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Search for "boronic ester" in Full Text gives 37 result(s) in Beilstein Journal of Organic Chemistry.

Solid-phase synthesis of biaryl bicyclic peptides containing a 3-aryltyrosine or a 4-arylphenylalanine moiety

  • Iteng Ng-Choi,
  • Àngel Oliveras,
  • Lidia Feliu and
  • Marta Planas

Beilstein J. Org. Chem. 2019, 15, 761–768, doi:10.3762/bjoc.15.72

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  • peptidyl resin 4 bearing a 4-iodo- and a 4-boronophenylalanine residue. The latter would be incorporated at the N-terminus of the peptide sequence which would avoid the decomposition of the boronic ester during the coupling steps [26]. The intramolecular Suzuki–Miyaura cross coupling of 4 followed by
  • )/H2O (95:2.5:2.5) for 2 h affording the linear boronopeptide H-Phe(4-B(OH)2)-Ala-Gln-Leu-Gln-Phe(4-I)-βAla-Gln-OpNB in >99% purity, which was characterized by mass spectrometry. The boronic acid function resulted from hydrolysis of the boronic ester during HPLC analysis as shown by mass spectrometry
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Published 22 Mar 2019

Synergistic approach to polycycles through Suzuki–Miyaura cross coupling and metathesis as key steps

  • Sambasivarao Kotha,
  • Milind Meshram and
  • Chandravathi Chakkapalli

Beilstein J. Org. Chem. 2018, 14, 2468–2481, doi:10.3762/bjoc.14.223

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  • useful protocol to build indene derivatives by employing SM coupling and RCM in sequence. To this end, the SM coupling of triflate 7 was accomplished by using pinacol boronic ester 8 in the presence of a palladium catalyst to give the cross-coupling product 9 (75%). Later on, exposure of the diolefinic
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Published 21 Sep 2018

Intramolecular glycosylation

  • Xiao G. Jia and
  • Alexei V. Demchenko

Beilstein J. Org. Chem. 2017, 13, 2028–2048, doi:10.3762/bjoc.13.201

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  • ]. Arylboronic esters have recently been probed by Toshima and co-workers as a successful linkage for the IAD method [109]. The arylboronic sugar derivatives, such as 79, can be easily obtained from the corresponding 4,6-diol 78 and a arylboronic acid in toluene at reflux (Scheme 19). Boronic ester 79 was then
  • . Conversely, the galacto-configured boronic ester acceptor 82 was used, the α-(1→6)-linked product 83 was formed in 70% yield. Again, the regioselectivity of glycosylation is driven by the less-hindered boron–oxygen bond, which is from C-6 face in the case of galactose (intermediate B, Scheme 19). In the case
  • al. explored the use of ortho-dihydroxyboryl-substituted benzyl thioglycosides as a delivery method for the leaving group-based intramolecular glycosylation [129]. They hypothesized that if boronic acid-derived donor 100 is activated in the presence of glycosyl acceptor 101, the boronic ester 102
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Published 29 Sep 2017

Practical synthetic strategies towards lipophilic 6-iodotetrahydroquinolines and -dihydroquinolines

  • David R. Chisholm,
  • Garr-Layy Zhou,
  • Ehmke Pohl,
  • Roy Valentine and
  • Andrew Whiting

Beilstein J. Org. Chem. 2016, 12, 1851–1862, doi:10.3762/bjoc.12.174

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  • and 6-bromo-THQ 26 (synthesised using the optimised conditions for 21) were reacted under typical Suzuki conditions with boronic ester 27. Analysis of the crude 1H NMR spectra for the reactions indicated full conversion of the 6-iodo-THQ 21, but moderate conversion (56%) in the case of the 6-bromo-THQ
  • addition of DIBAL to 20a.a DIBAL reductions of quinolin-2-ones 23a–e using the optimised method to synthesise 22.a Comparing the reactivity of 6-iodo-THQ 21 and 6-bromo-THQ 26 in a typical Suzuki reaction with boronic ester 27 to give biaryl 28. Supporting Information Supporting information features full
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Published 16 Aug 2016

Scope and limitations of the dual-gold-catalysed hydrophenoxylation of alkynes

  • Adrián Gómez-Suárez,
  • Yoshihiro Oonishi,
  • Anthony R. Martin and
  • Steven P. Nolan

Beilstein J. Org. Chem. 2016, 12, 172–178, doi:10.3762/bjoc.12.19

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  • (3ad), acetals (3ae) and naphthyls (3af) were well tolerated and the corresponding vinyl ethers were obtained in moderate to high yields (50–98%). On the contrary, the use of azide (3ag) or boronic ester (3ah) functionalities did not afford the desired products [29]. The latter case can be explained
  • due to formation of the corresponding gem-diaurated aryl species, by reaction of catalyst [{Au(IPr)}2(µ-OH)][BF4] with the boronic ester [30], thus inhibiting the catalytic activity. The electronic properties of the phenol were also examined. If the electron density on the phenol is decreased, its
  • phenylacetylene [30]. As in the case of the formation of a gem-diaurated species when boronic ester 3h was used, it appears that in situ formation of highly stable diaurated species, inhibits catalytic activity. These results suggest that while both electron-rich/poor alkynes are tolerated by our methodology, the
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Published 01 Feb 2016

Assembly of synthetic Aβ miniamyloids on polyol templates

  • Sebastian Nils Fischer and
  • Armin Geyer

Beilstein J. Org. Chem. 2015, 11, 2646–2653, doi:10.3762/bjoc.11.284

Graphical Abstract
  • template 16 to obtain threefold boronic ester 17. The miniamyloid 17 assembles from seven components by imine and boronic ester bonds between the peptides and the template. The relative orientation and spacing of the peptides mimic the assembly of peptides in Alzheimer β-amyloids. Keywords: Alzheimer
  • -terminal boronic acid 2. Peptide boronic acids of type 1 were synthesized on polymer-bound diethanolamine (PS-DEAM resin), according to the protocol in Supporting Information File 1, Figure S1 [21]. The electron-poor boronic acid 2, which was expected to be more reactive in boronic ester formation, was
  • only low tendencies of boronic ester formation [23]. Therefore, we turned to cis-dihydroxylated 5, which exhibited a unique reactivity towards boronic acids because it forms two anellated cis-fused rings. 5 shows 86% esterification after drying in a 1:1 mixture with the arylboronic acid 6, a single
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Published 17 Dec 2015

Clean and fast cross-coupling of aryl halides in one-pot

  • Valerica Pandarus,
  • Geneviève Gingras,
  • François Béland,
  • Rosaria Ciriminna and
  • Mario Pagliaro

Beilstein J. Org. Chem. 2014, 10, 897–901, doi:10.3762/bjoc.10.87

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  • 3 h. Table 1, entry 3 shows that 3-bromopyridine is entirely converted in the boronic acid pinacol ester in 3 h over 2 mol % SiliaCat DPP-Pd. The resulting boronic ester is then smoothly coupled with 4-bromotoluene in 83% in 3 h, or with 2-bromotoluene in 82% in 3 h (Table 1, entry 4), over the same
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Published 22 Apr 2014

Boron-substituted 1,3-dienes and heterodienes as key elements in multicomponent processes

  • Ludovic Eberlin,
  • Fabien Tripoteau,
  • François Carreaux,
  • Andrew Whiting and
  • Bertrand Carboni

Beilstein J. Org. Chem. 2014, 10, 237–250, doi:10.3762/bjoc.10.19

Graphical Abstract
  • gave access to the homoallylic alcohols 35 in 77–86% yields. Alternatively, the presence of an allylic boronic ester group in the cycloadduct 33 was exploited in carrying out first the addition to 4-nitrobenzaldehyde to afford 36. Further normal-electron demand [4 + 2]-cycloaddition step with N
  • -phenylmaleimide furnished the single tricyclic compound 37 (Scheme 26). The initial boronic ester group of 38, the direct precursor of 32, can be also converted into a trifluoroborate substituent by treatment with KHF2 in MeOH/H2O to increase the reactivity of the dienyl moiety towards electron-poor dienophiles
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Published 22 Jan 2014

Incorporation of perfluorohexyl-functionalised thiophenes into oligofluorene-truxenes: synthesis and physical properties

  • Neil Thomson,
  • Alexander L. Kanibolotsky,
  • Joseph Cameron,
  • Tell Tuttle,
  • Neil J. Findlay and
  • Peter J. Skabara

Beilstein J. Org. Chem. 2013, 9, 1243–1251, doi:10.3762/bjoc.9.141

Graphical Abstract
  • then reacted with bis(pinacolato)diboron to afford boronic ester 8. The synthetic route to 2-iodo-4-perfluorohexylthiophene (13) (Scheme 2) began with treatment of 3-bromothiophene (1) with lithium bis(trimethylsilyl)amide and chlorotrimethylsilane to afford 2-trimethylsilyl-3-bromothiophene (9
  • /ethanol solution. Lithiation and treatment with perfluorohexyliodide afforded 12, which was deprotected with tetrabutylammonium fluoride to afford 13. The boronic ester 16 was then synthesised by the same steps applied to obtain compound 8 (see Scheme 1). T1-3FTh and T1-4FTh were then synthesised by
  • Suzuki coupling of tribromohexahexyltruxene 17, which was synthesised according to our previously published method [14], and the relevant boronic ester, 8 or 16 (Scheme 3). T4-4FTh (Scheme 4) was synthesised by coupling compound 16 with T3Br. The latter compound was obtained by our previously published
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Published 27 Jun 2013

Aryl nitrile oxide cycloaddition reactions in the presence of pinacol boronic acid ester

  • Sarah L. Harding,
  • Sebastian M. Marcuccio and
  • G. Paul Savage

Beilstein J. Org. Chem. 2012, 8, 606–612, doi:10.3762/bjoc.8.67

Graphical Abstract
  • favouring the oxidation of carbon–boron bonds, which makes boronic ester chemistry chemoselective, is a constraint that potentially limits the utility of nitrile oxide cycloadditions in the presence of a boronic acid ester. 4-Formylphenylboronic acid pinacol ester 4 is commercially available or easily
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Published 19 Apr 2012

Molecular recognition of organic ammonium ions in solution using synthetic receptors

  • Andreas Späth and
  • Burkhard König

Beilstein J. Org. Chem. 2010, 6, No. 32, doi:10.3762/bjoc.6.32

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Published 06 Apr 2010

Convenient methods for preparing π-conjugated linkers as building blocks for modular chemistry

  • Jiří Kulhánek,
  • Filip Bureš and
  • Miroslav Ludwig

Beilstein J. Org. Chem. 2009, 5, No. 11, doi:10.3762/bjoc.5.11

Graphical Abstract
  • moieties is usually accomplished by cross-coupling reactions, in particular by the Suzuki–Miyaura [26][27] or the Sonogashira [28] reactions. Consequently, the availability of the suitably substituted π-conjugated linkers of various lengths bearing boronic ester functionality or terminal acetylene is
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Published 14 Apr 2009
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