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Search for "bromine" in Full Text gives 332 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.

Synthesis of odorants in flow and their applications in perfumery

  • Merlin Kleoff,
  • Paul Kiler and
  • Philipp Heretsch

Beilstein J. Org. Chem. 2022, 18, 754–768, doi:10.3762/bjoc.18.76

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  • achieved within milliseconds initializing bromine–lithium exchange of bromochloromethane to generate (chloromethyl)lithium. This carbenoid species readily reacts with terpenyl pinacol boronates 17, resulting in the formation of intermediate 18, which undergoes 1,2-anionotropic rearrangement to the
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Published 27 Jun 2022

Mechanochemical halogenation of unsymmetrically substituted azobenzenes

  • Dajana Barišić,
  • Mario Pajić,
  • Ivan Halasz,
  • Darko Babić and
  • Manda Ćurić

Beilstein J. Org. Chem. 2022, 18, 680–687, doi:10.3762/bjoc.18.69

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  • four mechanistic pathways could be involved in this reaction [51]. Three of them involve oxidative addition followed by reductive elimination. Neutral NBS or the hydrogen bond complex NBS∙∙∙TsOH are bromine donors in two of them, while protonated NBS is engaged in the third. The fourth mechanism
  • proceeds by electrophilic cleavage with neutral NBS or the hydrogen bond complex NBS∙∙∙TsOH as a bromine source. Here we present the mechanochemical selective halogenation of unsymmetrically substituted azobenzenes by NXS (X = Cl, Br, or I). The liquid-assisted grinding of para-halogenated derivatives of
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Published 15 Jun 2022

Menadione: a platform and a target to valuable compounds synthesis

  • Acácio S. de Souza,
  • Ruan Carlos B. Ribeiro,
  • Dora C. S. Costa,
  • Fernanda P. Pauli,
  • David R. Pinho,
  • Matheus G. de Moraes,
  • Fernando de C. da Silva,
  • Luana da S. M. Forezi and
  • Vitor F. Ferreira

Beilstein J. Org. Chem. 2022, 18, 381–419, doi:10.3762/bjoc.18.43

Graphical Abstract
  • menadione (10), as was demonstrated by Minisci and co-workers [66]. In this work, the oxidation of 17 with 60% aqueous hydrogen peroxide, using bromine and sulfuric acid as catalysts, provided menadione in 90% yield (Table 2, entry 1) [66]. According to the proposed mechanism, the first step involves the
  • by treating menadione (10) with molecular bromine in the presence of sodium acetate and acetic acid in 76% yield. With brominated compound 82 at hands, the authors obtained four menadione derivatives 83a–d functionalized with organochalcogenic moieties after treatment of compound 82 with the
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Published 11 Apr 2022

Ready access to 7,8-dihydroindolo[2,3-d][1]benzazepine-6(5H)-one scaffold and analogues via early-stage Fischer ring-closure reaction

  • Irina Kuznetcova,
  • Felix Bacher,
  • Daniel Vegh,
  • Hsiang-Yu Chuang and
  • Vladimir B. Arion

Beilstein J. Org. Chem. 2022, 18, 143–151, doi:10.3762/bjoc.18.15

Graphical Abstract
  • the nitro group but also to cyclization and the reductive elimination of bromine to afford 3a. The synthesis of 3b could be realized in 58% yield by using iron powder under acidic conditions. Reaction of methyl 5-(2-nitrophenyl)-4-oxopentanoate [44] and 1-benzyl-1-phenylhydrazine [36] hydrochloride in
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Published 26 Jan 2022

DABCO-promoted photocatalytic C–H functionalization of aldehydes

  • Bruno Maia da Silva Santos,
  • Mariana dos Santos Dupim,
  • Cauê Paula de Souza,
  • Thiago Messias Cardozo and
  • Fernanda Gadini Finelli

Beilstein J. Org. Chem. 2021, 17, 2959–2967, doi:10.3762/bjoc.17.205

Graphical Abstract
  • ). Surprisingly, decent amounts of product were observed when the reaction was performed without the use of DABCO (Table 1, entry 9). This result indicates an alternative mechanism can be possible for aryl ketone formation when there are no bicyclic amines in the reaction media. Recent works indicate a bromine
  • addition experiment with methyl acrylate (Supporting Information File 1, Table S5), along with the strong dependence of aryl bromide electronics on the yield indicate the protagonism of the nickel-aryl bromide system. We hypothesized a HAT step by the bromine radical, generated by nickel complex photolysis
  • , in a similar fashion of previous reports [31][32]. However, addition of bromide from external sources led to diminished yields (Supporting Information File 1, Table S6). Also, DFT calculations demonstrated that a HAT reaction between bromine radical and isovaleraldehyde is a barrierless reaction
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Published 21 Dec 2021

A two-phase bromination process using tetraalkylammonium hydroxide for the practical synthesis of α-bromolactones from lactones

  • Yuki Yamamoto,
  • Akihiro Tabuchi,
  • Kazumi Hosono,
  • Takanori Ochi,
  • Kento Yamazaki,
  • Shintaro Kodama,
  • Akihiro Nomoto and
  • Akiya Ogawa

Beilstein J. Org. Chem. 2021, 17, 2906–2914, doi:10.3762/bjoc.17.198

Graphical Abstract
  • , and bromolactones are important synthetic intermediates for selectively, effectively, and practically introducing lactone units into organic molecules [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18]. Among brominated lactones, the α-bromolactone, in which the bromine atom is located at
  • reaction with bromine (Scheme 1a) [37][38]. While the industrial demand for α-bromolactones has grown in recent years, the above-mentioned laboratory-level synthetic methods are not suitable for scale-up because LDA, TMSCl, and enol silyl ethers are sensitive to moisture and air, as well as being expensive
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Published 09 Dec 2021

Synthetic strategies toward 1,3-oxathiolane nucleoside analogues

  • Umesh P. Aher,
  • Dhananjai Srivastava,
  • Girij P. Singh and
  • Jayashree B. S

Beilstein J. Org. Chem. 2021, 17, 2680–2715, doi:10.3762/bjoc.17.182

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Published 04 Nov 2021

Synthesis and investigation on optical and electrochemical properties of 2,4-diaryl-9-chloro-5,6,7,8-tetrahydroacridines

  • Najeh Tka,
  • Mohamed Adnene Hadj Ayed,
  • Mourad Ben Braiek,
  • Mahjoub Jabli and
  • Peter Langer

Beilstein J. Org. Chem. 2021, 17, 2450–2461, doi:10.3762/bjoc.17.162

Graphical Abstract
  • -5,6,7,8-tetrahydroacridine (4a) (Table 1, entries 1–6). Towards a better understanding of the regioselectivity of the coupling, we carried out a series of experiments with decreased amounts of phenylboronic acid. In all cases, the cross-coupling took place at both bromine atoms of 4a and we could never
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Published 20 Sep 2021

Enantioselective PCCP Brønsted acid-catalyzed aminalization of aldehydes

  • Martin Kamlar,
  • Robert Reiberger,
  • Martin Nigríni,
  • Ivana Císařová and
  • Jan Veselý

Beilstein J. Org. Chem. 2021, 17, 2433–2440, doi:10.3762/bjoc.17.160

Graphical Abstract
  • crystallization from ethyl acetate. This was demonstrated for products 3a and 3f, that were obtained in enantiomeric purities of 93% and 97% ee, respectively (Scheme 1). Next, we turned our attention to the substitution of anthranilamide (Scheme 2). First, the effect of bromine as a slightly electron-withdrawing
  • substituent on the aromatic ring was investigated. The position of bromine on the aromatic ring had a dramatic effect on the enantiomeric purity of the formed products 3k–n. When a bromine substituent is introduced in the “3” position of anthranilamide, the enantiomeric enrichment of aminal 3k reached only 30
  • % ee. In contrast, substitution with bromine either in position “4” and “5” led to a formation of products 3l and 3m with enantiomeric purities of 70% ee and 80% ee, respectively. Finally, reaction with anthranilamide substituted with bromine in position “6” led to corresponding aminal 3n with an
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Published 16 Sep 2021

A novel methodology for the efficient synthesis of 3-monohalooxindoles by acidolysis of 3-phosphate-substituted oxindoles with haloid acids

  • Li Liu,
  • Yue Li,
  • Tiao Huang,
  • Dulin Kong and
  • Mingshu Wu

Beilstein J. Org. Chem. 2021, 17, 2321–2328, doi:10.3762/bjoc.17.150

Graphical Abstract
  • order to further extend the substrate scope, we tried using hydrobromic acid (40%) as a bromine source in the reaction, and the results are summarized in Scheme 3. Generally, the phosphate substrates 2 substituted with electron-donating substituents were more reactive than those with electron
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Published 07 Sep 2021

Halides as versatile anions in asymmetric anion-binding organocatalysis

  • Lukas Schifferer,
  • Martin Stinglhamer,
  • Kirandeep Kaur and
  • Olga García Macheño

Beilstein J. Org. Chem. 2021, 17, 2270–2286, doi:10.3762/bjoc.17.145

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  • oxycarbenium ion, which enables high enantioselectivities up to 95% ee and yields up to 91%. Furthermore, an investigation of the involved halide counter-anion revealed that chloride was the most potent one in regards of both yield and enantioinduction. Bromine and iodine on the other hand, afforded the final
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Published 01 Sep 2021

Photoredox catalysis in nickel-catalyzed C–H functionalization

  • Lusina Mantry,
  • Rajaram Maayuri,
  • Vikash Kumar and
  • Parthasarathy Gandeepan

Beilstein J. Org. Chem. 2021, 17, 2209–2259, doi:10.3762/bjoc.17.143

Graphical Abstract
  • ]. Homolysis of the excited nickel(II) species 7-V results in the formation of a bromine radical, which then readily abstracts the allylic C(sp3)‒H to give the allylic radical species. Thus, the generated allylic radical species rebound to nickel complex and followed by reductive elimination delivers the
  • enantioselectivities. A wide range of aryl bromides 3 were tested with alkylbenzenes 25 under ambient reaction conditions and afforded the desired products 26 in moderate yields and good enantioselectivities. Based on their control experiments and mechanistic studies, it was postulated that a bromine radical might be
  • ]. Notably, this method proceeds through a unique mechanism (Figure 18) involving five steps: i) anion exchange between the iridium catalyst and nickel catalyst; ii) generation of a bromine radical and nickel(I) species in the photocatalytic cycle; iii) hydrogen atom abstraction events between the bromine
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Published 31 Aug 2021

Chemical syntheses and salient features of azulene-containing homo- and copolymers

  • Vijayendra S. Shetti

Beilstein J. Org. Chem. 2021, 17, 2164–2185, doi:10.3762/bjoc.17.139

Graphical Abstract
  • polymerization of azulene (1) by iodine or bromine to obtain polyazulene–iodine/bromine complexes (PAz-I2/PAz-Br2) (Scheme 1). The PAZ-I2 complex was found to be insoluble whereas PAZ-Br2 was sparingly soluble in most of the organic solvents. Although no structure was proposed for these polymer complexes, based
  • . The author hopes that this review might stimulate such research efforts in the future. Chemical structure, numbering scheme, and resonance form of azulene. Iminium zwitterionic resonance forms of poly[2(6)-aminoazulene] 31. Synthesis of polyazulene-iodine (PAz-I2) and polyazulene-bromine (PAz-Br2
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Published 24 Aug 2021

Recent advances in the syntheses of anthracene derivatives

  • Giovanni S. Baviera and
  • Paulo M. Donate

Beilstein J. Org. Chem. 2021, 17, 2028–2050, doi:10.3762/bjoc.17.131

Graphical Abstract
  • products 24. Next, the key step was introducing chlorine, bromine, or iodine substituents by halodesilylation of 24. With the halogenated products 25 in hands, the authors employed DDQ in the oxidation/aromatization step, to obtain the di- and tetrahaloanthracenes 26 in good yields (61–85%) [39]. This
  • indenoanthracene derivatives to study their optical, electrochemical, and thermal properties [46]. The authors prepared dialkynyl-substituted indenoanthracenes 61, containing alkyl or bromine substituents, from the corresponding indenoantraquinones 59 in two steps in good to excellent yields (57–92%) (Scheme 13
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Published 10 Aug 2021

2,4-Bis(arylethynyl)-9-chloro-5,6,7,8-tetrahydroacridines: synthesis and photophysical properties

  • Najeh Tka,
  • Mohamed Adnene Hadj Ayed,
  • Mourad Ben Braiek,
  • Mahjoub Jabli,
  • Noureddine Chaaben,
  • Kamel Alimi,
  • Stefan Jopp and
  • Peter Langer

Beilstein J. Org. Chem. 2021, 17, 1629–1640, doi:10.3762/bjoc.17.115

Graphical Abstract
  • anthranilic acid with 2.2 equivalents of bromine in acetic acid as previously reported [64]. Subsequently, the POCl3-mediated cyclodehydration of 1 and cyclohexanone afforded 2 through an adapted reported procedure (Scheme 1) [65]. Tetrahydroacridine 2 represents a novel synthetic building block for Pd
  • using 0.6 mol % of tetrakis(triphenylphosphine)palladium(0) and 1.2 mol % of copper iodide (Scheme 2, Table 1). The reaction proceeded chemoselectively at the two carbon–bromine bonds giving 2,4-bis(phenylethynyl)-9-chloro-5,6,7,8-tetrahydroacridine (4a). This result was not entirely predictable, as the
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Published 16 Jul 2021

A recent overview on the synthesis of 1,4,5-trisubstituted 1,2,3-triazoles

  • Pezhman Shiri,
  • Ali Mohammad Amani and
  • Thomas Mayer-Gall

Beilstein J. Org. Chem. 2021, 17, 1600–1628, doi:10.3762/bjoc.17.114

Graphical Abstract
  • irrespective of the nature and position of the substituent [39]. The supposed reaction mechanism for the reaction is shown in Scheme 3. Initially, the presence of bromine as an electron-withdrawing substituent lowers the LUMO energy to facilitate the cycloaddition process of acrolein with organic azide. The
  • that the reaction requires a strict control of the temperature in the different steps, while the nature and position of the substituents of the aryl azide do not influence the yield of the reaction. The use of aliphatic alkynes, as well as the replacement of bromine and chlorine with iodine, leads to a
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Published 13 Jul 2021
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  • [37]. Bromine (2 mL, 29.2 mmol) was added dropwise to a suspension of truxene 7 (2 g, 5.84 mmol) in CH2Cl2 (15 mL) at rt. The reaction mixture was stirred for 16 h at the same temperature and the excess of bromine was removed by bubbling N2 through the solution. Then the solid was filtered, washed
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Published 02 Jun 2021

Fritsch–Buttenberg–Wiechell rearrangement of magnesium alkylidene carbenoids leading to the formation of alkynes

  • Tsutomu Kimura,
  • Koto Sekiguchi,
  • Akane Ando and
  • Aki Imafuji

Beilstein J. Org. Chem. 2021, 17, 1352–1359, doi:10.3762/bjoc.17.94

Graphical Abstract
  • reaction of (1-fluorovinyl)magnesium chloride with isopropylmagnesium chloride competed with the FBW rearrangement to give a mixture of alkyne 4a and alkene 10 in 69% and 13% yield, respectively (Table 1, entry 4, Scheme 4a, and Scheme 2c) [20]. Both the sulfoxide/magnesium exchange reaction and bromine
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Published 28 May 2021

Icilio Guareschi and his amazing “1897 reaction”

  • Gian Cesare Tron,
  • Alberto Minassi,
  • Giovanni Sorba,
  • Mara Fausone and
  • Giovanni Appendino

Beilstein J. Org. Chem. 2021, 17, 1335–1351, doi:10.3762/bjoc.17.93

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  • the chemistry of naphthalene. The last one dates from 1887 and deals with the formation of isomers in the electrophilic aromatic substitution of naphthalene with chlorine and bromine [32]. This work was done in collaboration with Pietro Biginelli (1860–1937), the only collaborator of Guareschi who
  • bromine in the presence of other halogens [67]. The test is based on the action of sulfitic leucobases of triphenylmethane dyes, such the decolorized fuchsine (Schiff reagent), which develops a deep violet color in the presence of traces of bromine. The reaction is very sensitive and selective for bromine
  • chemist Georges Denigès (1859–1951), who, however, published his discovery of the same reaction six months after the disclosure by Guareschi. The ability of the test to distinguish between iodine and bromine is remarkable and difficult to explain in the light of the mechanism by which the Schiff reagent
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Published 25 May 2021

Structural effects of meso-halogenation on porphyrins

  • Keith J. Flanagan,
  • Maximilian Paradiz Dominguez,
  • Zoi Melissari,
  • Hans-Georg Eckhardt,
  • René M. Williams,
  • Dáire Gibbons,
  • Caroline Prior,
  • Gemma M. Locke,
  • Alina Meindl,
  • Aoife A. Ryan and
  • Mathias O. Senge

Beilstein J. Org. Chem. 2021, 17, 1149–1170, doi:10.3762/bjoc.17.88

Graphical Abstract
  • affected by both halogen type and metal insertion. In compound 1 the main motifs seen are the face-to-face stacking at 3.326(4) Å (Figure 2A) and the tilted edge-on interaction (≈64°) (Figure 2B). The other motif seen is the inline interactions where layers of porphyrins are lined up with the bromine atoms
  • porphyrin conformation are observed due to the metal center insertion. The first of these is the stacking between the porphyrin rings (at 3.581(3) Å), which now features the bromine atoms pointing in opposite directions with a ruffled conformation of the porphyrin macrocycle (Figure 3A). Moreover, a similar
  • motif of bromine atoms pointing towards the phenyl rings is visible in this structure and seems to be a staple of this series (Figure 3B). Secondly, the edge-on interaction in this structure has changed, where the pyrrole moiety is pointing towards the face of the porphyrin macrocycle as seen in Figure
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Published 14 May 2021

N-tert-Butanesulfinyl imines in the asymmetric synthesis of nitrogen-containing heterocycles

  • Joseane A. Mendes,
  • Paulo R. R. Costa,
  • Miguel Yus,
  • Francisco Foubelo and
  • Camilla D. Buarque

Beilstein J. Org. Chem. 2021, 17, 1096–1140, doi:10.3762/bjoc.17.86

Graphical Abstract
  • using DMF as solvent. After addition, a subsequent intramolecular cyclization involving the resulting amide and the vicinal carbon with bromine atoms took place. By contrary, when the reaction was carried out in THF, the elimination process was suppressed, leading exclusively to enantiomerically pure α
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Published 12 May 2021

Manganese/bipyridine-catalyzed non-directed C(sp3)–H bromination using NBS and TMSN3

  • Kumar Sneh,
  • Takeru Torigoe and
  • Yoichiro Kuninobu

Beilstein J. Org. Chem. 2021, 17, 885–890, doi:10.3762/bjoc.17.74

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  • gram scale. The introduced bromine atom can be converted into fluorine and allyl groups. Keywords: bromination; C–H transformation; hydrogen abstraction; manganese; radical; Introduction Organic halides are versatile precursors for various synthetic protocols and are frequently used to introduce a
  • high temperatures in the absence of a catalyst (Scheme 1a) [14][15][16]. However, these reactions do not exhibit any selectivity due to the indiscriminate attack of bromine radicals on the C–H bonds in the substrate, which leads to the formation of a mixture of halogenated products. Electrophilic and
  • reaction proceeded regioselectively at the methine C(sp3)–H bond of isoamyl benzoate (1b) to give 2b in 64% yield. Isoamyl benzoates bearing halogen atoms, such as fluorine, chlorine, or bromine, on the phenyl ring were also suitable substrates and gave C(sp3)–H brominated products 2c–e in 49–60% yields
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Published 22 Apr 2021

Synthesis of dibenzosuberenone-based novel polycyclic π-conjugated dihydropyridazines, pyridazines and pyrroles

  • Ramazan Koçak and
  • Arif Daştan

Beilstein J. Org. Chem. 2021, 17, 719–729, doi:10.3762/bjoc.17.61

Graphical Abstract
  • complete conversion to 4l, revealing its ease of oxidation compared to the chloro derivative 3k. In addition, dihydrotetrazines 6k and 6l could not be isolated, as probably compound 6k decomposed completely in the reaction medium and 6l decomposed following a bromine transfer to dibenzosuberenone (1
  • mechanism illustrated in Scheme 4, tetrazine 6l first tautomerizes into 7, from which dibenzosuberenone (1) receives bromine to give 5l via bromonium 8. As tetrazine 9 was unstable under the current reaction conditions, it decomposed and could not be observed [65]. In the second part of the study
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Published 15 Mar 2021

Mesoionic tetrazolium-5-aminides: Synthesis, molecular and crystal structures, UV–vis spectra, and DFT calculations

  • Vladislav A. Budevich,
  • Sergei V. Voitekhovich,
  • Alexander V. Zuraev,
  • Vadim E. Matulis,
  • Vitaly E. Matulis,
  • Alexander S. Lyakhov,
  • Ludmila S. Ivashkevich and
  • Oleg A. Ivashkevich

Beilstein J. Org. Chem. 2021, 17, 385–395, doi:10.3762/bjoc.17.34

Graphical Abstract
  • -(methylsulfonyl)-1-phenyl-1H-tetrazole with substitution of bromine and methylsulfonyl groups giving the corresponding tetrazolium salts or conjugate aminides. The obtained mesoionic tetrazoles have been characterized by elemental analysis, FTIR, NMR, and UV–vis spectroscopy, TGA/DSC analysis and for 1,3-di-tert
  • tetrazole-5-aminides were carried out as a part of studies of mesoionic compounds [22][23][24]. Earlier, we reported the facile preparation of 1,3-di-tert-butyltetrazolium-5-aminide [25], which was later used for the synthesis of the first tetrazolium halocuprate [26] and also shown to react with bromine
  • and 5-(methylsulfonyl)-1-phenyl-1H-tetrazole and substitute bromine and methylsulfonyl groups giving tetrazolium salts or conjugate aminides. The obtained mesoionic tetrazoles have been characterized by elemental analysis, FTIR, NMR and UV–vis spectroscopy, TGA/DSC analysis, and for 1,3-di-tert
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Published 08 Feb 2021

CF3-substituted carbocations: underexploited intermediates with great potential in modern synthetic chemistry

  • Anthony J. Fernandes,
  • Armen Panossian,
  • Bastien Michelet,
  • Agnès Martin-Mingot,
  • Frédéric R. Leroux and
  • Sébastien Thibaudeau

Beilstein J. Org. Chem. 2021, 17, 343–378, doi:10.3762/bjoc.17.32

Graphical Abstract
  • brominated derivatives 72-Br, the corresponding side-chain arylation reaction occurred at −60 °C, but a further hydrodehalogenation led to the bromine-free derivatives 75. For the chlorinated derivatives 72-Cl, a similar side-chain arylation−hydrodehalogenation sequence occurred, but an additional Friedel
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Published 03 Feb 2021
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