- Synthesis of β-oxo carbonyl and thiocarbonyl compounds via basic sulfur abstraction
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Sulfur abstraction from suitable thioesters represents a mild method for the formation of carbon-carbon bonds and the formation of 1,3-dicarbonyl compounds. A study of the scope and limitations of this reaction for the synthesis of these or mixed 1,3-carbonyl/thiocarbonyl compounds by a base promoted sulfur abstraction rearrangement is described. These reactions were typically very clean and the products were obtained in good yield (65–95%) in just 30 min. This method is particularly efficient for the introduction of thiocarbonyl containing groups. Thus, it constitutes a synthetic strategy for the generation of a new carbon-carbon bond and the regioselective preparation of mixed β-dicarbonyl compounds.
- Silva, Saúl,Maycock, Christopher D.
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- Synthesis, electrochemical, structural and theoretical study of new derivatives of O[sbnd]B[sbnd]N and O[sbnd]B[sbnd]O heterocycles
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Three new oxazaborine and two boron diketonate derivatives containing different structural motifs were synthesized and studied using NMR, electrochemistry (CV, RDV, and dc-polarography), UV–Vis spectra and X-ray structure analysis. The experimental data were correlated with quantum chemical calculations. The main attention was focused on determination of the first oxidation and the first reduction potentials, their relationship to the calculated HOMO and LUMO energies and to their UV–Vis spectra. The electrochemical data reflect the structure–redox properties relationship depending on location of oxidation and reduction center.
- Mikysek, Tomá?,Kvapilová, Hana,Dou?ová, Hana,Josefík, Franti?ek,?im?nek, Petr,R??i?ková, Zdeňka,Ludvík, Ji?í
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p. 465 - 472
(2016/12/02)
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- O -Iodoxybenzoic Acid (IBX)-Iodine Mediated One-Pot Deacylative Sulfonylation of 1,3-Dicarbonyl Compounds: A Synthesis of β-Carbonyl Sulfones
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A combination of o-iodoxybenzoic acid (IBX) and a catalytic amount of iodine is found to promote a facile one-pot deacylative sulfonylation reaction of 1,3-dicarbonyl compounds with sodium sulfinates to yield β-carbonyl sulfones. The present method provides the target products bearing a wide variety of functional groups in one step and in good yields.
- Katrun, Praewpan,Songsichan, Teerawat,Soorukram, Darunee,Pohmakotr, Manat,Reutrakul, Vichai,Kuhakarn, Chutima
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supporting information
p. 1109 - 1121
(2017/02/24)
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- ARYL BETA DIKETONES AND THEIR USE A ODORANTS
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The present invention refers to aryl beta diketones of the formula (I) wherein Y, R1, R2 and R3 have the same meaning as given in the description. The invention further refers to fragrance compositions and fragranced articles comprising them.
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-
Page/Page column 14; 15
(2017/12/09)
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- Method for preparing 2-methyl-1,3-dicarbonyl derivative
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The invention discloses a method for preparing a 2-methyl-1,3-dicarbonyl derivative. A 1,3-dicarbonyl derivative serves as an initiator, raw materials are easy to obtain, and a great variety of raw materials are available. The product obtained through the method has high type diversity and can be used directly or used for other further reactions. Besides, only organic peroxides and a catalytic amount of inorganic copper salt are used, so that cost is low. According to the method, a reaction is conducted in air, reaction conditions are mild, pollution is small, reaction time is short, the yield of the target product is high, reaction operation and aftertreatment are easy, and the method is suitable for industrial production.
- -
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Paragraph 0033
(2016/10/08)
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- Regioswitchable Palladium-Catalyzed Decarboxylative Coupling of 1,3-Dicarbonyl Compounds
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A palladium-catalyzed chemo- and regioselective coupling of 1,3-dicarbonyl compounds via an allylic linker has been developed. This reaction, which displays broad substrate scope, forms two C-C bonds and installs two all-carbon quaternary centers. The regioselectivity of the reaction can be predictably controlled by utilizing an enol carbonate of one of the coupling partners.
- Kenny, Miles,Christensen, Jeppe,Coles, Simon J.,Franckeviius, Vilius
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supporting information
p. 3926 - 3929
(2015/08/19)
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- Direct synthesis of 1,3-dicarbonyl compounds via radical coupling of aldehydes with ketones under metal-free conditions
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An efficient approach for the synthesis of 1,3-diketones from aldehydes and ketones has been developed using Bu4NI (TBAI) as the catalyst. In the presence of DTBP-TBHP/p-TsOH, aldehydes undergo radical coupling with ketones to provide the desired products in moderate to high yields at 120 °C. Although various substituents on the aromatic ring of aldehydes are well tolerable under the standard reaction conditions, the protocol is limited by the scope of ketones. The method exhibits advantages in terms of the easy access of the starting materials, operational simplicity, functional group tolerance, and the absence of metal catalyst.
- Shen, Xuqian,Borah, Arun Jyoti,Cao, Xihan,Pan, Weixiang,Yan, Guobing,Wu, Xiangmei
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supporting information
p. 6484 - 6487
(2015/11/16)
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- Oxidative umpolung ?±-alkylation of ketones
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We disclose a hypervalent iodine mediated ?±-alkylative umpolung reaction of carbonyl compounds with dialkylzinc as the alkyl source. The reaction is applicable to all common classes of ketones including 1,3-dicarbonyl compounds and regular ketones via their lithium enolates. The ?±-alkylated carbonyl products are formed in up to 93% yield. An ionic mechanism is inferred based on meticulous analysis, NMR studies, trapping and crossover experiments, and computational studies.
- Shneider, O. Svetlana,Pisarevsky, Evgeni,Fristrup, Peter,Szpilman, Alex M.
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supporting information
p. 282 - 285
(2015/03/05)
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- Catalytic decarboxylative alkenylation of enolates
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A palladium-catalyzed decarboxylative alkenylation of stabilized enolates has been developed, which gives rise to alkenylated dicarbonyl products from enol carbonates regioselectively with concomitant installation of a quaternary all-carbon center. The broad scope of the reaction has been demonstrated by successfully utilizing a range of enolates and external phenol nucleophiles.
- Schroeder, Sybrin P.,Taylor, Nicholas J.,Jackson, Paula,Franckevicius, Vilius
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supporting information
p. 3778 - 3781
(2013/08/23)
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- Substrate range of the titanium TADDOLate catalyzed asymmetric fluorination of activated carbonyl compounds
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The substrate range of the [TiCl2(TADDOLate)] (TADDOL=α,α,α′,α′-tetraaryl-1,3-dioxolane-4, 5-dimethanol)-catalyzed asymmetric α-fluorination of activated β-carbonyl compounds has been investigated. Optimal conditions for catalysis are characterized by using 5 mol-% of TiCl2(naphthalen-1- yl)-TADDOLate) as catalyst in a saturated (0.14 mol/l) MeCN solution of F-TEDA (1-(chloromethyl)-4-fluoro-1,4-diazoniabicyclo[2.2.2]octane bis- [tetrafluoroborate]) at room temperature. A series of α-methylated β-keto esters (3-oxobutanoates, 3-oxopentanoates) with bulky benzyl ester groups (60-90% ee) or phenyl ester (67-88% ee) have been fluorinated readily, whereas α-acyl lactones were also readily fluorinated, but gave lower inductions (13-46% ee). Double stereochemical differentiation in β-keto esters with chiral ester groups raised the stereoselectivity to a diastereomeric ratio (dr) of up to 96.5:3.5. For the first time, β-keto S-thioesters were asymmetrically fluorinated (62-91.5% ee) and chlorinated (83% ee). Lower inductions were observed in fluorinations of 1,3-diketones (up to 40% ee) and β-keto amides (up to 59% ee). General strategies for preparing activated β-carbonyl compounds as important model substrates for asymmetric catalytic α-functionalizations are presented (>60 examples). Copyright
- Bertogg, Andreas,Hintermann, Lukas,Huber, Dominique P.,Perseghini, Mauro,Sanna, Maria,Togni, Antonio
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experimental part
p. 353 - 403
(2012/05/07)
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- Copper(II) triflate catalyzed amination and aziridination of 2-Alkyl substituted 1,3-dicarbonyl compounds
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A method to prepare α-acyl-β-amino acid and 2,2-diacyl aziridine derivatives efficiently from Cu(OTf)2 + 1,10-phenanthroline (1,10-phen)-catalyzed amination and aziridination of 2-alkyl substituted 1,3-dicarbonyl compounds with PhI=NTs is described. By taking advantage of the orthogonal modes of reactivity of the substrate through slight modification of the reaction conditions, a divergence in product selectivity was observed. In the presence of 1.2 equiv of the iminoiodane, amination of the allylic C-H bond of the enolic form of the substrate, formed in situ through coordination to the Lewis acidic metal catalyst, was found to selectively occur and give the β-aminated adduct. On the other hand, increasing the amount of the nitrogen source from 1.2 to 2-3 equiv was discovered to result in preferential formal aziridination of the C-C bond of the 2-alkyl substituent of the starting material and formation of the aziridine product.
- Ton, Thi My Uyen,Tejo, Ciputra,Tiong, Diane Ling Ying,Chan, Philip Wai Hong
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experimental part
p. 7344 - 7350
(2012/06/16)
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- Regioselectivity switch: Gold(I)-catalyzed oxidative rearrangement of propargyl alcohols to 1,3-diketones
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The gold(I)-catalyzed oxidative rearrangement of propargyl alcohols provides an efficient and selective route to 1,3-diketones under mild conditions. Pyridine-N-oxides were used as external oxidants with, different from related substrates, no alkylidenecycloalkanones or oxetan-3-ones formed as side-products.
- Hashmi, A. Stephen K.,Wang, Tao,Shi, Shuai,Rudolph, Matthias
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p. 7761 - 7767
(2012/11/07)
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- Convenient synthesis of 2-pyridyl thioglycosides
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A reported method for preparation of a new class of pyridine thioglycosides via reaction of pyridine-2(1H)-thiones with 2,3,4-tri-O-acetyl-α-D-xylo- and -β-D-arabinopyranosyl bromides has been studied.
- Elgemeie, Galal,Eltamny, Elsayed,Elgawad, Ibraheim,Mahmoud, Nashwa
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scheme or table
p. 473 - 475
(2009/08/15)
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- Direct synthesis of 1,3-diketones by Rh-catalyzed reductive α-acylation of enones
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(Chemical Equation Presented) 1,3-Diketones were synthesized from α,β-unsaturated ketones by treatment with acid chlorides and Et 2Zn in the presence of RhCl(PPh3)3. This is a very simple and extremely chemoselective reaction to give the adduct at the α-position of α,β-unsaturated ketones.
- Sato, Kazuyuki,Yamazoe, Satoshi,Yamamoto, Rie,Ohata, Shizuka,Tarui, Atsushi,Omote, Masaaki,Kumadaki, Itsumaro,Ando, Akira
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supporting information; experimental part
p. 2405 - 2408
(2009/05/11)
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- Synthesis of valuable chiral intermediates by isolated ketoreductases: Application in the synthesis of α-alkyl-β-hydroxy ketones and 1,3-diols
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Regio- and stereoselective reductions of α-substituted 1,3-diketones to the corresponding β-keto alcohols or 1,3-diols by using commercially available ketoreductases (KREDs) are described. A number of α-monoalkyl- or dialkyl-substituted symmetrical as well as non-symmetrical diketones were reduced in high optical purities and chemical yields, in one or two enzymatic reduction steps. In most cases, two or even three out of the four possible diastereomers of α-alkyl-β-keto alcohols were synthesized by using different enzymes, and in two examples both ketones were reduced to the 1,3-diol. By replacing the α-alkyl substituent with the OAc group, 1-keto-2,3-diols, as well as 1,2,3-triols were synthesized in high optical purities. These enzymatic reactions provide a simple, highly stereoselective and quantitative method for the synthesis of different diastereomers of valuable chiral synthons from non-chiral, easily accessible 1,3-diketones.
- Kalaitzakis, Dimitris,Rozzell, J. David,Smonou, Ioulia,Kambourakis, Spiros
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p. 1958 - 1969
(2007/10/03)
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- Mild conversion of β-diketones and β-ketoesters to carboxylic acids
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A mild protocol for the conversion of β-ketoesters and β-diketones to carboxylic acids with use of CAN in CH3CN is described. The method is compatible with a number of functional groups, and can generate carboxylic acids under neutral conditions at room temperature. The reaction is fast and general, providing an alternative method to the commonly used malonic ester acid preparation. Initial mechanistic studies show that initial oxidation of the enol form of the β-dicarbonyl initiates the reaction. The presence of nitrate as an oxidant ligand or as an additive is critical for success of the reaction.
- Zhang, Yang,Jiao, Jingliang,Flowers II, Robert A.
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p. 4516 - 4520
(2007/10/03)
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- Synthesis of (+)-conagenin
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An efficient total synthesis of (+)-conagenin was achieved. The right fragment of conagenin, α-methylserine containing a quaternary stereocenter attached to nitrogen, was synthesized using allyl cyanate-to-isocyanate rearrangement. The left fragment, 2,4-
- Matsukawa, Yohei,Isobe, Minoru,Kotsuki, Hiyoshizo,Ichikawa, Yoshiyasu
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p. 5339 - 5341
(2011/11/14)
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- New auxiliaries for copper-catalyzed asymmetric Michael reactions: Generation of quaternary stereocenters at room temperature
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Dialkyl amides of L-valine, L-isoleucine, and L-tert-leucine (2) are excellent chiral auxiliaries for the construction of quaternary stereocenters at ambient temperature. Enaminoesters 3, prepared from these auxiliaries 2 and Michael donors 1. undergo a copper-catalyzed asymmetric Michael reaction with methyl vinyl ketone (MVK, 4) to afford products 5 in 70-90% yield and 90-99% ee (enantiomeric excess). The exclusion of moisture or oxygen is not necessary. The auxiliaries 2 are readily available by standard procedures. After workup they can be recovered almost quantitatively.
- Christoffers, Jens,Mann, Alexander
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p. 1014 - 1027
(2007/10/03)
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- Selective α-Mono- and α,α-Dialkylations of 1,3-Diketones Using Solid Base Prepared from Sodium Ethoxide and Alumina
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The alkylation of 1,3-diketones with alkyl halides using a solid base prepared from sodium ethoxide and alumina was carried out.The amount of 0.4 mol of sodium ethoxide on 50 g of alumina showed by best reactivity for alkylation.Selective mono- and dialky
- Yoshihara, Nobutoshi,Kitagawa, Teruhiro,Ihara, Ikuko,Hasegawa, Sadao,Hasegawa, Tadashi
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p. 1185 - 1187
(2007/10/02)
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- SELECTIVE C-ALKYLATION OF 1,3-DICARBONYL COMPOUNDS
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Lithium hydroxide-mediated alkylation of 1,3-dicarbonyl compounds proves to proceed with high efficiency and selectivity.
- Antonioletti, Roberto,Bonadies, Francesco,Orelli, Liliana Raquel,Scettri, Arrigo
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p. 237 - 238
(2007/10/02)
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- Reactions of copper(II) β-diketonates under free radical conditions. Preparation of highly congested β-diketones
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Copper(II) β-diketonates react with alkyl bromides under free radical conditions to give highly congested β-diketones such as 3-(1-adamantyl)-3-alkylpentane-2,4-diones. Another typical free radical reagent: benzoyl peroxide, reacts also functionalizing the intercarbonyl positions.
- Lloris, Maria E.,Galvez, Nicanor,Marquet, Jorge,Moreno-Manas, Marcial
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p. 8031 - 8042
(2007/10/02)
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- A Convenient Reduction Method of β-Phenyl α,β-Unsaturated Carbonyl Compounds with Me3SiCl-NaI-ROH Reagent
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Treatment of β-phenyl α,β-unsaturated ketones, cinnamic acid and its ester with Me3SiCl-NaI-ROH reagent in hexane at room temperature gave the corresponding saturated carbonyl compounds in good yileds.A similar reaction of 2,4-hexadienoic acid afforded 4-hexanolide.
- Sakai, Takashi,Miyata, Kazuyoshi,Utaka, Masanori,Takeda, Akira
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p. 1063 - 1066
(2007/10/02)
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- The Allopolarization Principle and its Applications, IV. Substituent Effects in the Methylation of Enolate Anions
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The ratio of O- and C-methylated products in the reaction of the sodium salts of acetophenones 1, propiophenones 3, phenylacetones 5, β-dicarbonyl compounds 12, α-cyanocarbonyl compounds 13, acetaldehyde, propionaldehyde, and diethylketone with dimethyl sulfate, methyl iodide, and trimethyl phosphate in HMPTA has been determined with regard to the effect of substituents.In some cases the influence of solvents, concentration and temperature has also been studied.
- Gompper, Rudolf,Vogt, Hans-Hubert
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p. 2866 - 2883
(2007/10/02)
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- The Allopolarization Principle and its Applications, VI. The Alkylation of Enolate Anions: Polarity and Regioselectivity
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The O/C methylation ratio in the reaction of sodium enolates with dimethylsulfate depends on the polar (electronic) effect of substituents.The relative ?-charge density Px/y = lx/ly can be used as a measure for the polarity of ambifunctional anions; in case of enolate anions PO/C = lO/lC.The change of the regioselectivity Sf = log QO/QC in the alkylation of enolates is a function of a change in the polarity PO/C; ΔSf=f(ΔPx/y).The polar effect of substituents influences the charge control during the alkylation process via a change of the polarity of the enolate system: The higher the polarity of the anion, the stronger the charge control and the higher the yield of enol ether (O-alkylation). - Keywords: Alkylation, Enolate Anions
- Gompper, Rudolf,Vogt, Hans-Hubert,Wagner, Hans-Ulrich
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p. 1644 - 1652
(2007/10/02)
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