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9 article(s) from Yoshida, Jun-ichi

Stereoselective nucleophilic addition reactions to cyclic N-acyliminium ions using the indirect cation pool method: Elucidation of stereoselectivity by spectroscopic conformational analysis and DFT calculations

Koichi Mitsudo,
Junya Yamamoto,
Tomoya Akagi,
Atsuhiro Yamashita,
Masahiro Haisa,
Kazuki Yoshioka,
Hiroki Mandai,
Koji Ueoka,
Christian Hempel,
Jun-ichi Yoshida and
Seiji Suga

Letter
Published 24 May 2018

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1. Graphical Abstract
2. Scheme 1: Generation and reaction of cationic species generated by “indirect cation pool” methods.
  
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3. Figure 1: (a) ¹H NMR of N-acyliminium ion C1 in CD₂Cl₂ at −80 °C (600 MHz). (b) Preferred conformation of C1.
  
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4. Figure 2: (a) ¹H NMR spectrum of C3 in CD₂Cl₂ at −60 °C (400 MHz). (b) Preferred conformation of C3.
  
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5. Figure 3: (a) ¹H NMR spectrum of C5 in CD₂Cl₂ at −60 °C (400 MHz). (b) Preferred conformation of C5.
  
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6. Figure 4: Summary of the conformations of N-acyliminium ions C1–C6.
  
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7. Figure 5: Stevens’ hypothesis on the tendency of the addition of nucleophiles to N-acyliminium ions. The subs...
  
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8. Figure 6: A plausible mechanism of the observed diastereoselective reaction of the N-acyliminium ions.
  
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9. Figure 7: Comparison of ΔG for the pseudo-equatorial and pseudo-axial conformations of C1–C6 at the B3LYP/6-3...
  
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Beilstein J. Org. Chem. 2018, 14, 1192–1202, doi:10.3762/bjoc.14.100

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Switching the reaction pathways of electrochemically generated β-haloalkoxysulfonium ions – synthesis of halohydrins and epoxides

Akihiro Shimizu,
Ryutaro Hayashi,
Yosuke Ashikari,
Toshiki Nokami and
Jun-ichi Yoshida

Full Research Paper
Published 13 Feb 2015

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1. Graphical Abstract
2. Scheme 1: Synthesis of halohydrins and epoxides through β-haloalkoxysulfonium ions generated by the reaction ...
  
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3. Scheme 2: Proposed reaction mechanisms for the syntheses of bromohydrin 5a-Br and epoxide 6a.
  
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4. Scheme 3: Mechanistic study using ¹⁸O-DMSO.
  
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Beilstein J. Org. Chem. 2015, 11, 242–248, doi:10.3762/bjoc.11.27

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Electrochemical selenium- and iodonium-initiated cyclisation of hydroxy-functionalised 1,4-dienes

Philipp Röse,
Steffen Emge,
Jun-ichi Yoshida and
Gerhard Hilt

Full Research Paper
Published 28 Jan 2015

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1. Graphical Abstract
2. Scheme 1: Cobalt-catalysed 1,4-hydrovinylation.
  
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3. Scheme 2: Electrochemical selenoalkoxylation of 2.
  
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4. Scheme 3: Electrochemical iodoalkoxylation of 2.
  
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Beilstein J. Org. Chem. 2015, 11, 174–183, doi:10.3762/bjoc.11.18

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Redox active dendronized polystyrenes equipped with peripheral triarylamines

Toshiki Nokami,
Naoki Musya,
Tatsuya Morofuji,
Keiji Takeda,
Masahiro Takumi,
Akihiro Shimizu and
Jun-ichi Yoshida

Letter
Published 22 Dec 2014

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1. Graphical Abstract
2. Figure 1: Two synthetic approaches toward the peripherally functionalized dendronized polystyrenes (blue dott...
  
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3. Figure 2: Preparation of the dendrimer having peripheral bromo groups and their conversion to diarylamino gro...
  
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4. Figure 3: Preparation of dendronized polystyrenes having peripheral diarylamino groups.
  
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5. Figure 4: MALDI–TOF MS analysis of the dendronized polystyrene with peripheral bromo groups.
  
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6. Figure 5: Cyclic voltammograms of dendronized polystyrene 9 (black line), model compound 10 (blue line), and ...
  
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Beilstein J. Org. Chem. 2014, 10, 3097–3103, doi:10.3762/bjoc.10.326

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Flow microreactor synthesis in organo-fluorine chemistry

Hideki Amii,
Aiichiro Nagaki and
Jun-ichi Yoshida

Review
Published 05 Dec 2013

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1. Graphical Abstract
2. Scheme 1: Direct fluorination using microreactor systems.
  
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3. Scheme 2: Use of DAST in continuous-flow reactors.
  
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4. Scheme 3: Flow microreactor synthesis of fluorinated epoxides.
  
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5. Scheme 4: Highly controlled isomerization of gem-difluoroalkenes.
  
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6. Scheme 5: Flow system for catalytic aromatic fluorination.
  
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7. Scheme 6: Continuous-flow reactor for electrophilic aromatic fluorination.
  
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8. Scheme 7: Examples of [¹⁸F]-radiolabeled molecular imaging probes.
  
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9. Scheme 8: Flow microreactor synthesis of dipeptides.
  
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10. Scheme 9: Flow synthesis involving S_NAr reactions.
  
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11. Scheme 10: Flow synthesis of fluoroquinolone antibiotics.
  
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12. Scheme 11: Highly controlled formation of PFPMgBr.
  
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13. Scheme 12: Selective flow synthesis of photochromic diarylethenes.
  
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14. Scheme 13: Flow microreactor system for perfluoroalkylation by generation of perfluoroalkyllithiums in the pre...
  
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15. Scheme 14: Integrated flow microreactor system for perfluoroalkylation by generation of perfluoroalkyllithiums...
  
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Beilstein J. Org. Chem. 2013, 9, 2793–2802, doi:10.3762/bjoc.9.314

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Electrochemical generation of 2,3-oxazolidinone glycosyl triflates as an intermediate for stereoselective glycosylation

Toshiki Nokami,
Akito Shibuya,
Yoshihiro Saigusa,
Shino Manabe,
Yukishige Ito and
Jun-ichi Yoshida

Letter
Published 28 Mar 2012

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1. Graphical Abstract
2. Scheme 1: Electrochemical conversion of thioglycosides to glycosyl triflates.
  
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3. Figure 1: ¹H NMR spectrum of glycosyl triflate 2a.
  
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4. Scheme 2: Triflic acid mediated isomerization of β-glycoside.
  
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Beilstein J. Org. Chem. 2012, 8, 456–460, doi:10.3762/bjoc.8.52

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Homocoupling of aryl halides in flow: Space integration of lithiation and FeCl₃ promoted homocoupling

Aiichiro Nagaki,
Yuki Uesugi,
Yutaka Tomida and
Jun-ichi Yoshida

Full Research Paper
Published 02 Aug 2011

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1. Graphical Abstract
2. Scheme 1: Halogen–lithium exchange of p-bromoanisole followed by reaction with methanol.
  
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3. Figure 1: Flow microreactor system for halogen–lithium exchange of aryl halide followed by reaction with meth...
  
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4. Figure 2: Effects of the temperature (T) and the residence time in R1 (t^R1) on the yield of anisole in the Br...
  
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5. Scheme 2: Halogen-lithium exchange of p-bromoanisole followed by oxidative homocoupling with FeCl₃.
  
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6. Figure 3: Integrated flow microreactor system for oxidative homocoupling reaction of aryllithium with FeCl₃. ...
  
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7. Figure 4: Effects of the temperature (T) and the residence time in R2 (t^R2) on the yield of 4,4'-dimethoxybip...
  
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Beilstein J. Org. Chem. 2011, 7, 1064–1069, doi:10.3762/bjoc.7.122

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Synthesis of unsymmetrically substituted biaryls via sequential lithiation of dibromobiaryls using integrated microflow systems

Aiichiro Nagaki,
Naofumi Takabayashi,
Yutaka Tomida and
Jun-ichi Yoshida

Full Research Paper
Published 29 Apr 2009

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1. Graphical Abstract
2. Scheme 1: Sequential introduction of two electrophiles onto dibromobiaryls using Br-Li exchange reactions.
  
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3. Scheme 2: Br-Li exchange reaction of 2,2′-dibromobiphenyl (1) with n-BuLi using a conventional macrobatch rea...
  
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4. Figure 1: Microflow system for Br-Li exchange reaction of 2,2′-dibromobiphenyl (1). T-shaped micromixer: M1 (...
  
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5. Figure 2: Effect of temperature and residence time in Br-Li exchange reaction of 2,2′-dibromobiphenyl (1) usi...
  
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6. Figure 3: A microflow system for sequential introduction of two electrophiles. T-shaped micromixer: M1 (ø = 2...
  
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7. Scheme 3: Br-Li exchange reaction of 4,4′-dibromobiphenyl (17) with n-BuLi using a conventional macrobatch re...
  
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8. Figure 4: Microflow system for Br-Li exchange reaction of 4,4′-dibromobiphenyl (17). T-shaped micromixer: M1 ...
  
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9. Figure 5: Effect of temperature and residence time in Br-Li exchange reaction of 4,4′-dibromobiphenyl (17) us...
  
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Beilstein J. Org. Chem. 2009, 5, No. 16, doi:10.3762/bjoc.5.16

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Generation of pyridyl coordinated organosilicon cation pool by oxidative Si-Si bond dissociation

Toshiki Nokami,
Ryoji Soma,
Yoshimasa Yamamoto,
Toshiyuki Kamei,
Kenichiro Itami and
Jun-ichi Yoshida

Preliminary Communication
Published 08 Feb 2007

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1. Graphical Abstract
2. Scheme 1: Electrochemical generation of carbocations by oxidative C-C bond dissociation.
  
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3. Scheme 2: Electrochemical generation and accumulation of organosilicon cation by oxidative Si-Si bond dissoci...
  
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4. Figure 1: Oxidation potentials (E_d; decomposition potential) of disilanes determined by rotating disk electro...
  
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5. Figure 2: Optimized structures of radical cations of 1,2-diphenyldisilane and 1,2-bis [o-(2-pyridyl)- phenyl]...
  
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6. Scheme 3: Electrochemical generation of organosilicon cation 3d.
  
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7. Figure 3: CSI-MS of organosilicon cation 3d at 0°C.
  
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8. Figure 4: Optimized structures of organosilicon cation 3d and silyl radical 4d by DFT calculations (B3LYP/LAN...
  
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9. Scheme 4: Reaction of organosilicon cation 3d with p-tolylmagnesium bromide.
  
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Beilstein J. Org. Chem. 2007, 3, No. 7, doi:10.1186/1860-5397-3-7

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