- 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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Read Online
- A chemoselective and regioselective catalytic way to a novel nine-membered lactone
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Cyclocarbonylation of dihydromyrcenol into the corresponding lactone can be selectively performed in the presence of PdCl2(PPh3)2)/SnCl2·2H 2O and 4 A? molecular sieves.
- Lenoble, Géraldine,Urrutigo?ty, Martine,Kalck, Philippe
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Read Online
- Total Synthesis and Biological Investigation of (?)-Artemisinin: The Antimalarial Activity of Artemisinin Is not Stereospecific
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Here, we describe an efficient and diversity-oriented entry to both (?)-artemisinin (1) and its natural antipode (+)-artemisinin, starting from commercially and readily available S-(+)- and R-(?)-citronellene, respectively. Subsequently, we answered the still open question regarding the specificity of artemisinins action. By using a drug-sensitive Plasmodium falciparum NF54 strain, we showed that the antimalarial activity of artemisinin is not stereospecific. Our straightforward and biomimetic approach to this natural endoperoxide enables the synthesis of artemisinin derivatives that are not accessible through applying current methods and may help to address the problem of emerging resistance of Plasmodium falciparum towards artemisinin.
- Krieger, Johannes,Smeilus, Toni,Kaiser, Marcel,Seo, Ean-Jeong,Efferth, Thomas,Giannis, Athanassios
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Read Online
- Method for preparing guaipyridine type sesquiterpenoid alkaloid
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The invention relates to a method for preparing guaipyridine type sesquiterpenoid alkaloids. The method is characterized in that a plurality of guaipyridine type sesquiterpenoid alkaloids are obtained by changing segments of intermediates and changing subsequent functional groups, and asymmetric total synthesis of rupestine D and guaipyridine is realized. The method has the characteristic of flexible divergent synthesis, and provides a new way for subsequent screening of compounds with better biological activity. Rupestine D and guaipydine, which are obtained by the method, are subjected to optical rotation, nuclear magnetic data, high-resolution mass spectrum, single crystal and other contrasts with a naturally separated sample, so that the chemical structure and the spatial configuration of the rupestine D and guaipydine are determined.
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Paragraph 0036-0039
(2021/09/21)
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- 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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- Process for the Catalytic Reversible Alkene-Nitrile Interconversion
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The present invention refers to processes for catalytic reversible alkene-nitrile interconversion through controllable HCN-free transfer hydrocyanation.
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Page/Page column 28
(2017/09/02)
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- Elaboration of Sterically Hindered δ-Lactones through Ring-Closing Metathesis: Application to the Synthesis of the C1-C27 Fragment of Hemicalide
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The synthesis of the C1-C27 fragment of hemicalide, a marine metabolite displaying a unique potent antiproliferative activity, has been accomplished. The synthetic approach highlights a remarkably efficient ring-closing metathesis reaction catalyzed by Nolan ruthenium indenylidene complexes to elaborate the highly substituted δ-lactone framework.
- Lecourt, Camille,Boinapally, Srikanth,Dhambri, Sabrina,Boissonnat, Guillaume,Meyer, Christophe,Cossy, Janine,Sautel, Fran?ois,Massiot, Georges,Ardisson, Janick,Sorin, Geoffroy,Lannou, Marie-Isabelle
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p. 12275 - 12290
(2016/12/23)
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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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- Thermal isomerization of (+)-cis- and (-)-trans-pinane leading to (-)-β-citronellene and (+)-isocitronellene
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Catalyzed and uncatalyzed rearrangement reactions of terpenoids play a major role in laboratory and industrial-scale synthesis of fine chemicals. Herein, we present our results on the thermally induced isomerization of pinane (1). Investigation of the thermal behavior of (+)-cis- (la) and (-)-trans-pinane (1b) in a flow-type reactor reveals significant differences in both reactivity and selectivity concerning the formation of (-)-β-citronellene (2) and (+)-isocitronellene (3) as main products. Possible explanations for these results are discussed on the basis of reaction mechanism and groundstate geometries for 1a and 1b. To identify side reactions caused from ene cyclizations of 2 and 3, additional pyrolysis experiments were conducted that enabled the identification of almost all compounds in the network of C 10H18-hydrocarbon products formed from 1.
- Stolle, Achim,Ondruschka, Bernd,Bonrath, Werner,Netscher, Thomas,Findeisen, Matthias,Hoffmann, Markus M.
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experimental part
p. 6805 - 6814
(2009/08/07)
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- Synthesis of all the six components of the female-produced contact sex pheromone of the German cockroach, Blattella germanica (L.)
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All of the following six components of the female sex pheromone of the German cockroach, Blattella germanica (L.) were synthesized: (3S,11S)-3,11-dimethyl-2-nonacosanone (1), its 29-hydroxy derivative 2, its 29-oxo derivative 3, (3S,11S)-3,11-dimethyl-2-heptacosanone (4), its 27-hydroxy derivative 5, and its 27-oxo derivative 6. Both the enantiomers of citronellal were employed as the chiral sources and Wacker oxidation was employed for the introduction of the carbonyl group at C-2.
- Mori, Kenji
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p. 4060 - 4071
(2008/09/20)
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- Comprehensive kinetic and mechanistic considerations for the gas-phase behaviour of pinane-type compounds
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The thermal behaviour of selected pinane-type compounds, α-pinene (1), β-pinene (2), pinane (3) and nopinone (4), has been investigated. The conversion of the bicyclic starting materials to their acyclic and monocyclic isomers as well as the consecutive reactions of the acyclic main isomerisation products are discussed. The conversion of 1-4 in a reaction network is presented and the experimental evidence for the formation of pyrolysis products by a biradical pathway is discussed. In addition to these results a kinetic model describing the isomerisation of the bicyclic compounds to their acyclic and monocyclic isomers is presented. A good correlation between kinetic simulations and experimental data is revealed. Wiley-VCH Verlag GmbH & Co. KGaA, 2007.
- Stolle, Achim,Ondruschka, Bernd,Bonrath, Werner
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p. 2310 - 2317
(2008/02/08)
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- Tuning selectivity in terpene chemistry: Selective hydrogenation versus cascade reactions over copper catalysts
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The selectivity of Cu/Al2O3 under very mild catalytic hydrogenation conditions can be tuned only by switching the solvent. Geraniol can be converted in a one-pot one-step process into a mixture of citronellol and menthol in hydrocarbon solvents or reduced to citronellol with 98% selectivity in 2-propanol without any additive. Both reactions can be applied to essential oils or synthetic mixtures containing geraniol, citronellal and nerol.
- Zaccheria,Ravasio,Fusi,Rodondi,Psaro
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p. 1267 - 1272
(2007/10/03)
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- Facile generation of alkenes and dienes from tosylates
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Several aldol products resulting from Evans aldol reactions were converted to primary alcohols. After conversion to the corresponding tosylates, heating with NaI and DBU in dimethoxyethane (glyme) effected clean elimination to the terminal olefin. This simple one-pot procedure was applied to other tosylates and a tosylate derived from a homoallylic alcohol. The latter gave rise to a diene.
- Phukan, Prodeep,Bauer, Matthias,Maier, Martin E.
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p. 1324 - 1328
(2007/10/03)
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- CATALYST FIXED ON A CARRIER AND USED FOR THE METATHESIS OF OLEFINS
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The present invention relates to a novel, heterogeneous catalyst which is suitable, in particular, for olefin metathesis. This catalyst is immobilized on an inorganic support and contains at least one active rhenium compound containing at least one carbene group and, if desired, further functional groups. The rhenium compound is bonded to the material used as support by a chemical bond.
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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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- Dihydromyrcenol carbonylation catalyzed by palladium-tin precursors: Selectivity of the reaction drawn by the experimental conditions and the co-reactants
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The methoxycarbonylation of dihydromyrcenol 1 has been carried out in the presence of the catalytic system [PdCl2(PPh3)2] -SnCl2·2H2O-2PPh3. This study shows that it is possible to reduce t
- Lenoble, Géraldine,Urrutigoty, Martine,Kalck, Philippe
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- Revisit to the reduction of allylic chlorides to less substituted olefins by a low-valent chromium species in the presence of a proton source
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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.
- Omoto, Mineko,Kato, Nobuo,Sogon, Tetsuya,Mori, Akira
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p. 939 - 941
(2007/10/03)
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- Palladium-catalyzed asymmetric reduction of racemic allylic esters with formic acid: Effects of phosphine ligands on isomerization of π- allylpalladium intermediates and enantioselectivity
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A new MOP ligand (lb), (R)-(+)-2-(bis(3- trifluoromethylphenyl)phosphino)-2'-methoxy-1,1'-binaphthyl, was found to be more enantioselective than other MOP ligands for the palladium-catalyzed asymmetric reduction of α,α-disubstituted allylic esters with formic acid. The reduction of DL-2-(1-naphthyl)-3-buten-2-yl benzoate gave 3-(1-naphthyl)- 1-butene of 90% ee. The higher enantioselectivity of lb is ascribed to fast syn-anti isomerization of π-allylpalladium intermediates formed by oxidative addition of allylic ester to a palladium(0) species. The rate of syn-anti isomerization was measured by the magnetization saturation transfer in 1H NMR. (C) 2000 Elsevier Science Ltd.
- Kawatsura, Motoi,Uozumi, Yasuhiro,Ogasawara, Masamichi,Hayashi, Tamio
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p. 2247 - 2257
(2007/10/03)
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- Chemical and electrochemical reductions of some allyl type halides catalyzed by vitamin B12
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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.
- Petrovic, Zorica D.,Konstantinovic,Scheffold,Milosavljevic
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p. 765 - 768
(2007/10/03)
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- First Enantioselective Protonation of Prochiral Allyltrimethyltins Using Lewis Acid Assisted Chiral Br?nsted Acids
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The LBA which is prepared from tin tetrachloride and optically active binaphthol or its monomethyl ether is a highly effective reagent for the enantioselective protonation of prochiral allyltrimethyltins. The absolute stereochemical selectivity is quite different from that in the protonation of silyl enol ethers which we reported earlier.
- Ishihara, Kazuaki,Ishida, Yuji,Nakamura, Shingo,Yamamoto, Hisashi
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p. 758 - 760
(2007/10/03)
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- Assessment of the activity of 8'diphenylphosphino-8'-methoxy-1,1'- binaphthyl as a ligand for palladium-catalyzed reactions
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A monodentate phosphine, 8-diphenylphosphino-8'-methoxy-1,1'-binaphthyl, was shown to be active as a ligand in palladium-catalyzed reactions, including the reduction of allylic carbonates with formic acid, hydrosilylation of a terminal olefin, and hydroboration of but-1-en-3-yne, even though it has a highly hindered lone pair.
- Fuji, Kaoru,Sakurai, Minoru,Kinoshita, Takayoshi,Tada, Toshiji,Kuroda, Akio,Kawabata, Takeo
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p. 1524 - 1526
(2007/10/03)
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- Tertiary phosphine compound and transition metal complex comprising the same as ligand
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A tertiary phosphine compound of the formula (1): STR1 wherein R1 and R2 represent independently from each other a hydrogen atom or a methyl group, or together form --CH=CH--CH=CH--; R3 is a hydrogen atom or a cycloalkyl group having 5 to 7 carbon atoms or a lower alkyl group which may be substituted with a halogen atom, a lower alkoxy group, a lower alkoxyalkoxy group or a phenyl group; X1 is a halogen atom when both R1 and R2 are hydrogen atoms, or a hydrogen atom, a halogen atom, a lower alkyl group or a lower alkoxy group when at least one of R1 and R2 is not a hydrogen atoms; and m is an integer of 1 to 5, which is useful as a ligand of a transition metal complex that can catalyze various reactions.
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- Process for the preparation of optically active cycloolefins
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A process for the preparation of optically active cycloolefins based upon reaction of optically active dienes in the presence of catalyst compositions comprising molybdenum and tungsten complexes.
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- Subsituted 4-(2-alkenylsulfinyl)morpholines : preparation and conversion into the corresponding sulfinic acids and esters. Stereochemistry of olefin formation by hydrolytic desulfinylation of allylic sulfinamides.
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By reaction with 4-(chlorosulfenyl)morpholine in the presence of triethylamine, several substituted allylic alcohols have been converted into the title sulfinamides.As a complementary method, the new α-lithio allylic sulfinamides have been prepared and efficiently alkylated with organic halides.The boron trifluoride-etherate catalyzed treatment of the allylic sulfinamides with simple saturated alcohols provided the corresponding alkyl sulfinates while propargylic and allylic alcohols opened a route to various α,α'-bis-unsaturated sulfones.Efficient conditions for the acid-catalyzed hydrolysis of allylic sulfinamides are described and some allylic sulfinic acids bearing an electron-withdrawing group were isolated.Smooth fragmentation of the homoconjugated sulfinic acids gave the corresponding (E)-olefins stereoselectively. - Key words: sigmatropic rearrangement / allylic sulfinamide / allylic sulfinic ester / organolithium derivative / sulfone / retro-ene reaction / sulfur dioxide elimination / stereochemistry
- Baudin, Jean-Bernard,Julia, Sylvestre
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p. 196 - 214
(2007/10/02)
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- Practical catalyst for cyclic metathesis. Synthesis of functional and/or enantiopure cycloalkenes
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The oxo-tungsten complex trans-WOCl2(OAr)2 (Ar = 2,6-dibromophenyl) is prepared by reaction of WOCl4 with 2 equiv of 2,6-dibromophenol. A variety of nonconjugated dienes are cleanly cyclized to the corresponding cycloalkenes using 2 mol % of this catalyst in combination with 4 mol % of tetraethyllead. All three components of the catalyst system are commercially available. The catalytic reactions are typically complete in 1 h at 90 °C and allow the synthesis of chiral cycloalkenes with little or no loss in optical activity. For example, (R)-and (5)-citronellene have been cyclized to the corresponding (R)- or (S)-3-methylcyclopentenes in 97% enantiomeric excess. The cyclization is compatible with a variety of functional groups including some ester, amide, and ether derivatives. Tri- (but not tetra-) substituted cycloalkenes could be prepared using this catalyst.
- Nugent, William A.,Feldman, Jerald,Calabrese, Joseph C.
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p. 8992 - 8998
(2007/10/02)
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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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- A new optically active monodentate phosphine ligand, (R)-(+)-3-diphenylphosphino-3'-methoxy-4,4'-biphenanthryl (MOP-phen): Preparation and use for palladium-catalyzed asymmetric reduction of allylic esters with formic acid
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(R)-(+)-3-Diphenylphosphino-3'-methoxy-4,4'-biphenanthryl (MOP-phen, 8) was prepared starting with (-)-3,3'-dihydroxy-4,4'-biphenanthryl. The absolute configuration of (+)-8 was determined to be R by X-ray crystal structure analysis of its π-allylpalladium complex. The monodentate optically active phosphine 8 was found to be a more enantioselective ligand than (R)-(+)-2-diphenylphosphino-2'-methoxy- 1,1'-binaphthyl (MOP, 1a) for palladium-catalyzed asymmetric reduction of allylic esters with formic acid giving optically active olefins of up to 85% ee.
- Hayashi,Iwamura,Uozumi,Matsumoto,Ozawa
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p. 526 - 532
(2007/10/02)
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- Preparation and Some Reactions of Allylic Indium Reagents
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A variety of allylic indium sesquihalides were readily prepared by the reaction of indium powder with allylic halides in DMF at room temperature.Protonation of the allylindium reagents proceeded regiospecifically at the γ-position of the allylic group to give 1-propenes.A facile transformation of α-pinene to β-pinene was achieved via a myrtenylindium intermediate.Oxygenation of the allylic indium reagents gave mixtures of allylic alcohol isomers in moderate yields.The coupling of the allylindium reagents with cyclic imides gave diverse products depending on the structures of the substrates and the reagents.Stannylation with tributylchlorostannane occurred exclusively at the α-carbon, yielding allyltributylstannanes; E,Z isomerization of the allylic double bond depended largely upon the substitution pattern on the allylic moiety.
- Araki, Shuki,Shimizu, Toshio,Johar, Perminder S.,Jin, Shun-Ji,Butsugan, Yasuo
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p. 2538 - 2542
(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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- UNSATURATED SULFINAMIDES III. CONVERSION OF SEVERAL 4-(2'-ALKENESULFINYL)-MORPHOLINES INTO THE CORRESPONDING SULFINATE ESTERS, UNSYMMETRICAL BISALLYLIC SULFONES AND OLEFINS. ISOLATION OF SOME FUNCTIONALISED 2-ALKENESULFINIC ACIDS.
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The boron trifluoride etherate-catalysed treatment of the unsaturated sulfinamides (1a-e) with simple saturated alcohols afforded the corresponding alkyl sulfinates 2 whereas allylic alcohols provided the bisallylic sulfones 4.Efficient conditions for the acid-catalysed hydrolysis of the unsaturated sulfinamides 1 are described and some allylic sulfinic acids bearing an electronwithdrawing group 6 were isolated.Smooth fragmentation of the homoconjugated sulfinic acids gave the corresponding olefins 5 and 7.
- Baudin, Jean-Bernard,Julia, Sylvestre A.
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p. 3255 - 3258
(2007/10/02)
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- Photochemical Transformations VI: Organic Iodides (Part 5) - Templet Effect of Transition Metal Ions on Photocyclization of Some Olefinic Acyclic Terpene Iodides
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Photocyclization of citronellyl iodide in the presence of certain transition metal salts especially CuCl, results in a significant increase (from 16percent to 35percent) in the yield of the cyclization products.Similar results have been obtained with geranyl and neryl iodides (11, 17).This enhancement of cyclization/elimination ratio is sought to be explained in terms of a templet effect of the transition metal ion.
- Subbarao, Kanury V.,Damodaran, N. P.,Dev, Sukh
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p. 1008 - 1011
(2007/10/02)
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- Palladium-catalysed Preparation of 1,2-Dienes by Selective Hydrogenolysis of Alk-2-ynyl Cabonates with Ammonium Formate
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1,2-Dienes were prepared by the selective hydrogenolysis of alk-2-ynyl carbonates with HCO2NH4 catalysed by Pd2(dba)3*CHCl3-P(n-Bu)3 (dba = dibenzylideneacetone).
- Tsuji, Jiro,Sugiura, Teruo,Yuhara, Masami,Minami, Ichiro
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p. 922 - 924
(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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- 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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- Functionalization of terminal trisubstituted alkenes and derivatives thereof
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The invention relates to a process for preparing compounds having the general structure: STR1 wherein R is hydrogen or an acyclic or alicyclic fragment containing between one and about ten carbon atoms, and R1 is hydrogen or an alkyl containing between one and about four carbon atoms or an aryl group.
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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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- 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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- PHOTOCHEMICAL TRANSFORMATIONS-II ORGANIC IODIDES-II: CITRONELLYL IODIDE, 2,3-DIHYDRO-6(Z)-FARNESYL AND 2,3-DIHYDRO-6(E)-FARNESYL IODIDES
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Experimental parameters governing ?-electrons participation during photolysis of citronellyl iodide have been investigated.Photoproducts resulting from irradiation of 2,3-dihydro-6(Z)- and 2,3-dihydo-6(E)-farnesyl iodides have been characterised.
- Saplay, K. M.,Sahni, Ranjana,Damodaran, N. P.,Dev, Sukh
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p. 1455 - 1461
(2007/10/02)
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