Trifluoromethyl-substituted tetrathiafulvalenes

• Olivier Jeannin,
• Frédéric Barrière and
• Marc Fourmigué

Beilstein J. Org. Chem. 2015, 11, 647–658, doi:10.3762/bjoc.11.73

• extremely soluble, a consequence of the presence of the CF3 groups and there was no crystal growth on the anode. However, with 1c as electroactive donor molecule and (n-Bu4N)(FeCl4) as electrolyte, layering of the CH2Cl2 solutions after electrolysis with pentane afforded crystals of a 1:1 phase formulated

TTFs nonsymmetrically fused with alkylthiophenic moieties

• Rafaela A. L. Silva,
• Bruno J. C. Vieira,
• Marta M. Andrade,
• Isabel C. Santos,
• Sandra Rabaça,
• Dulce Belo and
• Manuel Almeida

Beilstein J. Org. Chem. 2015, 11, 628–637, doi:10.3762/bjoc.11.71

• immediately before its use. The system was sealed under nitrogen and after ca. 3 days, using a current density of 1 μA·cm−2, dark brown plate-shaped crystals were collected in the anode and washed with dichloromethane. Redox properties Cyclic voltammetry data were obtained using a BAS C3 Cell Stand. The

Highly selective generation of vanillin by anodic degradation of lignin: a combined approach of electrochemistry and product isolation by adsorption

• Dominik Schmitt,
• Carolin Regenbrecht,
• Marius Hartmer,
• Florian Stecker and
• Siegfried R. Waldvogel

Beilstein J. Org. Chem. 2015, 11, 473–480, doi:10.3762/bjoc.11.53

• using the most productive anode materials. Under the conditions described, the electrochemical process usually resulted in moderate yields of 1 <2.0 wt % per electrolysis run but the selectivity towards vanillin (1) formation is outstanding (Figure 1). The only other volatile byproduct formed in much

• observed. Besides the applied anode materials, the current density has a tremendous influence on the achievable yield. Rather low current densities <2.0 mA∙cm−2 usually result in the highest yields of vanillin (1) independent of the electrode materials. Especially, Co-based materials are very sensitive to

• improve the accessibility of possible reaction sites located rather inside the lignin particle to the anode surface and high temperatures >100 °C are usually chosen for efficient degradation processes. Due to limited solubility of the commonly used Kraft lignin in aqueous systems, it was necessary to set

Electrochemical oxidation of cholesterol

• Jacek W. Morzycki and
• Andrzej Sobkowiak

Beilstein J. Org. Chem. 2015, 11, 392–402, doi:10.3762/bjoc.11.45

• -compartment glass cell equipped with platinum mesh electrodes (cathode and anode) was filled with a cholesteryl acetate (1a) solution in acetonitrile containing ammonium tetrafluoroborate as a supporting electrolyte. The constant potential technique mainly afforded 7-hydroxylated products (7a and 8a; 19–38

• oxygen is possible. A stereoselective electrochemical method of the chlorination of steroidal Δ5-olefins was described by Takayama et al. [38]. The oxidation of cholesterol was carried out in an undivided cell under constant current conditions in CH2Cl2/MeCN/H2O (2:2:1), the cathode and anode being

• chlorination of some Δ5-steroids (Scheme 5) was reported by Milisavljević and Vukićević [40]. The electrolyses were carried out in dichloromethane under galvanostatic conditions with a graphite anode in an undivided cell. The supporting electrolyte tetraethylamonium chloride was a source of chloride ions

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

• (galvanostatic) electrolysis [4]. When a constant current is passed through an electrolysis cell, the potential at the anode increases until it reaches that of the substrate in solution with the lowest oxidation potential. It then remains constant at that potential until the effective concentration of the

• substrate at the anode decreases to the point that the rate of substrate oxidation is small relative to the rate of electron transfer. At that point, the potential at the anode begins to increase and the selectivity of the reaction for the initial substrate is lost. When a low current density is used for

• the reaction. In this way, a series of substrates can be selectively oxidized using the same reaction conditions even if the substrates have significantly different oxidation potentials. For most of the following cases discussed, reticulated vitreous carbon (RVC) is used as a highly porous anode

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

• acetonitrile. Then, the cell was equipped with a platinum plate anode and cathode and electrolysed under a constant current (10 mA, 6.67 mA/cm2) at 20 °C until completion was detected by TLC and GC–MS analysis. Then, 15 mL water were added, the mixture was extracted with diethyl ether (three times 15 mL

• 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

3α,5α-Cyclocholestan-6β-yl ethers as donors of the cholesterol moiety for the electrochemical synthesis of cholesterol glycoconjugates

• Aneta M. Tomkiel,
• Adam Biedrzycki,
• Jolanta Płoszyńska,
• Dorota Naróg,
• Andrzej Sobkowiak and
• Jacek W. Morzycki

Beilstein J. Org. Chem. 2015, 11, 162–168, doi:10.3762/bjoc.11.16

• substrates (sterol donors, sugar alcohol) and the resulting glycoconjugate, the possibility that side processes will occur increases as the anode potential is more positive and the glycoconjugate concentration grows. A series of blank experiments proved that the electrochemical activation of i-steroidal

• electrolysis the potential of the anode was monitored and the process was stopped when the potential reached the value of +2.3 V vs Ag/0.1 M AgNO3 to avoid the occurrence of undesired oxidation processes. The reactions were also monitored by TLC and stopped when no further increase in the concentration of the

• used as an anode. All measurements were performed at 25 °C. The sugar (1,2:3,4-di-O-isopropylidene-α-D-galactopyranose; 7) [9] and steroidal substrates, 3α,5α-cyclocholestan-6β-ol (i-cholesterol; 6a) [10], 6β-methoxy-3α,5α-cyclocholestane (6b) [11], and 6β-ethoxy-3α,5α-cyclocholestane (6c) [12], were

Highly selective electrochemical fluorination of dithioacetal derivatives bearing electron-withdrawing substituents at the position α to the sulfur atom using poly(HF) salts

• Bin Yin,
• Shinsuke Inagi and
• Toshio Fuchigami

Beilstein J. Org. Chem. 2015, 11, 85–91, doi:10.3762/bjoc.11.12

• -withdrawing effect of a substituent greatly affects the electron-transfer step from the substrate to the anode. At first, anodic fluorination of ethyl α,α-bis(phenylthio)acetate (1b) [30][31] was carried out at platinum plate electrodes in an undivided cell using various solvents in the presence of Et3N·3HF

The Shono-type electroorganic oxidation of unfunctionalised amides. Carbon–carbon bond formation via electrogenerated N-acyliminium ions

• Alan M. Jones and
• Craig E. Banks

Beilstein J. Org. Chem. 2014, 10, 3056–3072, doi:10.3762/bjoc.10.323

• introduction of the nucleophile to the C–X bond that contains the electroauxiliary (Scheme 4). Similarly, α-silyl-carbamates undergo low potential anodic oxidation reactions with complete regiocontrol and in special cases diastereoselectivity [34][35]. Interestingly, a porous graphite felt anode and a

• anode and a platinum wire coil is used as the cathode; the flow cell is placed into a dry ice bath to maintain the −78 °C temperature required. Cation flow systems can be used to prepare individual molecules and combined with the concept of combinatorial chemistry to generate libraries of compounds. A

• are anode and cathode) (viz. Figure 2). This technique of microflow mixing can also be applied to the synthesis of polymers [29]. A single channel miniaturised microfluidic electrolysis cell that is modular with other microfluidic techniques has now been developed to perform anodic methoxylation

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

• oxidation of catechol in the presence of 4-hydroxycoumarin was reported by Tabaković et al. (Scheme 25, left) [69]. Using an undivided cell, an aqueous sodium acetate electrolyte and a graphite anode, the product was obtained in 95% yield. In a similar fashion, benzofurans of type 68 and 69 were synthesized

Solution processable diketopyrrolopyrrole (DPP) cored small molecules with BODIPY end groups as novel donors for organic solar cells

• Diego Cortizo-Lacalle,
• Calvyn T. Howells,
• Upendra K. Pandey,
• Joseph Cameron,
• Neil J. Findlay,
• Anto Regis Inigo,
• Tell Tuttle,
• Peter J. Skabara and
• Ifor D. W. Samuel

Beilstein J. Org. Chem. 2014, 10, 2683–2695, doi:10.3762/bjoc.10.283

• molecules [24][30][52], these devices do show a comparable photoinduced spectral response. A comparatively low fill factor of 26–27% was observed as a result of poor energy level alignment at the anode side leading to low efficiency. Other parameters governing performance such as short-circuit current

Electrocarboxylation: towards sustainable and efficient synthesis of valuable carboxylic acids

• Roman Matthessen,
• Jan Fransaer,
• Koen Binnemans and
• Dirk E. De Vos

Beilstein J. Org. Chem. 2014, 10, 2484–2500, doi:10.3762/bjoc.10.260

• order to close the electron cycle. Electrons supplied at the cathode must emerge from an oxidation reaction occurring at the anode (Scheme 6). The electrochemical system should be optimized to prevent unfavorable interference between both reactions, since such conflicts cause electric current to be lost

• clear further in this review. An overview of different possible setups for obtaining carboxylic acids is given in Scheme 6. Electrocarboxylation reactions can either be conducted with a sacrificial anode, like magnesium or aluminum, or with an inert anode, like platinum or carbon. Most research has been

• , the gradual consumption of the anode material is a major drawback for industrial applications. Not only is it rather expensive to consume such large amounts of metal; it also strongly hinders the implementation of a continuous process. Additionally, in order to obtain the free acids, an acid

The effect of permodified cyclodextrins encapsulation on the photophysical properties of a polyfluorene with randomly distributed electron-donor and rotaxane electron-acceptor units

• Aurica Farcas,
• Ana-Maria Resmerita,
• Pierre-Henri Aubert,
• Flavian Farcas,
• Iuliana Stoica and
• Anton Airinei

Beilstein J. Org. Chem. 2014, 10, 2145–2156, doi:10.3762/bjoc.10.222

• , IP and EA compared to any of the constituents, which is necessary for electronic applications. The diagram with HOMO/LUMO levels and the work function of the indium tin oxide (ITO) coated glass substrates with poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) (anode) and Ca or Al

• compounds in addition to the work function of the indium tin oxide (ITO) coated glass substrates with poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) (anode) and Ca or Al (cathode) are available. Supporting Information File 554: Characterization data of the compounds: FTIR, 1H NMR

Domino reactions of 2H-azirines with acylketenes from furan-2,3-diones: Competition between the formation of ortho-fused and bridged heterocyclic systems

• Alexander F. Khlebnikov,
• Mikhail S. Novikov,
• Viktoriia V. Pakalnis,
• Roman O. Iakovenko and
• Dmitry S. Yufit

Beilstein J. Org. Chem. 2014, 10, 784–793, doi:10.3762/bjoc.10.74

• spectrometers. IR spectra were recorded on a Bruker TENSOR 27 spectrometer for tablets in KBr. Single-crystal X-ray data for 3a were collected at 100 K on a Bruker Proteum R diffractometer (FR-591 rotating anode generator, Pt-135 CCD detector) equipped with Cobra (Oxford Cryosystems) open-flow cryostat. Data

Gallium-containing polymer brush film as efficient supported Lewis acid catalyst in a glass microreactor

• Rajesh Munirathinam,
• Roberto Ricciardi,
• Richard J. M. Egberink,
• Jurriaan Huskens,
• Michael Holtkamp,
• Herbert Wormeester,
• Uwe Karst and
• Willem Verboom

Beilstein J. Org. Chem. 2013, 9, 1698–1704, doi:10.3762/bjoc.9.194

• AXS, Berlin, Germany) with an air-cooled molybdenum anode for X-ray generation. The excitation settings were 50 kV and 750 mA and quartz glass disks were used as sample carriers. The analysis was performed by signal integration over 500 seconds. For the determination, the signal of gallium (Kα1

Spectroscopic characterization of photoaccumulated radical anions: a litmus test to evaluate the efficiency of photoinduced electron transfer (PET) processes

• Maurizio Fagnoni,
• Stefano Protti,
• Davide Ravelli and
• Angelo Albini

Beilstein J. Org. Chem. 2013, 9, 800–808, doi:10.3762/bjoc.9.91

• methods [1][2][3][4][5][6]. A radical ion formed at a cathode/anode finds itself in an environment where electrons/holes are abundant. Likewise, reducing/oxidizing chemicals must be used at a sufficiently high concentration to be active, and again the radical ions are formed in an environment where a

Photoionisation of the tropyl radical

• Kathrin H. Fischer,
• Patrick Hemberger,
• Andras Bodi and
• Ingo Fischer

Beilstein J. Org. Chem. 2013, 9, 681–688, doi:10.3762/bjoc.9.77

• threshold photoelectrons by detecting them in coincidence with ions. The spectrometer is a combination of a Wiley–McLaren time-of-flight (TOF) mass spectrometer [48] and a velocity map imaging setup [49]. The latter is equipped with a position sensitive detector with a delay line anode (Roentdek DLD40

Continuous preparation of carbon-nanotube-supported platinum catalysts in a flow reactor directly heated by electric current

• Alicja Schlange,
• Antonio Rodolfo dos Santos,
• Ulrich Kunz and
• Thomas Turek

Beilstein J. Org. Chem. 2011, 7, 1412–1420, doi:10.3762/bjoc.7.165

• a homemade DMFC test station equipped with high impedance potentiometer (Delta Elektronika SM3000) was used. The active area of the single cell with parallel flow field was 5 cm2. The platinum loading for both electrodes, anode and cathode, was 1 mg·cm−2, respectively. The fuel cell performance

• tests were carried out at 80 °C with pure oxygen as an oxidant (200 mL·min−1). 1 M MeOH solution at a flow rate of 5 mL·min−1 was supplied to the anode. The cathode layer was prepared using synthesized Pt/CNT catalysts, while the anode was fabricated using commercial Pt/Ru catalyst from BASF (40 wt % Pt

• oil bath. X-ray diffraction patterns for the as-received CNT and the three Pt/CNT samples taken at intervals of 25 min in the tubular reactor. Comparison of performance in DMFC with Pt/CNT oil bath and Pt/CNT tubular reactor samples as cathode catalysts (Pt loading of 1 mg·cm−2 on each anode and

A practical microreactor for electrochemistry in flow

• Kevin Watts,
• William Gattrell and
• Thomas Wirth

Beilstein J. Org. Chem. 2011, 7, 1108–1114, doi:10.3762/bjoc.7.127

• 1,2-diphenylethane (7a) were obtained with the device depicted in Figure 1; the reactions are shown in Scheme 3. The Kolbe reaction did not seem to be a very suitable reaction for a flow reactor due to the large amount of carbon dioxide and hydrogen that is formed at the anode during the

• place with an iodoarene that is oxidized at the anode. The radical cation then undergoes a reaction with the other arene to form an intermediate, followed by the loss of a second electron [23]. The solvent system consisted of acetonitrile, sulfuric acid (2 M) and acetic anhydride, which was reported to

• increase the selectivity of the coupling reaction [21]. The sulfuric acid acts both as a counter reaction to the oxidation at the anode, with proton reduction, and simultaneously provides a counter ion for the positively charged iodonium salt. It also acts as an electrolyte in the reaction described above

Redox-active tetrathiafulvalene and dithiolene compounds derived from allylic 1,4-diol rearrangement products of disubstituted 1,3-dithiole derivatives

• Filipe Vilela,
• Peter J. Skabara,
• Christopher R. Mason,
• Thomas D. J. Westgate,
• Asun Luquin,
• Simon J. Coles and
• Michael B. Hursthouse

Beilstein J. Org. Chem. 2010, 6, 1002–1014, doi:10.3762/bjoc.6.113

• . All data were collected at 150 K, on a Nonius KappaCCD area detector diffractometer, at the window of a Nonius FR591 rotating anode (λ MoKα = 0.7106 Å). A correction was applied to account for absorption effects by means of comparing equivalent reflections, using the program SORTAV [32][33]. A

Synthesis and crystallographic analysis of meso-2,3-difluoro-1,4-butanediol and meso-1,4-dibenzyloxy-2,3-difluorobutane

• Bruno Linclau,
• Leo Leung,
• Jean Nonnenmacher and
• Graham Tizzard

Beilstein J. Org. Chem. 2010, 6, No. 62, doi:10.3762/bjoc.6.62

• Bruker Nonius Kappa CCD Area Detector equipped with a Bruker Nonius FR591 rotating anode (λ(MoKα) = 0.71073 Å) at 120 K driven by COLLECT [50] and processed by DENZO [51] software and corrected for absorption by using SADABS [52]. The structures were determined in SHELXS-97 and refined using SHELXL-97

Low temperature enantiotropic nematic phases from V-shaped, shape-persistent molecules

• Matthias Lehmann and
• Jens Seltmann

Beilstein J. Org. Chem. 2009, 5, No. 73, doi:10.3762/bjoc.5.73

• performed by using a standard copper anode (2.2 kW) source with pinhole collimation equipped with a X-ray mirror (Osmic typ CMF15-sCu6) and a Bruker detector (High-star) with 1024 × 1024 pixels. The diffraction data were calibrated by using silver behenate as a calibration standard [37]. The X-ray patterns