High-pressure activation for the solvent- and catalyst-free syntheses of heterocycles, pharmaceuticals and esters

• Kelsey Plasse,
• Valerie Wright,
• Guoshu Xie,
• R. Bernadett Vlocskó,
• Alexander Lazarev and
• Béla Török

Beilstein J. Org. Chem. 2025, 21, 1374–1387, doi:10.3762/bjoc.21.102

• instrument is depicted in Figure 1. The core of the instrument is the intensifier which generates the required pressure by amplifying the relatively low pressure (about 140 psi) supplied by an air compressor. The intensifier pressurizes the water in the pressure chamber where the sealed samples are placed

• reaction time. Even the less reactive aniline gave nearly quantitative isolated yields in less than an hour, while the 1 bar control reaction yielded no detectable products. In addition to the excellent yields, the products were isolated without any purification, using a simple air-drying process to remove

• removing the reaction vessel from the pressure chamber, the cap was removed and the solid material was collected and dried by a simple air-drying. After drying 96.92 g of the product was obtained. The purity of the product was determined by an Agilent 7250 GC-QTOF mass spectrometer operated in electron

Oxetanes: formation, reactivity and total syntheses of natural products

• Peter Gabko,
• Martin Kalník and
• Maroš Bella

Beilstein J. Org. Chem. 2025, 21, 1324–1373, doi:10.3762/bjoc.21.101

• oxetane sulphonyl fluorides can be conveniently prepared in 4 steps from 3-oxetanone and are sufficiently stable at room temperature and to air/moisture. The coupling proceeds upon gentle heating in the presence of K2CO3 as the only additive and affords the aminooxetanes in high yields, even for

Recent advances and future challenges in the bottom-up synthesis of azulene-embedded nanographenes

• Bartłomiej Pigulski

Beilstein J. Org. Chem. 2025, 21, 1272–1305, doi:10.3762/bjoc.21.99

• ]. Notably, PAH 109 forms an air-stable radical cation after oxidation. A similar intramolecular oxidation of two adjacent azulene units was also reported with the use of FeCl3 as an oxidant [73] or in one step during Suzuki coupling between 1,8-dibromonaphthalene and borylated azulene [74]. The ease of

• isomers of pentacene (167), hexacene (168) and heptacene (169) were isolated in very good yields. Compounds 167–169 exhibit excellent photostability under ambient air and light conditions, as compared to their isoelectronic acene counterparts, and red-shifted azulene like optical absorption with tail up

Synthesis of β-ketophosphonates through aerobic copper(II)-mediated phosphorylation of enol acetates

• Alexander S. Budnikov,
• Igor B. Krylov,
• Fedor K. Monin,
• Valentina M. Merkulova,
• Alexey I. Ilovaisky,
• Liu Yan,
• Bing Yu and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2025, 21, 1192–1200, doi:10.3762/bjoc.21.96

• best results were obtained employing 20 mol % of copper(II) sulfate pentahydrate and 2-fold excess of 2a in MeCN at 70 °C under air atmosphere (Table 1, entry 1). In the absence of copper sulfate, no reaction product was detected (Table 1, entry 2). Notably, employing anhydrous copper sulfate afforded

• radicals and product 3 can be described by several pathways. The direct oxidation of 2 by Cu(II) A leads to the formation of P-centered radical E and Cu(I) B. Under air atmosphere, the formed Cu(I) species B can react with molecular oxygen resulting in the formation of peroxycopper intermediate C [75][76

• stirred for 3 hours at 70 °C under air (air condenser) and then cooled to room temperature, and rotary-evaporated under reduced pressure. An additional evaporation step using a rotary vane pump (0.5 mmHg) at 80 °C was made for the evaporation of phosphite excess. The residue was isolated by column

Recent advances in synthetic approaches for bioactive cinnamic acid derivatives

• Betty A. Kustiana,
• Galuh Widiyarti and
• Teni Ernawati

Beilstein J. Org. Chem. 2025, 21, 1031–1086, doi:10.3762/bjoc.21.85

• CuBr promoted hydrogen atom abstraction from the amide 94 resulting in the benzylic radical species 95, followed by oxidation to give acyliminium species 96. Luque and co-workers (2020) developed a biogenic carbonate of CuO–CaCO3 to catalyze solvent- and additive-free amidation reactions in air

• the catalyst surface 159 using air as O2 source (Scheme 49A) [24]. On the other hand, Wang and co-workers (2019) employed a porous boron nitride (pBN)-supported Au catalyst (Au/pBN) to prepare the ester 44, also via the formation of hemiacetal under O2 atmosphere (Scheme 49B) [25]. Wei and co-workers

• intermediate 168 formed through hydride transfer from 167 (Scheme 54A) [95]. Similarly, Huang and co-workers (2020) employed the same NHC catalyst but used ambient air as the external oxidant for acyl azolium intermediate formation (Scheme 54B) [96]. On the other hand, Ohshima and co-workers (2020) directly

Harnessing tethered nitreniums for diastereoselective amino-sulfonoxylation of alkenes

• Shyam Sathyamoorthi,
• Appasaheb K. Nirpal,
• Dnyaneshwar A. Gorve and
• Steven P. Kelley

Beilstein J. Org. Chem. 2025, 21, 947–954, doi:10.3762/bjoc.21.78

• are operationally very simple and only use commercial I(III) reagents and sulfonic acids, amounting to a metal-free protocol for alkene amino-oxygenation. No special precautions need be taken to exclude air or ambient moisture, and the products are amenable to further transformations. Keywords

• and only used commercial I(III) reagents and sulfonic acids. The products were quite stable in the reaction conditions and withstood standard purification protocols. No special precautions were taken to exclude air or ambient moisture, and the products were amenable to further transformations. We

Chitosan-supported CuI-catalyzed cascade reaction of 2-halobenzoic acids and amidines for the synthesis of quinazolinones

• Xuhong Zhao,
• Weishuang Li,
• Mengli Yang,
• Bojie Li,
• Yaoyao Zhang,
• Lizhen Huang and
• Lei Zhu

Beilstein J. Org. Chem. 2025, 21, 839–844, doi:10.3762/bjoc.21.67

• , entries 14 and 15, 80 and 40% yields). In addition, when the reaction time was reduced, the yields decreased accordingly (Table 1, entries 16−18, 70−94% yields). Finally, when the reaction was carried out under open air, the catalytic activity decreased and only 45% yield of the target product was

Recent advances in the electrochemical synthesis of organophosphorus compounds

• Babak Kaboudin,
• Milad Behroozi,
• Sepideh Sadighi and
• Fatemeh Asgharzadeh

Beilstein J. Org. Chem. 2025, 21, 770–797, doi:10.3762/bjoc.21.61

• or ketones. They used nickel foam as both anode and cathode electrodes in an undivided cell under air at room temperature. The reaction was carried out in the presence of KI as an electrolyte, a key additive, and acetone as a solvent. HI increases the reaction yield due to the activation of the

• presence of air, no product was formed. This finding indicates that iodide salt plays a crucial role in driving the reaction and acts as a catalyst in the reaction process. The electronic properties of the substituents on the compounds influenced the reaction yield. Phenol with the –OMe group produced a

• , the C3-phosphorylated product was also formed. In 2024, Mdluli et al. [67] reported an electrochemical method for synthesizing iminophosphoranes. In this method, iminophosphorane was investigated due to its air stability and the presence of a UV–vis chromophore, which enables the analysis of the

Copper-catalyzed domino cyclization of anilines and cyclobutanone oxime: a scalable and versatile route to spirotetrahydroquinoline derivatives

• Qingqing Jiang,
• Xinyi Lei,
• Pan Gao and
• Yu Yuan

Beilstein J. Org. Chem. 2025, 21, 749–754, doi:10.3762/bjoc.21.58

• cyclobutanone oxime using a copper-catalyzed reaction under ambient air conditions (Scheme 1c). Results and Discussion With these considerations in mind, we explored the feasibility of synthesizing cyclobutane-fused spirotetrahydroquinolines (STHQs) through the reaction of arylamines with cyclobutanone oxime

• ) trifluoroacetate (Cu(TFA)2) as the catalyst (20 mol %) under ambient air at 80 °C for 12 hours; the product 3aa was isolated by chromatographic purification (Table 1, entry 1). The use of other solvents, including acetonitrile (MeCN), tetrahydrofuran (THF), toluene, acetone and methanol (MeOH), resulted in

• spirotetrahydroquinoline (STHQ) scaffolds. Substrate scope. General reaction conditions: aniline 1 (0.2 mmol), 2 (0.4 mmol), and Cu(TFA)2 (0.04 mmol) in hexane (2.0 mmol) under air atmosphere, 12 h, 80 °C. Yields refer to isolated yields. Scale-up reaction.a Proposed mechanism. Optimization of reaction conditions.a

Asymmetric synthesis of fluorinated derivatives of aromatic and γ-branched amino acids via a chiral Ni(II) complex

• Maurizio Iannuzzi,
• Thomas Hohmann,
• Michael Dyrks,
• Kilian Haoues,
• Katarzyna Salamon-Krokosz and
• Beate Koksch

Beilstein J. Org. Chem. 2025, 21, 659–669, doi:10.3762/bjoc.21.52

• fluorinated amino acids that can be synthesized from a single starting material is a unique feature of this method, making it an important cornerstone of fluoropeptide chemistry. Experimental General information Air- and hydrolysis-sensitive reactions were carried out under exclusion of air and water in

Photocatalyzed elaboration of antibody-based bioconjugates

• Marine Le Stum,
• Eugénie Romero and
• Gary A. Molander

Beilstein J. Org. Chem. 2025, 21, 616–629, doi:10.3762/bjoc.21.49

• available and inexpensive Ru(bpy)3, along with a water-soluble, air- and moisture-stable Ni(dabpy)Br2 catalyst. Moreover, they demonstrated that this system works efficiently in aqueous conditions, making it highly suitable for applications involving antibodies. These characteristics make the method highly

Deep-blue emitting 9,10-bis(perfluorobenzyl)anthracene

• Long K. San,
• Sebastian Balser,
• Brian J. Reeves,
• Tyler T. Clikeman,
• Yu-Sheng Chen,
• Steven H. Strauss and
• Olga V. Boltalina

Beilstein J. Org. Chem. 2025, 21, 515–525, doi:10.3762/bjoc.21.39

• , bulky fluorinated substituents, such as perfluoroalkyls and perfluoroaryls, have been predicted by DFT [16] and shown experimentally [17], to improve the air- and photostability of acene-containing materials, by increasing their electron affinity and/or by sterically blocking reactive sites

• , respectively. In this work, we explored the effects of the bulky and electron-withdrawing substituent perfluorobenzyl (BnF) on the photophysical properties and on the air- and photostability of ANTH for the first time. We hypothesized that the steric bulk of BnF and the flexibility of the –CF2– moiety between

• ANTH and the –C6F5 group might provide the desired spatial isolation of the ANTH (and other PAH) cores, and result in enhanced photoluminescence by disrupting close π–π stacking in the solid state. In addition, air- and photostability might also be improved due to the steric and electronic properties

Synthesis of N-acetyl diazocine derivatives via cross-coupling reaction

• Thomas Brandt,
• Pascal Lentes,
• Jeremy Rudtke,
• Michael Hösgen,
• Christian Näther and
• Rainer Herges

Beilstein J. Org. Chem. 2025, 21, 490–499, doi:10.3762/bjoc.21.36

• cross-coupling reactions were performed by an organic halide reacting with an organotin compound. A great advantage of the used organostannanes is the easy accessibility, and their high air and moisture stability, so that usually a wide range of functional groups can be introduced under mild conditions

Photomechanochemistry: harnessing mechanical forces to enhance photochemical reactions

• Francesco Mele,
• Ana M. Constantin,
• Andrea Porcheddu,
• Raimondo Maggi,
• Giovanni Maestri,
• Nicola Della Ca’ and
• Luca Capaldo

Beilstein J. Org. Chem. 2025, 21, 458–472, doi:10.3762/bjoc.21.33

• Na2CO3 was ground in a mortar at room temperature for 3–5 min. Second, the reaction mixture was transferred into a quartz tube, heated to 50 °C (heating mantle) for 18 h, while being irradiated with blue LEDs under air-equilibrated conditions. In these conditions, product 3.3 was isolated in excellent

• ]. As an example, the authors were able to convert 4,4’-dimethoxybenzhydrol (6.1) to 4,4’-dimethoxybenzophenone (6.2) in 74% yield after isolation using 5 mol % RFTA under air (24 h), all performed without any additional solvent (Scheme 6). The authors noted that the reaction proceeds via a molten state

The effect of neighbouring group participation and possible long range remote group participation in O-glycosylation

• Rituparna Das and
• Balaram Mukhopadhyay

Beilstein J. Org. Chem. 2025, 21, 369–406, doi:10.3762/bjoc.21.27

• . performed glycosylations under solvent-free conditions with poorly reactive disarmed per-O-acetylated (15) and per-O-benzoylated (18) glycosyl donors on being activated in air aided by catalytic amounts of a mild promoter, methanesulphonic acid (Scheme 3) [92]. The ester group was capable of conjugating

Red light excitation: illuminating photocatalysis in a new spectrum

• Lucas Fortier,
• Corentin Lefebvre and
• Norbert Hoffmann

Beilstein J. Org. Chem. 2025, 21, 296–326, doi:10.3762/bjoc.21.22

• alcohols 32. Notably, this protocol is both energy-efficient and operationally simple, with the reaction being carried out under air in ethanol, a low-toxicity solvent. Moreover, the scalability of the reaction was demonstrated with larger-scale experiments (up to 5 mmol), achieving excellent yields and

• 40 has been proven to be the most efficient photocatalyst, promoting key transformations such as the aza-Henry reaction with 44 to give 45 under NIR light irradiation (Figure 6b). The reaction was found to critically depend on the presence of oxygen in the air for it to proceed. Through optimization

Visible-light-promoted radical cyclisation of unactivated alkenes in benzimidazoles: synthesis of difluoromethyl- and aryldifluoromethyl-substituted polycyclic imidazoles

• Yujun Pang,
• Jinglan Yan,
• Nawaf Al-Maharik,
• Qian Zhang,
• Zeguo Fang and
• Dong Li

Beilstein J. Org. Chem. 2025, 21, 234–241, doi:10.3762/bjoc.21.15

• , entries 10–13), and conducting the reaction under air instead of nitrogen significantly lowered the yield (Table 1, entry 14). Control experiments showed that the absence of PIDA resulted in no reaction (Table 1, entry 15), while the use of a 40 W light source or the absence of visible light also reduced

Cu(OTf)₂-catalyzed multicomponent reactions

• Sara Colombo,
• Camilla Loro,
• Egle M. Beccalli,
• Gianluigi Broggini and
• Marta Papis

Beilstein J. Org. Chem. 2025, 21, 122–145, doi:10.3762/bjoc.21.7

• process by using α-diazoketones, nitroalkenes and primary amines, in the presence of air as oxidant. The mechanism involved the formation of α-ketocarbene XXVI from α-diazoketone, able to react with the amine affording imine XXV after copper-catalyzed oxidative dehydrogenation. The subsequent [3 + 2

• , which favors the approach of the reaction centers. It is again a metal coordination that activates the C–C double bond towards an intramolecular reaction to give the tetrahydropyrazole XXX via formation of a C–N bond. The final oxidation in air gives the 4,5-dihydropyrazole 31. Cu(OTf)2 is also capable

Ceratinadin G, a new psammaplysin derivative possessing a cyano group from a sponge of the genus Pseudoceratina

• Shin-ichiro Kurimoto,
• Kouta Inoue,
• Taito Ohno and
• Takaaki Kubota

Beilstein J. Org. Chem. 2024, 20, 3215–3220, doi:10.3762/bjoc.20.267

• C24H2679Br281Br2N4O6Na, 808.84426; found, 808.84502. Cytotoxicity assay L1210 murine leukemia cells were cultured in RPMI-1640 supplemented with 10% FBS, and KB epidermoid carcinoma cells were cultured in DMEM supplemented with 10% FBS. All cells were incubated at 37 °C in a humidified atmosphere of 5% CO2 and 95% air

Germanyl triazoles as a platform for CuAAC diversification and chemoselective orthogonal cross-coupling

• John M. Halford-McGuff,
• Thomas M. Richardson,
• Aidan P. McKay,
• Frederik Peschke,
• Glenn A. Burley and
• Allan J. B. Watson

Beilstein J. Org. Chem. 2024, 20, 3198–3204, doi:10.3762/bjoc.20.265

• equiv), DMF, air, rt, 2 h. (iv) Pd(dtbpf)Cl2 (10 mol %), 2-acetylthiophen-3-ylboronic acid (1.2 equiv), K3PO4 (2.0 equiv), iPrOH/H2O 3:4, N2, 85 °C, 16 h. (v) Pd(dtbpf)Cl2 (2.0 mol %), 1-naphthylzinc bromide (1.2 equiv), THF, N2, 45 °C, 16 h. (vi) Cu(OAc)2·H2O (30 mol %), B(OH)3 (2.0 equiv), DBU (2.0

• equiv), MeCN, air, 70 °C, 24 h. (vii) Cu(OAc)2·H2O (30 mol %), B(OH)3 (2.0 equiv), piperidine (2.0 equiv), MeCN, air, 70 °C, 24 h. See Supporting Information File 1 for full details. Supporting Information The research data supporting this publication can be accessed at https://doi.org/10.17630

Surprising acidity for the methylene of 1,3-indenocorannulenes?

• Shi Liu,
• Märt Lõkov,
• Sofja Tshepelevitsh,
• Ivo Leito,
• Kim K. Baldridge and
• Jay S. Siegel

Beilstein J. Org. Chem. 2024, 20, 3144–3150, doi:10.3762/bjoc.20.260

• compounds tend to deprotonate to form highly stable anions. The air stability of TBF conforms to that model. In contrast, although the dianion of BFC can be generated with tert-butoxide under inert atmosphere, in the presence of water it quenches and exposed to oxygen it oxidizes to form the diketone

• pentabenzocorannulene would produce air-stable radical and ionic PAHs, and that coupling such fragments would lead to stable redox-active carbon sheets. Conclusion In conclusion, the “surprise” in the surprising pKa for BIC and FIC was in our expectation of the deprotonated forms as poorly delocalized fluorenyl anions

Advances in the use of metal-free tetrapyrrolic macrocycles as catalysts

• Mandeep K. Chahal

Beilstein J. Org. Chem. 2024, 20, 3085–3112, doi:10.3762/bjoc.20.257

• , cyclam (tetraazacyclotetradecane), phthalocyanines, corroles and their supramolecular frameworks have been widely used as both homogeneous and heterogeneous electrocatalysts for various energy conversion and storage techniques, such as fuel cells, water splitting devices, and rechargeable metal–air

• the UV–vis spectrum revealed a red shift, indicating the presence of diprotonated H4TPP2+ macrocycle (Figure 21a). Fc addition into an air-saturated DCE solution containing 18 (H2TPP) and HTB led to oxidation of Fc to Fc+ and initiated the ORR process (Figure 20b). The rate of ferrocene oxidation (Fc

Advances in radical peroxidation with hydroperoxides

• Oleg V. Bityukov,
• Pavel Yu. Serdyuchenko,
• Andrey S. Kirillov,
• Gennady I. Nikishin,
• Vera A. Vil’ and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2024, 20, 2959–3006, doi:10.3762/bjoc.20.249

• -butylperoxy radical. Peroxidation of β-naphthols 88 with TBHP under an air atmosphere was explored using CuBr as the catalyst resulting in the quaternary peroxide derivatives 89 in good yields (Scheme 32) [86]. An alternative approach to introducing the tert-butylperoxy moiety into phenols is the use of

The charge transport properties of dicyanomethylene-functionalised violanthrone derivatives

• Sondos A. J. Almahmoud,
• Joseph Cameron,
• Dylan Wilkinson,
• Michele Cariello,
• Claire Wilson,
• Alan A. Wiles,
• Peter J. Skabara and
• Graeme Cooke

Beilstein J. Org. Chem. 2024, 20, 2921–2930, doi:10.3762/bjoc.20.244

• . The substrates were washed using deionised H2O, acetone, and isopropanol before being dried over a stream of compressed air. Octadecyltrichlorosilane (30 μM) was dropcast onto the substrate for 5 minutes before the substrate was washed with toluene. The substrate was then dried over compressed air. A

Recent advances in transition-metal-free arylation reactions involving hypervalent iodine salts

• Ritu Mamgain,
• Kokila Sakthivel and
• Fateh V. Singh

Beilstein J. Org. Chem. 2024, 20, 2891–2920, doi:10.3762/bjoc.20.243

• can present limitations. However, a more efficient method for synthesizing sulfilimines emerged in 2023, involving the selective S-arylation of sulfenamides 97 with diaryliodonium salts 98 at ambient temperature in the presence of air (Scheme 39). These innovative approaches offer promising

• product yield increased [93]. Similarly, the arylation of sulfonamides can also be achieved by using t-BuONa in toluene for an hour at room temperature in the presence of air (conditions D) [94]. The mechanism of the reaction involves formation of anionic intermediates I and II by the action of the base