- One-pot synthesis of γ-diketones, γ-keto esters, and conjugated cyclopentenones from nitroalkanes
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Conjugated addition of primary nitroalkanes to α,β-unsaturated ketones or α,β-unsaturated esters, in the presence of two equivalents of DBU, allows the one-pot prepration of γ-diketones or γ-keto esters, respectively. When 2-aryl-1-nitroethane derivatives
- Ballini, Roberto,Barboni, Luciano,Bosica, Giovanna,Fiorini, Dennis
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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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- 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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- 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 0231
(2017/12/15)
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- Synthesis of furans, pyrroles and pyridazines by a ruthenium-catalysed isomerisation of alkynediols and in situ cyclisation
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Alkyne-1,4-diols are readily available substrates which are isomerised to 1,4-diketones using Ru(PPh3)3(CO)H2/xantphos as a catalyst. In situ cyclisation into furans, pyrroles and pyridazines has been achieved under suitable conditions.
- Pridmore, Simon J.,Slatford, Paul A.,Taylor, James E.,Whittlesey, Michael K.,Williams, Jonathan M.J.
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supporting information; experimental part
p. 8981 - 8986
(2009/12/27)
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- 2,5-Disubstituted furans from 1,4-alkynediols
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1,4-Alkynediols serve as readily available starting materials for isomerisation to 1,4-diketones, which can be converted in situ into the corresponding furans by acid-catalysed dehydration. A range of 2,5-disubstituted furans was prepared using the ruthenium-based catalyst Ru(PPh3)3(CO)H2 with Xantphos at 1 mol % loading.
- Pridmore, Simon J.,Slatford, Paul A.,Williams, Jonathan M.J.
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p. 5111 - 5114
(2008/02/09)
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- Unprecedented, selective Nef reaction of secondary nitroalkanes promoted by DBU under basic homogeneous conditions
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Secondary nitrocompounds can be converted into the corresponding ketones under basic conditions using DBU in acetonitrile. Primary nitroalkanes are unaffected by these conditions. Elsevier Science Ltd. All rights reserved.
- Ballini, Roberto,Bosica, Giovanna,Fiorini, Dennis,Petrini, Marino
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p. 5233 - 5235
(2007/10/03)
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- Neighboring group participation in Lewis acid-promoted [3 + 4] and [3 + 5] annulations. The synthesis of oxabicyclo[3.n.1]alkan-3-ones
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Lewis acids are employed as catalysts in the annulation of 1,4- and 1,5-dicarbonyl dielectrophiles with bis(trimethylsilyl) end ethers of β-diketones and β-keto esters. A variety of 2-(alkoxycarbonyl)-m-oxabicyclo[3.n.1]alkan-3-ones can be constructed by this process in which two new carbon-carbon bonds are generated. Unusually high regiocontrol is observed, and good to excellent stereochemical control can be achieved at virtually every position on the new carbocycles. Intramolecular neighboring group participation is proposed to explain the unusually high selectivities attained in the annulation reaction.
- Molander, Gary A.,Camera, Kimberly O.
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p. 830 - 846
(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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- MECHANISM OF RECYCLIZATION OF FURANS TO THIOPHENES AND SELENOPHENES UNDER ACID CATALYSIS. 1. KINETIC STUDIES OF THE REACTION OF 2,5-DIALKYLFURANS WITH HYDROGEN SULFIDE IN THE PRESENCE OF HYDROCHLORID ACID
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The transformation of 2,5-dialkylfurans to thiophene by reaction with hydrogen sulfide in the presence of hydrochloric acid was studied.The reaction was found to be first order with respect to the furan; the rate of consumption of the furan did not change with the increasing length of one of the alkyl substituents.Recrystalization in the presence of acid proceeds in two independent directions: through the formation of an intermediate dicarbonyl compound, and by direct conversion of the furan to a thiophene.Kinetic data showed that the reaction occurs mainly by the second route.
- Voronin, S. P.,Gubina, T. I.,Markushina, I. A.,Kharchenko, V. G.
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p. 1113 - 1117
(2007/10/02)
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- Nitro Olefins and Organoaluminum Compounds: A Powerful Synthetic Tool in Organic Chemistry
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M species react with α-nitro olefins showing an unusual aptitude for a preferential transfer of saturated alkyl groups; M (R' = phenyl, benzyl, allyl) species, on the other hand, are able to transfer unsaturated groups with high chemosele
- Pecunioso, Angelo,Menicagli, Rita
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p. 2391 - 2396
(2007/10/02)
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- REMOTE OXIDATION OF KETONES TO γ- AND δ-DIKETONES
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A single stage remote oxidation of ketones to γ- and δ-diketones has been carried out in a sodium peroxysulfate-iron(II) sulfate system.
- Troyanskii, E.I.,Mizintsev, V. V.,Lazareva, M. I.,Demchuk, D. V.,Nikishin, G. I.
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p. 1879 - 1884
(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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- 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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- THE PREPARATION OF 1,4-DICARBONYL COMPOUNDS BY PHOTOREACTION OF KETONES IN THE PRESENCE OF OXIDANTS
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Phenyl alkyl ketones were photo-irradiated in the presence of Cr(VI) or Mn(VII) oxidants to yield 1,4-dicarbonyl compounds regiospecifically while 2-octanone gave a regioisomeric mixture of 2,5-, 2,6-, and 2,7-octadiones.
- Mitani, Michiharu,Tamada, Mamoru,Uehara, Shin-ichi,Koyama, Kikuhiko
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p. 2805 - 2808
(2007/10/02)
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- A Convenient Preparative Method of Jasmone and its Related Compounds
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The reaction of (Z)-hept-4-enoic acid (1) with vinylmagnesium bromide gave (Z)-undeca-1,8-dien-5-one (2).The oxidation of the terminal vinylic group of (2) affords (Z)-undec-8-ene-2,5-dione (3).Jasmone (4) was obtained by the usual alkali cyclization of (3).A variety of alkylcyclopentenones were prepared by the same method.
- Watanabe, Shoji,Fujita, Tsutomu,Suga, Kyoichi,Haibara, Michio
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p. 1739 - 1741
(2007/10/02)
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- Process for the preparation of ketones
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The invention concerns a new process for the preparation of ketones; according to this process ketones are prepared from aldehydes and unsaturated compounds in the presence of bases using quaternary ammonium salts as catalysts.
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