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Search for "ketone" in Full Text gives 662 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.

When metal-catalyzed C–H functionalization meets visible-light photocatalysis

  • Lucas Guillemard and
  • Joanna Wencel-Delord

Beilstein J. Org. Chem. 2020, 16, 1754–1804, doi:10.3762/bjoc.16.147

Graphical Abstract
  • performed under air at high temperatures. The coupling exhibited a broad substrate scope and the procedure tolerated a variety of even sensitive functional groups, including trifluoromethyl, ketone, or ester motifs. Unsymmetrical alkynes were also compatible, although the cyclization provided the desired
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Published 21 Jul 2020

Pauson–Khand reaction of fluorinated compounds

  • Jorge Escorihuela,
  • Daniel M. Sedgwick,
  • Alberto Llobat,
  • Mercedes Medio-Simón,
  • Pablo Barrio and
  • Santos Fustero

Beilstein J. Org. Chem. 2020, 16, 1662–1682, doi:10.3762/bjoc.16.138

Graphical Abstract
  • cyclized product was observed when using the trifluoromethyl ketone derivative 12d. Secondly, PKR with enynes 14 containing fluorinated propargyl alcohol groups yielded diastereoisomeric mixtures of pyrrolidine ring-fused cyclopentenones 15 in good yields (67–85%) but low diastereoselectivities. Finally
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Published 14 Jul 2020

Fluorohydration of alkynes via I(I)/I(III) catalysis

  • Jessica Neufeld,
  • Constantin G. Daniliuc and
  • Ryan Gilmour

Beilstein J. Org. Chem. 2020, 16, 1627–1635, doi:10.3762/bjoc.16.135

Graphical Abstract
  • in the transformation, the catalytic process was repeated in the presence of H218O. Through isotope-shift experiments (please see Supporting Information File 1), it was possible to establish that the aryl ketone of the product contains the 18O atom (ΔδC = 4.42 Hz) [57][58][59]. Formation of the
  • Hammett analyses, have identified key determinants that are essential for reaction efficiency. X-ray crystal structure analysis of ketone 2 reveals a dihedral angle of φO=C-C-F = −3.7°. Although the origin of this specificity requires clarification, this fluorohydration reaction constitutes a rare case of
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Published 10 Jul 2020

Facile synthesis of 7-alkyl-1,2,3,4-tetrahydro-1,8-naphthyridines as arginine mimetics using a Horner–Wadsworth–Emmons-based approach

  • Rhys A. Lippa,
  • John A. Murphy and
  • Tim N. Barrett

Beilstein J. Org. Chem. 2020, 16, 1617–1626, doi:10.3762/bjoc.16.134

Graphical Abstract
  • tetrahydronaphthyridines predominantly revolve around late-stage hydrogenation of fully aromatic 1,8-naphthyridine derivatives 3, usually prepared via an acid or base-catalysed Friedländer reaction between 2-aminonicotinaldehyde (1) and the corresponding ketone 2 (Scheme 1). Both reactions employ harsh conditions with
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Published 08 Jul 2020

Photoredox-catalyzed silyldifluoromethylation of silyl enol ethers

  • Vyacheslav I. Supranovich,
  • Vitalij V. Levin and
  • Alexander D. Dilman

Beilstein J. Org. Chem. 2020, 16, 1550–1553, doi:10.3762/bjoc.16.126

Graphical Abstract
  • employed in photoredox reactions to scavenge acidic byproducts [28][29], could not be employed. Silane 1 is easily destroyed by bases (even by the amide group [30]) followed by the rapid addition of difluorocarbene to silyl enol ethers [19][20]. Disappointingly, we were unable to isolate ketone 3a using
  • -donating functional groups. Substrates containing pyridine, furan, and thiophene as heterocyclic fragments were also successfully converted into the corresponding alcohols 4. However, in the reaction of the enol ether derived from 2-acetyl-N-methylpyrrole, ketone 3p did not undergo reduction with sodium
  • borohydride, and the decreased reactivity of this ketone allowed its isolation. A proposed mechanism for the photoredox fluoroalkylation reaction is shown in Scheme 3. The photoexcited catalyst converts silane 1 into difluoromethylsilyl-based radical. The efficiency of [AuCl(μ-dppm)]2 compared to other
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Published 29 Jun 2020

Heterogeneous photocatalysis in flow chemical reactors

  • Christopher G. Thomson,
  • Ai-Lan Lee and
  • Filipe Vilela

Beilstein J. Org. Chem. 2020, 16, 1495–1549, doi:10.3762/bjoc.16.125

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Published 26 Jun 2020

An overview on disulfide-catalyzed and -cocatalyzed photoreactions

  • Yeersen Patehebieke

Beilstein J. Org. Chem. 2020, 16, 1418–1435, doi:10.3762/bjoc.16.118

Graphical Abstract
  • decomposes into ketone or aldehyde products (Scheme 9). However, in the absence of light or oxygen, disulfide could not catalyze the oxidative cleavage of olefins. It was proposed that disulfide and the olefin might be able to form a charge-transfer complex, which may rationalize the unconventional homolysis
  • to the enone 63 and posterior hydrogen transfer from thiol to the intermediate 64 forms the ketone intermediate 65 (pathway 1). This ketone intermediate 65 is also accessible by an ionic addition in the dark (pathway 2). The tautomerization of the ketone 65 yields the enol form 66, which reacts with
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Published 23 Jun 2020

Recent synthesis of thietanes

  • Jiaxi Xu

Beilstein J. Org. Chem. 2020, 16, 1357–1410, doi:10.3762/bjoc.16.116

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Published 22 Jun 2020

Synthesis of 3-substituted isoxazolidin-4-ols using hydroboration–oxidation reactions of 4,5-unsubstituted 2,3-dihydroisoxazoles

  • Lívia Dikošová,
  • Júlia Laceková,
  • Ondrej Záborský and
  • Róbert Fischer

Beilstein J. Org. Chem. 2020, 16, 1313–1319, doi:10.3762/bjoc.16.112

Graphical Abstract
  • , even at a lower temperature. The structures of 9a–c were definitely confirmed on the basis of 13C NMR spectra. The chemical shifts in the range of 210.8–215.0 ppm for the carbonyl carbon atom clearly indicated the presence of a ketone. With the isoxazolidin-4-ones 9a–c in hand, we were ready to examine
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Published 16 Jun 2020

Ferrocenyl-substituted tetrahydrothiophenes via formal [3 + 2]-cycloaddition reactions of ferrocenyl thioketones with donor–acceptor cyclopropanes

  • Grzegorz Mlostoń,
  • Mateusz Kowalczyk,
  • André U. Augustin,
  • Peter G. Jones and
  • Daniel B. Werz

Beilstein J. Org. Chem. 2020, 16, 1288–1295, doi:10.3762/bjoc.16.109

Graphical Abstract
  • thioketone (8b) obtained from ferrocenyl(β-naphthyl) ketone [31] is reported for the first time (see Supporting Information File 1). General procedure: A solution of 0.3 mmol of the corresponding cyclopropane 5 in 5 mL of dichloromethane was stirred for 5 min. Then, 0.5 mmol of the corresponding ferrocenyl
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Published 10 Jun 2020

Oxime radicals: generation, properties and application in organic synthesis

  • Igor B. Krylov,
  • Stanislav A. Paveliev,
  • Alexander S. Budnikov and
  • Alexander O. Terent’ev

Beilstein J. Org. Chem. 2020, 16, 1234–1276, doi:10.3762/bjoc.16.107

Graphical Abstract
  • is stable at 25 °C in n-hexane. In pure form it is storable only at −78 °C as a solid. At room temperature, radical 8 is a blue oil. When storing 8 in the dark without solvent at 25 °C for a week, the following decomposition products were identified: di-tert-butyl ketone (9, 42%), di-tert-butyl
  • nitroimine (10, 20%), and pivalonitrile (11, 4%) [45]. The proposed scheme for the decomposition of di-tert-butyliminoxyl radical (8) is presented in Scheme 3 [35][45]. It includes formation of C–O dimer 4f followed by the fragmentation to iminyl radical 12, ketone 9, and nitric oxide. The formation of
  • hydrogen atom abstraction from the CH-reagent (MeCN, 52 or 53). Ketone oximes of both aromatic (products 54a–c) and aliphatic structures (54d,e) were successfully used in coupling with acetonitrile. The C–O coupling product 54f of acetonitrile with benzaldoxime was obtained in a lower yield. The aromatic
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Published 05 Jun 2020

Photocatalysis with organic dyes: facile access to reactive intermediates for synthesis

  • Stephanie G. E. Amos,
  • Marion Garreau,
  • Luca Buzzetti and
  • Jerome Waser

Beilstein J. Org. Chem. 2020, 16, 1163–1187, doi:10.3762/bjoc.16.103

Graphical Abstract
  • tetrahydrofuran (8.1), giving access to the key C(sp3) radical. The nickel catalyst, after an oxidative addition with the aryl bromide 8.2 and intercepting the alkyl radical species, gave the radical cross-coupling product 8.3 upon a reductive elimination. Other diaryl ketone dyes, such as 9-fluorenone, have been
  • acceptors 18.2 to afford the desired ketone 18.3. Recently, the Melchiorre group reported a carbamoyl radical-mediated metallaphotoredox synthesis of arylamides (Scheme 19) [91]. In this protocol, excited-state 4CzIPN (OD6) oxidizes a 4-carbamoyl-1,4-dihydropyridine 19.1, which then fragments, releasing the
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Published 29 May 2020

The charge-assisted hydrogen-bonded organic framework (CAHOF) self-assembled from the conjugated acid of tetrakis(4-aminophenyl)methane and 2,6-naphthalenedisulfonate as a new class of recyclable Brønsted acid catalysts

  • Svetlana A. Kuznetsova,
  • Alexander S. Gak,
  • Yulia V. Nelyubina,
  • Vladimir A. Larionov,
  • Han Li,
  • Michael North,
  • Vladimir P. Zhereb,
  • Alexander F. Smol'yakov,
  • Artem O. Dmitrienko,
  • Michael G. Medvedev,
  • Igor S. Gerasimov,
  • Ashot S. Saghyan and
  • Yuri N. Belokon

Beilstein J. Org. Chem. 2020, 16, 1124–1134, doi:10.3762/bjoc.16.99

Graphical Abstract
  • , including the ring opening of epoxides by water and alcohols. A Diels–Alder reaction between cyclopentadiene and methyl vinyl ketone was also catalyzed by F-1 in heptane. Depending on the polarity of the solvent mixture, the CAHOF F-1 could function as a purely heterogeneous catalyst or partly dissociate
  • ketone with cyclopentadiene was also efficiently promoted by the CAHOF F-1 in heptane at room temperature (Scheme 4). After three hours, the catalyst was filtered, and the filtrate was evaporated to give a mixture of the endo and exo adducts in a 3.5:1 ratio and a yield of 52%. A reaction carried out
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Published 26 May 2020

Copper-based fluorinated reagents for the synthesis of CF2R-containing molecules (R ≠ F)

  • Louise Ruyet and
  • Tatiana Besset

Beilstein J. Org. Chem. 2020, 16, 1051–1065, doi:10.3762/bjoc.16.92

Graphical Abstract
  • ). The reaction was efficient (65 examples, up to 97% yield), showed a good functional group tolerance (i.e., cyano, ester, ketone) and even heteroarenes such as pyridine, quinoline and quinoxaline were functionalized with the four fluorinated moieties (Scheme 17). In situ-generated copper-based
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Published 18 May 2020

Recent applications of porphyrins as photocatalysts in organic synthesis: batch and continuous flow approaches

  • Rodrigo Costa e Silva,
  • Luely Oliveira da Silva,
  • Aloisio de Andrade Bartolomeu,
  • Timothy John Brocksom and
  • Kleber Thiago de Oliveira

Beilstein J. Org. Chem. 2020, 16, 917–955, doi:10.3762/bjoc.16.83

Graphical Abstract
  • photoarylation of isopropenyl acetate. The corresponding α-aryl ketone was obtained in 28–53% overall yield depending on the scale. An 8 h experiment was conducted in a continuous steady-state mode, producing the same α-aryl ketone in 48% yield on a 3 gram-scale (Scheme 5B). Photoredox catalysis is not limited
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Published 06 May 2020

Copper catalysis with redox-active ligands

  • Agnideep Das,
  • Yufeng Ren,
  • Cheriehan Hessin and
  • Marine Desage-El Murr

Beilstein J. Org. Chem. 2020, 16, 858–870, doi:10.3762/bjoc.16.77

Graphical Abstract
  • scaffolds such as gem-disubstituted (21k) and trisubstituted (21i and 21n,o) aziridines (Scheme 11). Furthermore, the reaction conditions are compatible with aldehyde, ester or ketone functions. Metalloenzymes routinely rely on 3d metals and amino acid-derived coordination spheres to perform complex (multi
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Published 24 Apr 2020

Aldehydes as powerful initiators for photochemical transformations

  • Maria A. Theodoropoulou,
  • Nikolaos F. Nikitas and
  • Christoforos G. Kokotos

Beilstein J. Org. Chem. 2020, 16, 833–857, doi:10.3762/bjoc.16.76

Graphical Abstract
  • -butyl ketone (1) yields acetone (4) and propylene (3). Reaction (2) of Scheme 1 refers to a type II intramolecular rearrangement of crotonaldehyde (5) to 3-butenal (7). The triplet state energy donors were quenched by diacetyl and cis-2-butene. In 1970, Cocivera and Trozzollo studied the photolysis of
  • , McGinniss and co-workers reported the polymerization of methyl methacrylate (26, MMA) by employing 4,4’-bis(N,N-diethylamino)benzophenone (27, DEABP) as the photoinitiator (Scheme 7) [35]. It was already well-accepted that aminoaromatic compounds, such as Michler’s ketone (28) and DEABP (27), present large
  • -one, as well as formaldehyde (35), efficiently initiated the polymerization of MAA (42), and butanone was the most efficient compound. Since acrylates and methacrylates can be photopolymerized by self-initiation, a blank experiment without the use of any aliphatic ketone 44 or formaldehyde (35) was
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Published 23 Apr 2020

Reaction of indoles with aromatic fluoromethyl ketones: an efficient synthesis of trifluoromethyl(indolyl)phenylmethanols using K2CO3/n-Bu4PBr in water

  • Thanigaimalai Pillaiyar,
  • Masoud Sedaghati and
  • Gregor Schnakenburg

Beilstein J. Org. Chem. 2020, 16, 778–790, doi:10.3762/bjoc.16.71

Graphical Abstract
  • due to either reducing the electrophilicity of the ketone or the presence of enolizable protons in α-position to the keto group in basic medium. Supporting this hypothesis, the reaction of 1a with 1,1,1-trifluoro-3-phenyl-2-propanone (2l), which has a 3-methylene group also did not proceed at all. The
  • corresponding products (3m: 94%, 3n: 93%, 3o: 90%) in excellent yields. Next, the scope of substituted indoles was studied with trifluoromethyl ketone 2a, and the results are shown in Table 3. In the case of a simple indole (1b), the corresponding product 3p was isolated in 96% yield. Indoles bearing electron
  • -. 5-, 6-, and 7-azaindoles, 1g–j) provided the corresponding products in the range from 91–97% yield (3u–x). We applied the developed protocol to reactions of other heterocyclic systems such as indazole (4), benzimidazole (5), carbazole (6), benzofuran (7), and benzothiophene (8) with ketone 2a
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Published 20 Apr 2020

Combining enyne metathesis with long-established organic transformations: a powerful strategy for the sustainable synthesis of bioactive molecules

  • Valerian Dragutan,
  • Ileana Dragutan,
  • Albert Demonceau and
  • Lionel Delaude

Beilstein J. Org. Chem. 2020, 16, 738–755, doi:10.3762/bjoc.16.68

Graphical Abstract
  • , an intramolecular Ru-catalyzed alkene-alkyne (Ru-AA) coupling and a late-stage epoxidation were readily accomplished, while the installation of the α,α′-dihydroxy ketone through a dihydroxylation proved difficult. Noteworthy, the structural elucidation of the THP ring of des-epoxy-amphidinolide N
  • affording a protected tetracyclic kempane derivative. The latter was further converted into (+)-kempene-2 (14a) in 91% yield by deprotection and acetylation (Scheme 17). A reduction of the intermediate ketone with lithium aluminum hydride followed by an acetylation finally led to (+)-kempene-1 (14b) and
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Published 16 Apr 2020

Synthesis of organic liquid crystals containing selectively fluorinated cyclopropanes

  • Zeguo Fang,
  • Nawaf Al-Maharik,
  • Peer Kirsch,
  • Matthias Bremer,
  • Alexandra M. Z. Slawin and
  • David O’Hagan

Beilstein J. Org. Chem. 2020, 16, 674–680, doi:10.3762/bjoc.16.65

Graphical Abstract
  • . The synthesis of the diastereoisomers of spiro LC candidates 11a and 11b also started from ketone 15 as illustrated in Scheme 4. Treatment of ketone 15 with methylenetriphenylphosphine which was generated in situ from methyltriphenylphosphonium bromide (PPh3CH3Br), generated exo-methylene cyclohexane
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Published 14 Apr 2020

Microwave-assisted efficient and facile synthesis of tetramic acid derivatives via a one-pot post-Ugi cascade reaction

  • Yong Li,
  • Zheng Huang,
  • Jia Xu,
  • Yong Ding,
  • Dian-Yong Tang,
  • Jie Lei,
  • Hong-yu Li,
  • Zhong-Zhu Chen and
  • Zhi-Gang Xu

Beilstein J. Org. Chem. 2020, 16, 663–669, doi:10.3762/bjoc.16.63

Graphical Abstract
  • investigated the effect of different inorganic and organic bases (Table 1). It was interesting to note that all of the bases tested in the study afforded the desired enol tetramic acid derivative 7a after the reaction was heated under the microwave irradiation conditions. The ketone compound 6a could be the
  • removing the solvent under a gentle stream of nitrogen. Different amines, acids, and isonitriles were subjected to the one-pot protocol to give the corresponding tetramic acid derivatives 7 from the ketone intermediates 6 in good yields over two steps (51–75%) after the purification of the products by
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Published 09 Apr 2020

Asymmetric synthesis of CF2-functionalized aziridines by combined strong Brønsted acid catalysis

  • Xing-Fa Tan,
  • Fa-Guang Zhang and
  • Jun-An Ma

Beilstein J. Org. Chem. 2020, 16, 638–644, doi:10.3762/bjoc.16.60

Graphical Abstract
  • conditions underwent well and gave rise to CF2-functionalized α-chloro-β-amino ketone 5c in 89% yield with >99% ee and >50:1 dr (confirmed by X-ray spectroscopy) [46]. Conclusion In summary, an array of chiral CF2-functionalized aziridines was constructed from in situ-formed aldimines and difluorodiazoetyl
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Published 07 Apr 2020

Preparation and in situ use of unstable N-alkyl α-diazo-γ-butyrolactams in RhII-catalyzed X–H insertion reactions

  • Maria Eremeyeva,
  • Daniil Zhukovsky,
  • Dmitry Dar’in and
  • Mikhail Krasavin

Beilstein J. Org. Chem. 2020, 16, 607–610, doi:10.3762/bjoc.16.55

Graphical Abstract
  • reaction of cyclopropylamine with N-phenyl-α-diazo-2-pyrrolidone [2]) can be rationalized, as proposed previously [2], either by the oxidation of diazolactam 6c to a respective ketone (a process described in the literature for other α-diazocarbonyl compounds [6]), followed by a nucleophilic attack of
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Published 02 Apr 2020

Recent advances in photocatalyzed reactions using well-defined copper(I) complexes

  • Mingbing Zhong,
  • Xavier Pannecoucke,
  • Philippe Jubault and
  • Thomas Poisson

Beilstein J. Org. Chem. 2020, 16, 451–481, doi:10.3762/bjoc.16.42

Graphical Abstract
  • the haloketone. Hence, after being excited by light, the excited [Cu(I)]* complex gave an electron to the α-haloketone. Then, the ketone radical combined with allyltributyltin to generate a Bu3Sn radical. A final electron transfer from the Bu3Sn radical to [Cu(II)] regenerated the Cu(I) catalyst
  • present on the pypzs ligand, and activates the carbonyl group. The PCET occurs, furnishing a ketyl radical that can react with another molecule (ketone or aldehyde), delivering the pinacol product. A final HAT with another equivalent of HEH or HEH+ delivers the product, and the resulting radical cation of
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Published 23 Mar 2020

Photophysics and photochemistry of NIR absorbers derived from cyanines: key to new technologies based on chemistry 4.0

  • Bernd Strehmel,
  • Christian Schmitz,
  • Ceren Kütahya,
  • Yulian Pang,
  • Anke Drewitz and
  • Heinz Mustroph

Beilstein J. Org. Chem. 2020, 16, 415–444, doi:10.3762/bjoc.16.40

Graphical Abstract
  • cyclic ketone with POCl3 and DMF in CH2Cl2 in the case of the amino substituted derivatives in high yields. This reference also describes the synthesis of the chain builders cb-3 and cb-4. It occurred by a similar procedure. Synthesis of cb5 and cb6 was already reported [68]. The heptamethine pattern
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Published 18 Mar 2020
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