Selective preparation of tetrasubstituted fluoroalkenes by fluorine-directed oxetane ring-opening reactions

Clément Q. Fontenelle,
Thibault Thierry,
Romain Laporte,
Emmanuel Pfund and
Thierry Lequeux

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Published 07 Aug 2020

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1. Graphical Abstract
2. Figure 1: Representative fluorinated nucleos(t)ides and acyclonucleotides.
  
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3. Figure 2: Acyclonucleotides as nucleotide surrogates.
  
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4. Figure 3: Olefination approaches and ring-opening of oxetane derivatives.
  
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5. Scheme 1: Preparation of fluoroakylidene-oxetanes and their ring-opening reactions.
  
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6. Scheme 2: Synthesis of benzyloxy-substituted fluoroethylidene-oxetane derivative 8.
  
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7. Scheme 3: Effect of the medium on the selective formation of derivative 10.
  
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8. Scheme 4: Mechanism for the formation of dihydrofuran 10.
  
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9. Scheme 5: Mechanism for the formation of unsaturated lactones 14 and 15.
  
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10. Scheme 6: Opening reaction of ethyl 2-(oxetanyl-3-idene)acetate (16).
  
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11. Scheme 7: Functionalization of bromomethyllactone 15 and its analogues.
  
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12. Scheme 8: Functionalization by substitution reaction of the bromide E-1d vs ring-opening reaction of the oxet...
  
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13. Scheme 9: Preparation of tetrasubstituted fluoroalkenes.
  
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Beilstein J. Org. Chem. 2020, 16, 1936–1946, doi:10.3762/bjoc.16.160

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Synergy between supported ionic liquid-like phases and immobilized palladium N-heterocyclic carbene–phosphine complexes for the Negishi reaction under flow conditions

Edgar Peris,
Raúl Porcar,
María Macia,
Jesús Alcázar,
Eduardo García-Verdugo and
Santiago V. Luis

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Published 06 Aug 2020

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1. Graphical Abstract
2. Scheme 1: Synthesis of NHC-supported catalysts.
  
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3. Scheme 2: Negishi benchmark reaction.
  
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4. Figure 1: Negishi reaction catalyzed by immobilized NHC–Pd complexes. Conditions: methyl 4-bromobenzoate (0.2...
  
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5. Scheme 3: Synthesis of immobilized NHC–Pd–RuPhos.
  
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6. Figure 2: Negishi model reaction between 5 and 6 under flow conditions catalyzed by 4b. V = 0.535 mL, 363 mg ...
  
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7. Figure 3: Negishi model reaction under flow conditions catalyzed by 8a. V = 2.9 mL, 1.25 g of catalyst, resid...
  
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8. Figure 4: Negishi reaction between 5 and 6 catalyzed by 8a in the presence of SILLPs. a) Yield (%) vs time fo...
  
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9. Figure 5: TEM images of the polymers after the Negishi reaction between 5 and 6. a) 8a, bar scale 20 nm, PdNP...
  
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10. Scheme 4: Pd species immobilized onto SILLPs. i) 1 g SILLP 10, 100 mg PdCl₂ in milli-Q^® water (100 mL 1% HCl,...
  
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11. Figure 6: Negishi reaction between 5 and 6 catalyzed by 11. 1 equiv methyl 4-bromobenzoate (6, 0.25 mmol), 2 ...
  
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12. Figure 7: Negishi reaction between 5 and 6 under flow conditions catalyzed by 8a in the presence of a scaveng...
  
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13. Figure 8: Effect of the structure of the SILLP scavenger for the Negishi reaction between 5 and 6 under flow ...
  
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14. Figure 9: TEM images of the polymer after the Negishi reaction between 5 and 6 under flow conditions. a) 8a + ...
  
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Beilstein J. Org. Chem. 2020, 16, 1924–1935, doi:10.3762/bjoc.16.159

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Regiodivergent synthesis of functionalized pyrimidines and imidazoles through phenacyl azides in deep eutectic solvents

Paola Vitale,
Luciana Cicco,
Ilaria Cellamare,
Filippo M. Perna,
Antonio Salomone and
Vito Capriati

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Published 05 Aug 2020

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1. Graphical Abstract
2. Scheme 1: One-pot synthesis of 2,5-diarylpyrazines (A) (path a) or 2-aroyl-(4 or 5)-aryl-(1H)-imidazoles (B) ...
  
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3. Scheme 2: Transformation of phenacyl bromide (1a) in ChCl/Gly into phenacyl azide (2a) and 2-benzoyl-(4 or 5)...
  
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4. Scheme 3: Synthesis of 2-aroyl-(4 or 5)-aryl-(1H)-imidazoles 3. Scope of the reaction. Typical conditions: 1 ...
  
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5. Scheme 4: Proposed mechanism for the formation of 2-aroyl-(4 or 5)-aryl-(1H)-imidazoles 3/3' from α-phenacyl ...
  
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6. Scheme 5: Proposed mechanism for the formation of 2-benzoyl-(4 or 5)-phenyl-(1H)-imidazoles 3a/3a' and 2,4-di...
  
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7. Scheme 6: Scope of the synthesis of 2,4-diaroyl-6-arylpyrimidines 7. Typical conditions: 2 (0.3 mmol), Et₃N (...
  
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Beilstein J. Org. Chem. 2020, 16, 1915–1923, doi:10.3762/bjoc.16.158

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Design, synthesis and application of carbazole macrocycles in anion sensors

Alo Rüütel,
Ville Yrjänä,
Sandip A. Kadam,
Indrek Saar,
Mihkel Ilisson,
Astrid Darnell,
Kristjan Haav,
Tõiv Haljasorg,
Lauri Toom,
Johan Bobacka and
Ivo Leito

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Published 04 Aug 2020

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1. Graphical Abstract
2. Figure 1: The biscarbazolylurea moiety.
  
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3. Figure 2: The structure of the solid-contact ion-selective electrode (sensor): a) glassy carbon as the electr...
  
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4. Figure 3: Studied receptor molecules.
  
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5. Figure 4: MC001 and MC003 lowest energy conformers (COSMO-RS) showing intramolecular bonds. Color coding: whi...
  
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6. Figure 5: a) Complex of MC008 with acetate; b) complex of MC006 with formate; c) complex of MC007 with lactat...
  
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7. Scheme 1: The synthetic pathway to receptors CZ016 and MC001–MC014. The reaction yield for 2–3a/3b is given a...
  
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8. Figure 6: Binding affinities of the studied receptors towards different carboxylates in DMSO-d₆/H₂O (99.5%:0....
  
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9. Figure 7: Impedance spectra of sensors with each of the membranes. The spectra were recorded in 0.1 M sodium ...
  
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10. Figure 8: Calibration curves for each of the membranes. The calibrations were performed by diluting 0.1 M sod...
  
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11. Figure 9: The influence of solution pH on the potential responses of the sensor prototypes (three sensors for...
  
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12. Figure 10: Potentiometric selectivity coefficients of interfering anions (relative to acetate) determined usin...
  
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Beilstein J. Org. Chem. 2020, 16, 1901–1914, doi:10.3762/bjoc.16.157

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Natural dolomitic limestone-catalyzed synthesis of benzimidazoles, dihydropyrimidinones, and highly substituted pyridines under ultrasound irradiation

Kumar Godugu,
Venkata Divya Sri Yadala,
Mohammad Khaja Mohinuddin Pinjari,
Trivikram Reddy Gundala,
Lakshmi Reddy Sanapareddy and
Chinna Gangi Reddy Nallagondu

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Published 03 Aug 2020

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1. Graphical Abstract
2. Figure 1: The benzimidazoles I–IV, dihydropyrimidinones/-thiones V–VIII, and 2-amino-4-aryl-3,5-dicarbonitril...
  
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3. Scheme 1: NDL-catalyzed synthesis of i) 1,2-disubstituted benzimidazoles 3, ii) dihydropyrimidinones/-thiones ...
  
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4. Figure 2: XRD pattern of the NDL catalyst.
  
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5. Figure 3: FTIR spectrum of the NDL catalyst.
  
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6. Figure 4: Raman spectrum of the NDL catalyst.
  
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7. Figure 5: SEM images of the NDL catalyst.
  
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8. Figure 6: EDAX analysis of the NDL catalyst.
  
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9. Scheme 2: Unexpected formation of the bisimine I, 3h, from o-phenylenediamine (1) and salicylaldehyde (2h).
  
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10. Figure 7: ¹H NMR spectrum of 2,2'-((1E,1'E)-(1,2-phenylenebis(azanylylidene))bis (methanylylidene))diphenol (...
  
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11. Figure 8: XRD pattern of a) the fresh NDL catalyst; b) the recovered NDL catalyst after the 7th cycle of the ...
  
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Beilstein J. Org. Chem. 2020, 16, 1881–1900, doi:10.3762/bjoc.16.156

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Stereoselective Biginelli-like reaction catalyzed by a chiral phosphoric acid bearing two hydroxy groups

Xiaoyun Hu,
Jianxin Guo,
Cui Wang,
Rui Zhang and
Victor Borovkov

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Published 31 Jul 2020

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1. Graphical Abstract
2. Scheme 1: Synthesis of chiral phosphoric acid 3.
  
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3. Scheme 2: Synthesis of methylated chiral phosphoric acid 7.
  
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4. Scheme 3: Control experiment with catalyst 7.
  
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5. Figure 1: A plausible chiral transition-state structure in the Biginelli-like reaction catalyzed by phosphori...
  
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Beilstein J. Org. Chem. 2020, 16, 1875–1880, doi:10.3762/bjoc.16.155

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Three new O-isocrotonyl-3-hydroxybutyric acid congeners produced by a sea anemone-derived marine bacterium of the genus Vibrio

Dandan Li,
Enjuro Harunari,
Tao Zhou,
Naoya Oku and
Yasuhiro Igarashi

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Published 29 Jul 2020

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1. Graphical Abstract
2. Figure 1: Structures of the compounds 1–5.
  
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3. Figure 2: COSY (bold lines) and selected HMBC correlations (arrows) for 1–4.
  
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4. Figure 3: a) Distribution of positive (red) and negative (blue) Δδ₍_S₋_R₎ values (in ppm) calculated from the ...
  
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Beilstein J. Org. Chem. 2020, 16, 1869–1874, doi:10.3762/bjoc.16.154

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On the hydrolysis of diethyl 2-(perfluorophenyl)malonate

Ilya V. Taydakov and
Mikhail A. Kiskin

Letter
Published 28 Jul 2020

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1. Graphical Abstract
2. Figure 1: Phenylmalonic acids.
  
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3. Scheme 1: Synthesis of diethyl 2-phenylmalonate (4).
  
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4. Scheme 2: Synthesis of diethyl 2-(perfluorophenyl)malonate (3).
  
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5. Figure 2: Esters of fluorine-substituted 2-phenylmalonic acids.
  
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6. Scheme 3: Hydrolysis of diethyl 2-(perfluorophenyl)malonate (3).
  
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7. Figure 3: Molecular structure of 2-(perfluorophenyl)acetic acid (12).
  
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8. Scheme 4: Formation of 2-(perfluorophenyl)acetic acid (12).
  
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Beilstein J. Org. Chem. 2020, 16, 1863–1868, doi:10.3762/bjoc.16.153

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Synthesis, docking study and biological evaluation of ᴅ-fructofuranosyl and ᴅ-tagatofuranosyl sulfones as potential inhibitors of the mycobacterial galactan synthesis targeting the galactofuranosyltransferase GlfT2

Marek Baráth,
Jana Jakubčinová,
Zuzana Konyariková,
Stanislav Kozmon,
Katarína Mikušová and
Maroš Bella

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Published 27 Jul 2020

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1. Graphical Abstract
2. Figure 1: Target ᴅ-fructofuranosyl and ᴅ-tagatofuranosyl sulfones 1‒3.
  
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3. Figure 2: Molecular representation of the best binding poses of the four compounds with the predicted highest...
  
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4. Scheme 1: Reagents and conditions: a) 1. (BnO)₂P-NMe₂, 1H-tetrazole, 0 °C→rt, 1 h, 2. m-CPBA, 0 °C→rt, 1.5‒2 ...
  
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5. Scheme 2: Reagents and conditions: a) PivCl, pyridine, CH₂Cl₂, rt, overnight; b) BnBr, NaOH, TBAB, THF, reflu...
  
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6. Scheme 3: Reagents and conditions: a) EtSH, BF₃∙OEt₂, CH₂Cl₂, 0 °C, 2 h; b) 1. (BnO)₂P-NMe₂, 1H-tetrazole, 0 ...
  
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7. Scheme 4: Reagents and conditions: a) PhSH, or iPrSH, BF₃·OEt₂, CH₂Cl₂, −5 °C, 1 h; b) BF₃·OEt₂, Ac₂O, 0 °C, ...
  
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8. Scheme 5: Reagents and conditions: a) 1. (BnO)₂P-NMe₂, 1H-tetrazole, 0 °C→rt, 1 h, 2. m-CPBA, 0 °C→rt, 1.5‒2 ...
  
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9. Figure 3: TLC analysis of the effects of the target compounds at 500 μM on the production of lower lipid-link...
  
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10. Figure 4: TLC analysis of the dose effects of the compounds 1bα and 3a on production of lower lipid-linked ga...
  
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Beilstein J. Org. Chem. 2020, 16, 1853–1862, doi:10.3762/bjoc.16.152

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Polarity effects in 4-fluoro- and 4-(trifluoromethyl)prolines

Vladimir Kubyshkin

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Published 23 Jul 2020

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1. Graphical Abstract
2. Figure 1: A) Three types of the backbone amino acid structures that are included in protein translation: glyc...
  
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3. Figure 2: The set of amino acids examined in this study.
  
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4. Figure 3: Design of the model system.
  
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5. Figure 4: Propagation of the C⁴-conformation into the values of the J coupling in the C²H–C³H₂ fragments.
  
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6. Figure 5: Preferred side-chain conformations according to the multiplicity data.
  
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7. Figure 6: A) The basicity reduction from the introduction of the dipoles reflects the preferred conformation ...
  
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8. Figure 7: The lipophilicity data of the model compounds.
  
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9. Figure 8: The expectations regarding the amide-bond rotation preferences in 1–4.
  
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10. Figure 9: The explanation for the difference in the rotation barriers in the diastereomeric (A), 4-(trifluoro...
  
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11. Figure 10: A) The structures of difluorinated model compounds 5 and 6, and the fluorine-free reference 7. B) B...
  
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Beilstein J. Org. Chem. 2020, 16, 1837–1852, doi:10.3762/bjoc.16.151

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