Confirmation of the stereochemistry of spiroviolene

• Yao Kong,
• Yuanning Liu,
• Kaibiao Wang,
• Tao Wang,
• Chen Wang,
• Ben Ai,
• Hongli Jia,
• Guohui Pan,
• Min Yin and
• Zhengren Xu

Beilstein J. Org. Chem. 2024, 20, 852–858, doi:10.3762/bjoc.20.77

• amount of the C-9 epimerization product 11 might be explained by a competing radical oxidation of the organoborane intermediate IM-16 by oxygen when the oxidation step is opened to air [32][33]. On the other hand, an alternative mechanism for the formation of 11 involving the oxidation of the 9-epi-IM-16

Advancements in hydrochlorination of alkenes

• Daniel S. Müller

Beilstein J. Org. Chem. 2024, 20, 787–814, doi:10.3762/bjoc.20.72

• interest as the starting materials are inexpensive bulk chemicals and the reactions can be carried out under air without any particular precautions. Radical hydrochlorination reactions Cobalt and iron-promoted radical hydrochlorination reactions are part of the large family of metal hydride hydrogen atom

Organic electron transport materials

• Joseph Cameron and
• Peter J. Skabara

Beilstein J. Org. Chem. 2024, 20, 672–674, doi:10.3762/bjoc.20.60

• orthogonal processing. One of the biggest challenges with n-type materials is air stability. This is explained by the redox potentials of water (−0.66 V vs standard calomel electrode (SCE)) and oxygen (+0.024 V vs SCE, +0.57 V vs SCE) [2][3]. Therefore, it has been observed that once the overpotential

• required for these redox reactions to progress is taken into consideration, a lowest unoccupied molecular orbital (LUMO) energy ≤ −4.0 eV (relative to vacuum) is required for air stable electron transport materials [2] and this is a common target for researchers developing these types of materials. In

• general, this restriction also applies to n-dopants, compounds that reduce electron transport materials, which are important for increasing the electrical conductivity of n-type materials. However, there have been elegant solutions developed to counteract this, where air-stable dimers can be used which

Mono or double Pd-catalyzed C–H bond functionalization for the annulative π-extension of 1,8-dibromonaphthalene: a one pot access to fluoranthene derivatives

• Nahed Ketata,
• Linhao Liu,
• Ridha Ben Salem and
• Henri Doucet

Beilstein J. Org. Chem. 2024, 20, 427–435, doi:10.3762/bjoc.20.37

• fluoranthenes that cannot be obtained by the double C–H bond functionalization method. Both procedures employ commercially available 1,8-dibromonaphthalene, arenes and arylboronic acids with an air-stable catalyst combined with KOPiv as an inexpensive base. These two complementary synthetic schemes, which

• from Acros. KOPiv (95%) was purchased from Doug Discovery. These compounds were not purified before use. All reagents were weighed and handled in air. All reactions were carried out under an inert atmosphere with standard Schlenk techniques. 1H, 19F and 13C NMR spectra were recorded on Bruker Avance

Synthesis of π-conjugated polycyclic compounds by late-stage extrusion of chalcogen fragments

• Aissam Okba,
• Pablo Simón Marqués,
• Kyohei Matsuo,
• Naoki Aratani,
• Hiroko Yamada,
• Gwénaël Rapenne and
• Claire Kammerer

Beilstein J. Org. Chem. 2024, 20, 287–305, doi:10.3762/bjoc.20.30

• the corresponding planar HBC at room temperature upon acidic treatment under air, thus triggering SeO-elimination as well as cyclodehydrogenation in a single step. As mentioned above, oxepine derivatives display higher stability compared to other chalcogen heteropines and direct oxygen extrusion from

Unveiling the regioselectivity of rhodium(I)-catalyzed [2 + 2 + 2] cycloaddition reactions for open-cage C₇₀ production

• Cristina Castanyer,
• Anna Pla-Quintana,
• Anna Roglans,
• Albert Artigas and
• Miquel Solà

Beilstein J. Org. Chem. 2024, 20, 272–279, doi:10.3762/bjoc.20.28

• larger orifices in C70 derivatives given that the larger cavity compared to its C60 counterpart can facilitate the encapsulation of multiple atoms and molecules [40][43][53][54]. To fulfil this objective, compound 2a was subjected to oxidative cleavage by exposing it to light in the presence of air

Nucleophilic functionalization of thianthrenium salts under basic conditions

• Xinting Fan,
• Duo Zhang,
• Xiangchuan Xiu,
• Bin Xu,
• Yu Yuan,
• Feng Chen and
• Pan Gao

Beilstein J. Org. Chem. 2024, 20, 257–263, doi:10.3762/bjoc.20.26

• introduced a pioneering method for synthesizing air- and moisture-stable arylthianthrenium salts [11]. This novel approach involves the utilization of tetra-fluorothianthrene sulfoxide (TFT=O) or thianthrene sulfoxide (TT=O), which react with arenes under mild conditions, exhibiting exclusive

• in 88% yield under the following optimal conditions: S-(alkyl)thianthrenium salt 1a and 4-bromothiophenol (2a) as the model substrates, N,N-diisopropylethylamine (DIPEA) as the base, were added to a vessel in air; after stirring for 16 hours at room temperature, the corresponding product was isolated

• using nucleophiles directly, without the need for an external metal catalyst. Synthetic application of thianthrenium salts. Substrate scope. Reaction conditions: alkylthianthrenium salts 1 (0.3 mmol), thiophenols 2 (0.2 mmol), DIPEA (0.4 mmol) in 2.0 mL of MeCN at room temperature for 16 h under air

Synthesis of the 3’-O-sulfated TF antigen with a TEG-N₃ linker for glycodendrimersomes preparation to study lectin binding

• Mark Reihill,
• Hanyue Ma,
• Dennis Bengtsson and
• Stefan Oscarson

Beilstein J. Org. Chem. 2024, 20, 173–180, doi:10.3762/bjoc.20.17

• following acetylation without purification of the intermediate, why the synthesis is high-yielding (20% overall yield) and easily scalable (9 g of protected disaccharide 7 and 1 gram of target 2 were synthesized). Experimental General methods All reactions containing air- and moisture-sensitive reagents

• were carried out under an inert atmosphere of nitrogen in oven-dried glassware with magnetic stirring. N2-flushed plastic syringes were used to transfer air- and moisture-sensitive reagents. All reactions were monitored by thin-layer chromatography (TLC) on Merck® DC-Alufolien plates precoated with

Copper-promoted C5-selective bromination of 8-aminoquinoline amides with alkyl bromides

• Changdong Shao,
• Chen Ma,
• Li Li,
• Jingyi Liu,
• Yanan Shen,
• Chen Chen,
• Qionglin Yang,
• Tianyi Xu,
• Zhengsong Hu,
• Yuhe Kan and
• Tingting Zhang

Beilstein J. Org. Chem. 2024, 20, 155–161, doi:10.3762/bjoc.20.14

• , China 10.3762/bjoc.20.14 Abstract An efficient and practical method for the synthesis of C5-brominated 8-aminoquinoline amides via a copper-promoted selective bromination of 8-aminoquinoline amides with alkyl bromides was developed. The reaction proceeds smoothly in dimethyl sulfoxide (DMSO) under air

• -amidequinolines (1, 0.2 mmol, 1.0 equiv), BrR (2, 0.8 mmol, 4.0 equiv), Cu(OAc)2·H2O (8.0 mg, 0.04 mmol, 20 mol %), K2CO3 (27.6 mg, 0.2 mmol, 1.0 equiv), and DMSO (1.0 mL). The tube was sealed with a Teflon cap under air, then the mixture was stirred at 100 ºC for 12 h. After completion, the reaction mixture was

• the C5-selective bromination of 8-aminoquinoline amides. Substrate scope of the 8-aminoquinoline amides. Reaction conditions: 1 (0.2 mmol), 2a (0.8 mmol), Cu(OAc)2·H2O (20 mol %), K2CO3 (0.2 mmol), DMSO (1.0 mL), stirred under air at 100 ºC for 12 h. Isolated yield. Substrate scope of the bromoalkanes

Optimizing reaction conditions for the light-driven hydrogen evolution in a loop photoreactor

• Pengcheng Li,
• Daniel Kowalczyk,
• Johannes Liessem,
• Mohamed M. Elnagar,
• Dariusz Mitoraj,
• Radim Beranek and
• Dirk Ziegenbalg

Beilstein J. Org. Chem. 2024, 20, 74–91, doi:10.3762/bjoc.20.9

• 80% of the global energy market for decades [1][2][3]. However, the combustion of fossil fuels contributes greatly to environmental degradation, global warming, and air pollution, which further damages public health [4][5][6]. Given the nature of how fossil fuels are formed, which takes millions of

• air or sampling mistakes. The long-term stability of the photocatalyst was initially tested in the loop photoreactor with a photocatalyst loading of 0.22 g L−1, a stirring speed of 560 rpm, a photon flux of 4.70 μmol s−1, and an inert gas flow rate of 75 mL min−1. Figure 9 shows the hydrogen

Preparing a liquid crystalline dispersion of carbon nanotubes with high aspect ratio

• Keiko Kojima,
• Nodoka Kosugi,
• Hirokuni Jintoku,
• Kazufumi Kobashi and
• Toshiya Okazaki

Beilstein J. Org. Chem. 2024, 20, 52–58, doi:10.3762/bjoc.20.7

• flowing air (200 mL/min) at a ramping rate of 1 °C/min. The Raman and absorption spectra were obtained from DWCNT thin film on a silicon substrate. The DWCNT thin film was prepared using vacuum filtration. Raman measurements were conducted using a HORIBA T64000 532 nm laser, while far-infrared (FIR

• the dispersion. The specimen was air-dried until the film was completely dried. The DWCNT orientations of the film were observed by POM (OLYMPUS, BX51) and SEM (HITACHI High-Tech, SU8200). The degree of alignment was determined through analysis of the polarized optical absorption spectra by a Jasco V

Using the phospha-Michael reaction for making phosphonium phenolate zwitterions

• Matthias R. Steiner,
• Max Schmallegger,
• Larissa Donner,
• Johann A. Hlina,
• Christoph Marschner,
• Judith Baumgartner and
• Christian Slugovc

Beilstein J. Org. Chem. 2024, 20, 41–51, doi:10.3762/bjoc.20.6

• phosphorus signal for 2d). Stability tests were also performed in two different deuterated solvents, CDCl3 and DMSO-d6. No air or moisture exclusion was applied. The tests were performed at room temperature and at 60 °C. 1H and 31P NMR spectra of the solutions were taken after 24, 48 and 72 h. At room

1-Butyl-3-methylimidazolium tetrafluoroborate as suitable solvent for BF₃: the case of alkyne hydration. Chemistry vs electrochemistry

• Marta David,
• Elisa Galli,
• Richard C. D. Brown,
• Marta Feroci,
• Fabrizio Vetica and
• Martina Bortolami

Beilstein J. Org. Chem. 2023, 19, 1966–1981, doi:10.3762/bjoc.19.147

• weakly coordinating or not-coordinating organic or inorganic anions. They have interesting physicochemical properties that differentiate them from the organic solvents commonly used in synthesis [74][75][76][77]. Importantly, they have a very low vapour pressure, and therefore do not behave as air

• . Therefore, while confirming the presence of the adduct, we could not quantify it. The next choice was DBU (1,8-diazabicyclo[5,4,0]undec-7-ene). The DBU-BF3 adduct is reported to be very stable in water and in air and not subjected to hydrolysis [115]. The DBU solubility in BMIm-BF4 was confirmed by NMR

Aldiminium and 1,2,3-triazolium dithiocarboxylate zwitterions derived from cyclic (alkyl)(amino) and mesoionic carbenes

• Nedra Touj,
• François Mazars,
• Guillermo Zaragoza and
• Lionel Delaude

Beilstein J. Org. Chem. 2023, 19, 1947–1956, doi:10.3762/bjoc.19.145

• instantaneous formation of the desired zwitterionic adducts, as evidenced by the appearance of an intense orange-red color. The solvent was removed and the residues were brought back to air, washed with n-pentane, and dried under high vacuum to afford pseudo-cross-conjugated mesomeric betaines 4a–c in high

• air and moisture, followed by an aqueous work-up. These results sharply contrasted with those obtained previously with a range of imidazolinium, benzimidazolium, or imidazolium salts, which were successfully converted into NHC·CS2 zwitterions under mild aerobic conditions [75]. Yet, the greater proton

Beyond n-dopants for organic semiconductors: use of bibenzo[d]imidazoles in UV-promoted dehalogenation reactions of organic halides

• Kan Tang,
• Megan R. Brown,
• Chad Risko,
• Melissa K. Gish,
• Garry Rumbles,
• Phuc H. Pham,
• Oana R. Luca,
• Stephen Barlow and
• Seth R. Marder

Beilstein J. Org. Chem. 2023, 19, 1912–1922, doi:10.3762/bjoc.19.142

• strong reductants with effective potentials of ca. −2 V vs ferrocenium/ferrocene, yet are relatively stable to air due to the coupling of redox and bond-breaking processes. Here, we examine their use in accomplishing electron transfer-induced bond-cleavage reactions, specifically dehalogenations. The

• ) that simple one- or two-electron donors capable of exergonic ground-state electron transfer to these substrates will be rather air sensitive, complicating their handling and use. In addition some molecular reductants can themselves react with the reactive intermediates; for example, the dehalogenation

• of alkyl halides, RX, by CoCp2 (Cp = η5-cyclopentadienyl; E = −1.3 V vs FeCp2+/0), gives CoCp2+ and X−, but the organic radicals R• react with another molecule of CoCp2 to afford CoCp(η4-C5H5R) [7]. In some cases, issues of reductant air sensitivity can be circumvented by the use of photocatalysts in

Biphenylene-containing polycyclic conjugated compounds

• Cagatay Dengiz

Beilstein J. Org. Chem. 2023, 19, 1895–1911, doi:10.3762/bjoc.19.141

• stability, showing no signs of degradation over an extended period when kept in the dark, both in solid form and in solution under air. In the final phase of the study, the authors investigated the charge-transport properties of compond 34a in OFET. Since the charge-transport properties are significantly

Aromatic systems with two and three pyridine-2,6-dicarbazolyl-3,5-dicarbonitrile fragments as electron-transporting organic semiconductors exhibiting long-lived emissions

• Karolis Leitonas,
• Brigita Vigante,
• Dmytro Volyniuk,
• Audrius Bucinskas,
• Pavels Dimitrijevs,
• Sindija Lapcinska,
• Pavel Arsenyan and
• Juozas Vidas Grazulevicius

Beilstein J. Org. Chem. 2023, 19, 1867–1880, doi:10.3762/bjoc.19.139

• for compound REF. The increments of PL are different for the toluene, chloroform, and THF solutions. This observation shows that the TADF properties of compounds 6–9 are sensitive to the medium. For example, the ratios of PL intensities of deoxygenated and air-equilibrated toluene, chloroform, and THF

• . Photoelectrical and charge-transporting properties The ionization potentials (IPPE) of thin films were obtained by photoelectron emission (PE) spectroscopy in air (Figure 7 and Table 1). To generate photoelectrons detectable by a counter electrode within the PE experiments, a low-power deuterium UV lamp was used

• of dilute toluene, THF, and chloroform solutions (10−5 M) and of the films of compounds 6–9. PL spectra (a) and PL decay curves (b) of air-equilibrated (as prepared) and deoxygenated toluene solutions of compounds 6–9. PL spectra (c) and PL decay curves (d) of the films of molecular mixtures of mCP

Recent advancements in iodide/phosphine-mediated photoredox radical reactions

• Tinglan Liu,
• Yu Zhou,
• Junhong Tang and
• Chengming Wang

Beilstein J. Org. Chem. 2023, 19, 1785–1803, doi:10.3762/bjoc.19.131

• showcased broad applicability, operational simplicity, and utilized easily obtainable and air-stable phosphonium salts 54 as convenient photoinduced Rf radical reagents. Conclusion In recent years, the field of synthetic chemistry has experienced significant advancements in iodide/phosphine-based photoredox

Selectivity control towards CO versus H₂ for photo-driven CO₂ reduction with a novel Co(II) catalyst

• Lisa-Lou Gracia,
• Philip Henkel,
• Olaf Fuhr and
• Claudia Bizzarri

Beilstein J. Org. Chem. 2023, 19, 1766–1775, doi:10.3762/bjoc.19.129

• . calcd for C38H28CoN10S2·CH3OH: C, 60.07; N, 17.96; H, 4.11; S, 8.22; found: C, 60.05; N, 17.84; H, 3.66; S, 8.18. Photocatalytic CO2 reduction Typically, the tests were performed in glass vials (20 mL) equipped with a screw-cap septum. The solutions were prepared under air and CO2 (or argon) was bubbled

Quinoxaline derivatives as attractive electron-transporting materials

• Zeeshan Abid,
• Liaqat Ali,
• Sughra Gulzar,
• Faiza Wahad,
• Raja Shahid Ashraf and
• Christian B. Nielsen

Beilstein J. Org. Chem. 2023, 19, 1694–1712, doi:10.3762/bjoc.19.124

• electronics [51]. Hasegawa and colleagues focused on achieving air-stable n-channel conduction by synthesizing thiadiazole-fused quinoxalineimide derivatives, Qx47–Qx49. The team optimized the molecular packing and solubility by incorporating solubilizing N-substituted alkyl chains. The resulting molecules

• exhibited low LUMO levels and two-dimensional carrier transport, enabling OFET performance. The moderate air-stable n-channel mobility of 0.044 cm2 V−1 s−1 demonstrated the suitability of these derivatives for electron transport [52]. Hayashi et al. introduced a new avenue for developing n-type N

• the earlier [54]. Recently, Ding et al. prepared a novel air-stable n-type benzothiophene endcapped azaarene (BTPQ) and its sulfonated derivative (BSPQ). By introducing nitrogen atoms and sulfonyl groups, the researchers modulated the molecular energy levels and achieved the energy level requirements

Benzoimidazolium-derived dimeric and hydride n-dopants for organic electron-transport materials: impact of substitution on structures, electrochemistry, and reactivity

• Swagat K. Mohapatra,
• Khaled Al Kurdi,
• Samik Jhulki,
• Georgii Bogdanov,
• John Bacsa,
• Maxwell Conte,
• Tatiana V. Timofeeva,
• Seth R. Marder and
• Stephen Barlow

Beilstein J. Org. Chem. 2023, 19, 1651–1663, doi:10.3762/bjoc.19.121

• wide range of semiconductors, they must exhibit low ionization energies and thus air sensitivity. One approach to circumvent this issue is to identify systems where the electron-transfer process is coupled to other chemical reactions, increasing the kinetic stability of the dopant to air, and thus

• increasing its ease of storage and handling. Arguably, the most widely investigated air-inert n-dopants are 1,3-dimethyl-2,3-dihydrobenzo[d]imidazoles (DMBI-H, 1H, Figure 1); these species have been known for decades (e.g., 1aH, one of the simplest such derivatives, was first reported in 1954 [6]), but were

• only introduced in n-dopants in 2010, when Bao and co-workers reported the use of N-DMBI-H (1bH, Figure 1) to n-dope fullerenes [7]. Although widely used, due to their facile synthesis, structural tunability, and good air stability in the solid state, 1H derivatives are relatively limited in dopant

Tying a knot between crown ethers and porphyrins

• Maksym Matviyishyn and
• Bartosz Szyszko

Beilstein J. Org. Chem. 2023, 19, 1630–1650, doi:10.3762/bjoc.19.120

• , accommodating the axially-positioned water molecule on the cobalt(III) centre. The latter assembled into a remarkable hexagonal wheel architecture when exposed to air in THF, as evidenced by XRD (Figure 12). The hexagonal wheel [16-Co(III)]6 was stabilised by intramolecular hydrogen bonding between the water

• single crystal XRD. Compound 43 formed stable cation radicals upon adding different oxidising agents, such as AgSbF6, TFA, and CuCl2. The cation radicals showed relative stability and remained undeteriorated on air for over a week. The crowned porphyrinoids incorporating two pyrroloindole units 44 were

Radical chemistry in polymer science: an overview and recent advances

• Zixiao Wang,
• Feichen Cui,
• Yang Sui and
• Jiajun Yan

Beilstein J. Org. Chem. 2023, 19, 1580–1603, doi:10.3762/bjoc.19.116

• glycoprotein (≈1–2%), laccase (≈0.2%), and stellacyanin (≈0.02%) [6][7]. Urushiol is the main active coating-forming ingredient of the resin. A typical urushiol is shown in Scheme 2. In a humid and warm environment, urushiol absorbs oxygen from air and is oxidized to a phenolic oxygen free radical under the

Lewis acid-promoted direct synthesis of isoxazole derivatives

• Dengxu Qiu,
• Chenhui Jiang,
• Pan Gao and
• Yu Yuan

Beilstein J. Org. Chem. 2023, 19, 1562–1567, doi:10.3762/bjoc.19.113

• compared with DMSO and DMF (Table 1, entries 8 and 9). The reaction yield was decreased to 21% when increasing the temperature to 140 °C under standard conditions (Table 1, entry 10). Finally, the nitrogen atmosphere was essential since the yield substantially decreased under air atmosphere (Table 1, entry

Synthesis and biological evaluation of Argemone mexicana-inspired antimicrobials

• Jessica Villegas,
• Bryce C. Ball,
• Katelyn M. Shouse,
• Caleb W. VanArragon,
• Ashley N. Wasserman,
• Hannah E. Bhakta,
• Allen G. Oliver,
• Danielle A. Orozco-Nunnelly and
• Jeffrey M. Pruet

Beilstein J. Org. Chem. 2023, 19, 1511–1524, doi:10.3762/bjoc.19.108

• smoothly to the dihydroberberine in the absence of the copper salt [37]. This suggests the Cu2+ may be involved in aiding in the air-oxidation to the fully aromatic berberine core. The prime benefit of the route shown in Scheme 1 is the ease of introducing structural variability, as the precursor is easily