Mechanisms for radical reactions initiating from N-hydroxyphthalimide esters

• Carlos R. Azpilcueta-Nicolas and
• Jean-Philip Lumb

Beilstein J. Org. Chem. 2024, 20, 346–378, doi:10.3762/bjoc.20.35

• , wherein the activation of complex 74 takes place through SET under constant current electrolysis [64]. The Glorius and Y. Fu groups have independently proposed the formation of analogous charge-transfer complexes involving NHPI esters, bis(pinacolato)diboron (B2pin2), and Lewis bases (pyridine or

• ] (Scheme 33A). The mechanism of this redox neutral reaction involves reductive fragmentation of the radical precursor 3 mediated by the cathode under constant-current electrolysis (Scheme 33B). The resulting alkyl radical 9 attacks the protonated quinoline 168, forming radical cation intermediate 169

Redox-active molecules as organocatalysts for selective oxidative transformations – an unperceived organocatalysis field

• Elena R. Lopat’eva,
• Igor B. Krylov,
• Dmitry A. Lapshin and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2022, 18, 1672–1695, doi:10.3762/bjoc.18.179

• benzyl iodides generated in situ. Electrolysis conditions: Constant current electrolysis until anodic potential 1.12 V vs Fc/Fc+, divided cell, reticulated vitreous carbon (RVC) anode(+). Electrochemical oxidative C–O/C–N coupling of alkylarenes with NHPI. Electrolysis conditions: Constant current

• electrolysis (2–3 F/mol) until potential rised by 0.5–0.8 V above initial potential; undivided cell, reticulated vitreous carbon (RVC) anode(+):Pt cathode(−). Chemoselective alcohol oxidation catalyzed by TEMPO. ABNO-catalyzed oxidative C–N coupling of primary alcohols with primary amines. ACT-catalyzed

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

Beilstein J. Org. Chem. 2022, 18, 1249–1255, doi:10.3762/bjoc.18.130

• the in situ generation of α-iodocarbonyl ketones from constant current electrolysis (CCE) of ketones in the presence of iodide ions. It is worth noting that we have also reported an electrochemical method for the synthesis of 2-aminothiazoles via the one-pot direct α-C–H functionalization of ketones

• results mentioned above, the optimal reaction conditions are as follows: constant current electrolysis was performed in an undivided cell equipped with a graphite plate as working electrode and counter electrode, using 0.1 mmol of NH4I as the mediator and DMSO/H2O (1 mL + 14 mL) as the solvent in the

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

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

Beilstein J. Org. Chem. 2022, 18, 1154–1158, doi:10.3762/bjoc.18.119

• cm; immersed 1.8 cm into solution). A constant current electrolysis was performed at room temperature. After application of the desired amount of charge, the electrolysis was stopped, and the solvent was removed in vacuo. The residue was purified by silica gel column chromatography (CH2Cl2). (a

Electrogenerated base-promoted cyclopropanation using alkyl 2-chloroacetates

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

Beilstein J. Org. Chem. 2022, 18, 1116–1122, doi:10.3762/bjoc.18.114

• cathodic chamber, 1 (0.5 mmol) was dissolved in 0.3 M Bu4NBr in DMF (4.0 mL) and 0.3 M Bu4NBr in DMF (4.0 mL) was introduced to the anodic chamber. Constant current electrolysis at 12 mA until 1.0 F/mol was consumed in the cathode yielded the corresponding compound 2 in a 46% yield (Table 1, entry 1

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

Beilstein J. Org. Chem. 2022, 18, 1040–1046, doi:10.3762/bjoc.18.105

• , Hokkaido 060-8628, Japan 10.3762/bjoc.18.105 Abstract Electrochemical Friedel–Crafts-type amidomethylation was successfully carried out by a novel electrochemical oxidation system using a quasi-divided cell and trialkylammonium tetrafluoroborates, such as iPr2NHEtBF4. Constant current electrolysis of

• ), electricity (Table 3, entries 2 and 4–6), and the effect of concentration of the supporting electrolyte, the best result was obtained by a constant current electrolysis of 1 in DMA containing 0.05 or 0.1 M iPr2NHEtBF4 with 4 F/mol of electricity at −10 °C to yield amidomethylation product 2 in 79% 1H NMR

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

Beilstein J. Org. Chem. 2022, 18, 350–359, doi:10.3762/bjoc.18.39

• -current electrolysis in a flow microreactor with fixed channel dimensions, the electricity can be controlled by changing the current density or flow rate. As shown in entries 1 and 2 of Table 4, the yield of 3a increased with the electricity (caused by an increase in the current density) and reached a

• reaction, the electrons themselves act as reagents, so electricity affects the degree of reaction progress. In addition, excessive electricity may also cause undesired electrochemical reactions, and it is thus extremely important to estimate the optimal electricity for the desired reaction. For constant

A review of asymmetric synthetic organic electrochemistry and electrocatalysis: concepts, applications, recent developments and future directions

• Munmun Ghosh,
• Valmik S. Shinde and
• Magnus Rueping

Beilstein J. Org. Chem. 2019, 15, 2710–2746, doi:10.3762/bjoc.15.264

• as an additional supporting electrolyte along with chiral 55c (Scheme 22) [42][57]. In 2003, Nishiguchi’s group explored the anodic oxidation of enol acetates 57 upon constant current electrolysis in an undivided cell at −78 ºC in a mixture of solvents containing (S)-tetraethylammonium

• oxidation by raising the energy of the HOMO upon enolate formation. Upon constant current electrolysis of a mixture of 85 and 86 in an undivided ElectraSyn 2.0 cell in presence of 2,6-lutidine as an external base and catalyst 87, products with tertiary carbon stereocenters as well as all-carbon quaternary

• ). Constant current electrolysis of 89 in a single compartment cell using a sacrificial Mg anode was conducted in the presence of a Ni catalyst and chiral ligand 90. After esterification and purification, 91 was isolated in a good yield and with moderate enantioselectivity [70]. In another recent report, Guo

Anodic oxidation of bisamides from diaminoalkanes by constant current electrolysis

• Tatiana Golub and
• James Y. Becker

Beilstein J. Org. Chem. 2018, 14, 861–868, doi:10.3762/bjoc.14.72

• : anodic oxidation; bisamides; constant current electrolysis; methoxylation; Introduction It is well known that the anodic oxidation of amides involving a hydrogen atom at the α-position to the N atom could undergo alkoxylation, carboxylation and hydroxylation at this position [1][2][3][4][5] (Scheme 1

• potential. Also it is not surprising that the derivative with EWG (IV) is more difficult to oxidize than that with EDG (III). All bisamides derivatives exhibit one irreversible cathodic wave (not shown, at −2.2 to −2.4 V). Constant current electrolysis (CCE) at a current density of 20 mA/cm2 was carried out

• ·4H2O in H2SO4] for amides of type I. Preparative TLC was carried out by using 20 × 20 cm of glass plates coated with silica gel 60 F254. Evaporation of solvents was performed at reduced pressure using a rotary evaporator. Constant current electrolysis Constant current electrolysis at preparative scale

Electrochemical Corey–Winter reaction. Reduction of thiocarbonates in aqueous methanol media and application to the synthesis of a naturally occurring α-pyrone

• Ernesto Emmanuel López-López,
• José Alvano Pérez-Bautista,
• Fernando Sartillo-Piscil and
• Bernardo A. Frontana-Uribe

Beilstein J. Org. Chem. 2018, 14, 547–552, doi:10.3762/bjoc.14.41

• stable under the electrolysis conditions. The reaction can be driven by both, controlled potential and constant current electrolysis with excellent results, which is convenient for application in organic chemistry laboratories. Cyclic voltammetry of thiocarbonates 4 (left) and 6 (right); c = 1 × 10−3 M

Functionalization of N-arylglycine esters: electrocatalytic access to C–C bonds mediated by n-Bu₄NI

• Mi-Hai Luo,
• Yang-Ye Jiang,
• Kun Xu,
• Yong-Guo Liu,
• Bao-Guo Sun and
• Cheng-Chu Zeng

Beilstein J. Org. Chem. 2018, 14, 499–505, doi:10.3762/bjoc.14.35

• undivided cell under constant current electrolysis. It was observed that n-Bu4NI promotes the reaction dramatically and higher yields of α-functionalized products were afforded compared with the direct electrolysis. Results and Discussion Initially, N-arylglycine ester 1a and C–H nucleophile 1,3,5

• -trimethoxybenzene (2a) were chosen as model compounds to optimize the electrolytic conditions. As shown in Table 1, when constant current electrolysis (CCE) of 1a and 2a was performed in an undivided cell equipped with 0.1 M LiClO4 in CH3CN in the presence of AcOH using two graphite plates as anode and cathode, the

Photovoltaic-driven organic electrosynthesis and efforts toward more sustainable oxidation reactions

• Bichlien H. Nguyen,
• Robert J. Perkins,
• Jake A. Smith and
• Kevin D. Moeller

Beilstein J. Org. Chem. 2015, 11, 280–287, doi:10.3762/bjoc.11.32

• the reaction, over 90% of the initial substrate can be consumed before this loss of selectivity occurs. Hence, at low current densities a constant current electrolysis reaction automatically adjusts to the potential of the substrate to be oxidized and then remains at that potential for the majority of

• [8]. With efforts to address the electrolyte problem already underway in the community, we turned our attention to the source of electricity. Since the potential at the electrodes in a constant current electrolysis automatically adjusts to match that of the substrates, in principle, any source of

• oxidation strategies, which can be used to generate new carbon–carbon bonds, functionalize amides, and capitalize on the reagent-based selectivity associated with chemical oxidants. In all cases, the use of constant current electrolysis conditions allows the potential at the anode surface to be adjusted to

Cathodic reductive coupling of methyl cinnamate on boron-doped diamond electrodes and synthesis of new neolignan-type products

• Taiki Kojima,
• Rika Obata,
• Tsuyoshi Saito,
• Yasuaki Einaga and
• Shigeru Nishiyama

Beilstein J. Org. Chem. 2015, 11, 200–203, doi:10.3762/bjoc.11.21

• unprecedented neolignan-type dimeric compounds. Results and Discussion Cathodic reduction on BDD electrode The ester methyl cinnamate (1a) was electrolyzed under constant current electrolysis (CCE) conditions in a divided cell. Solvents used for the reactions played a significant role in providing the desired

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

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

Beilstein J. Org. Chem. 2015, 11, 174–183, doi:10.3762/bjoc.11.18

• iodide were placed in the anode chamber. The reaction was performed at constant current electrolysis (10 mA) at 0 °C. It is considerable that the presence of 2,6-lutidine is crucial for a successful reaction. In the absence of 2,6-lutidine only traces of the product can be observed and oxidation of the

• 1,3-dienes with allyloxy-trimethylsilane or allyl alcohol has been elaborated. Those 1,4-dienols have been transformed into tetrahydrofuran or pyran derivatives by constant current electrolysis of suitable selenium and iodonium precursors. The reactions proceed in acceptable to good yields in regio

• fiber anode and carbon fiber cathode. Each chamber was charged with 10 mL TBABF4 solution (0.3 M in acetonitrile) and 2,6-lutidine (2.0 equiv). The anodic chamber was charged with the 1,4-diene (1.0 equiv) and sodium iodide (1.1 equiv). Constant current electrolysis (10 mA) was carried out at 0 °C until

Recent advances in the electrochemical construction of heterocycles

• Robert Francke

Beilstein J. Org. Chem. 2014, 10, 2858–2873, doi:10.3762/bjoc.10.303

• , resulting in N-tosylated pyrrolidine products (Scheme 2, X = NHTs) [35][36]. The reactions can be carried out under galvanostatic conditions (C.C.E. = constant current electrolysis) at room temperature in an undivided cell using a vitreous carbon anode. The presence of a proton scavenger is necessary in