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Search for "C–O bond" in Full Text gives 152 result(s) in Beilstein Journal of Organic Chemistry.

A selective removal of the secondary hydroxy group from ortho-dithioacetal-substituted diarylmethanols

  • Anna Czarnecka,
  • Emilia Kowalska,
  • Agnieszka Bodzioch,
  • Joanna Skalik,
  • Marek Koprowski,
  • Krzysztof Owsianik and
  • Piotr Bałczewski

Beilstein J. Org. Chem. 2018, 14, 1229–1237, doi:10.3762/bjoc.14.105

Graphical Abstract
  • -dithianyl derivatives is facilitated by oxophilic zinc which preferentially binds to the OH oxygen atoms (bond dissociation energies for Zn–O and Zn–S are 284 and 205 kJ/mol, respectively) [67]. The weakened CO bond is thus more susceptible to the borohydride attack to produce the corresponding
  • are to be expected. This task is additionally difficult to accomplish due to a chemical similarity of oxygen and sulfur, two neighboring heteroatoms from the main group VI of the periodic table. A longer atomic radius of sulfur than oxygen should make the C–S bond weaker and more reactive than the CO
  • bond and consequently the reduction of the former should a priori occur preferentially [53][54][55]. According to the best of our knowledge, there are no literature reports concerning selective reductions of dibenzylic hydroxy groups in the presence of ortho-acetal or ortho-thioacetal functions. Such
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Published 29 May 2018

One hundred years of benzotropone chemistry

  • Arif Dastan,
  • Haydar Kilic and
  • Nurullah Saracoglu

Beilstein J. Org. Chem. 2018, 14, 1120–1180, doi:10.3762/bjoc.14.98

Graphical Abstract
  • molecular structure of 4,5-benzotropone (11) was determined by Hata’s group [50]. X-ray diffraction analysis showed that the molecule is approximately planar and the bond alternation in the seven-membered ring and C=O bond length support satisfactory aromaticity. 2.1. Synthesis of 4,5-benzotropone (11
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Published 23 May 2018

Hypervalent iodine(III)-mediated decarboxylative acetoxylation at tertiary and benzylic carbon centers

  • Kensuke Kiyokawa,
  • Daichi Okumatsu and
  • Satoshi Minakata

Beilstein J. Org. Chem. 2018, 14, 1046–1050, doi:10.3762/bjoc.14.92

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  • O bond formation has received considerably less attention, even though it represents a promising strategy for the synthesis of valuable alcohol derivatives. One of the classical methods for the decarboxylative CO bond formation of aliphatic carboxylic acids involves the use of stoichiometric
  • operation, and the use of readily available and environmentally friendly oxidants. However, despite the great potential of this approach with respect to a decarboxylative CO bond-forming reaction, the oxidation system was only applied to reactions of uronic acids and α-amino acids [22][23][24], and further
  • indicated that the reaction proceeds via the formation of an alkyl iodide and the corresponding iodine(III) species as key intermediates. In this context, we concluded that the use of such an oxidation system, combined with the judicious choice of solvent, would enable a decarboxylative CO bond forming
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Published 15 May 2018

Phosphodiester models for cleavage of nucleic acids

  • Satu Mikkola,
  • Tuomas Lönnberg and
  • Harri Lönnberg

Beilstein J. Org. Chem. 2018, 14, 803–837, doi:10.3762/bjoc.14.68

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Published 10 Apr 2018

Cobalt-catalyzed directed C–H alkenylation of pivalophenone N–H imine with alkenyl phosphates

  • Wengang Xu and
  • Naohiko Yoshikai

Beilstein J. Org. Chem. 2018, 14, 709–715, doi:10.3762/bjoc.14.60

Graphical Abstract
  • substrates and alkenyl electrophiles would offer a complementary approach for the C–H alkenylation [12]. In particular, C–H alkenylations by way of alkenyl CO bond cleavage has attracted much attention because of the ready accessibility of the corresponding alkenyl electrophiles (e.g., acetate, phosphate
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Published 28 Mar 2018

High-yielding continuous-flow synthesis of antimalarial drug hydroxychloroquine

  • Eric Yu,
  • Hari P. R. Mangunuru,
  • Nakul S. Telang,
  • Caleb J. Kong,
  • Jenson Verghese,
  • Stanley E. Gilliland III,
  • Saeed Ahmad,
  • Raymond N. Dominey and
  • B. Frank Gupton

Beilstein J. Org. Chem. 2018, 14, 583–592, doi:10.3762/bjoc.14.45

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  • screening of bases, the pKa of the amine and alcohol groups present in compound 12 were given careful consideration in order to minimize CO bond formation (Table 4). NaOH or KOH in ethanol gave low (<40%) conversion, whereas using K2CO3 in ethanol gave 82% conversion to HCQ (Table 4, entry 3). Attempts
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Published 08 Mar 2018

Electrochemical Corey–Winter reaction. Reduction of thiocarbonates in aqueous methanol media and application to the synthesis of a naturally occurring α-pyrone

  • Ernesto Emmanuel López-López,
  • José Alvano Pérez-Bautista,
  • Fernando Sartillo-Piscil and
  • Bernardo A. Frontana-Uribe

Beilstein J. Org. Chem. 2018, 14, 547–552, doi:10.3762/bjoc.14.41

Graphical Abstract
  • beneficial effect of β-oxygen substituents in radical deoxygenation [37], is dramatically favoured when the radical precursor group (or atom) is oriented antiperiplanar to the CO bond via orbital interaction between the SOMO with the C−O σ* orbital [35]. Therefore, stabilization of intermediate E, which is
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Published 02 Mar 2018

5-Aminopyrazole as precursor in design and synthesis of fused pyrazoloazines

  • Ranjana Aggarwal and
  • Suresh Kumar

Beilstein J. Org. Chem. 2018, 14, 203–242, doi:10.3762/bjoc.14.15

Graphical Abstract
  • product 4,5-dihydro-1H-pyrazolo[3,4-b]pyridine-6(7H)-one 53 was formed due to CO bond cleavage from cyclic ester 51. Bazgir et al. [56] described the synthesis of spiro[indoline-3,4'-pyrazolo[3,4-b]pyridine]-2,6'(1'H)-diones 55 by an efficient three-component procedure from the reaction of 5
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Published 25 Jan 2018

From dipivaloylketene to tetraoxaadamantanes

  • Gert Kollenz and
  • Curt Wentrup

Beilstein J. Org. Chem. 2018, 14, 1–10, doi:10.3762/bjoc.14.1

Graphical Abstract
  • to −20 °C. However, it dimerizes at room temperature to afford an 88% yield of the thermally very stable dimer 3, which still carries a ketene function [16]. Compound 3 is formed through a [2 + 4] cycloaddition between one molecule of the α-oxoketene 2 and the carbonyl C=O bond of a second molecule
  • . It is noteworthy that in the presence of DMSO a different dimer 7 is formed, again in high yield, originating from a [2 + 4] cycloaddition between a molecule of the α-oxoketene and the ketene C=O bond of the second molecule (Scheme 3) [17]. The treatment of the dimeric ketene 3 with nucleophiles
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Published 02 Jan 2018

Conformational preferences of α-fluoroketones may influence their reactivity

  • Graham Pattison

Beilstein J. Org. Chem. 2017, 13, 2915–2921, doi:10.3762/bjoc.13.284

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  • preferred for α-fluoroacetophenone, which places the C–F bond in the same plane as the C=O bond, making orbital interactions impossible. Although orbital interactions between chlorine’s lone pairs and the C=O π* orbital are expected to be weak, at least α-chloroacetophenone has a lowest energy gauche
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Published 29 Dec 2017

Acid-catalyzed ring-opening reactions of a cyclopropanated 3-aza-2-oxabicyclo[2.2.1]hept-5-ene with alcohols

  • Katrina Tait,
  • Alysia Horvath,
  • Nicolas Blanchard and
  • William Tam

Beilstein J. Org. Chem. 2017, 13, 2888–2894, doi:10.3762/bjoc.13.281

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  • represent the first examples of ring-openings of cyclopropanated 3-aza-2-oxabicyclo[2.2.1]alkenes that lead to the cleavage of the CO bond instead of the N–O bond. Different acid catalysts were tested and it was found that pyridinium toluenesulfonate in methanol gave the best yields in the ring-opening
  • ], and cycloadditions using nitrile oxides to provide 15 and 16 [7]. In the literature, there are also many examples of the cleavage of the CO bond of 3-aza-2-oxabicyclic alkenes 1 (Scheme 3). This includes the use of protic acid [8], using metal catalysts such as Pd [9], Fe or Cu [10], In [11
  • -oxabicyclo[2.2.1]alkenes reductively cleave the N–O bond (a) (Scheme 4), therefore, no examples cleaving the CO bond have been reported in the literature. In this paper, we aim to explore the use of an acid catalyst with an alcohol nucleophile on the ring-opening of cyclopropanated 3-aza-2-oxabicyclic
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Published 27 Dec 2017

Recent progress in the racemic and enantioselective synthesis of monofluoroalkene-based dipeptide isosteres

  • Myriam Drouin and
  • Jean-François Paquin

Beilstein J. Org. Chem. 2017, 13, 2637–2658, doi:10.3762/bjoc.13.262

Graphical Abstract
  • negative charge, with a dipole moment of 1.4 D. Finally, the monofluoroalkene has the ability to accept a hydrogen bond through the fluorine atom [9]. Geometrically, the monofluoroalkene is quite similar to the amide bond. The C=O bond of the amide is 1.228 Å, compared to 1.376 Å for the C–F bond, and the
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Published 12 Dec 2017

Dialkyl dicyanofumarates and dicyanomaleates as versatile building blocks for synthetic organic chemistry and mechanistic studies

  • Grzegorz Mlostoń and
  • Heinz Heimgartner

Beilstein J. Org. Chem. 2017, 13, 2235–2251, doi:10.3762/bjoc.13.221

Graphical Abstract
  • converts into the orthoester 10 via insertion into the CO bond. The reaction mechanism for the formation of 8 and 9 comprises the initial attack of the nucleophilic carbene onto the electron-deficient C atom of E-1b to give an intermediate zwitterion 11. The latter undergoes two competitive reactions. The
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Published 24 Oct 2017

Mechanochemical synthesis of small organic molecules

  • Tapas Kumar Achar,
  • Anima Bose and
  • Prasenjit Mal

Beilstein J. Org. Chem. 2017, 13, 1907–1931, doi:10.3762/bjoc.13.186

Graphical Abstract
  • process to stabilize the carbocation species. This method was proved to be efficient by performing the reaction at 9.7 mmol scale to obtain 84% yield of the product. CO bond formation reaction Carbon–oxygen (C–O) bonds are widely present in molecules containing ester, carbamate and amino acid, etc. [88
  • ]. Traditional solution-based CO bond synthesis generally needs large amount of solvents, excess chlorinating agent, harsh reaction conditions, a tedious isolation process, etc. compared to solvent-less grinding or mechanomilling [89]. In 2011, Mack and co-workers applied the high-speed ball milling (HSBM
  • alcohols or amines as nucleophile [92]. When 2 equiv of CDI was treated with alcohol in a mixer mill at 30 Hz, within 15 min imidazolecarboxylic acid derivatives were isolated with a new CO bond formation (Scheme 22). C–X bond forming reactions Carbon–halogen (C–X) bond forming reactions are also
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Published 11 Sep 2017

Conformational impact of structural modifications in 2-fluorocyclohexanone

  • Francisco A. Martins,
  • Josué M. Silla and
  • Matheus P. Freitas

Beilstein J. Org. Chem. 2017, 13, 1781–1787, doi:10.3762/bjoc.13.172

Graphical Abstract
  • positive nitrogen, such as in the 3-fluoropiperidinium cation [7][8][9][10][11][12][13]. The carbonyl group also plays a determinant role in the conformational isomerism of ketones and aldehydes [14][15][16][17]. Here the α-carbonyl substituent can interact with the C=O bond, either through a dipolar
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Published 24 Aug 2017

Chiral phase-transfer catalysis in the asymmetric α-heterofunctionalization of prochiral nucleophiles

  • Johannes Schörgenhumer,
  • Maximilian Tiffner and
  • Mario Waser

Beilstein J. Org. Chem. 2017, 13, 1753–1769, doi:10.3762/bjoc.13.170

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  • limitations of asymmetric phase-transfer catalysis. Hence, it is without doubt that the introduction and development of such highly selective transformations will be one of the important and challenging targets in the future. α-Hydroxylations and oxygenations The stereoselective formation of a CO bond in the
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Published 22 Aug 2017

Theoretical simulation of the infrared signature of mechanically stressed polymer solids

  • Matthew S. Sammon,
  • Milan Ončák and
  • Martin K. Beyer

Beilstein J. Org. Chem. 2017, 13, 1710–1716, doi:10.3762/bjoc.13.165

Graphical Abstract
  • backbone is compensated by a strengthening of the free CO bond. This is obviously not the case as the bond seems to be completely unaffected by the external force, which is in line with a negligible change of the CO bond length, from 1.22 to 1.21 Å. The calculated spectra in the fingerprint area are
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Published 17 Aug 2017

Synthesis of alkynyl-substituted camphor derivatives and their use in the preparation of paclitaxel-related compounds

  • M. Fernanda N. N. Carvalho,
  • Rudolf Herrmann and
  • Gabriele Wagner

Beilstein J. Org. Chem. 2017, 13, 1230–1238, doi:10.3762/bjoc.13.122

Graphical Abstract
  • electrophilic than that of the C=O bond. However, with bulkier alkynes (e.g., 1-adamantylacetylene or 1-methoxy-1-ethynylcyclohexane), an attack at the carbonyl group becomes more pronounced. Presumably, the C=O carbon atom in 3-oxo-camphorsulfonylimine is sterically more accessible, whereas the sulfonylimine C
  • the literature, using a variety of reducing agents. All of them lead either to complete or to unselective reduction of the C=N and C=O bond. Thus, LiAlH4 reduces the C=O and C=N group of 3, and 3-exo-hydroxycamphorsultam is obtained in good yields [16]. Under Meerwein–Ponndorf–Verley conditions (Al
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Published 26 Jun 2017

Transition-metal-catalyzed synthesis of phenols and aryl thiols

  • Yajun Liu,
  • Shasha Liu and
  • Yan Xiao

Beilstein J. Org. Chem. 2017, 13, 589–611, doi:10.3762/bjoc.13.58

Graphical Abstract
  • has not been reported. In this review, a brief overview is given of the recent advances in synthetic strategies for both phenols and aryl thiols. Keywords: aryl thiol; CO bond; C–S bond; phenol; transition metal; Introduction Phenols and aryl thiols serve as both important intermediates in organic
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Published 23 Mar 2017

Studies directed toward the exploitation of vicinal diols in the synthesis of (+)-nebivolol intermediates

  • Runjun Devi and
  • Sajal Kumar Das

Beilstein J. Org. Chem. 2017, 13, 571–578, doi:10.3762/bjoc.13.56

Graphical Abstract
  • Sharpless asymmetric dihydroxylation as the sole source of chirality [27]. For the synthesis of chroman derivative 2, first a base-mediated intramolecular SNAr reaction was envisioned for the aryl CO bond formation under transition-metal-free conditions [28][29][30]. The additional benefit of this strategy
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Published 21 Mar 2017

Identification, synthesis and mass spectrometry of a macrolide from the African reed frog Hyperolius cinnamomeoventris

  • Markus Menke,
  • Pardha Saradhi Peram,
  • Iris Starnberger,
  • Walter Hödl,
  • Gregory F.M. Jongsma,
  • David C. Blackburn,
  • Mark-Oliver Rödel,
  • Miguel Vences and
  • Stefan Schulz

Beilstein J. Org. Chem. 2016, 12, 2731–2738, doi:10.3762/bjoc.12.269

Graphical Abstract
  • visible, but their abundance is so low that their diagnostic value is largely decreased. Another limitation is that mass spectra of unsaturated unbranched macrolactones, formally derived from ω-hydroxy acids, do not show the characteristic ions generated by pathways a or b. Obviously, the primary CO bond
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Published 13 Dec 2016

Palladium-catalyzed ring-opening reactions of cyclopropanated 7-oxabenzonorbornadiene with alcohols

  • Katrina Tait,
  • Oday Alrifai,
  • Rebecca Boutin,
  • Jamie Haner and
  • William Tam

Beilstein J. Org. Chem. 2016, 12, 2189–2196, doi:10.3762/bjoc.12.209

Graphical Abstract
  • the nucleophile at bridgehead carbon A, resulting in cleavage of the CO bond. Through deprotonation at the bridgehead position and an internal rearrangement, 2-methyldihydronaphthalen-1-ols 9 could be formed. This type 1 ring opening has been accomplished by our group through the use of organocuprate
  • nucleophiles [30]. The second type of predicted ring opening (type 2) involves the attack of the nucleophile at the external cyclopropane carbon B, resulting in the cleavage of the cyclopropane C–C bond followed by a CO bond cleavage to produce 2-substituted dihydronaphthalenols 10. Under thermal conditions
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Published 14 Oct 2016

Superelectrophilic activation of 5-hydroxymethylfurfural and 2,5-diformylfuran: organic synthesis based on biomass-derived products

  • Dmitry S. Ryabukhin,
  • Dmitry N. Zakusilo,
  • Mikhail O. Kompanets,
  • Anton A.Tarakanov,
  • Irina A. Boyarskaya,
  • Tatiana O. Artamonova,
  • Mikhail A. Khohodorkovskiy,
  • Iosyp O. Opeida and
  • Aleksander V. Vasilyev

Beilstein J. Org. Chem. 2016, 12, 2125–2135, doi:10.3762/bjoc.12.202

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  • (Table 2), this reaction, most probably, proceeds through an SN2 pathway, where “pure” heteroaromatic cation B is not formed. At least the reaction may go through late transition state, in which the CO bond in the CH2O+H2 group is rather elongated, resulting in a larger positive charge on this carbon
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Published 05 Oct 2016

Ionic liquids as transesterification catalysts: applications for the synthesis of linear and cyclic organic carbonates

  • Maurizio Selva,
  • Alvise Perosa,
  • Sandro Guidi and
  • Lisa Cattelan

Beilstein J. Org. Chem. 2016, 12, 1911–1924, doi:10.3762/bjoc.12.181

Graphical Abstract
  • in the ionic liquid were involved in the reaction. It was therefore proposed that an interaction of the quaternary ammonium center with the carbonyl oxygen of glycerol carbonate (GlyC) could weaken the C=O bond (Scheme 15). It is worth mentioning that glycidol was previously obtained at much higher
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Published 26 Aug 2016

Rearrangements of organic peroxides and related processes

  • Ivan A. Yaremenko,
  • Vera A. Vil’,
  • Dmitry V. Demchuk and
  • Alexander O. Terent’ev

Beilstein J. Org. Chem. 2016, 12, 1647–1748, doi:10.3762/bjoc.12.162

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Published 03 Aug 2016
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