- The enantiomeric discrimination of 5-hexyl-2-methyl3,4-dihydro-2h-pyrrole by sulfobutyl ether-β-cyclodextrin: A case study
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1-Pyrrolines are important intermediates of active natural products, such as the 2,5dialkyl-1-pyrroline derivatives found in fire ant venoms. Here, 5-hexyl-2-methyl-3,4-dihydro-2Hpyrrole was synthesized by the enzymatic transamination/cyclization of 2,5-undecadione, and enantiodifferenciation was successfully achieved by capillary electrophoresis with sulfobutyl ether-βcyclodextrin as the chiral selector. The rationale of the enantiomeric discrimination was based on the results of a docking simulation that revealed the higher affinity of (S)-5-hexyl-2-methyl-3,4-dihydro2H-pyrrole for the sulfobutyl ether-β-cyclodextrin.
- Costa, Bruna Z.,Kawano, Daniel F.,Loureiro, Hugo C.,Marsaioli, Anita J.,Romero-Orejón, Katherine L.,de Jesus, Dosil P.
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Read Online
- Polymer-supported Thiazolium Salt Catalysts: A Model System for the Thiamine Dependent Enzymes
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A polymer-supported thiazolium salt has been prepared which catalyses the addition of aldehydes to activated olefins in the absence of added base.
- Sell, Charles S.,Dorman, Linda A.
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Read Online
- Synthesis method of dihydrojasmonone
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The invention discloses a synthesis method of dihydrojasmonone, belongs to the technical field of perfume synthesis, aims to solve the problems that raw materials are difficult to prepare and high in price, and the fragrance of a product is impure, and relates to a method for synthesizing dihydrojasmonone by reacting halogenated n-hexane and magnesium chips under a solvent condition to generate an n-hexyl Grignard reagent under anhydrous and nitrogen protection, carrying out catalytic coupling on the n-hexyl Grignard reagent and acetyl propionyl chloride through vanadium trichloride to generate undecane-2,5-dione, and carrying out condensation ring closing on undecane-2,5-dione under an alkaline condition. In the synthesis route, the used raw materials are cheap and easy to obtain, and other auxiliary reagents are all industrial basic raw materials, so that the price is low; reaction steps are short, and reaction conditions are simple; and in addition, the reaction yield is relatively high and is kept at 64-72%, and the purity is relatively high and is kept at about 98%, so that the method is suitable for realizing industrial production and has relatively high application value.
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Paragraph 0024-0027
(2021/07/31)
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- Synthesis of Diketones, Ketoesters, and Tetraketones by Electrochemical Oxidative Decarboxylation of Malonic Acid Derivatives: Application to the Synthesis of cis-Jasmone
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Disubstituted malonic acid derivatives are smoothly converted into diketones and ketoesters in good to excellent yield (68% to 91%) under electrochemical conditions. The scope can be extended to transform trisubstituted bis-malonic acids into tetraketones in 77% to 86% yield. The new method was applied to the total synthesis of cis-jasmone.
- Ma, Xiaofeng,Du, Le,Luo, Xiya,Markó, István E.,Dewez, Damien F.,Lam, Kevin
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p. 12044 - 12055
(2019/03/01)
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- Synthesis of 2,5-Disubstituted Pyrrolidine Alkaloids via A One-Pot Cascade Using Transaminase and Reductive Aminase Biocatalysts
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A multi-enzymatic cascade process involving transaminases (TAs) and reductive aminases (RedAms) to produce enantiomerically pure 2,5-disubstituted pyrrolidine alkaloids from their respective 1,4-diketones is reported. Several TAs were screened and the best results for diketone monoamination were obtained with an R-selective TA from Mycobacterium chlorophenicum and with an S-selective TA from Bacillus megaterium. Pyrroline reduction was best performed by a reductive aminase from Ajellomyces dermatitidis (AdRedAm). Finally, a biocatalytic one-pot cascade was implemented using the aforementioned enzymes and a variety of 2-methyl-5-alkylpyrrolidines were produced with high (>99 %) conversion, diastereomeric and enantiomeric excess values.
- Costa, Bruna Z.,Galman, James L.,Slabu, Iustina,France, Scott P.,Marsaioli, Anita J.,Turner, Nicholas J.
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p. 4733 - 4738
(2018/09/25)
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- Synthesis of Diketones, Ketoesters, and Tetraketones by Electrochemical Oxidative Decarboxylation of Malonic Acid Derivatives: Application to the Synthesis of cis-Jasmone
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Disubstituted malonic acid derivatives are smoothly converted into diketones and ketoesters in good to excellent yield (68% to 91%) under electrochemical conditions. The scope can be extended to transform trisubstituted bis-malonic acids into tetraketones in 77% to 86% yield. The new method was applied to the total synthesis of cis-jasmone.
- Ma, Xiaofeng,Dewez, Damien F.,Du, Le,Luo, Xiya,Markó, István E.,Lam, Kevin
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- NOVEL PROCESS FOR PREPARING SYNTHESIS INTERMEDIATES USING PRODUCTS OF NATURAL ORIGIN AND USE OF THE INTERMEDIATES OBTAINED
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Disclosed is a process for preparing a product of formula I: wherein the reaction is catalyzed both by thiamine or a thiamine salt and by ascorbic acid in a form which is free or salified or an organic acid salt of an alkaline metal, preferably sodium acetate, potassium tartrate, sodium succinate, or a reductone, preferably 2-hydroxypropanedial or 2,3-dihydroxycyclopent-2-ene-1-one in an organic solvent.
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Paragraph 0229-0230
(2017/12/15)
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- Flow synthesis using gaseous ammonia in a Teflon AF-2400 tube-in-tube reactor: Paal-Knorr pyrrole formation and gas concentration measurement by inline flow titration
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Using a simple and accessible Teflon AF-2400 based tube-in-tube reactor, a series of pyrroles were synthesised in flow using the Paal-Knorr reaction of 1,4-diketones with gaseous ammonia. An inline flow titration technique allowed measurement of the ammonia concentration and its relationship to residence time and temperature.
- Cranwell, Philippa B.,O'Brien, Matthew,Browne, Duncan L.,Koos, Peter,Polyzos, Anastasios,Pe?a-López, Miguel,Ley, Steven V.
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scheme or table
p. 5774 - 5779
(2012/08/28)
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- Regioselective cobalt-catalysed hydrovinylation for the synthesis of non-conjugated enones and 1,4-diketones
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The highly regioselective cobalt-catalysed 1,4-hydrovinylation of terminal alkenes with 2-trimethylsilyloxy-1,3-butadiene generates in a stereospecific fashion unsaturated E-configured silyl enol ether intermediates that are suitable for diastereoselective Mukaiyama-aldol reactions with bulky aliphatic aldehydes. The acidic hydrolysis of the enol ethers to γ,δ- unsaturated ketones followed by ozonolysis can be used for the synthesis of various 1,4-diketones and polycarbonyl derivatives. The 1,4-diketones and polycarbonyl derivatives were successfully tested for the synthesis of some mono- and bis-pyrrole derivatives. The γ,δ-unsaturated ketones are useful building blocks (e.g., in natural product synthesis) and can be generated in a one-pot procedure. Copyright
- Kersten, Laura,Hilt, Gerhard
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supporting information; experimental part
p. 863 - 869
(2012/05/04)
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- Acylation of electrophilic olefins through decatungstate-photocatalyzed activation of aldehydes
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(Chemical Equation Presented) With tungsten and lamp: Ketones were prepared by the photocatalytic generation of acyl radicals from aldehydes and trapping them with equimolar amounts of electrophilic alkenes. Photocatalysis with tetrabutylammonium decatungstate is effective also at low temperatures (-20 to -50°C), thus minimizing radical decarbonylation and allowing acylation by highly substituted aldehydes. EWG = electron-withdrawing group.
- Esposti, Silvia,Dondi, Daniele,Fagnoni, Maurizio,Albini, Angelo
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p. 2531 - 2534
(2008/03/11)
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- Chemistry of ketone α,β-dianions. Acylation reactions of dianion cuprates by acid chlorides
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The cross-coupling reaction of dianion cuprates, generated from ketone α,β-dianions and copper salts, with acid chlorides, was studied. The reaction gave good to moderate yields of unsymmetrical 1,4-diketones. The consecutive treatment of a dianion cuprate with cyclohexanecarbonyl chloride and methyl iodide or two different acid chlorides gave 2-methyl-substituted 1,4-diketone or triketone, respectively.
- Ryu, Ilhyong,Ikebe, Masanobu,Sonoda, Noboru,Yamato, Shin-Ya,Yamamura, Go-Hei,Komatsu, Mitsuo
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p. 1257 - 1259
(2007/10/03)
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- One step preparation of 1,4-diketones from methyl ketones and α-bromomethyl ketones in the presence of ZnCl2·t-BuOH·Et2NR as a condensation agent
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1,4-Diketones have been prepared in one step from methyl ketones and α-bromomethyl ketones under the action of ZnCl2·t-BuOH·Et2NR as a condensation agent with moderate to high yields. The mechanistic pathway of the reaction is proposed to go through aldol condensation of ketones followed by 1,3-dehydro-bromination of aldol products and cleavage of activated cyclopropyl intermediates.
- Nevar,Kel'in,Kulinkovich
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p. 1259 - 1262
(2007/10/03)
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- Synthesis of 1,4-diketones via α-metallohydrazones
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Undecan-2,5-dione (IV) and 8-Nonen-2,5-dione (V), key intermediates in the synthesis of dihydrojasmone and allethrone respectively have been prepared via regio selective alkylation of α-metallohydrazones in good yields.
- Trehan,Singh, Labh,Arora,Singh, Vasundhara,Kad
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p. 708 - 710
(2007/10/03)
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- Chemoselective conversion of conjugated nitroalkenes into ketones by sodium borohydride-hydrogen peroxide: A new synthesis of 4-oxoalkanoic acids, dihydrojasmone and (±)exo-brevicomin
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A new, simple, cheap, and practical procedure for the direct transformation of α,β-unsaturated nitroalkenes into ketones has been realized by the NaBH4/H2O2 system. By this method, other functional groups such as C-C double bonds, ketals or aromatic nitro groups were preserved. Application of this methodology to the preparation of 4-oxoalkanoic acids, dihydrojasmone, and (±)-exobrevicomin is also reported.
- Ballini,Bosica
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p. 723 - 726
(2007/10/02)
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- Oxidation of Ethers by NO3(radical) Generated from NO3- with Anodic Oxidation
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A radical NO3 generated by anodic oxidation of NO3- was found to be an effective species to the oxidation of ethers to the corresponding carboxylic acids and ketones, and this reaction was successfully applied to the synthesis of dihydrojasmone.
- Shono, Tatsuya,Yamamoto, Yoshinari,Takigawa, Katsuya,Maekawa, Hirofumi,Ishifune, Manabu,Kashimura, Shigenori
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p. 1045 - 1048
(2007/10/02)
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- A new, simple, and general synthesis of 1,3-, 1,4- and 1,5-diketones from functionalized nitroalkanes
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Herein is reported the utilization of protected nitro ketones, in the synthesis of 1,3-, 1,4-, and 1,5-diketones, by their condensation with aldehydes then conversion of the obtained conjugated nitroalkenes into monoprotected carbonyl derivatives which, by removal of the protecting group, gives diketones.
- Ballini,Bartoli
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p. 965 - 967
(2007/10/02)
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- SIMPLE PREPARATION OF 3-METHYL-2-PENTYL-2-CYCLOPENTEN-1-ONE (DIHYDROJASMONE)
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A two-step method has been developed for the preparation of 2,5-undecanedione, which is a reported precursor of dihydrojasmone, by the condensation of heptanoyl chloride and methallyl chloride and subsequent reaction of the product, 1,2-dichloro-2-methyl-4-decanone, with sodium methylate in methanol with subsequent acid work-up of the reaction mixture.
- Sorokin, V. L.,Kulinkovich, O. G.
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p. 930 - 932
(2007/10/02)
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- Hydroacylation of Alkyl Vinyl Ketones and Acrylic Esters Using Organotetracarbonylferrates. Synthesis of 1,4-Dicarbonyl Compounds
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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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- Synthesis of 1,4-diketones by reaction of bicyclic lactams derived from 4-oxoalkanoic acids with organolithium compounds
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Bicyclic lactams obtained from ethyl 4-oxoalkanoates and 2-aminoethanol add saturated and unsaturated aliphatic lithium compounds forming the corresponding 1,4-diketones in 41-61% yield after acidic hydrolysis.
- Wedler,Schick
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p. 543 - 544
(2007/10/02)
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- 2,2-Dimethyl-1,3-oxathiane 3,3-dioxide: A γ-hydroxypropyl anion equivalent
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The reaction of 4-lithio-2,2-dimethyl-1,3-oxathiane 3,3-dioxide with various electrophiles is presented. Acylation of the anion provided labile 4-acyl-2,2-dimethyl-1,3-oxathiane 3,3-dioxides which underwent desulfonation with silica gel to produce γ-hydroxy ketones with three carbon unit elongation. Thus, 4-lithio-2,2-dimethyl-1,3-oxathiane 3,3-dioxide was shown to be a useful synthetic equivalent of a γ-hydroxypropyl anion. Methyl esters proved to be the best acylating agents in this reaction. Synthetic utility of this carbon chain elongation was illustrated by the syntheses of dl-lanceol and dl-dihydrojasmone.
- Fuji,Usami,Kiryu,Node
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p. 852 - 858
(2007/10/02)
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- Facile Synthesis of 1,4-Diketones via Palladium Complex Catalyzed Isomerization of Alkynediols
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Alkynediols isomerized under the catalysis of Pd(dba)3*CHCl3 + 2n-Bu3P in acetonitrile at 80 deg C to give 1,4-diketones in high yields.This experimentally simple and economically synthetic method is illustrated with examples including substituents such as alkyl, alkenyl, and aryl groups.The order of reactivity of the substituents in this reaction is aryl >/= alkenyl > alkyl.Alkenyl-substituted alkynediols chemoselectively isomerized to the corresponding α,β-unsaturated 1,4-diketones.The usefulness of this novel method is examplified by the synthesis of dihydrojasmone.
- Lu, Xiyan,Ji, Jianguo,Ma, Dawei,Shen, Wei
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p. 5774 - 5778
(2007/10/02)
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- A convenient synthesis of 1,4-diketones
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A simple and short synthesis of 1,4-diketones was achieved via 2-chloro-5-methylthio-2,5-hexadienes and their hydrolysis with titanium tetrachloride.
- Motoyoshiya,Hongo,Tanaka,Hayashi
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p. 997 - 1000
(2007/10/02)
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- Double Alkylation of Carbon Monoxide via Free Radicals: Synthesis of Unsymmetrical Ketones
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A novel method for the synthesis of unsymmetrical ketones via the free radical carbonylation of alkyl halides is described.The mechanism of the reaction involves the trapping of an alkyl free radical by CO, the addition of the acyl free radical so formed to an alkene, and termination of the reaction by the abstraction of a hydrogen atom from tributyltin hydride by the product acyl-substituted free radical.
- Ryu, Ilhyong,Kusano, Kazuya,Yamazaki, Hiroshi,Sonoda, Noboru
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p. 5003 - 5005
(2007/10/02)
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- An Effective and Selective Conjugate Propargylation Reaction of Stannylallenes to α,β-Unsaturated Carbonyl Compounds and α-Nitro Olefins
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Stannylallenes (1) reacted with α,β-unsaturated carbonyl compounds and α-nitro olefins in the presence of TiCl4 to give the corresponding conjugate propargylation products.Thus, the reaction of 1 with cyclic and acyclic α,β-unsaturated carbonyl compounds (2) gave β-propargylic ketones (3) in high yields.With α-nitro olefins (4), two types of products, β-propargylic nitroalkanes (5) and α-propargylic ketones (6), were obtained selectively depending on the presence or absence of the α-substituent of 4.Transformation of the products (6) to cyclopentenone derivatives (10 and 12) are also described.
- Haruta, Jun-ichi,Nishi, Koichi,Matsuda, Satoshi,Akai, Shuji,Tamura, Yasumitsu,Kita, Yasuyuki
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p. 4853 - 4859
(2007/10/02)
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- ORGANOTIN HOMOENOLATE EQUIVALENTS - ACCESS TO β-ACYL- AND β-ARYL-PROPIONALDEHYDES THROUGH HETEROSUBSTITUTED ALLYLTINS AND VINYLTINS
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Although, α-ethoxycrotyltributyltin can be used as an equivalent of the homoenolate anion CH3-CHCH2CHO in reactions with acyl chlorides, the non-substituted α-ethoxyallyltributyltin could not be employed in this way. γ-Methoxyvinyltins, easily prepared by hydrostannation of propargylic ethers, are successfully employed as synthetic equivalents of the homoenolate anions -CH2CH2CHO and -CH2CH2COCH3 in reactions with acyl chlorides.A silylated γ-methoxyvinyltin, which is both a vinyltin and an allylsilane, reacts with acyl chlorides and aryl bromides as a promising equivalent of the homoenolate anion -CH2CH2CHO and tolerates a wide range of other reactive functional groups.
- Verlhac, Jean-Baptiste,Pereyre, Michel,Quintard, Jean-Paul
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p. 6399 - 6412
(2007/10/02)
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- A facile synthesis of 1,4-diketones
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1,4-Diketones may conveniently be synthesized by the addition of 2-methylcyclopropenyllithium to N-methoxy-N-methylcarboxamides followed by hydrolysis of intermediate cyclopropyl ketone adducts on silica gel. The new method has been applied to the synthesis of cis-jasmone.
- Bergman,Nilsson,Wickberg
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p. 2783 - 2786
(2007/10/02)
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- DIVERGENT SYNTHESIS OF 1,3- AND 1,4-DIKETONES FROM β-METHOXY-γ-PHENYLTHIO KETONES ACCESSIBLE THROUGH NOVEL PHENYLTHIO MIGRATION REACTION
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Both 1,3- and 1.4-diketones are obtained from common precursors, β-methoxy-γ-phenylthio ketones.These compounds are derived through the novel phenylthio migration reaction of the aldehyde adducts with methoxy(phenylthio)-methane upon exposure to enol silyl ethers.The compounds thus obtained are converted into 1,3- and 1,4-diketones.
- Sato, Tsuneo,Inoue, Masami,Kobara, Satoru,Otera, Junzo,Nozaki, Hitosi
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- Hydroacylation of Simple Alkyl Vinyl Ketones Using Organotetracarbonylferrates
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Alkyl vinyl ketones were hydroacylated by organotetracarbonylferrates to the corresponding 1,4-diketones in good yields in dipolar aprotic solvents such as dimethylacetamide.The addition of 18-Crown-6 made an increase of the yields.
- Yamashita, Masakazu,Tashika, Haruyoshi,Suemitsu, Rikisaku
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p. 691 - 692
(2007/10/02)
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- A NEW READY ROUTE TO 1,4-KETOALDEHYDES AND 1,4-DIKETONES WITH APPLICATION TO THE SYNTHESIS OF Z-JASMONE AND DIHYDROJASMONE
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A new three-step synthesis in good overall yield of 1,4-ketoaldehydes and 1,4-diketones is described.The method involves two sequential coupling reaction of reagents with S-phenyl carbonochloridothioate in the presence of nickel(II) or iron(III) complexes as catalysts.Application of this reaction to the synthesis of Z-jasmone and dihydrojasmone is also described.
- Fiandanese, V.,Marchese, G.,Naso, F.
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p. 3587 - 3590
(2007/10/02)
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- NAD(P)+-NAD(P)H Models. 65. Photochemical Reductive Desulfonylation of β-Keto Sulfones with Hantzsch Ester
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A new procedure for the reductive desulfonylation of β-keto sulfones is described.The reaction proceeds under a photochemical conditions with the Hantzsch ester in pyridine in the presence of ruthenium(II).Various functional groups are unaffected under the reaction conditions.Application of the procedure to the syntheses of certain natural products is also described.
- Fujii, Masayuki,Nakamura, Kaoru,Mekata, Hidevuki,Oka, Shinzaburo,Ohno, Atsuyoshi
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p. 495 - 500
(2007/10/02)
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- One-Step Synthesis of 1,4-Diketones by Nucleophilic Reaction to Tricarbonyl Complexes of α,β-Unsaturated Ketones
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Tricarbonyliron complexes of 3-buten-2-one, 3-penten-2-one, and 4-phenyl-3-buten-2-one reacted with organolithium and Grignard reagents to afford 1,4-diketones in one step, some of the products are amenable to convertion to natural products.
- Kitahara, Haruo,Tozawa, Yasuyuki,Fujita, Seikou,Tajiri, Akio,Morita, Noboru,Asao, Toyonobu
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p. 3362 - 3364
(2007/10/02)
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- Synthesis and Application of Imidazole Derivatives: Preparation of Various Diketones from 1,n-Bis(1-methyl-1H-imidazol-2-yl)alkane-1,n-diones
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Reaction of 1,n-bis(1-methyl-1H-imidazol-2-yl)alkane-1,n-dione (8) with an excess of Grignard reagent was examined.In the cases of n = 4 and 5, precursors (14) for synthesis of various asymmtric 1,4- and 1,5-diketones (12: R1 R2), respectively, were obtained in good yields by treating 8 with an excess of methylmagnesium iodide in ether followed by trimethylsilylation.In the case of n >/= 8, the two carbonyl groups of 8 were both attacked by the Grignard reagent, and the products (11: R1=R2=CH3) were convertible to symmetrical diketones (12: R1=R2=CH3) in good yields.In cases of n = 6 and 7, the mode of the Grignard reaction was transitional between the two types.Keywords - 2-acyl-1H-imidazole; 1,n-bis(1-methyl-1H-imidazol-2-yl)-1,n-alkanedione; diketone synthesis; asymmetric diketone; symmetric diketone; Grignard reaction; dihydrojasmone; cis-jasmone; muscone; 2-(1-hydroxy-1-alkyl)-1-methyl-1H-imidazole
- Hayakawa, Satoshi,Baba, Junko,Okamoto, Masao,Ohta, Shunsaku
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- New Methods and Reagents in Organic Synthesis; 73. Trimethylsilyldiazomethane: A Convenient Reagent for the Conversion of Aliphatic Aldehydes to the Homologous Methyl Ketones
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Trimethylsilyldiazomethane reacts smoothly with aliphatic aldehydes in the presence of magnesium bromide (1.5 eqiv) to give homologous methyl ketones after direct treatment with 10percent hydrochloric acid/methanol (1:1).
- Aoyama, Toyohiko,Shioiri, Takayuki
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p. 228 - 229
(2007/10/02)
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- SYNTHESIS AND APPLICATION OF IMIDAZOLE DERIVATIVES. SYNTHESIS OF (1-METHYL-1H-IMIDAZOL-2-YL)METHANOL DERIVATIVES AND CONVERSION INTO CARBONYL COMPOUNDS
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(1-methyl-2H-imidazol-2-yl)methanol derivatives ( 4 and 7 ) were prepared by treating carbonyl compounds with 2-lithio-1-methyl-1H-imidazole ( 2 ) or by treating 2-acyl-1H-imidazoles ( 3 ) with organometallic reagents or sodium borohydride.The alcohols ( 4 and 7 ) were convertible into the carbonyl compounds via the corresponding quaternary salts ( 8 and 10 ).The stable (1-methyl-1H-imidazol-2-yl)methanol system, , can be regarded as a masked form of the carbonyl group as well as a synthon of the group.Keywords - (1-methyl-1H-imidazol-2-yl)methanol; 2-acyl-1-methyl-1H-imidazole; carbonyl compound synthesis; β-ketoester; protecting group; latent functionality; symmetric ketone; dihydrojasmone
- Ohta, Shunsaku,Hayakawa, Satoshi,Nishimura, Kazuko,Okamoto, Masao
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p. 1058 - 1069
(2007/10/02)
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- MICHAEL ADDITION OF NOVEL ACYL ANION EQUIVALENTS GENERATED BY THE ELECTROREDUCTION OF OXAZOLINIUM SALTS TO ACTIVATED OLEFINS
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Electroreduction of oxazolinium salts gave novel acyl anion equivalents (AAEs), and the Michael addition of these AAEs to activated olefins has been found to be promoted effectively by the addition of chlorotrimethylsilane into the reaction system.This reaction was applied to the synthesis of cis-jasmone and dihydrojasmone.
- Shono, Tatsuya,Kashimura, Shigenori,Yamaguchi, Yoshihide,Kuwata, Fumitaka
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p. 4411 - 4414
(2007/10/02)
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- Selenium in Organic Synthesis: A Novel Route to 1-Phenylselenobutadienes and 1,4-Dicarbonyl Compounds
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Two approaches to 1-phenylseleno-1,3-butadienes 5 are reported, via phenylselenoalkenylidene phosphoranes and phenylselenoalkenals, respectively. 1,4-Dicarbonyl compounds are prepared from the 1-phenylselenobutadienes or from the phenylselenoalkenals.
- Comasseto, J. V.,Brandt, C. A.
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p. 146 - 149
(2007/10/02)
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- A New Synthetic Method for the Preparation of Ketones by Denitration of α-Nitro Ketones
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The sequence of acylation of nitroalkanes and subsequent denitration of the resulting α-nitro ketones provides a new and general method for the preparation of ketones.
- Ono, Noboru,Fujii, Masayuki,Kaji, Aritsune
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p. 532 - 535
(2007/10/02)
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- SYNTHESES OF DIKETONIC INTERMEDIATES FOR THE TOTAL SYNTHESES OF DIHYDROJASMONE, cis-JASMONE AND dl-MUSCONE STARTING FROM 1,n-DI(1-METHYL-1H-IMIDAZOL-2-YL)-1,n-ALKANEDIONE
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2,15-Dihydroxy-2,15-di(1-methyl-1H-imidazol-2-yl)hexadecane (3) was obtained by treating 1,14-(1-methyl-1H-imidazol-2-yl)-1,14-tetradecadione (2b) with an excess of CH3MgI, while 1,4-di(1-methyl-1H-imidazol-2-yl)-4-trimethylsilyloxy-2-pentanone (6; R1 = TMS) was obtained by the similar treatment of 1,4-(1-methyl-1H-imidazol-2-yl)-1,4-butadione (2a) followed by trimethylsilylation.These products (3 and 6) were convertible into the known diketonic intermediates for the synthesis of dl-muscone, dihydrojasmone and cis-jasmone.
- Ohta, Shunsaku,Hayakawa, Satoshi,Tamai, Yoshimi,Yuasa, Teruyuki,Okamoto, Masao
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p. 141 - 146
(2007/10/02)
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- ACYLSILANE-MEDIATED NUCLEOPHILIC ACYLATION OF α,β-UNSATURATED CARBONYL DERIVATIVES
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A number of 1,4-diketones and of γ-keto esters can be prepared regiospecifically under mild conditions by employing a TBACN-catalysed Michael addition of acylsilanes to α,β-unsaturated carbonyl derivatives.
- degl'Innocenti, Alessandro,Ricci, Alfredo,Mordini, Alessandro,Reginato, Gianna,Colotta, Vittoria
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p. 645 - 648
(2007/10/02)
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- A Synthesis of 4-Oxo Carboxylic Acids, 4-Oxo Aldehydes, and 1,4-Diketones from γ-Lactones
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The α-methyldiphenylsilyl derivatives of γ-butyrolactone, γ-valerolactone, and the cis lactone of 2-hydroxycyclohexaneacetic acid have been reacted with Grignard reagents.The α-silylated lactones of γ-butyrolactone and γ-valerolactone react with a single equivalent of Grignard reagent to give a 2-substituted 4,5-dihydrofuran, which can be hydrolyzed and oxidized to 4-oxo carboxylic acids, 1,4-diketones, or 4-oxo aldehydes.The α-silylated fused lactone failed to react with ethylmagnesium bromide in refluxing tetrahydrofuran.An X-ray crystal structure of this silylated lactone indicated that this lack of reactivity is due to steric factors.
- Betancourt de Perez, Rosa M.,Fuentes, Lelia M.,Larson, Gerald L.,Barnes, Charles L.,Heeg, Mary Jane
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p. 2039 - 2043
(2007/10/02)
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- JASMONOIDS: PART 1. DICARBANION ALKYLATION APPROACH TO SYNTHESIS OF Z-JASMONE/DIHYDROJASMONE
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Application of the dicarbanion alkylation strategy to 2-acetyl-4-methyl-butyrolactone 1 has resulted in a 4 step/5 step synthesis of dihydrojasmone 6a/z-jasmone 7 respectively.
- Reddy, R. Thimma,Nayak, U. R.
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p. 713 - 722
(2007/10/02)
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- ETHOXYACETYLENE: A USEFUL BUILDING BLOCK FOR THE ORGANOCOPPER(I) MEDIATED SYNTHESIS OF 1,4-DIKETONES
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Ethoxyacetylene (I) has been converted by organocopper(I) species into (E)-2-ethoxy-1-alkenylcopper(I) compounds (II).The adducts II have been to shown be useful intermediates for preparation of 1,4-diketones (VI).Two routes to VI were used: (i) sequential treatment of II with allyl bromide, 3.0 N HCl, and PdCl2/CuCl in DMF/H2O, and (ii) sequential treatment of II with 2,3-dibromopropane and Hg(OAc)2.A dienone was formed from the first procedure when after the reaction of II with allyl bromide the product was treated first with the PdCl2/CuCl.
- Wijkens, P.,Vermeer, P.
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p. 247 - 256
(2007/10/02)
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- A Simple Synthesis of 2-Cyclopentenone: Synthesis of Dihydrojasmone and α-Cuparenone
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A simple synthesis of substituted 2-cyclopentenone has been illustrated through the syntheses of dihydrojasmone and α-cuparenone.The route involves elaboration of α,β-unsaturated ketone to 2-cyclopentenone through (i) methylene transfer to double bond, (ii) nucleophilic ring-opening by thiophenoxide anion, (iii) chlorination of thioether and (iv) generation of carbonyl group from α-chlorothioether to afford 1,4-diketone which subsequently cyclises with alkali to the desired 2-cyclopentenone.
- Anand, R. C.,Ranjan, H.
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p. 673 - 674
(2007/10/02)
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- UN ANION β-ACYLE MASQUE DANS LES REACTIONS D'ACYLATION: LE DERIVE LITHIE DU DIOXOLANNE DU LEVULATE DE TRIMETHYLSILYLE
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An organolithium reagent derived form trimethylsilyl-4,4-ethylenedioxypentanoate reacts with mixed carboxylic-carbonic anhydrides as a homoenolate anion equivalent.Several monoethylene acetals of 1,4-diketones and the corresponding diketones are synthesized by this way.
- Moreau, Jean-Louis,Couffignal, Renee
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p. 139 - 144
(2007/10/02)
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- Addition of Aldehydes to Activated Double Bonds, XXXV. α-Keto Acids as an Equivalent for Aldehydes in the Thiazolium Salt-Catalyzed Addition
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α-Keto acids can be used instead of aldehydes in the thiazolium salt-catalyzed addition to vinyl ketones.The yields of γ-diketones 1-7 resulting from the aliphatic α-keto acids are equivalent with those obtained from the aldehydes.The diketo acids 9-19 are prepared from the easily accessible 2-oxodiacids.Phenylpyruvic acids are easier to prepare than the phenylacetaldehydes and give better yields compared with the corresponding aldehydes in the addition to vinyl ketones leading to the γ-diketones 20-29.These diketones are converted to cyclopentenones.The dihydrofurylglyoxylic ester 40 leads to the diketone 43, which is converted to the diketone 44.There is no aldehyde known equivalent to that keto acid.
- Stetter, Hermann,Lorenz, Guenther
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p. 1115 - 1125
(2007/10/02)
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