Additive-controlled chemoselective inter-/intramolecular hydroamination via electrochemical PCET process

• Kazuhiro Okamoto,
• Naoki Shida and
• Mahito Atobe

Beilstein J. Org. Chem. 2024, 20, 264–271, doi:10.3762/bjoc.20.27

• 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) as an additive. These results provide fundamental insights for the design of PCET-based redox reaction systems under electrochemical conditions. Keywords: amidyl radical; cyclic voltammetry; electrosynthesis; hydroamination; proton coupled electron transfer

A new oxidatively stable ligand for the chiral functionalization of amino acids in Ni(II)–Schiff base complexes

• Alena V. Dmitrieva,
• Oleg A. Levitskiy,
• Yuri K. Grishin and
• Tatiana V. Magdesieva

Beilstein J. Org. Chem. 2023, 19, 566–574, doi:10.3762/bjoc.19.41

• including the thiolation discussed above). Insertion of the t-Bu group also makes the (GlyNi)L7 complex more soluble in diethyl ether as compared to the parent (GlyNi)L1 complex (21.3 mg/1 mL vs <1 mg/1 mL in Et2O; see Figure 3). This is beneficial for electrosynthesis, simplifying the separation of the

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

• Shinsuke Inagi and
• Mahito Atobe

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

• /bjoc.18.158 Keywords: electron transfer; electrosynthesis; organic electrochemistry; redox-active materials; Electrochemistry is now a powerful tool in organic chemistry not only for analyzing the electron transfer behavior of organic molecules and macromolecules, but also for driving organic

• reactions to produce value-added products. Electrochemical synthesis (or simply electrosynthesis) is increasingly recognized for the high academic and industrial importance, in line with the concept of green chemistry proposed in 1998 and the Sustainable Development Goals (SDGs) adopted by the United

• Nations in 2015. This is evidenced by the recent publication of special issues on organic electrosynthesis in various academic journals [1][2][3][4][5]. In addition to the conventional two- or three-electrode batch-type electrolytic cells, recent developments include microflow electrolytic reactors

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

Beilstein J. Org. Chem. 2022, 18, 1488–1498, doi:10.3762/bjoc.18.156

• complex molecule, the synthesis of a complex, two-dimensional addressable surface requires a new type of selectivity – "site-selectivity". The use of electrosynthesis is essential for obtaining this selectivity. With the substrate on the surface of the array, a hydroquinone/quinone redox couple was then

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 generated α-iodoketone was proposed to be the key active species. Keywords: 2-aminothiazoles; electrosynthesis; indirect electrolysis; halide ion; Introduction Thiazoles are prevalent structural motifs in a wide range of natural products [1] and synthetic molecules possessing various

• . Organic electrosynthesis has been recognized as a green, modern, and safe technique, since electrons can be used as an alternative for oxidants or reductants [30][31][32][33][34][35][36][37][38]. During our continuous interests in halide-mediated indirect electrolysis [39][40][41][42], we have achieved

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

Beilstein J. Org. Chem. 2022, 18, 1166–1176, doi:10.3762/bjoc.18.121

• base complexes; stereoselective electrosynthesis; voltammetric testing; Introduction Electrochemistry provides a direct access to highly reactive species by means of harnessing electrons or electron holes as reagents [1][2]. This capacity can be efficiently exploited in organic synthesis for rational

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

• -doped diamond electrode; electrosynthesis; oxidation; Introduction Selective oxidation of aromatic alkyl side chains is an important molecular transformation process to obtain various rubbers, resins, fine chemicals, and other industrial products [1][2]: terephthalic acid from p-xylene, cumene

• straightforward electro-conversion of cumene into acetophenone using boron-doped diamond (BDD) electrodes. The BDD’s wide potential window enabled the direct anodic oxidation of cumene to afford a key reaction intermediate, which cannot be realized by other electrodes such as graphite and Ni. Electrosynthesis is

Electrochemical vicinal oxyazidation of α-arylvinyl acetates

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

Beilstein J. Org. Chem. 2022, 18, 1026–1031, doi:10.3762/bjoc.18.103

• diverse α-azidoketones in good yields without the use of a stoichiometric amount of chemical oxidant. A range of functionality is shown to be compatible with this transformation, and further applications are demonstrated. Keywords: azide; azidoketone; electrosynthesis; enol acetate; radical

• have reported a manganese dioxide-catalyzed radical azidation of enol acetates to afford the corresponding azidoketones using dioxygen as the oxidant (Scheme 1A) [14]. The adoption of electrosynthesis in green and sustainable redox transformations has been experiencing a dynamic renaissance [15][16][17

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

Beilstein J. Org. Chem. 2022, 18, 979–990, doi:10.3762/bjoc.18.98

• 1,3-diketones [21], etc. Electrosynthesis is considered as a more sustainable approach to perform chemical reactions, and an interesting alternative to conventional synthetic methods both in laboratory and industry processes. In fact, the electron may be considered to be a clean reagent, which

• replaces toxic chemical redox reagents and dangerous procedures [22][23][24][25]. At present, electrosynthesis in batch is more widely used and reported in literature, but some disadvantages can be encountered: the need for high concentrations of supporting electrolyte, poor performance for synthesis such

• at the cathode is usually H2 evolution [29]. The use of divided cells is less common in organic electrosynthesis, mainly due to complications inherent with membranes. Useful cathodic processes are less exploited in organic electrochemistry. In the context of NHC organocatalysis in flow

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

• , organic electrosynthetic reactions, which are driven by direct electron transfer to and from the electrodes, can produce highly reactive species under ambient conditions without the use of harmful and precious chemicals. Therefore, electrosynthesis has been actively researched in recent years as a green

• introduced to the microreactor by a syringe pump (KDS100, KdScientific Muromachi Kikai) during the electrosynthesis. Electroreductive cyclization was conducted using a potentiogalvanostat (HABF-501A, Hokuto Denko). High-performance liquid chromatography (HPLC) analysis for 3a and 4 was performed with a

Electrocatalytic C(sp³)–H/C(sp)–H cross-coupling in continuous flow through TEMPO/copper relay catalysis

• Bin Guo and
• Hai-Chao Xu

Beilstein J. Org. Chem. 2021, 17, 2650–2656, doi:10.3762/bjoc.17.178

• for electrosynthesis and have been employed to reduce the use of supporting electrolyte, facilitate reaction scale-up, and increase reaction efficiency [20][21][22][23][24][25][26][27][28][29][30][31][32]. Despite these advantages of continuous-flow electrosynthesis and the intense interests in

• transition-metal electrocatalysis [33][34][35][36][37][38][39], transition-metal electrocatalysis in continuous flow remains underexplored [40]. With our continued interests in transition-metal electrocatalysis [41][42] and continuous-flow electrosynthesis [43][44][45][46][47][48], we report herein the

• electrosynthesis was conducted in a microreactor equipped with two Pt electrodes as the anode and cathode and operated with a constant current (Table 1). Under the optimized conditions, a solution of tetrahydroisoquinoline 1a (1 equiv), alkyne 2 (1.5 equiv), Cu(OTf)2 (10 mol %), TEMPO (20 mol %), n-Bu4NPF6 (0.2

On the application of 3d metals for C–H activation toward bioactive compounds: The key step for the synthesis of silver bullets

• Renato L. Carvalho,
• Amanda S. de Miranda,
• Mateus P. Nunes,
• Roberto S. Gomes,
• Guilherme A. M. Jardim and
• Eufrânio N. da Silva Júnior

Beilstein J. Org. Chem. 2021, 17, 1849–1938, doi:10.3762/bjoc.17.126

• in the azidation of inert C(sp3)–H bonds using organic electrosynthesis in a straightforward procedure, enabling the azidation of a series of primary, secondary and tertiary alkyl moieties (Scheme 22B and C) [144]. In general, the new methodology proved to be resource-economic and straightforward

• retinoic acid receptor agonist analogue 63 and an estrone acetate derivative 64 (Scheme 22D). A seminal work involving manganese-catalyzed C–H organic electrosynthesis and photoredox catalysis was reported in the same year by Lei and co-workers, also regarding the azidation of alkyl scaffolds (Scheme 23A

When metal-catalyzed C–H functionalization meets visible-light photocatalysis

• Lucas Guillemard and
• Joanna Wencel-Delord

Beilstein J. Org. Chem. 2020, 16, 1754–1804, doi:10.3762/bjoc.16.147

• –H activations, visible-light-induced photocatalysis, electrosynthesis, enzyme catalysis, and others. Each of these techniques aims at accessing complex molecules while limiting ecological footprint. Over the last decade, the metal-catalyzed C–H activation established itself as one of the most

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

• redox mediators, electroauxiliaries, supporting electrolyte, types of catalysts; and many other controlling factors [5][6][7]. The complex history of organic electrosynthesis has been revisited in detail in a number of articles [8][9][10][11][12]. The two sequential reviews from Baran’s group and

• Waldvogel’s group focused on the advancements achieved in the development of synthetic methods as well as applications of organic electrosynthesis reported since 2000 [13][14]. Moreover, in his recent article, Moeller have nicely demonstrated that both physical and organic chemistry are indispensable for

• methods can be achieved by using suitable chiral sources [16]. Several groups of organic chemists have been involved in establishing and improving the effectiveness of chiral inductors for electrosynthesis; as a result, a number of reports have been published in this important field of synthetic organic

A diastereoselective approach to axially chiral biaryls via electrochemically enabled cyclization cascade

• Hong Yan,
• Zhong-Yi Mao,
• Zhong-Wei Hou,
• Jinshuai Song and
• Hai-Chao Xu

Beilstein J. Org. Chem. 2019, 15, 795–800, doi:10.3762/bjoc.15.76

• the electrosynthesis was investigated by varying the peripheral substituents of the carbamate substrate 2 (Scheme 2). The pyridyl ring could be substituted at positions 4, 5 and 6 with a range of substituents with diverse electronic properties such as OMe (3e), Br (3f), CF3 (3g), CN (3h), Cl (3i), and

Cobalt–metalloid alloys for electrochemical oxidation of 5-hydroxymethylfurfural as an alternative anode reaction in lieu of oxygen evolution during water splitting

• Jonas Weidner,
• Stefan Barwe,
• Kirill Sliozberg,
• Stefan Piontek,
• Justus Masa,
• Ulf-Peter Apfel and
• Wolfgang Schuhmann

Beilstein J. Org. Chem. 2018, 14, 1436–1445, doi:10.3762/bjoc.14.121

• with the same electrode. Electrolysis of HMF using a CoB modified nickel foam electrode at 1.45 V vs RHE achieved close to 100% selective conversion of HMF to FDCA at 100% faradaic efficiency. Keywords: alternative anode reaction; electrocatalysis; electrosynthesis; HMF oxidation; hydrogen evolution

Spectroelectrochemical studies on the effect of cations in the alkaline glycerol oxidation reaction over carbon nanotube-supported Pd nanoparticles

• Dennis Hiltrop,
• Steffen Cychy,
• Karina Elumeeva,
• Wolfgang Schuhmann and
• Martin Muhler

Beilstein J. Org. Chem. 2018, 14, 1428–1435, doi:10.3762/bjoc.14.120

• complicates the total oxidation reaction, because numerous intermediates occur that need to be oxidized efficiently without poisoning the catalyst. Another important utilization of glycerol is the electrosynthesis of fine chemicals. It is a highly suitable precursor for valuable chemicals such as DL-glyceric

• biopolymers like polyesters and polyurethanes [4]. The route to higher functionalized products starting from glycerol via electrosynthesis offers several advantages compared with thermal gas-phase oxidation processes. In the aqueous environment low temperatures and pressures are applied allowing a higher

• in the electrolyte by blocking surface sites that are required for the carbon bond cleavage. To the best of our knowledge, there are no studies focusing on the cation effect on the glycerol electrooxidation reaction using Pd-based materials. With respect to FC applications and the electrosynthesis of

Polysubstituted ferrocenes as tunable redox mediators

• Sven D. Waniek,
• Jan Klett,
• Christoph Förster and
• Katja Heinze

Beilstein J. Org. Chem. 2018, 14, 1004–1015, doi:10.3762/bjoc.14.86

• electrosynthesis. Keywords: cyclic voltammetry; ferrocene; paramagnetic NMR spectroscopy; redox mediator; spectroelectrochemistry; Introduction Since its discovery, ferrocene (FcH) has been established as versatile redox-active building block [1][2][3]. Ferrocene can be reversibly oxidized to the 17 valence

Electrochemically modified Corey–Fuchs reaction for the synthesis of arylalkynes. The case of 2-(2,2-dibromovinyl)naphthalene

• Fabiana Pandolfi,
• Isabella Chiarotto and
• Marta Feroci

Beilstein J. Org. Chem. 2018, 14, 891–899, doi:10.3762/bjoc.14.76

• in the previous paper) [25]. In order to ascertain the role of the solvent in this electrosynthesis, we carried out an electrolysis in DMF instead of ACN on a Pt cathode at the controlled potential of −2.00 V vs SCE, corresponding to the first reduction wave of 1a (Table 1, entry 2). The current flow

• influence the outcome of an electrosynthesis, so we carried out electrolyses of 1a using a glassy carbon cathode (Table 1, entry 8) and a silver cathode (Table 1, entry 9). In both cases the working potential was that of the first reduction wave. In the case of glassy carbon, the electrolysis could not be

• electrode material. This voltammetric analysis shows that the cathodic reduction of both 1a and 3a could lead to the formation of the desired alkyne 2a. To ascertain this hypothesis and to get information on the nature of the intermediates of the electrochemical process, we carried out the electrosynthesis

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

• -(pent-1-enyl)-α-pyrone and trans-6-(pent-1,4-dienyl)-α-pyrone, which are naturally occurring metabolites isolated from Trichoderma viride and Penicillium, in high chemical yield and with excellent stereo selectivity. Keywords: Corey–Winter reaction; electrosynthesis; 6-pentyl-2H-pyran-2-ones; reduction

An alternative to hydrogenation processes. Electrocatalytic hydrogenation of benzophenone

• Cristina Mozo Mulero,
• Alfonso Sáez,
• Jesús Iniesta and
• Vicente Montiel

Beilstein J. Org. Chem. 2018, 14, 537–546, doi:10.3762/bjoc.14.40

• ohmic drop at the whole process. In the case of organic electrosynthesis, electrocatalytic hydrogenation of aromatic ketones, specifically acetophenone, has been recently carried out [22][23] achieving a high selectivity using the above-mentioned technology. In this work, we have chosen benzophenone, as

• factor was defined as the Pd electrochemically active surface divided by the geometric total area, expressed in (cm2 Pd) cm−2 (vide supra). Electrosynthesis reactions were performed using a 25 cm2 PEM single cell fuel cell (EFC-25-01 model from ElectroChem Inc.) acting as polymer electrolyte membrane

• cathode. Fractional conversion of benzophenone as a function of coulombic passed charge using the PEMER; 0.5 M benzophenone as starting solution in ethanol/H2O (90:10 v/v) + 0.1 M H2SO4. Pd0.02/C/T electrode. Plot of cell voltage versus time obtained from a preparative electrosynthesis performed at 10 mA

The selective electrochemical fluorination of S-alkyl benzothioate and its derivatives

• Shunsuke Kuribayashi,
• Tomoyuki Kurioka,
• Shinsuke Inagi,
• Ho-Jung Lu,
• Biing-Jiun Uang and
• Toshio Fuchigami

Beilstein J. Org. Chem. 2018, 14, 389–396, doi:10.3762/bjoc.14.27

• ; electrosynthesis; fluorobenzothiophenone; selective fluorination; Introduction Due to the interesting properties of fluorine atoms and carbon–fluorine bonds, organofluorine compounds are widely used in various fields like pharmaceutical chemistry, agrochemistry, and materials sciences [1][2]. Therefore, the

Cathodic hydrodimerization of nitroolefins

• Michael Weßling and
• Hans J. Schäfer

Beilstein J. Org. Chem. 2015, 11, 1163–1174, doi:10.3762/bjoc.11.131

• formation; 1,4-dinitrocompounds; electrosynthesis; nitroalkene; Introduction Olefins being activated by an electron withdrawing group can be hydrodimerized by cathodic reduction [1][2]. Thereby, the cathode serves as cheap, versatile, immobilized and mostly non-polluting reagent providing economical and

Electrosynthesis and electrochemistry

• Siegfried R. Waldvogel

Beilstein J. Org. Chem. 2015, 11, 949–950, doi:10.3762/bjoc.11.105

• Siegfried R. Waldvogel Institute for Organic Chemistry, Johannes Gutenberg University Mainz, Duesbergweg 10–14, 55128 Mainz, Germany 10.3762/bjoc.11.105 Keywords: chemical method; electrochemistry; electrosynthesis; sustainability; Since the pioneering work of Kolbe, electrochemistry and

• current unsteady supply does not match the demand. Thus, the use of abundant electric power in electrosynthetic processes seems to be rational because high valorisation can be expected. Therefore, electrosynthesis fulfils all requirements for “green chemistry” [4]. When changing feed stocks and natural

• molecules. Such electro-oxidative treatment generates potential metabolites that can be then biologically studied [10]. The combination of electrosynthesis with other powerful techniques, such as ultrasonic treatment and flow microcells, will push the electrosynthetic applications beyond current limits [11

IR and electrochemical synthesis and characterization of thin films of PEDOT grown on platinum single crystal electrodes in [EMMIM]Tf₂N ionic liquid

• Andrea P. Sandoval,
• Marco F. Suárez-Herrera and
• Juan M. Feliu

Beilstein J. Org. Chem. 2015, 11, 348–357, doi:10.3762/bjoc.11.40

• ) has shown an enhancement in stability, organization and electroactivity [12][13][14]. These characteristics are obtained mainly because of the dry medium, their wide electrochemical window, and their low nucleophilicity. Therefore, during the electrosynthesis of conducting polymers the overoxidation

• begins at 0.9 V in Pt(111) and Pt(110) while in Pt(100) it starts at 1.0 V. The loop observed during the first scans (Figure 1a – insert) is typical of the electrosynthesis of conducting polymers both in organic media [17] and in ILs [2][18][19]. This characteristic has been well described by Heinze et