14049-11-7Relevant academic research and scientific papers
Catalytic performance of a boron peroxotungstate complex under homogeneous and heterogeneous conditions
Santos, Isabel C.M.S.,Balula, Salete S.,Sim?es, Mário M.Q.,Cunha-Silva, Luís,Neves, M. Gra?a P.M.S.,De Castro, Baltazar,Cavaleiro, Ana M.V.,Cavaleiro, José A.S.
, p. 87 - 94 (2013)
The preparation and characterization (FT-IR, FT-Raman, 11B MAS NMR, diffuse reflectance, elemental analysis) of a novel boron peroxotungstate (BTBA)4H[BW4O24] (BTBA = benzyltributylammonium) is reported, along with its use in the homogeneous oxidation of cis-cyclooctene, geraniol, linalool and (-)-carveol with H 2O2 as oxidant and acetonitrile as solvent. High catalytic activity was registered for all the substrates studied under homogeneous conditions, namely 99% of conversion of geraniol after 2 h, 93% for linalool after 5 h, 74% for cis-cyclooctene after 6 h, and 100% for (-)-carveol after 2 h of reaction. Some oxidation studies were carried out with the Venturello complex, [PW4O24]3-, in the same conditions. Furthermore, the boron peroxotungstate (BW4) was immobilized using two different strategies: (a) BW4 anchored into a functionalized silica (aptesSiO2) giving BW4@aptesSiO2 and (b) BW4 encapsulated on a metal organic framework, commonly referred as MIL-101, giving BW4@MIL-101. The catalytic activity of both heterogeneous materials was investigated for geraniol oxidation and the results were compared with those obtained with BW4 under homogeneous conditions. The encapsulated boron peroxotungstate (BW4@MIL-101) gave rise to the best results, reaching complete conversion of geraniol after 3 h of reaction and 78% selectivity for 2,3-epoxygeraniol. Additionally, this heterogeneous catalyst could be reused without appreciable loss of catalytic activity, affording similar 2,3-epoxygeraniol selectivity. The heterogeneous catalysts' stability was also investigated after the oxidation reactions by different characterization techniques.
COMPOUNDS OF THE PYRAN SERIES AS COMPONENTS OF THE ESSENTIAL OILS OF Tanacetum boreale AND Ajania fastigiata
Dembitskii, A. D.,Krotova, G. I.,Suleeva, R.,Yurina, R. A.
, p. 310 - 312 (1985)
It has been established that the essential oils of Tanacetum boreale and Ajania fastigiata contain as their main components 3-hydroxy-2,2,6-trimethyl-6-vinyltetrahydropyran and its acylated and oxidized derivatives.
Actinidia arguta: Volatile compounds in fruit and flowers
Matich, Adam J.,Young, Harry,Allen, John M.,Wang, Mindy Y.,Fielder, Simon,McNeilage, Mark A.,MacRae, Elspeth A.
, p. 285 - 301 (2003)
More than 240 compounds were detected when the volatile components of the flowers and the fruit from several Actinidia arguta genotypes were investigated. Around 60-70 different compounds were extracted from individual tissues of each genotype. Two different methods of volatile sampling (headspace and solvent) favoured different classes of compounds, dependent upon their volatilities and solubilities in the flower or fruit matrices. The compounds extracted from flowers largely comprised linalool derivatives including the lilac aldehydes (12a-d) and alcohols (13a-d), 2,6-dimethyl-6-hydroxyocta-2,7-dienal (8), 8-hydroxylinalool (9), sesquiterpenes, and benzene compounds that are presumed metabolites of phenylalanine and tyrosine. Extracts of fruit samples contained some monoterpenes, but were dominated by esters such as ethyl butanoate, hcxanoate, 2-methylbutanoate and 2-methylpropanoate, and by the aldehydes hexanal and hex-E2-enal. A number of unidentified compounds were also detected, including 8 from flowers that are so closely related that they are either isomers of one compound or two or more closely related compounds. This is the first report of the presence of a range of linalool derivatives in Actinida.
Divergent Total Syntheses of Yaequinolone-Related Natural Products by Late-Stage C-H Olefination
Ces, Sabela Vega,Fernández-Ibá?ez, M. ángeles,Jia, Wen-Liang
supporting information, p. 6259 - 6277 (2021/05/29)
Divergent total syntheses of 10 yaequinolone-related natural products have been achieved for the first time by late-stage C-H olefination of 3,4-dioxygenated 4-aryl-5-hydroxyquinolin-2(1H)-ones, core structures of this family of natural products. A robust synthetic methodology to construct the core structures has been established, and the C-H olefination reaction has been carried out with synthetically useful yields and high levels of site-selectivity under mild reaction conditions in the presence of a Pd/S,O-ligand catalyst.
Catalytic homogeneous oxidation of monoterpenes and cyclooctene with hydrogen peroxide in the presence of sandwich-type tungstophosphates [M4(H2O)2(PW9O34)2]n?, M = CoII, MnII and FeIII
Santos, Isabel C.M.S.,Gamelas, José A.F.,Duarte, Tiago A.G.,Sim?es, Mário M.Q.,Neves, M. Gra?a P.M.S.,Cavaleiro, José A.S.,Cavaleiro, Ana M.V.
, p. 593 - 599 (2016/12/16)
Catalytic efficiency of tetrabutylammonium salts of sandwich tungstophosphates B‐α‐[M4(H2O)2(PW9O34)2]n?, M = CoII, MnII, FeIII, was studied in the oxidation of (R)-(+)-limonene, geraniol, linalool, linalyl acetate, carveol, and cis-cyclooctene with hydrogen peroxide, in acetonitrile. Oxidation of (R)-(+)-limonene gave limonene-1,2-diol as main product. Epoxidation of linalool takes place preferentially at the more substituted 6,7-double bond, the corresponding 6,7-epoxide reacting further, yielding furano- and pyrano-oxides, via intramolecular cyclization. Oxidation of linalyl acetate occurred preferentially at the more substituted 6,7-double bond for Mn4(PW9)2, affording 6,7-epoxide at 82% selectivity. Linalyl acetate 1,2-epoxide was the major product with 51% and 77% selectivity for Co4(PW9)2 and Fe4(PW9)2, respectively. Oxidation of carveol occurred with very good conversions in the presence of Mn4(PW9)2, Co4(PW9)2 and Fe4(PW9)2, yielding carvone and carveol 1,2-epoxide in similar amounts. Oxidation of cis-cyclooctene gave only the epoxide, while oxidation of geraniol at room temperature afforded 2,3-epoxygeraniol as the major product.
Vanadyl arsenates as catalysts for selective oxidation of organic sulfides and alkenes
Berrocal, Teresa,Larrea, Edurne S.,Iglesias, Marta,Arriortua, Maria I.
scheme or table, p. 176 - 182 (2011/03/23)
Two vanadyl arsenates templated with ethylendiamonium (EnVAs) and piperazonium (PipVAs) were evaluated as catalysts for the oxidation of thioethers and alkenes, using H2O2 and t-butyl hydroperoxide (TBHP) as oxidants. The intrinsic activity of EnVAs was higher than that of PipVAs for the oxidation of sulfides. Similar results were obtained when using either H2O2 or TBHP as oxidants. However, the sterical effects were enhanced when TBHP was used and higher selectivities towards sulfoxides were achieved with this oxidant. The catalytic activity of the V-based materials in the epoxidation of simple alkenes and allylic alcohols was assessed. Upon reuse, both materials show no significant decrease in their catalytic properties.
Vanadium(V)-catalyzed oxidation of (3R)-linalool - The selective formation of furanoid linalool oxides and their conversion into isocyclocapitelline derivatives
Hartung, Jens,Drees, Simone,Geiss, Barbara,Schmidt, Philipp
, p. 223 - 226 (2007/10/03)
Oxidation of (3R)-linalool (2) with tert-butyl hydroperoxide (TBHP) occurs at the 6,7-position to selectively afford linalool oxide cis-1, if catalyzed by vanadium(V) Schiff base complexes 4. Substituted tetrahydrofuran cis-1 and its isomer trans-1 served
(Schiff-base)vanadium(v) complex-catalyzed oxidations of substituted bis(homoallylic) alcohols - Stereoselective synthesis of functionalized tetrahydrofurans
Hartung, Jens,Drees, Simone,Greb, Marco,Schmidt, Philipp,Svoboda, Ingrid,Fuess, Hartmut,Murso, Alexander,Stalke, Dietmar
, p. 2388 - 2408 (2007/10/03)
Vanadium(v) complexes 4 have been prepared from tridentate Schiff-base ligands 3 and VO(OEt)3. All vanadium(v) compounds were characterized (IR, UV/Vis, and 51V NMR spectroscopy, and in selected examples by X-ray diffraction analysis) and were applied as oxidation catalysts for the stereoselective synthesis of functionalized tetrahydrofurans 2 starting from substituted bis(homoallylic) alcohols 1 (mono- or trisubstituted C-C double bonds). Oxidation of secondary or tertiary 1-alkyl-, 1-vinyl-, or 1-phenyl-substituted 5,5-dimethyl-4-penten-1-ols under optimized conditions [TBHP as primary oxidant and 1,2-(amino)indanol-derived vanadium(v) reagent 4g as catalyst] provided 2,5-cis-configured tetrahydrofurans in synthetically useful yields and diastereoselectivities (22-96% de). On the other hand, trans-disubstituted oxolanes (62%-96 de) were obtained from oxidations of 2- or 3-alkyl- and 2- or 3-phenyl-substituted 5,5-dimethyl-4-penten-1-ols bis(homoallylic) allyhc) alcohols. Treatment of 4-penten-1-ols (i.e. substrates with monosubstituted olefinic π-bonds) with TBHP and catalytic amounts of vanadium(v) complex 4g furnished trans-disubstituted tetrahydrofurans as major products (20-96% de), no matter whether an alkyl or a phenyl substituent was located in position 1, 2, or 3 of the alkenol chain. The mechanism of this reaction has been investigated in detail. Based on results from 51V NMR spectroscopy and competition kinetics, it proceeds by a transition metal-peroxy pathway. In an initial step, TBHP coordinates to, for example, N-(2-oxidophenyl)salicylideniminato-derived vanadium complex 4a. Subsequent alkenol binding gives rise to a "loaded" vanadium(v) peroxy complex (e.g. 60) which facilitates diastereoselective oxygen transfer, presumably onto a coordinated substrate. This step leads to the formation of functionalized tetrahydrofurans as major products. TBHP binding to the remaining vanadium(v) complex then allows a regeneration of the active oxidant, for example peroxy complex 57. The origin of the observed diastereoselectivity in this oxidation has been studied in an independent stereochemical analysis. Thus, diastereomerically enriched epoxy alcohol (1R,4R)-10 was prepared. Its treatment with 1,2-(amino)indanol-derived vanadium complex 4g affords a 91:9 mixture of cis-2-(1-hydroxy-1-methylethyl)-5-(phenyl)tetrahydrofuran (cis-6) and cis-2,2-dimethyl-6-(phenyl)tetrahydropyran-3-ol (cis-7). Similarly, a 39:61 mixture of heterocycles trans-6 and trans-7 was obtained from epoxy alcohol (1S,4R)-10, if treated with Lewis acid 4g. ( Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003).
Oxidation of α-hydroxy containing monoterpenes using titanium silicate catalysts: Comments on regioselectivity and the role of acidity
Schofield, Lee J.,Kerton, Owain J.,McMorn, Paul,Bethell, Donald,Ellwood, Simon,Hutchings, Graham J.
, p. 1475 - 1481 (2007/10/03)
The regioselective epoxidation of monoterpenes in the liquid phase has been studied using the titanosilicates TS-1 and TiAlβ. A range of oxidants (hydrogen peroxide, tert-butyl hydroperoxide and urea-hydrogen peroxide complex) have been studied in detail. The allylic alcohols linalool and geraniol have been studied alongside the non-allylic alcohol citronellol and the diene dihydromyrcene to help determine the role of the hydroxy group in these reactions. Dihydromyrcene is selectively epoxidised at the more electron rich double bond regardless of the catalyst-oxidant-solvent system used. Geraniol can undergo allylic assisted epoxidation with TS-1-acetone-hydrogen peroxide and TiAlβ-acetonitrile-urea-hydrogen peroxide. With TiAlβ-hydrogen peroxide-methanol, the reaction shows an induction period in the conversion of geraniol which is considered to be characteristic of the autocatalytic removal of titanium from the catalyst framework. Reactions with citronellol show this titanium removal is entirely due to the presence of the allylic alcohol moiety. Finally, epoxidation of linalool and the subsequent in situ conversion of the epoxide to the furano- and pyrano-oxides were studied. The ratio of furano- and pyrano-oxides formed was considered to be due, in part, to the pore geometry and the Br?nsted acidity of the catalyst.
Organic processes initiated by non-classical energy sources
Nuechter, Matthias,Ondruschka, Bernd,Jungnickel, Anja,Mueller, Ute
, p. 579 - 586 (2007/10/03)
Non-classical energy sources such as microwave energy, ultrasound and mechanoenergy and their combination with UV-VIS radiation are new tools in synthetic chemistry and chemical processing. Here we describe the application of microwave treatment for selected organic reactions such as (i) enzymatic transesterification of optically active alcohols, (ii) mercury-sensitized gas-phase photolysis of hydrocarbons in the microwave field, (iii) environmentally benign oxidations of olefins and (iv) the application of mechanoenergy separately and in combination with microwave irradiation for special oxidation reactions. Copyright
