalyzed by vitamin B12 have been studied. Geranyl bromide 1 and methyl (2E, 6E) 8-bromo-3,7-dimethylocta-2,6- dienoate 2 have been used as substrates and subjected to chemical and electrochemical reduction. The formation and distribution of the reaction products of these substrates can be explained by free radical mechanisms, namely by reductive reactions of some functional groups, rearrangements and intermolecular coupling of intermediate radicals.
