- A Novel Catalytic Effect of Lead on the Reduction of a Zinc Carbenoid with Zinc Metal Leading to a Geminal Dizinc Compound. Acceleration of the Wittig-Type Olefination with the RCHX2-TiCl4-Zn Systems by Addition of Lead
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A catalytic amount of lead promotes further reduction of zinc carbenoid (ICH2ZnI) with zinc in THF to give a geminal dizinc compound (CH2(ZnI)2), which is a key intermediate for the methylenation of carbonyl compounds with a CH2I2, zinc, and TiCl4 system.
- Takai, Kazuhiko,Kakiuchi, Tadahiro,Kataoka, Yasutaka,Utimoto, Kiitiro
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Read Online
- Chemoselective Carbon-Carbon Bond Formation Reactions of Zirconacyclopentenes
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The reaction of zirconacyclopentenes with allyl chloride in the presence of a copper salt and a lithium or magnesium salt proceeds at the alkenyl carbon on zirconium with high chemoselectivity; selective C-C bond formation at the alkyl carbon was also achieved by treatment of zirconacyclopentenes with a copper salt and a lithium or magnesium salt, methanol and allyl chloride.
- Kasai, Kayoko,Kotora, Martin,Suzuki, Noriyuki,Takahashi, Tamotsu
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Read Online
- A Method for preparing alpha-olefins from Biomass-derived fat and oil
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The present invention relates to a method for preparing alpha-olefins from biomass-derived fats and oils. According to the preparation method, all of the various saturated or unsaturated fatty acids in the biomass-derived fats and oils can be prepared into alpha-olefins, and a conventional problem that the saturated fatty acids do not participate in a reaction or a mixture is generated due to polyunsaturated fatty acids can be solved. Thus, the present invention can be advantageously used to prepare alpha-olefins from biomass.
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Paragraph 0191-0202; 0239-0242
(2020/09/22)
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- Alkene synthesis by photocatalytic chemoenzymatically compatible dehydrodecarboxylation of carboxylic acids and biomass
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Direct conversion of renewable biomass and bioderived chemicals to valuable synthetic intermediates for organic synthesis and materials science applications by means of mild and chemoselective catalytic methods has largely remained elusive. Development of artificial catalytic systems that are compatible with enzymatic reactions provides a synergistic solution to this enduring challenge by leveraging previously unachievable reactivity and selectivity modes. We report herein a dual catalytic dehydrodecarboxylation reaction that is enabled by a crossover of the photoinduced acridine-catalyzed O-H hydrogen atom transfer (HAT) and cobaloxime-catalyzed C-H-HAT processes. The reaction produces a variety of alkenes from readily available carboxylic acids. The reaction can be embedded in a scalable triple-catalytic cooperative chemoenzymatic lipase-acridine-cobaloxime process that allows for direct conversion of plant oils and biomass to long-chain terminal alkenes, precursors to bioderived polymers.
- Nguyen, Vu T.,Nguyen, Viet D.,Haug, Graham C.,Dang, Hang T.,Jin, Shengfei,Li, Zhiliang,Flores-Hansen, Carsten,Benavides, Brenda S.,Arman, Hadi D.,Larionov, Oleg V.
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p. 9485 - 9498
(2019/10/11)
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- An Engineered Self-Sufficient Biocatalyst Enables Scalable Production of Linear α-Olefins from Carboxylic Acids
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Fusing the decarboxylase OleTJE and the reductase domain of P450BM3 creates a self-sufficient protein, OleT-BM3R, which is able to efficiently catalyze oxidative decarboxylation of carboxylic acids into linear α-olefins (LAOs) under mild aqueous conditions using O2 as the oxidant and NADPH as the electron donor. The compatible electron transfer system installed in the fusion protein not only eliminates the need for auxiliary redox partners, but also results in boosted decarboxylation reactivity and broad substrate scope. Coupled with the phosphite dehydrogenase-based NADPH regeneration system, this enzymatic reaction proceeds with improved product titers of up to 2.51 g L-1 and volumetric productivities of up to 209.2 mg L-1 h-1 at low catalyst loadings (~0.02 mol%). With its stability and scalability, this self-sufficient biocatalyst offers a nature-friendly approach to deliver LAOs.
- Lu, Chen,Shen, Fenglin,Wang, Shuaibo,Wang, Yuyang,Liu, Juan,Bai, Wen-Ju,Wang, Xiqing
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p. 5794 - 5798
(2018/06/01)
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- A durable nanocatalyst of potassium-doped iron-carbide/alumina for significant production of linear alpha olefins via Fischer-Tropsch synthesis
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Improvement of activity, selectivity, and stability of the catalyst used in Fischer-Tropsch synthesis (FTS) to produce targeted hydrocarbon products has been a major challenge. In this work, the potassium-doped iron-carbide/alumina (K-Fe5C2/Al2O3), as a durable nanocatalyst containing small iron-carbide particles (~ 10 nm), was applied to high-temperature Fischer-Tropsch synthesis (HT-FTS) to optimize the production of linear alpha olefins. The catalyst, suitable under high space velocity reaction conditions (14–36 N L gcat?1 h?1) based on the well-dispersed potassium as an efficient base promoter on the active iron-carbide surface, shows very high CO conversion (up to ~90%) with extremely high activity (1.41 mmolCO gFe?1 s?1) and selectivity for C5–C13 linear alpha olefins.
- Park, Ji Chan,Jang, Sanha,Rhim, Geun Bae,Lee, Jin Hee,Choi, Hyunkyoung,Jeong, Heon-Do,Youn, Min Hye,Lee, Dong-Wook,Koo, Kee Young,Kang, Shin Wook,Yang, Jung-Il,Lee, Ho-Tae,Jung, Heon,Kim, Chul Sung,Chun, Dong Hyun
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p. 190 - 198
(2018/08/01)
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- Anhydride-Additive-Free Nickel-Catalyzed Deoxygenation of Carboxylic Acids to Olefins
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A nickel-catalyzed route for direct, anhydride-additive-free deoxygenation of fatty acids to the corresponding olefins has been developed. The transformation is catalyzed by simple nickel salts of the type NiX2 (X = halide, acetate, acetylacetonate), uses PPh3 as a stoichiometric reductant, and exhibits selectivity for generation of linear α-olefin products. The reaction was rendered cocatalytic in PPh3 using 1,1,3,3-tetramethyldisiloxane (TMDS) as terminal reductant for the in situ reduction of OPPh3 and catalytic Cu(OTf)2
- John, Alex,Hillmyer, Marc A.,Tolman, William B.
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supporting information
p. 506 - 509
(2017/04/21)
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- Selective Decarbonylation of Fatty Acid Esters to Linear α-Olefins
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Selective decarbonylation of p-nitrophenol esters of fatty acids to the corresponding linear α-olefins (LAOs) was achieved using palladium catalysis. After extensive ligand screening, a mixed-ligand system exploiting the trans-spanning diphosphine XantPhos and an N-heterocyclic carbene (IPr) was identified as the most effective in yielding high α-selectivity and high conversions of the ester (>98% selectivity, >90% conversion using 2.5 mol % of PdCl2 and 5 mol % of the ligands, 190 °C, 2-2.5 h). On the basis of insights from modeling at the density functional level of theory, we propose that the mixed-ligand set achieves high α-selectivity by promoting olefin dissociation from the palladium center following β-hydride elimination, which is especially facilitated both by the combined steric bias of the mixed-ligand set and by the ability of the XantPhos ligand to coordinate in both mono- and bidentate fashions.
- John, Alex,Dereli, Büsra,Ortunìo, Manuel A.,Johnson, Hillis E.,Hillmyer, Marc A.,Cramer, Christopher J.,Tolman, William B.
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p. 2956 - 2964
(2017/08/21)
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- CATALYTIC ESTER DECARBONYLATION
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A process of preparing olefins of the formula (I) is described herein: with R1 being a substituted or unsubstituted (C1-C30)hydrocarbyl, and R2 being a substituted or unsubstituted (C1-C20)hydrocarbyl. The process includes reacting a compound of formula (II) wherein Ar is chosen from in the presence of a palladium-based catalyst and an organic solvent. A process of preparing olefins of the formula (III) is also described: with R3 being a substituted or unsubstituted (C1-C30)hydrocarbyl, R4 being a substituted or unsubstituted (C1-C20)hydrocarbyl, and R5 being a substituted or unsubstituted (C1-C30) hydrocarbyl. The process includes reacting a compound of formula (IV) wherein Ar is chosen from with a compound of formula (V) wherein Ar is chosen from in the presence of a palladium-based catalyst and an organic solvent.
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Paragraph 0087-0088
(2016/08/07)
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- PALLADIUM-CATALYZED DECARBONYLATION OF FATTY ACID ANHYDRIDES FOR THE PRODUCTION OF LINEAR ALPHA OLEFINS
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The present invention is directed to methods of forming olefins, especially linear alpha olefins from fatty acids or anhydrides, each method comprising: contacting an amount of precursor carboxylic acid anhydride with a palladium catalyst comprising a bidentate bis-phosphine ligand in a reaction mixture so as to form an olefin in a product with the concomittant formation and removal of CO and water from the reaction mixture, either directly or indirectly, wherein the reaction mixture is maintained with a sub-stoichiometric excess of a sacrificial carboxylic acid anhydride, an organic acid, or both, said sub-stoichiometric excess being relative to the amount of the precursor carboxylic acid anhydride. The precursor carboxylic acid anhydride may be added to the reaction mixture directly or formed in situ by the reaction between at least one precursor carboxylic acid with a stoichiometric amount of the sacrificial acid anhydride.
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Page/Page column
(2014/06/23)
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- Palladium-catalyzed decarbonylative dehydration of fatty acids for the production of linear alpha olefins
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A highly efficient palladium-catalyzed decarbonylative dehydration reaction of carboxylic acids is reported. This method transforms abundant and renewable even-numbered natural fatty acids into valuable and expensive odd-numbered alpha olefins. Additionally, the chemistry displays a high functional group tolerance. The process employs a low loading of palladium catalyst and proceeds under solvent-free and relatively mild conditions.
- Liu, Yiyang,Kim, Kelly E.,Herbert, Myles B.,Fedorov, Alexey,Grubbs, Robert H.,Stoltz, Brian M.
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supporting information
p. 130 - 136
(2014/03/21)
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- Microbial biosynthesis of medium-chain 1-alkenes by a nonheme iron oxidase
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Aliphatic medium-chain 1-alkenes (MCAEs, ~10 carbons) are "drop-in" compatible next-generation fuels and precursors to commodity chemicals. Mass production of MCAEs from renewable resources holds promise for mitigating dependence on fossil hydrocarbons. An MCAE, such as 1-undecene, is naturally produced by Pseudomonas as a semivolatile metabolite through an unknown biosynthetic pathway. We describe here the discovery of a single gene conserved in Pseudomonas responsible for 1-undecene biosynthesis. The encoded enzyme is able to convert medium-chain fatty acids (C10-C14) into their corresponding terminal olefins using an oxygen-activating, nonheme iron-dependent mechanism. Both biochemical and X-ray crystal structural analyses suggest an unusual mechanism of β-hydrogen abstraction during fatty acid substrate activation. Our discovery unveils previously unidentified chemistry in the nonheme Fe(II) enzyme family, provides an opportunity to explore the biology of 1-undecene in Pseudomonas, and paves the way for tailored bioconversion of renewable raw materials to MCAE-based biofuels and chemical commodities.
- Rui, Zhe,Li, Xin,Zhu, Xuejun,Liu, Joyce,Domigan, Bonnie,Barr, Ian,Cate, Jamie H. D.,Zhang, Wenjun
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p. 18237 - 18242
(2015/02/19)
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- Investigation of hydrocarbon generation mechanism by polarizing the carboxy-group of fatty acid salt with microwave radiation
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Triglycerides can be converted to renewable hydrocarbons fuel which can be used as engine fuels by alkali pyrolysis decarboxylation and cracking processes. The purpose of present study was to explore decarboxylation mechanism of fatty acid salt with microwave radiation. Sodium stearate, potassium stearate, sodium oleate and sodium laurate was chosen as a model compound. The carboxy-terminal of this dipolar molecule was further polarized with microwave radiation. The Lorentz force of ions of dipolar molecules were moved in accordance with the way of electromagnetic waves, contribute to the formation of carbanion, which effectively promote the decarboxylation reaction. Moreover, the polarity of carboxy-terminal was stronger, more easily decarboxylation. The surface of glycerol formed a High-Temperature Locus in microwave radiation reaction system, facilitate the decarboxylation processe, in adition to played a role as the hydrogen donor for this high dielectric value compound. C8-C20 n-alkanes and n-alk-1-enes were arranged regular in liquid products. It proved the feasibility to derive renewable hydrocarbon fuel from sodium salt of fatty acids by microwave pyrolysis.
- Wang,Liu,Ruan,Wen,Wan,Zhang
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p. 369 - 375
(2014/06/09)
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- Stabilization of long-chain intermediates in solution. octyl radicals and cations
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The rearrangements of 1-octyl, 1-decyl and 1-tridecyl intermediates obtained from thermal lead(IV) acetate (LTA) decarboxylation of nonanoic, undecanoic and tetradecanoic acid were investigated experimentally through analysis and distribution of the products. The relationships between 1,5-, 1,6- and possibly existing 1,7-homolytic hydrogen transfer in 1-octyl-radical, as well as successive 1,2-hydride shift in corresponding cation have been computed via Monte-Carlo method. Taking into account that ratios of 1,5-/1,6-homolytic rearrangements in 1-octyl- and 1-tridecyl radical are approximately the same, the simulation shows very low involvement of 1,7-hydrogen rearrangement (1,5-/1,6-/1,7-hydrogen rearrangement = 85:31:1) in 1-octyl radical.
- Teodorovi?, Aleksandar V.,Badjuk, Dalibor M.,Stevanovi?, Nenad,Pavlovi?, Radoslav Z.
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- Photochemical method for producing hydrocarbons
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The present invention relates to a method of using radiation and (in one embodiment) solar energy and UV radiation to convert natural products, for example derivatives of vegetable oils, to lower molecular weight hydrocarbons. The invention further relates to a process whereby these hydrocarbons can be converted to vinyl monomers and used in the formation of plastics, solvents, fuels and the like.
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Page/Page column 10
(2012/02/14)
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- Iron-catalyzed decarbonylation reaction of aliphatic carboxylic acids leading to α-olefins
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The catalytic decarbonylation reaction of aliphatic carboxylic acids can be carried out in the presence of an iron complex, and it proceeds smoothly to give α-olefins with high selectivity. The Royal Society of Chemistry 2012.
- Maetani, Shinji,Fukuyama, Takahide,Suzuki, Nobuyoshi,Ishihara, Daisuke,Ryu, Ilhyong
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scheme or table
p. 2552 - 2554
(2012/03/26)
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- Efficient iridium-catalyzed decarbonylation reaction of aliphatic carboxylic acids leading to internal or terminal alkenes
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Vaska's complex, IrCl(CO)(PPh3)2, when combined with KI as an additive, served as an excellent catalyst for the decarbonylation of long-chain aliphatic carboxylic acids to give internal alkenes with high selectivity. On combination with KI and Ac2O as additives under controlled temperatures, decarbonylation proceeded to give terminal alkenes with high selectivity.
- Maetani, Shinji,Fukuyama, Takahide,Suzuki, Nobuyoshi,Ishihara, Daisuke,Ryu, Ilhyong
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experimental part
p. 1389 - 1394
(2011/04/25)
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- Cobalt-catalyzed reductive allylation of alkyl halides with allylic acetates or carbonates
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An efficient method for the direct allylation of alkyl halides catalyzed by simple cobalt(II) bromide has been developed. This reaction, using a variety of substituted allylic acetates or carbonates, provides the linear product as the major product. It displays broad substrate scope and good functional group tolerance. Copyright
- Qian, Xin,Auffrant, Audrey,Felouat, Abdellah,Gosmini, Corinne
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supporting information; experimental part
p. 10402 - 10405
(2011/12/03)
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- Fritsch-Buttenberg-Wiechell rearrangement to alkynes from gem-dihaloalkenes with lanthanum metal
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The first example of the FBW rearrangement using of lanthanum metal and a catalytic amount of iodine was disclosed. When gem-diiodo- and gem-dibromoalkenes were treated with lanthanum metal in the presence of a catalytic amount of iodine, the reductive dehalogenation of these compounds smoothly proceeded to produce the corresponding alkynes in moderate to good yields.
- Umeda, Rui,Yuasa, Takumi,Anahara, Namika,Nishiyama, Yutaka
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supporting information; experimental part
p. 1916 - 1919
(2011/05/14)
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- Copper-catalyzed allylation of alkyl halides with allylic grignard reagents
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Treatment of alkyl halides, including secondary and tertiary alkyl bromides, with allylic Grignard reagents in the presence of a catalytic amount of copper(II) triflate in diisopropyl ether at 25 °C yielded the corresponding allylated products in high yie
- Sai, Masahiro,Yorimitsu, Hideki,Oshima, Koichiro
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experimental part
p. 1194 - 1196
(2009/12/25)
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- Zinc homologation-elimination reaction of α-sulfinyl carbanions as a new route to olefins
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α-Lithiosulfinyl carbanions react either intermolecularly, after transmetalation into an organocopper derivative in an SN2-type process, with zinc carbenoids, or intramolecularly by higher-order zincates through a tandem zinc homologation-β-elimination reaction into the corresponding alkenes. α,α- and α,β-Disubstituted alkenes can also be produced through these two methodologies. Wiley-VCH Verlag GmbH & Co. KGaA, 2008.
- Abramovitch, Adi,Marek, Ilan
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experimental part
p. 4924 - 4931
(2009/05/27)
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- Avoiding olefin isomerization during decyanation of alkylcyano α,ω-dienes: A deuterium labeling and structural study of mechanism
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(Chemical Equation Presented) A two-step synthetic pathway involving decyanation chemistry for the synthesis of pure alkyl α,ω-dienes in quantitative yields is presented. Prior methodologies for the preparation of such compounds required 6-9 steps, sometimes leading to product mixtures resulting from olefin isomerization chemistry. This isomerization chemistry has been eliminated. Deuteration labeling and structural mechanistic investigations were completed to decipher this chemistry. Deuterium labeling experiments reveal the precise nature of this radical decyanation chemistry, where an alcohol plays the role of hydrogen donor. The correct molecular design to avoid competing intramolecular cyclization, and the necessary reaction conditions to avoid olefin isomerization during the decyanation process are reported herein.
- Rojas, Giovanni,Wagener, Kenneth B.
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p. 4962 - 4970
(2008/12/20)
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- Electrochemical enol ether/olefin cross-metathesis in a lithium perchlorate/nitromethane electrolyte solution
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(Chemical Equation Presented) Electrolytically generated four-membered-ring radical-cation intermediates are involved in the anodic olefin cross-metathesis of enol ethers and olefins in a lithium perchlorate/nitromethane electrolyte solution (see scheme). The reaction mechanism was investigated through deuterium-labeling studies.
- Miura, Teppei,Kim, Shokaku,Kitano, Yoshikazu,Tada, Masahiro,Chiba, Kazuhiro
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p. 1461 - 1463
(2007/10/03)
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- Semivolatile and volatile compounds in combustion of polyethylene
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The evolution of semivolatile and volatile compounds in the combustion of polyethylene (PE) was studied at different operating conditions in a horizontal quartz reactor. Four combustion runs at 500 and 850°C with two different sample mass/air flow ratios and two pyrolytic runs at the same temperatures were carried out. Thermal behavior of different compounds was analyzed and the data obtained were compared with those of literature. It was observed that α,ω-olefins, α-olefins and n-paraffins were formed from the pyrolytic decomposition at low temperatures. On the other hand, oxygenated compounds such as aldehydes were also formed in the presence of oxygen. High yields were obtained of carbon oxides and light hydrocarbons, too. At high temperatures, the formation of polycyclic aromatic hydrocarbons (PAHs) took place. These compounds are harmful and their presence in the combustion processes is related with the evolution of pyrolytic puffs inside the combustion chamber with a poor mixture of semivolatile compounds evolved with oxygen. Altogether, the yields of more than 200 compounds were determined. The collection of the semivolatile compounds was carried out with XAD-2 adsorbent and were analyzed by GC-MS, whereas volatile compounds and gases were collected in a Tedlar bag and analyzed by GC with thermal conductivity and flame ionization detectors.
- Font, Rafael,Aracil, Ignacio,Fullana, Andrés,Conesa, Juan A.
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p. 615 - 627
(2007/10/03)
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- α-Sulfinyl Carbanions as a New Source of Olefins
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(Matrix presented) Secondary α-lithiosulfinyl carbanions react either intermolecularly, after transmetalation into an organocopper derivative in an SN2-type process with zinc carbenoid, or intramolecularly via higher-order zincate to give, through a tandem zinc homologation-β- elimination reaction the corresponding alkenes. α,α-Disubstituted alkenes are only formed from tertiary α-lithiosulfinyl carbanions via the 1,2-metalate rearrangement.
- Abramovitch, Adi,Varghese, Jos P.,Marek, Ilan
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p. 621 - 623
(2007/10/03)
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- Triethylborane-mediated hydrogallation and hydroindation: Novel access to organogalliums and organoindiums
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Hydrogallation of carbon-carbon multiple bonds proceeds in the presence of triethylborane as a radical initiator. Several functionalities do not interfere with this reaction. Resulting alkenyl- and alkylgallium species can be trapped by several electrophiles. Highly regioselective radical addition of an indium hydride reagent to alkynes is also achieved. Various functionalities are tolerant under the reaction conditions. The reaction proceeds with complete anti stereoselectivity. Alkenylindiums obtained via hydroindation can be employed for the following cross-coupling reaction with aryl halides in one pot.
- Takami, Kazuaki,Mikami, Satoshi,Yorimitsu, Hideki,Shinokubo, Hiroshi,Oshima, Koichiro
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p. 6627 - 6631
(2007/10/03)
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- Polymers and surfactants on the basis of renewable resources
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A new strategy for the preparation of different polymers and special surfactants was developed. First, unsaturated fatty acid methyl esters obtained from plant oils were converted to terminally unsaturated esters and α-olefins by metathesis with ethylene using heterogeneous rhenium or homogeneous ruthenium catalysts. These esters were directly copolymerized with ethylene by an insertion-type palladium-catalyzed polymerization to functionalized polyolefins. Polyesters were synthesized by metathetical dimerization of ω-unsaturated esters and subsequent polycondensation of the produced internally unsaturated dicarboxylic esters or by acidic transesterification with petrochemical diols and additional acyclic diene metathesis polymerization, ω-epoxy fatty acid methyl esters, achieved by a new method of chemo-enzymatic epoxidation, were converted into polyethers with comb-structure catalyzed by aluminoxanes on the one hand and into sugar surfactants by nucleophilic ring-opening with amino carbohydrates on the other hand.
- Warwel, Siegfried,Bruese, Falk,Demes, Christoph,Kunz, Michael,Klaas, Mark Ruesch gen
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- Nucleic acids internally-derivatized with a texaphyrin metal complex and uses thereof
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Texaphyrin metal complex-oligonucleotide and -oligonucleotide analog conjugates are provided where the texaphyrin is bound to an internal linkage of the oligonucleotide or oligonucleotide analog, the conjugates having catalytic activity for the hydrolysis of ribonucleic acid. Further, conjugates demonstrating catalytic turnover are described, the conjugates being especially effective under conditions where the concentration of RNA target exceeds that of available conjugate.
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- Methylenation of carbonyl compounds by means of Nysted reagent
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Nysted reagent [cyclo-dibromodi-μ-methylene(μ-tetrahydrofuran)trizinc], a commercially available gem-dimetallic compound, reacted with aldehydes affording methylenated products in the presence of BF3?OEt2, whereas methylenation of ketones proceeded in the presence of BF3OEt2 and TiCl2.
- Matsubara, Seijiro,Sugihara, Masakazu,Utimoto, Kiitiro
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p. 313 - 315
(2007/10/03)
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- Phosphoramidite derivatives of macrocycles
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The invention is directed to phosphoramidite derivatives of macrocycles, such as porphyrins and expanded porphyrins, including sapphyrins and texaphyrins. The phosphoramidite derivatives are useful as intermediates in the preparation of macrocycle-oligonucleotide conjugates.
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- Alkylidenation of carbonyl compounds with gem-dizincioalkanes mediated with titanium dichloride
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Olefination of carbonyl compounds with gem-dizincio-alkanes, bis(iodozincio)methane, 1,1-bis(iodozincio)ethane, and bis(bromozincio)methyltrimethylsilane, afforded the corresponding olefins in good to excellent yields.
- Matsubara, Seijiro,Mizuno, Tsuyoshi,Otake, Tasuyuiki,Kobata, Masami,Utimoto, Kiitiro,Takai, Kazuhiko
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p. 1369 - 1371
(2007/10/03)
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- The Olefin Synthesis from β-Hydroxyalkylphosphonates Induced by Fluorides or Relatively Weak Bases
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β-Hydroxyalkylphosphonates, which were prepared readily from alkylphosphonates and carbonyl compounds, were treated with a fluoride ion such as CsF or with relatively weak bases such as K2CO3 in N,N-dimethylformamide to give the corresponding olefins in good yields. One molar equivalent of water to bases is effective for increasing the yields of olefins. The stereochemistry of erythro-dimethyl (2-hydroxy-1-methyl-2-phenyl)ethylphosphonate was determined by X-ray crystallographic analysis. Use of threo-isomer gave (E)-olefin exclusively, while that of erythro-enricned isomer afforded predominantly (Z)-olefin, indicating that the present olefination proceeds stereospecifically in a manner of syn-elimination.
- Kawashima, Takayuki,Ishii, Takafumi,Inamoto, Naoki,Tokitoh, Norihiro,Okazaki, Renji
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p. 209 - 219
(2007/10/03)
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- Method of expanded porphyrin-oligonucleotide conjugate synthesis
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The invention is directed to a method of incorporating expanded porphyrins, and particularly of incorporating a sapphyrin or a texaphyrin, before, during, or after chemical synthesis of an oligomer to form an expanded porphyrin-oligonucleotide conjugate, and particularly a sapphyrin- or texaphyrin-oligonucleotide conjugate. This method includes reacting derivatized nucleotides and a sapphyrin or a texaphyrin in a desired order in an automated or manual DNA synthesizer having a solid support to form a sapphyrin- or a texaphyrin-oligonucleotide conjugate.
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- Formation of symmetrical alkenes by homocoupling of metallated sulfones under nickel catalysis
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Summary -Allylic sulfones undergo a coupling reaction with organometallic compounds (Mg or Li) not only with copper catalysts but also with iron or nickel salts. With 7,7-disubstituted allylic sulfones and also saturated aliphatic sulfones, however, another reaction was observed whereby two molecules of the starting sulfone are coupled to give symmetrical alkenes. The scope of this reaction was investigated. Elsevier.
- Gai, Yonghua,Julia, Marc,Jean-Noe,Verpeaux
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p. 805 - 816
(2007/10/03)
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- Intramolecular Dehydration of β-Hydroxyalkylphosphonic Acid Monoesters. A Novel Type of Olefin Formation
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The title reaction using dicyclohexylcarbodiimide (DCC) gave stereospecifically the corresponding olefins in good yields via tetracoordinate 1,2-oxaphosphetanes.Use of more than one equivalent of DCC afforded better yields of the olefin.
- Kawashima, Takayuki,Nakamura, Mio,Nakajo, Akira,Inamoto, Naoki
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p. 1483 - 1486
(2007/10/02)
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- A Highly Catalytic and Selective Conversion of Carboxylic Acids to 1-Alkenes of One Less Carbon Atom
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An equimolar mixture of a carboxylic acid and acetic anhydride produces a reagent combination that undergoes a highly efficient decarbonylation/dehydration at 250 deg C using either Pd- or Rh-based catalyst systems, affording excellent yields of the corresponding 1-alkenes of one less carbon atom.
- Miller, Joseph A.,Nelson, Jeffrey A.,Byrne, Michael P.
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- Construction of bicyclic systems via a tandem free radical cyclopropylcarbinyl rearrangement-cyclisation strategy
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Regio- and stereospecific construction of bicyclic systems may be achieved by directed Simmons-Smith cyclopropanation of an allylic alcohol possessing a suitably positioned unsaturated acceptor, followed by a tandem free radical cyclopropylcarbinyl rearrangement-cyclisation reaction.
- Batey,Harling,Motherwell
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p. 8031 - 8052
(2007/10/02)
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- Process for making olefins
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Carboxylic acids are converted in high yields to olefins or high purity α-olefins by contacting a mixture of carboxylic acid and a carboxylic acid anhydride in the presence of a Group VIII metal or copper-containing catalyst at a temperature of from about 100° C. to about 300° C.
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- Stereospecific Reductive Desulfurization of Vinyl Sulfoxides with tert-Butyllithium and an Internal Proton Source
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Trienyl and allenyl phenyl sulfoxides can be reduced stereospecifically with retention of configuration in good yields using tert-butyllithium with methanol (MeOH) as an internal (in situ) proton source.The method can be easily modified to give stereospecifically deuterium-labeled compounds.While simple monoene sulfoxides afford attenuated yields of reduced olefin, the method is useful for the reduction of more sensitive and complex polyene sulfoxides as exemplified by the reduction of trienyl sulfoxides 2b, 3b, 9 and allenyl sulfoxide 10 and by a brief review of additional examples which have emerged from this laboratory.That the reduction proceeds through the direct protonation of sulfurane intermediates such as 35 or 35' is an attractive mechanistic hypothesis, but several other possibilities exist.A pathway involving a vinyllithium as a reactive intermediate is considered to be less likely.
- Theobald, Paula G.,Okamura, William H.
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p. 741 - 750
(2007/10/02)
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- ON THE STEREOSPECIFIC REDUCTION OF VINYLSULFOXIDES WITH THE POSSIBILITY OF DEUTERIUM LABELING
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Upon treating triene sulfoxide 2 or 3 in the presence of methanol (internal proton source) in ether with tert-butyllithium, the reduced product 4b or 4c, respectively, is obtaned with retention of configuration.A deuterium label can be incorporated by using methanol-d1 as the internal proton source.
- Theobald, Paula G.,Okamura, William H.
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p. 6565 - 6568
(2007/10/02)
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- LIQUID-CRYSTALLINE SOLVENTS AS MECHANISTIC PROBES. 23. NORRISH II REACTIONS OF 2- AND SYM-ALKANONES IN THE ISOTROPIC, SMECTIC B, AND CRYSTALLINE PHASES OF n-BUTYL STEARATE.
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n-Alkanones with the carbonyl group at the 2 or central positions (1 and 2, respectively) have been irradiated in the isotropic, smectic B, and two solid phases of n-butyl stearate (BS).The lengths of the ketones were varied from 11 to 31 carbons.The ratios of elimination/cyclization products and diastereomeric cyclobutanol products were measured for each as a function of temperature and BS phase.The effect of 1 and 2 on the phase transition temperatures of BS has been correlated with changes in the product ratios.The experiments demonstrate that a very sensitive cooperative relationship exists between the ease with which 1 and 2 fit into the ordered phases of BS and the degree to which the solvent matrices influence ketone photochemistry.The influence of solvent order on the product ratios is distinctly different for 1 and 2, and for the two product ratios from one ketone.
- Treanor, Richard L.,Weiss, Richard G.
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p. 1371 - 1392
(2007/10/02)
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- SmI2-Induced Deoxygenation of Epoxides and Its Application to Carbonyl Methylenation in Combination with Iodomethylation
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Deoxygenation of epoxides to olefins was effected by an efficient electron transfer system of SmI2-THF-HMPA in the presence of N,N-dimethylaminoethanol (DMAE) or glutaric anhydride.This procedure, in combination with the SmI2-induced iodomethylation, afforded a new, rapid and mild one-pot carbonyl methylenation method.
- Matsukawa, Mihaya,Tabuchi, Takanori,Inanaga, Junji,Yamaguchi, Masaru
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p. 2101 - 2102
(2007/10/02)
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- CHEMOSELECTIVE METHYLENATION WITH A METHYLENEDIANION SYNTHON
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The combination of CH2I2-Zn-Ti(OiPr)4 or CH2I2-Zn-Me3Al is effective for the selective methylenation of aldehydes.Selective methylenation of a ketone group is performed by pretreatment of a substrate with Ti(NEt2)4.
- Okazoe, Takashi,Hibino, Jun-ichi,Takai, Kazuhiko,Nozaki, Hitosi
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p. 5581 - 5584
(2007/10/02)
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- CARBONYL METHYLENATION OF EASILY ENOLIZABLE KETONES
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An organometallic reagent prepared from CH2I2, Zn, and TiCl4 is effective for methylenation of the title ketones.
- Hibino, Jun-ichi,Okazoe, Takashi,Takai, Kazuhiko,Nozaki, Hitosi
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p. 5579 - 5580
(2007/10/02)
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- THE EFFECTIVENESS OF A WEAK BASE IN THE OLEFIN SYNTHESIS FROM β-HYDROXYALKYLPHOSPHONATES
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β-Hydroxyalkylphosphonates were treated with a weak base such as potassium carbonate in N,N-dimethylformamide to give the corresponding olefins in good yields.
- Kawashima, Takayuki,Ishii, Takafumi,Inamoto, Naoki
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p. 1097 - 1100
(2007/10/02)
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- FLUORIDE ION INDUCED TERMINAL OLEFIN SYNTHESIS FROM β-HYDROXYALKYLPHOSPHONATES
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β-Hydroxyalkylphosphonates, prepared readily from alkylphosphonates and carbonyl compounds, were treated with a fluoride ion to give the corresponding olefins in fairly good yields.Use of CsF in N,N-dimethylformamide gave the best result.
- Kawashima, Takayuki,Ishii, Takafumi,Inamoto, Naoki
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p. 1375 - 1378
(2007/10/02)
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