Molecular and macromolecular electrochemistry: synthesis, mechanism, and redox properties

Shinsuke Inagi and
Mahito Atobe

Editorial
Published 26 Oct 2022

Beilstein J. Org. Chem. 2022, 18, 1505–1506, doi:10.3762/bjoc.18.158

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Synthesis of piperidine and pyrrolidine derivatives by electroreductive cyclization of imine with terminal dihaloalkanes in a flow microreactor

Yuki Naito,
Naoki Shida and
Mahito Atobe

Full Research Paper
Published 29 Mar 2022

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1. Graphical Abstract
2. Figure 1: Piperidine and pyrrolidine rings in biologically active compounds.
  
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3. Scheme 1: Conventional synthetic routes for piperidine derivatives.
  
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4. Scheme 2: Synthesis of 1,2-diphenylpiperidine (3a) by the electroreductive cyclization mechanism.
  
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5. Figure 2: Schematic diagram of the electroreductive cyclization for the synthesis of 1,2-diphenylpiperidine (...
  
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6. Figure 3: Yield of 3a for each fraction sample in the continuous flow reductive cyclization.
  
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Beilstein J. Org. Chem. 2022, 18, 350–359, doi:10.3762/bjoc.18.39

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Cathodic generation of reactive (phenylthio)difluoromethyl species and its reactions: mechanistic aspects and synthetic applications

Sadanobu Iwase,
Shinsuke Inagi and
Toshio Fuchigami

Full Research Paper
Published 20 Jul 2022

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1. Graphical Abstract
2. Scheme 1: Electrochemical gem-difluorination of sulfides bearing α-electron-withdrawing groups.
  
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3. Scheme 2: Electrochemical gem-difluorodesulfurization of dithioacetals.
  
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4. Scheme 3: Electrochemical gem-difluorodesulfurization of dithiocarbonate.
  
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5. Scheme 4: Cathodic reduction of 1.
  
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6. Figure 1: Cyclic voltammograms of (a) PhSCF₂Br (1, 8 mM) in 0.1 M n-Bu₄NClO₄/MeCN; (b) o-phthalonitrile (4 mM...
  
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7. Scheme 5: Indirect cathodic reduction of 1 using o-phthalonitrile as mediator.
  
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8. Scheme 6: Mechanism for the formation of product 3.
  
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9. Scheme 7: Reaction of compound 1 with PhS anions.
  
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10. Scheme 8: Cathodic reduction of compound 1 in the presence of α-methylstyrene at a high current density.
  
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11. Scheme 9: Indirect cathodic reduction of compound 1 in CD₃CN.
  
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12. Scheme 10: Indirect cathodic reduction of compound 1 in the presence of 1,1-diphenylethylene.
  
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13. Scheme 11: Reaction mechanism.
  
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Beilstein J. Org. Chem. 2022, 18, 872–880, doi:10.3762/bjoc.18.88

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Electroreductive coupling of 2-acylbenzoates with α,β-unsaturated carbonyl compounds: density functional theory study on product selectivity

Naoki Kise and
Toshihiko Sakurai

Full Research Paper
Published 02 Aug 2022

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1. Graphical Abstract
2. Scheme 1: Electroreductive coupling of phthalic anhydrides with α,β-unsaturated carbonyl compounds and subseq...
  
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3. Scheme 2: Electroreductive coupling of phthalimides with α,β-unsaturated carbonyl compounds and subsequent tr...
  
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4. Scheme 3: Electroreductive coupling of 2-acylbenzoates with α,β-unsaturated carbonyl compounds and subsequent...
  
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5. Scheme 4: Electroreductive coupling of 1a with 2a and subsequent transformation to 2-cyanonaphthalene-1-ol (3a...
  
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6. Scheme 5: Presumed reaction mechanism of electroreductive coupling of 1 with 2a and subsequent transformation...
  
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7. Scheme 6: Electroreductive coupling of 1a with 2c and subsequent treatment with 1 M HCl.
  
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Beilstein J. Org. Chem. 2022, 18, 956–962, doi:10.3762/bjoc.18.95

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Electrochemical and spectroscopic properties of twisted dibenzo[g,p]chrysene derivatives

Tomoya Imai,
Ryuhei Akasaka,
Naruhiro Yoshida,
Toru Amaya and
Tetsuo Iwasawa

Full Research Paper
Published 03 Aug 2022

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1. Graphical Abstract
2. Figure 1: a) DBC. b) Dependence of E_ox1 on the position of the MeO groups [43]. c) Previous work [52]. d) This work.
  
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3. Figure 2: CVs and SWVs of DBC derivatives in CH₂Cl₂ (≈1.0 × 10⁻³ M, see Supporting Information File 1 for details) including 5.0 × 10⁻² M ...
  
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4. Figure 3: DFT-optimized structures, orbital drawings of HOMO, schematic drawings of orbital interaction, and ...
  
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5. Figure 4: Absorption (solid line) and photoluminescence (dotted red line) spectra (upper graphs) in CH₂Cl₂ an...
  
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Beilstein J. Org. Chem. 2022, 18, 963–971, doi:10.3762/bjoc.18.96

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First example of organocatalysis by cathodic N-heterocyclic carbene generation and accumulation using a divided electrochemical flow cell

Daniele Rocco,
Ana A. Folgueiras-Amador,
Richard C. D. Brown and
Marta Feroci

Full Research Paper
Published 05 Aug 2022

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1. Graphical Abstract
2. Scheme 1: Electrochemical generation of NHC.
  
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3. Scheme 2: Transformation of electrochemically generated NHC into the corresponding thione by its reaction wit...
  
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4. Scheme 3: Umpolung of the aldehyde carbonyl carbon atom. Formation of the Breslow intermediate using NHCs.
  
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5. Figure 1: Schematic representation of a plane-parallel plate flow electrochemical reactor.
  
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6. Figure 2: C/PVDF anode before (A) and after (B) the first experiment (Table 1, entry 1).
  
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7. Scheme 4: Electrogenerated NHC-catalyzed self-annulation of cinnamaldehyde.
  
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8. Scheme 5: Byproduct obtained from the reaction between methanol and the Breslow intermediate.
  
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9. Figure 3: Expanded view of the electrochemical cell components: (a) Aluminium end plates; (b) insulating PTFE...
  
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Beilstein J. Org. Chem. 2022, 18, 979–990, doi:10.3762/bjoc.18.98

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Electrochemical vicinal oxyazidation of α-arylvinyl acetates

Yi-Lun Li,
Zhaojiang Shi,
Tao Shen and
Ke-Yin Ye

Letter
Published 12 Aug 2022

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1. Graphical Abstract
2. Scheme 1: From vinyl acetates to α-azidoketones.
  
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3. Scheme 2: Substrate scope. Reaction conditions: α-arylvinyl acetate (0.5 mmol), TMSN₃ (1.0 mmol), n-Bu₄NPF₆ (...
  
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4. Scheme 3: Derivatization of α-azidoketone 2.
  
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5. Scheme 4: Proposed mechanism.
  
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Beilstein J. Org. Chem. 2022, 18, 1026–1031, doi:10.3762/bjoc.18.103

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Electrochemical Friedel–Crafts-type amidomethylation of arenes by a novel electrochemical oxidation system using a quasi-divided cell and trialkylammonium tetrafluoroborate

Hisanori Senboku,
Mizuki Hayama and
Hidetoshi Matsuno

Letter
Published 18 Aug 2022

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1. Graphical Abstract
2. Scheme 1: Generation of N-acyliminium ion: previous and present works.
  
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3. Scheme 2: Electrochemical amidomethylation of indoles 4 in DMA.
  
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4. Scheme 3: Electrochemical amidomethylation of 3-methyl-1H-indole (7) in DMA.
  
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5. Scheme 4: Electrochemical amidomethylation of N-methyl-1H-indole (4a) in DMF.
  
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6. Scheme 5: Probable reaction pathway of the electrochemical amidomethylation.
  
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Beilstein J. Org. Chem. 2022, 18, 1040–1046, doi:10.3762/bjoc.18.105

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Synthesis, optical and electrochemical properties of (D–π)₂-type and (D–π)₂Ph-type fluorescent dyes

Kosuke Takemura,
Kazuki Ohira,
Taiki Higashino,
Keiichi Imato and
Yousuke Ooyama

Full Research Paper
Published 18 Aug 2022

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1. Graphical Abstract
2. Scheme 1: Synthesis of OTK-2 and OTT-2.
  
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3. Figure 1: (a) Photoabsorption and (b) fluorescence (λ_ex = λ_max,abs) spectra of OTK-2 [33] and OTT-2 in toluene. (...
  
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4. Figure 2: Cyclic voltammograms of OTK-2 and OTT-2 (0.1 mM) in DMF containing 0.1 M Bu₄NClO₄ at a scan rate of...
  
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5. Figure 3: (a) HOMO and (b) LUMO of OTK-2 [33] and OTT-2 derived from MO calculations (PM5, INDO/S method). The re...
  
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Beilstein J. Org. Chem. 2022, 18, 1047–1054, doi:10.3762/bjoc.18.106

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Electrochemical hydrogenation of enones using a proton-exchange membrane reactor: selectivity and utility

Koichi Mitsudo,
Haruka Inoue,
Yuta Niki,
Eisuke Sato and
Seiji Suga

Full Research Paper
Published 19 Aug 2022

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1. Graphical Abstract
2. Scheme 1: Designed electrochemical hydrogenation of enones 1 with a PEM reactor.
  
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3. Figure 1: Electrochemical setup of the PEM reactor: a) Electrochemical reduction system with the PEM reactor....
  
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4. Figure 2: Reaction profile of the electrochemical hydrogenation of 1a with a PEM reactor using a) Pd/C and b)...
  
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5. Scheme 2: Electrochemical hydrogenation of several enones 1 with a circulating PEM reactor using a Pd/C catho...
  
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6. Scheme 3: Electrochemical hydrogenation of several enones 1 with a circulating PEM reactor using an Ir/C cath...
  
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7. Scheme 4: Mechanistic studies.
  
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8. Scheme 5: Electroreduction of 1a with the circulating PEM reactor using H₂O as a proton source.
  
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Beilstein J. Org. Chem. 2022, 18, 1055–1061, doi:10.3762/bjoc.18.107

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Electrochemical formal homocoupling of sec-alcohols

Kosuke Yamamoto,
Kazuhisa Arita,
Masashi Shiota,
Masami Kuriyama and
Osamu Onomura

Letter
Published 22 Aug 2022

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1. Graphical Abstract
2. Scheme 1: Strategies for the synthesis of vic-1,2-diols.
  
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3. Scheme 2: Substrate scope. Reaction conditions: 1 (1.0 mmol), Et₄NBr (0.1 equiv), imidazole (0.05 equiv), MeC...
  
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4. Scheme 3: Investigation of cross-coupling reaction.
  
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5. Scheme 4: Large-scale experiment.
  
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6. Scheme 5: Control experiments. ^aDetermined by ¹H NMR using 1,3,5-trimethoxybenzene as an internal standard. ^b...
  
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7. Scheme 6: Proposed mechanism.
  
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Beilstein J. Org. Chem. 2022, 18, 1062–1069, doi:10.3762/bjoc.18.108

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Radical cation Diels–Alder reactions of arylidene cycloalkanes

Kaii Nakayama,
Hidehiro Kamiya and
Yohei Okada

Letter
Published 25 Aug 2022

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1. Graphical Abstract
2. Figure 1: Plausible mechanism of the radical cation Diels–Alder reaction (EDG: electron-donating group).
  
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3. Figure 2: Landscape of the radical cation Diels–Alder reaction.
  
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4. Scheme 1: Radical cation Diels–Alder reaction of β-methylstyrene.
  
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5. Scheme 2: Radical cation Diels–Alder reaction of β-methylanethole (1). Recovered starting material is reporte...
  
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6. Figure 3: Formal expression of radical cations.
  
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7. Scheme 3: Radical cation Diels–Alder reactions of the arylidene cycloalkanes (4–7). Recovered starting materi...
  
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8. Scheme 4: Scope of the radical cation Diels–Alder reaction of arylidene cycloalkanes (recovered starting mate...
  
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Beilstein J. Org. Chem. 2022, 18, 1100–1106, doi:10.3762/bjoc.18.112

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Electrogenerated base-promoted cyclopropanation using alkyl 2-chloroacetates

Kouichi Matsumoto,
Yuta Hayashi,
Kengo Hamasaki,
Mizuki Matsuse,
Hiyono Suzuki,
Keiji Nishiwaki and
Norihito Kawashita

Letter
Published 29 Aug 2022

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1. Graphical Abstract
2. Scheme 1: Formations of 1,2,3-trialkyl cyclopropanetricarboxylates. Previous reports (reactions 1–3) and this...
  
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3. Scheme 2: Plausible reaction mechanism. EGB = electrogenerated base.
  
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Beilstein J. Org. Chem. 2022, 18, 1116–1122, doi:10.3762/bjoc.18.114

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Synthesis of protected precursors of chitin oligosaccharides by electrochemical polyglycosylation of thioglycosides

Md Azadur Rahman,
Kana Kuroda,
Hirofumi Endo,
Norihiko Sasaki,
Tomoaki Hamada,
Hiraku Sakai and
Toshiki Nokami

Full Research Paper
Published 30 Aug 2022

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1. Graphical Abstract
2. Figure 1: Structures of chitin and chitosan oligosaccharides.
  
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3. Figure 2: Effect of the anomeric leaving group on the yield of oligosaccharides.
  
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4. Figure 3: Influence of the glycosylation temperature (T2) on the yield of oligosaccharides.
  
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5. Figure 4: Influence of temperatures of anodic oxidation (T1) and glycosylation (T2).
  
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6. Figure 5: MALDI–TOF MS spectra of oligosaccharides.
  
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7. Figure 6: Proposed structures of byproducts of electrochemical polyglycosylation.
  
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8. Figure 7: Proposed mechanisms of electrochemical polyglycosylation.
  
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9. Figure 8: Oxidative potential of monosaccharide 1a, disaccharide 2a, and trisaccharide 3a.
  
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10. Scheme 1: Electrochemical dimerization of tetrasaccharide 4a.
  
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11. Figure 9: Influence of cycle number on the yield of longer oligosaccharides 5a (n = 5)–8a (n = 8). Conditions...
  
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Beilstein J. Org. Chem. 2022, 18, 1133–1139, doi:10.3762/bjoc.18.117

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Electro-conversion of cumene into acetophenone using boron-doped diamond electrodes

Mana Kitano,
Tsuyoshi Saitoh,
Shigeru Nishiyama,
Yasuaki Einaga and
Takashi Yamamoto

Letter
Published 07 Sep 2022

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1. Graphical Abstract
2. Figure 1: (a) Cyclic voltammograms of a BDD electrode in MeCN solution containing cumene (1; 5 mM) and Et₄NClO...
  
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3. Figure 2: Proposed reaction mechanism of electro-conversion of cumene (1) into acetophenone (3).
  
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Beilstein J. Org. Chem. 2022, 18, 1154–1158, doi:10.3762/bjoc.18.119

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Reductive opening of a cyclopropane ring in the Ni(II) coordination environment: a route to functionalized dehydroalanine and cysteine derivatives

Oleg A. Levitskiy,
Olga I. Aglamazova,
Yuri K. Grishin and
Tatiana V. Magdesieva

Full Research Paper
Published 08 Sep 2022

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1. Graphical Abstract
2. Figure 1: Cyclic voltammograms obtained for complexes 1 (black), 2 (blue), 3 (green), 4 (red) (MeCN, 0.05 M Bu...
  
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3. Scheme 1: Synthesis of complex 4.
  
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4. Figure 2: Key correlations in the NOESY spectrum of complex (S)-4 and the corresponding characteristic fragme...
  
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5. Scheme 2: Reductive three-membered ring-opening and follow-up chemical steps.
  
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6. Figure 3: Correlations in the HMBC spectra of 6a and 6b and spin coupling constants in the ¹H NMR spectrum of ...
  
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7. Scheme 3: Electrochemically induced ring-opening followed by intramolecular cyclization.
  
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8. Scheme 4: One-pot multistep approach to the cysteine derivatives.
  
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9. Figure 4: Characteristic correlations in the NOESY spectra of diastereomeric complexes 10 and the correspondi...
  
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Beilstein J. Org. Chem. 2022, 18, 1166–1176, doi:10.3762/bjoc.18.121

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A one-pot electrochemical synthesis of 2-aminothiazoles from active methylene ketones and thioureas mediated by NH₄I

Shang-Feng Yang,
Pei Li,
Zi-Lin Fang,
Sen Liang,
Hong-Yu Tian,
Bao-Guo Sun,
Kun Xu and
Cheng-Chu Zeng

Full Research Paper
Published 15 Sep 2022

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1. Graphical Abstract
2. Scheme 1: Methods for the synthesis of thiazoles using active methylene ketones as starting materials.
  
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3. Scheme 2: Substrate scope. Reaction conditions: 1 (2 mmol), 2 (1 mmol), NH₄I (0.1 mmol), ᴅʟ-alanine (1 mmol),...
  
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4. Scheme 3: Up-scaling experiment.
  
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5. Scheme 4: Control experiments.
  
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6. Scheme 5: The proposed mechanism for the one-pot electrochemical synthesis of 2-aminothiazoles mediated by NH₄...
  
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Beilstein J. Org. Chem. 2022, 18, 1249–1255, doi:10.3762/bjoc.18.130

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Microelectrode arrays, electrosynthesis, and the optimization of signaling on an inert, stable surface

Kendra Drayton-White,
Siyue Liu,
Yu-Chia Chang,
Sakashi Uppal and
Kevin D. Moeller

Full Research Paper
Published 20 Oct 2022

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1. Graphical Abstract
2. Figure 1: Natural products YM-254890 and FR-900359.
  
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3. Figure 2: Diblock copolymers used for coating microelectrode arrays.
  
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4. Figure 3: An indirect method for detecting binding events.
  
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5. Scheme 1: A Cu(I)-catalyzed cross-coupling reaction on an array.
  
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6. Figure 4: A model study using an RGD peptide (C-PEG6-GGRGDGP) and integrin receptor (α5,β1).
  
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7. Figure 5: A failure in connection with the monitoring of binding events between a peptide and its G-protein t...
  
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8. Scheme 2: An array-based Chan–Lam coupling reaction.
  
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9. Figure 6: Potential for an immediate, rapid change in current. a) The binding event being monitored has alrea...
  
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10. Figure 7: Four cycles vs. twelve cycles and the effect on binding curve location.
  
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11. Figure 8: Repeating the experiment on different arrays. (a) A comparison between a 4-cycle placement reaction...
  
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12. Figure 9: Quantitative fluorescent study on variance of the polymer coating across the microelectrode surface...
  
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13. Scheme 3: A new method for decreasing the concentration of R6A on the surface of the electrodes.
  
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14. Figure 10: An initial study and the comparison of an R6A surface and a 1:1 R6A/cysteine methyl ester surface.
  
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15. Figure 11: Calibrating the array-based signaling experiment for monitoring small molecule G-protein interactio...
  
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Beilstein J. Org. Chem. 2022, 18, 1488–1498, doi:10.3762/bjoc.18.156

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Molecular and macromolecular electrochemistry: synthesis, mechanism, and redox properties

Molecular and macromolecular electrochemistry: synthesis, mechanism, and redox properties

Synthesis of piperidine and pyrrolidine derivatives by electroreductive cyclization of imine with terminal dihaloalkanes in a flow microreactor

Cathodic generation of reactive (phenylthio)difluoromethyl species and its reactions: mechanistic aspects and synthetic applications

Electroreductive coupling of 2-acylbenzoates with α,β-unsaturated carbonyl compounds: density functional theory study on product selectivity

Electrochemical and spectroscopic properties of twisted dibenzo[g,p]chrysene derivatives

First example of organocatalysis by cathodic N-heterocyclic carbene generation and accumulation using a divided electrochemical flow cell

Electrochemical vicinal oxyazidation of α-arylvinyl acetates

Electrochemical Friedel–Crafts-type amidomethylation of arenes by a novel electrochemical oxidation system using a quasi-divided cell and trialkylammonium tetrafluoroborate

Synthesis, optical and electrochemical properties of (D–π)₂-type and (D–π)₂Ph-type fluorescent dyes

Electrochemical hydrogenation of enones using a proton-exchange membrane reactor: selectivity and utility

Electrochemical formal homocoupling of sec-alcohols

Radical cation Diels–Alder reactions of arylidene cycloalkanes

Electrogenerated base-promoted cyclopropanation using alkyl 2-chloroacetates

Synthesis of protected precursors of chitin oligosaccharides by electrochemical polyglycosylation of thioglycosides

Electro-conversion of cumene into acetophenone using boron-doped diamond electrodes

Reductive opening of a cyclopropane ring in the Ni(II) coordination environment: a route to functionalized dehydroalanine and cysteine derivatives

A one-pot electrochemical synthesis of 2-aminothiazoles from active methylene ketones and thioureas mediated by NH₄I

Microelectrode arrays, electrosynthesis, and the optimization of signaling on an inert, stable surface

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