- Photo-induced radical borylation of hemiacetals via C–C bond cleavage
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In this study, we reported a photo-induced radical borylation of hemiacetal derivatives via C–C bond cleavage. This transformation can be realized under mild conditions with simple reaction settings and irradiation of visible light. A series of substrates, including both cyclic and linear hemiacetal derivatives, were effectively transformed to the borylation product in moderate to good yields. Finally, the mechanism was studied in detail by DFT calculations, suggesting insight of the radical borylation process.
- Liu, Qianyi,Zhang, Jianning,Zhang, Lei,Mo, Fanyang
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supporting information
(2021/01/05)
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- Calcium(II)- And Triflimide-Catalyzed Intramolecular Hydroacyloxylation of Unactivated Alkenes in Hexafluoroisopropanol
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We report an efficient intramolecular hydroacyloxylation of unactivated alkenes, offering a streamlined access to relevant γ-lactones, which features the utilization of either a calcium(II) salt or triflimide as a catalyst in hexafluoroisopropanol. This method could be applied to the synthesis of natural products and the late-stage functionalization of natural and bioactive molecules. Additionally, DFT computations were used to elucidate the twist of reactivity observed between the hydroamidation and hydroacyloxylation of unactivated alkenes regarding the formation of 5- and 6-membered rings.
- Qi, Chenxiao,Yang, Shengwen,Gandon, Vincent,Leb?uf, David
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supporting information
p. 7405 - 7409
(2019/10/02)
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- W(OTf)6-Catalyzed Synthesis of Γ-Lactones by Ring Contraction of Macrolides or Ring Closing of Terminal Hydroxyfatty Acids in Ionic Liquid
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γ-Lactones are an important class of fine chemical products and are widely used in perfumes, medicines, pesticides, dyes, and other fields. Herein, a new method for γ-lactones preparation based on ring contraction was developed. Starting from macrolides, W(OTf)6 was used to catalyze the ring-opening polymerization then depolymerization. The depolymerization step was not a common ring-closing process, and the carbon number of the ring was reduced one by one by rearrangement to form the most thermodynamically stable five-membered ring compounds. γ-Caprolactone (180 °C for 10 h) was obtained in a yield of 94 % when [EMIM]OTf was used as the solvent, and the yield of isolated product was up to 85 %. The interaction of various components and the reaction mechanism were studied by FTIR spectroscopy and 1H NMR spectroscopy, respectively. Furthermore, γ-lactones could be produced when the substrate was extended to terminal hydroxyfatty acids. Unexpectedly, the catalyst was poisoned by 1 equivalent of H2O added during the process and thus the yield decreased greatly. The reaction is green and simple, and proceeds in one pot with high atom economy (100 % for macrolides and with water as the only byproduct for terminal hydroxyfatty acid), which provides a promising approach to synthesizing γ-lactones.
- Xie, Zhong-Yu,Deng, Jin,Fu, Yao
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p. 2332 - 2339
(2018/07/31)
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- Transforming Olefins into γ,δ-Unsaturated Nitriles through Copper Catalysis
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We have developed a strategy to transform olefins into homoallylic nitriles through a mechanism that combines copper catalysis with alkyl nitrile radicals. The radicals are easily generated from alkyl nitriles in the presence of the mild oxidant di-tert-butyl peroxide. This cross-dehydrogenative coupling between simple olefins and alkylnitriles bears advantages over the conventional use of halides and toxic cyanide reagents. With this method, we showcase the facile synthesis of a flavoring agent, a natural product, and a polymer precursor from simple olefins.
- Wu, Xuesong,Riedel, Jan,Dong, Vy M.
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supporting information
p. 11589 - 11593
(2017/09/11)
-
- Nucleo-Palladation-Triggering Alkene Functionalization: A Route to γ-Lactones
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An unprecedented strategy for the highly effective synthesis of γ-lactones from homoallylic alcohols was achieved by palladium catalysis in one step. The protocol affords aryl, alkyl, and spiro γ-lactones directly from readily available homoallylic alcohols in good yields with excellent functional group tolerance and high chemoselectivity under mild conditions.
- Zheng, Meifang,Chen, Pengquan,Huang, Liangbin,Wu, Wanqing,Jiang, Huanfeng
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p. 5756 - 5759
(2017/11/10)
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- MnO2-promoted carboesterification of alkenes with anhydrides: A facile approach to γ-lactones
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An efficient carboesterification of alkenes with anhydrides promoted by MnO2 has been developed to afford functionalized γ-lactones in good to excellent yields. This method shows a broad substrate scope and provides a valuable and convenient synthetic tool for constructing γ-lactones.
- Wu, Lihuan,Zhang, Zhenming,Liao, Jianhua,Li, Jianxiao,Wu, Wanqing,Jiang, Huanfeng
-
supporting information
p. 2628 - 2631
(2016/02/18)
-
- 1H-pyrrole-2,4-dicarbonyl-derivatives and their use as flavoring agents
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The present invention primarily relates to 1H-pyrrole-2,4-dicarbonyl-derivatives of Formula (I) wherein R1, R2, R3, Z. Z' and J are as defined in the description, to mixtures thereof and to the use thereof as flavoring agents. The compounds in accordance with the present invention are suitable for producing, imparting, or intensifying an umami flavor. The invention further relates to flavoring mixtures, compositions for oral consumption as well as ready-to-eat, ready-to-use and semifinished products, comprising an effective amount of the compound of Formula (I) or of a mixture of compounds of Formula (I) and to specific methods for producing, imparting, modifying and/or intensifying specific flavor impressions.
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-
- Imidazo[1,2-a]pyridine-ylmethyl-derivatives and their use as flavoring agents
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The present invention primarily relates to imidazo[1,2-a]pyridine-ylmethyl-derivatives of Formula (I) wherein R1, R2, X, W e J are as defined in the description, to mixtures thereof and to the use thereof as flavoring agents. The compounds in accordance with the present invention are suitable for producing, imparting, or intensifying an umami flavor. The invention further relates to flavoring mixtures, compositions for oral consumption as well as ready-to-eat, ready-to-use and semifinished products, comprising an effective amount of the compound of Formula (I) and to specific methods for producing, imparting, modifying and/or intensifying specific flavor impressions.
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- Ruthenium pincer-catalyzed synthesis of substituted γ-butyrolactones using hydrogen autotransfer methodology
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The ruthenium pincer-catalyzed synthesis of γ-butyrolactones from 1,2-diols and malonates using borrowing-hydrogen methodology is reported. This regioselective domino-process takes place through catalytic C-C bond formation, followed by intramolecular transesterification. Herein, we show the Ru-MACHO-BH complex as a valuable catalyst in hydrogen autotransfer reactions.
- Pe?a-López, Miguel,Neumann, Helfried,Beller, Matthias
-
supporting information
p. 13082 - 13085
(2015/08/18)
-
- Direct room-temperature lactonisation of alcohols and ethers onto amides: An "amide strategy" for synthesis
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Last-minute deal: A direct lactonisation of ethers and alcohols onto amides that proceeds at room temperature under mild conditions is reported (see scheme). This allows the effective saving of up to two unproductive, sequential deprotection operations in synthetic sequences. Mechanistic studies are described, and a new "amide strategy" that exploits the dual robustness/late-stage selective activation properties of this functional group is outlined. Copyright
- Valerio, Viviana,Petkova, Desislava,Madelaine, Claire,Maulide, Nuno
-
supporting information
p. 2606 - 2610
(2013/03/14)
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- A new synthesis of γ-butyrolactones via AuCl3- or Hg(II)-catalyzed intramolecular hydroalkoxylation of 4-bromo-3-yn-1-ols
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An efficient conversion of 4-bromo-3-yn-1-ols to γ-butyrolactones via AuCl3-catalyzed electrophilic cyclization (hydroxyl-assisted regioselective hydration) in wet toluene is described. Various secondary and tertiary alcohols including benzylic systems were found to be equally reactive with moderate to excellent yields obtained in all cases.
- Reddy, Maddi Sridhar,Kumar, Yalla Kiran,Thirupathi, Nuligonda
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p. 824 - 827
(2012/04/05)
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- Copper-catalyzed intermolecular oxidative [3 + 2] cycloaddition between alkenes and anhydrides: A new synthetic approach to γ-lactones
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A new copper-catalyzed oxidative [3 + 2] cycloaddition of alkenes with anhydrides using oxygen as the sole oxidant to afford γ-lactones has been developed. This catalyzed cyclization process has a broad substrate scope and affords γ-lactones in good to excellent yields.
- Huang, Liangbin,Jiang, Huanfeng,Qi, Chaorong,Liu, Xiaohang
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supporting information; experimental part
p. 17652 - 17654
(2011/03/16)
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- PROCESS FOR PRODUCTION OF SUBSTITUTED CYCLOPENTANONE
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A substituted cyclopentanone represented by the formula (2) can be produced by hydrogenating the double bond in a compound represented by the formula (1) in the presence of a transition metal catalyst by using a carboxylic acid or a specific concentration of a carboxylic acid ester as a solvent. This process can produce a substituted cyclopentanone which is useful as an jasmine-flavored fragrance, an intermediate in the production of the fragrance or the like, in a simple and inexpensive manner at a high cis-form ratio; (1) wherein R1 and R2 represent a substituent having 1 to 8 carbon atoms; and (2) wherein R3 and R4 represent a substituent having 1 to 8 carbon atoms, may be the same as R1 and R2, and may be the same as each other.
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Page/Page column 76-77
(2008/06/13)
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- Lewis acid-catalysed isomerisation of thionolactones to thiolactones: inversion of configuration
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Boron trifluoride and indium(III) trifluoromethanesulfonate were found to efficiently catalyse the isomerisation of thionolactones to thiolactones in good yields. When applied to an optically active γ-thionolactone, the isomerisation reaction proceeded with a complete inversion of configuration by using BF3·Et2O.
- Filippi, Jean-Jacques,Fernandez, Xavier,Du?ach, Elisabet
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p. 6067 - 6070
(2007/10/03)
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- IBX/n-Bu4NBr/CH2Cl2-H2O: A new mild system for selective oxidation of secondary alcohols
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A new alternative system for the chemoselective oxidation of secondary hydroxyl group to ketone with IBX/n-Bu4NBr in CH2Cl 2-H2O has been developed. Under the reaction conditions, the secondary hydroxyl group was highly chemoselectively oxidized to the corresponding ketone, in moderate to good yields at rt, in the presence of primary hydroxyl group within the same molecule.
- Kuhakarn, Chutima,Kittigowittana, Krisada,Pohmakotr, Manat,Reutrakul, Vichai
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p. 8995 - 9000
(2007/10/03)
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- Cycloisomerization of olefinic carboxylic acids catalyzed by trifluoromethanesulfonic acid
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The trifluoromethanesulfonic acid-catalyzed cyclization of various differently substituted unsaturated carboxylic acids affords selectively substituted lactones in good yields. The reactions use 0.5 to 5% molar ratio of catalyst and can be run without solvent.
- Coulombel, Lydie,Dunach, Elisabet
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p. 153 - 160
(2007/10/03)
-
- Identification of novel decenoic acids in heated butter
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Novel decenoic acids such as (E)-4-decenoic acid and (E)- and (Z)-5-,6-decenoic acid were detected as minor components in heated butter using GC and GC/MS. The formation mechanism of these novel decenoic acids is discussed on the basis of the result of the reaction of δ-decalactone with active clay in a model experiment.
- Ito, Nobuhiko,Wada, Shigeru,Yamanaka, Yousuke,Takagaki, Hitoshi,Nakamura, Hironori
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p. 2416 - 2420
(2008/02/03)
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- Synthesis of deuterated γ-lactones for use in stable isotope dilution assays
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Two syntheses of deuterated γ-lactones for use as internal standards in stable isotope dilution assays (SIDA) were developed. [2,2,3,3- 2H4]-γ-Octa-, -γ-deca-, and -γ-dodecalactones with >89% deuterium incorporation were prepared in 27, 17, and 19% overall yields, respectively, by the reduction of a doubly protected hydroxypropiolic acid with deuterium gas. [3,3,4-2H 3]-γ-Octa- and -γ-dodecalactones were prepared in 6 and 23% yields with >92% deuterium incorporation by the free radical addition of 2-iodoacetamide to [1,1,2-2H3]-1-hexene and [1,1,2- 2H3]-1-decene, respectively. Reaction yields were highly dependent upon the purity of the 1-alkene starting material. The deuterated γ-lactones were evaluated as internal standards for SIDA.
- Hislop, J.O.-Anna,Hunt, Martin B.,Fielder, Simon,Rowan, Daryl D.
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p. 7075 - 7083
(2007/10/03)
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- Investigations of the scope and mechanism of the tandem hydroesterification/lactonization reaction
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(Chemical Equation Presented) Heating allylic and homoallylic alcohols and 2-pyridylmethyl formate in the presence of Ru3(CO)12 initiates a tandem sequence of hydroesterification and lactonization. Mechanistic studies suggest that regioselectivity and overall reaction efficiency are governed by the relative rates of reductive elimination and β-hydride elimination for the alkylruthenium intermediates.
- Wang, Lijun,Floreancig, Paul E.
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p. 4207 - 4210
(2007/10/03)
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- Tandem cross-metathesis/hydrogenation/cyclization reactions by using compatible catalysts
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(Matrix presented) A one-pot tandem cross-metathesis/hydrogenation/cyclization procedure was achieved at room temperature, under 1 atm of hydrogen, in the presence of a ruthenium catalyst and PtO2 showing the compatibility of the two catalysts. This tandem reaction allows the synthesis of substituted lactones and lactols from acrylic acid and acrolein, respectively, in the presence of unsaturated alcohols.
- Cossy, Janine,Bargiggia, Frederic,BouzBouz, Samir
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p. 459 - 462
(2007/10/03)
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- Process and catalyst for the production of y-butyrolactones
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Process for the catalytic preparation of y-butyrolactone having the general formulaby reacting an olefin with the general formula R1CHCH2, with an carboxylic acid with the general formula R2CH2COOH, wherein R1 and R2 represent the substituent R1 and R2 in the butyrolactone, which reaction is performed in presence of oxygen in contact with a catalyst comprising manganese and at least one basic metal oxide.
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- Radical addition of 2-iodoalkanamide or 2-iodoalkanoic acid to alkenes with a water-soluble radical initiator in aqueous media: Facile synthesis of γ-lactones
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Radical reactions in water or aqueous ethanol using a water-soluble radical initiator are described. Heating a mixture of 2-iodoacetamide and 5-hexen-1-ol in water at 75 °C in the presence of a water-soluble radical initiator, 4,4′-azobis 4-cyanopentanoic acid), afforded 5-(4-hydroxybutyl)dihydrofuran-2(3H)-one in 95% yield. The use of 2-iodoacetic acid in place of 2-iodoacetamide also gave the same γ-lactone in 93% yield. The reaction of 2-iodoacetamide with 1-octene in aqueous ethanol was initiated by 2,2′-azobis(2-methylpropanamidine) dihydrochloride to provide γ-decanolactone. Employing water as a solvent is crucial to obtain lactone in satisfactory yield.
- Yorimitsu,Wakabayashi,Shinokubo,Oshima
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p. 1963 - 1970
(2007/10/03)
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- Synthesis of γ-lactones and unsaturated bis γ-lactones via Cu-Fe-mediated reductive cyclization of di- and tri-α-halogenated carboxylic esters
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A new synthetic route to γ-substituted γ-butyrolactones from alkenes and α-dichloro ester, in the presence of CuCl (catalytic) and Fe(0) (stoichiometric) in acetonitrile, was established. A study of this reaction has demonstrated that the overall process consists of the following reaction steps: (a) addition of the dichloro ester to the olefin via CuCl catalysis; (b) selective reduction of the α-chloro atom in the resulting adduct by Fe(0); (c) cyclization of the resulting γ-chloro ester to γ-butyrolactone. Yields were improved by first carrying out step (a), then steps (b) and (c) in one pot. Selectivity was improved in the presence of a small amount of water. α-Trichloro esters also generated the γ-substituted γ-butyrolactone, albeit in lower yields and selectivity. The latter reaction gave rise to the formation of interesting by-products, namely new unsaturated bis-lactones.
- Somech, Iris,Shvo, Youval
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p. 153 - 159
(2007/10/03)
-
- Synthesis and Applications of Tetrahydrofuran-Stable Substituted (3-Lithioxyalkyl)- and (4-Lithioxyalkyl)lithiums, Modified with Magnesium 2-Ethoxyethoxide
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Substituted hydroxyalkyl phenyl sulfides 3 have been synthesized from the corresponding allylic or homoallylic alcohols 2. Regiospecific cleavage of the C - SPh bond of the sulfides 3 by lithium dispersion in tetrahydrofuran (THF) led to the synthesis of substituted (3-lithioxyalkyl)- and (4-lithioxyalkyl)lithiums 4, most of which share the ω carbon with a carbocyclic ring. The organolithiums were modified with magnesium 2-ethoxyethoxide in order to suppress their reactivity toward THF cleavage, thus offering the advantage of preparing storable ethereal solutions of certain types of (lithioxyalkyl)lithiums. This strategy appears to be of rather broad scope. The functionalized organolithiums prepared in this way react normally with electrophilic reagents with yields in the range 35-55%. Thus, carboxylations of 4 yielded lactones 5, some of which are natural products, while reactions of 4 with benzophenone and cyclic ketones yielded 1,4- and 1,5-diols 6 and 7, respectively.
- Kostas, Ioannis D.,Screttas, Constantinos G.
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p. 5575 - 5577
(2007/10/03)
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- Biotransformation of saturated monohydroxyl fatty acids to 2-tetrahydrofuranyl acetic acid derivatives: Mechanism of formations and the biological activity of 5-n-hexyl-tetrahydrofuran-2-acetic acid
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The transformation of 12-hydroxyoctadecanoic acid (12-HOA) to 5-n-hexyl-tetrahydofuran-2-acetic acid (5-HTFA) by Bacillus lentus NRRL B-14864 was carried out in the presence and absence of oligomycin, 2-bromooctanoic acid (2-BA), or sodium azide. Methyl esters of the transformation products were analyzed by gas chromatography and gas chromatography/mass spectroscopy. Results suggest that the production of 5-HTFA from 12-HOA by B-14864 was through the fatty acid beta-oxidation pathway. Three-day old driedfruit beetle pupae were topically treated with 5-HTFA to test for juvenile hormone activity, and 5-HTFA was found to possess juvenile hormone-like activity in pure form but not when it was diluted to 10 percent.
- Huang,Dowd,Keudell,Klopfenstein,Wen,Bagby,Lanser,Norton
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p. 1465 - 1469
(2007/10/03)
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- Microbial Transformation of 12-Hydroxyoctadecanoic Acid to 5-n-Hexyl-Tetrahydrofuran-2-Acetic Acid
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Stationary-phase cells of a corynebacterium (FUI-2) and a bacillus (NRRL B-14864) isolate, when grown aerobically in 1percent YE medium at 25 deg C, converted 12-hydroxystearic acid to a major compound, 5-n-hexyl-tetrahydrofuran-2-acetic acid, and other intermediate and minor compounds (6-hydroxydodecanoic acid, 4-hydroxydecanoic acid, 4-ketodecanoic acid and γ-decanolactone).The yields of 5-n-hexyl-tetrahydrofuran-2-acetic acid, 4-hydroxydecanoic acid, and γ-decanolactone, by Bacillus lentus NRRL B-14864 were 43percent, 18percent and 5percent, respectively, after 2.5 d of incubation. Key Words: Bacillus lentus, corynebacterium, D-(+)-12-hydroxy-octadecanoic acid, D-(+)-12-hydroxystearic acid, γ-decanolactone, 4-hydroxydecanoic acid, 6-hydroxydodecanoic acid, 4-ketodecanoic acid, 5-n-hexyl-tetrahydrofuran-2-acetic acid.
- Huang, J.-K.,Keudell, K. C.,Zhao, J.,Klopfenstein, W. E.,Wen, L.,et al.
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p. 323 - 326
(2007/10/02)
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- SmCl3-catalysed Electrosynthesis of γ-Butyrolactones from 3-Chloroesters and Carbonyl Compounds
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Electrosynthesis of γ-butyrolactones has been achieved by the direct reductive coupling of ethyl 3-chloropropionate and a series of carbonyl compounds in the presence of a catalytic amount of SmCl3.
- Hebri, Hassan,Dunach, Elisabet,Perichon, Jacques
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p. 499 - 500
(2007/10/02)
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- Hydroacylation of Alkyl Vinyl Ketones and Acrylic Esters Using Organotetracarbonylferrates. Synthesis of 1,4-Dicarbonyl Compounds
-
Alkyl vinyl ketones and acrylic esters were hydroacylated with organotetracarbonylferrates to the corresponding 1,4-diketones and 4-oxo carboxylic acid derivatives in good yield in dipolar aprotic solvents such as N,N-dimethylacetamide.Addition of 18-crown-6 improved the yield. cis-Jasmone and γ-jasmolactone were synthesized by use of these reactions.
- Yamashita, Masakazu,Tashika, Haruyoshi,Uchida, Masaya
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p. 1257 - 1261
(2007/10/02)
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- A Selective and Efficient Method for Alcohol Oxidations Mediated by N-Oxoammonium Salts in Combination with Sodium Bromite
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The oxidation of primary and secondary alcohols leading to aldehydes, carboxylic acids, and ketones has been carried out in a N-oxoammonium salts-NaBrO2 system.Sodium bromite as a stoichiometric oxidizing reagent activates N-oxyl compounds (recycling catalysts) to their N-oxoammonium salts in a weakly basic medium, which oxidize primary hydroxyl groups preferentially rather than secondary ones to the corresponding aldehydes.Calcium hypochlorite is used as an alternative terminal oxidant in the same media.The procedure, applicable to the selective formation of γ- and δ-lactones, β-hydroxy aldehydes, and 2-acetoxy ketones, is advantageous in terms of reagent cost, safety, and ease of operation.
- Inokuchi, Tsutomo,Matsumoto, Sigeaki,Nishiyama, Tokio,Torii, Sigeru
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p. 462 - 466
(2007/10/02)
-
- Regiospecific Carbonylation and Ring Expansion of Thietanes and Oxetanes Catalyzed by Cobalt and/or Ruthenium Carbonyls
-
Dicobalt octacarbonyl and triruthenium dodecacarbonyl together catalyze the regiospecific insertion of carbon monoxide into the least substituted carbon-heteroatom bond of a thietane or oxetane, affording thiobutyrolactones or butyrolactones in fine yields.
- Wang, Ming-De,Calet, Serge,Alper, Howard
-
-
- Production of lactones
-
Gamma-decalactone is obtained from a source of ricinoleic acid, for example castor oil, by incubation with Sp. odorusor Rh. glutinis. The product lactone is obtained by lactonising the product hydroxydecanoic acid. The lactone is of value in perfumery and flavours.
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- A NEW FACILE SYNTHESIS OF 2-ALKYLCYCLOPENT-2-ENONES
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A new, simple and short route to 2-alkylcyclopent-2-enones starting from inxpensive terminal epoxides is described.
- Bonsignore, S.,Dalcanale, E.,Martinengo, T.
-
p. 2241 - 2250
(2007/10/02)
-
- An Efficient Route for γ-Alkyl-γ-butyrolactones
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An efficient route for γ-alkyl-γ-butyrolactones (1) involving iodolactonisation is described.
- Gurjar, M. K.,Purandare, A. V.
-
p. 554 - 555
(2007/10/02)
-
- Preparation of (Triphenylsilyl)allyl Anion and (Triphenylgermyl)allyl Anion from 1-Propenyltriphenylsilane and 1-Propenyltriphenylgermane and Their Reactions with Electrophiles
-
Treatment of 1-propenyltriphenylsilane with n-BuLi in THF-HMPA provides (triphenylsilyl)allyl anion which is identical with an anion derived from 2-propenyltriphenylsilane and base.Generation of (triphenylgermyl)allyl anion is also described.Addition of alkyl halides or carbonyl compounds to these anions gives the corresponding adducts regioselectively.
- Wakamatsu, Kuni,Oshima, Koichiro,Utimoto, Kiitiro
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p. 2029 - 2032
(2007/10/02)
-
- Free Radical Addition of 2-Bromoalkanoic Acids to Alkenes
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The benzoyl peroxide-catalyzed reaction of 2-bromoalkanoic acids such as bromoacetic, 2-bromopropionic, and 2-bromobutyric acid with 1-alkenes was found to proceed thorough the addition of the C-Br bond across the double bond followed by cyclization affording 4-alkanolides in good yields.
- Nakano, Taichi,Kayama, Mikio,Nagai, Yoichiro
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p. 1049 - 1052
(2007/10/02)
-
- Indirect Electrooxidation of Alkohols and Aldehydes by Using a Double Mediatory System Consisting of RuO4/RuO2 and Cl+/Cl- Redoxes in an Aqueous-Organic Two-Phase System
-
A double mediatory system consisting of RuO4/RuO2 and Cl+/Cl- redox couples has been developed for the indirect electrooxidation of alcohols and aldehydes.The reaction proceeds in the following manner: (1) oxidation of the substrate with ruthenium tetraoxide (RuO4) in the organic layer, (2) regeneration of ruthenium tetraoxide from ruthenium dioxide (RuO2) with active chlorine species (Cl2 or +), and (3) oxidation of chloride ion to + on the anode in the aqueous layer.The range of applicability of the present procedure is discussed by oxidations of (1)secondary alcohols to ketones, (2) primary alcohols and aldehydes to carboxylic acid, (3) 1,n-diols to lactones and keto acids, and (4) carbohydrate derivatives.
- Torii, Sigeru,Inokuchi, Tsutomu,Sugiura, Toyoyuki
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p. 155 - 161
(2007/10/02)
-
- SUBSTITUENT DIRECTED OXIDATIVE CYCLIZATION WITH CETYLTRIMETHYLAMMONIUM PERMANGANATE: A GENERAL APPROACH TO THE SYNTHESIS OF γ- AND δ-LACTONES
-
Treatment of primary, secondary or tertiary γ- and δ-hydroxyolefins with cetyltrimethylammonium permanganate gives good yields of γ- and δ-lactones by oxidative cyclization, with loss of one carbon.
- Rathore, Rajendra,Vankar, Padma S.,Chandrasekaran, S.
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p. 4079 - 4082
(2007/10/02)
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- Manganese(III)-Mediated γ-Lactone Annulation
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The annulation of a γ-lactone ring onto an alkene by manganese(III) acetate oxidation of acetic acid was investigated.The regioselectivity of addition to unsymmetrically substituted alkenes is reported along with the stereoselectivity of addition to various acyclic and cyclic alkenes.Alkenes with ionization potentials above 8.2 eV were found to react in good yield.The role of acetic anhydride in these reactions was studied, and it was shown to be oxidized faster than acetic acid and also led to different products.The fate of oxidized acetic acid or anhydridein the absence of suitable acceptor molecule has also been quantitatively identified.The relationship of enolizability, or C-H acidity, of the carboxylic acid being oxidized was established quantitatively.
- Fristad, William E.,Peterson, John R.
-
-
- A New Method for Generating Trichlorotitanium(IV) Ester Homoenolates. Direct Tin-Titanium Exchange
-
Treatment of the β-tri-n-butylstannyl derivatives of esters with titanium tetrachloride in dichloromethane effects tin-titanium exchange to generate trichlorotitanium(IV) homoenolate derivatives of the esters, which may then be used in further reaction with electrophiles.
- Goswami, Ramanuj
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p. 5907 - 5909
(2007/10/02)
-
- γ-BUTYROLACTONE AUS METALLIERTEN ENAMINEN
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Enamines of type 1 with anion-stabilizing substituents a are available by Horner-reaction of suitable phosphonates aldehydes.Deprotonation of 1 gives aminoallyl anions 2, which react with carbonyl compounds (depending on a) either to butyrolactones 8 resp. 10 or to 6-membered lactons 13.This process amounts to synthesis of lactones from two carbonyl compounds and an α-aminosubstituted phosphonate.
- Costisella, Burkard,Gross, Hans,Schick, Hans
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p. 733 - 736
(2007/10/02)
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- FACTORS GOVERNING PRODUCT DISTRIBUTION IN THE OXIDATION OF ALKENES BY MANGANESE(III) ACETATE IN ACETIC ACID AND ACETIC ANHYDRIDE
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A systematic investigation has been carried out into the effect of different reaction parameters on the oxidation of oct-1-ene by manganese(III) acetate in acetic acid and acetic anhydride.The most important factor in dictating the ratio of products is the composition of the solvent.In the absence of anhydride γ-decanolactone is virtually the sole product.Even small quantitites of anhydride lead to the lactone being replaced by other products derived from cationic intermediates C6H13CH(1+)CH2COX (X = OH or OAc).Further increases in the amount of anhydride encourage the formation of decanoic acid until, in 90percent anhydride, this becomes the predominant product.The results cannot be interpreted simply in terms of competition for the alkene by the radicals (.)CH2CO2H and (.)CH2COOCOCH3.Decanoic acid formation is also favoured by low temperatures, low concentration of oxidants, and by the addition of acetate ions.A comparision is made of the efficiency of addition when the initiating species is manganese(III) or a peroxide.
- Midgley, Gary,Thomas, C. Barry
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p. 1537 - 1544
(2007/10/02)
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- Synthesis of γ- and δ-Lactones via Radical CC-Bond Formation Reaction
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Lactones 5 and 6 can be synthesized via solvomercuration of alkenes 1 and reductive CC-bond formation with acrylonitrile.
- Giese, Bernd,Hasskerl, Thomas,Luening, Ulrich
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p. 859 - 861
(2007/10/02)
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- Electroorganic Chemistry. Part 73. Electroreductive Cross-coupling of 3-Substituted Alkanoic Acid Esters with Aldehydes or Acid Anhydrides
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Elecroreductive cross-coupling reaction of 3-phenylthioalkanoic acids esters (4a) or quaternary ammonium salts of 3-aminoalkanoic acid esters (4b) with aldehydes gave the corresponding γ-lactones in one step.The cross-coupling reaction of (4b) with acid anhydrides leading to the formation of the corresponding γ-keto esters is also described.
- Shono, Tatsuya,Matsumura, Yoshihiro,Kashimura, Shigenori
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p. 1922 - 1935
(2007/10/02)
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- Electron-transfer Processes: Metal Salt Catalysed Oxidation of Olefins by Peroxydisulphate
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The reaction of simple olefins (oct-1-ene, oct-2-ene, cyclohexene, cycloheptene) with peroxydisulphate has been investigated under several conditions: (i) in aqueous medium and catalysis by AgI, FeII, and CuII; (ii) in acetic madium and catalysis by CuII, FeIII; (iii) in the presence of traps of nucleophilic alkyl radicals (protonated heteroaromatic bases and 1,4-benzoquinone either in water or in acetic acid).The catalyst and the radical trap govern the selectivity and allow a variety of new synthetic achievements.Evidence for a unified initial mechanism of electron transfer with formation of a radical cation from the olefin is reported to explain all the results.In water the radical cation gives a β-hydroxyalkyl radical, which, depending on the nature of the catalyst and the trap, can give the corresponding saturated alcohol by hydrogen abstraction, the products of CuII oxidation, or β-hydroxyalkylation of the heteroaromatic compound or 1,4-benzoquinone.In acetic acid the radical cation gives a β-acetoxyalkyl radical, which is oxidized to the corresponding allylic acetate by copper(II) acetate or trapped by the heteroaromatic base.
- Arnoldi, Claudio,Citterio, Attilio,Minisci, Francesco
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p. 531 - 542
(2007/10/02)
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- Process for producing lactones from unsaturated carbonyl compounds
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A method for producing an alkyl substituted lactone including the steps of alkylating an unsaturated ketone with a C1 -C12 alkyl organometallic reagent such as a Grignard reagent or an alkali metal alkyl, to form an unsaturated alcohol, and oxidatively cleaving the unsaturated alcohol to form the lactone, and recovering the lactone.
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- LACTONIZATION OF γ-HALO ESTERS WITH SILICA GEL CATALYST
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A facile synthesis of γ-butyrolactones by the lactonization of percentg-halo esters with silica gel catalyst and its application to the stereoselective synthesis of (+/-)-canadensolide are described
- Tsuboi, Sadao,Fujita, Hiroshi,Muranaka, Koichi,Seko, Katsuhiko,Takeda, Akira
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p. 1909 - 1912
(2007/10/02)
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