Silica gel with covalently attached bambusuril macrocycle for dicyanoaurate sorption from water

• Michaela Šusterová and
• Vladimír Šindelář

Beilstein J. Org. Chem. 2025, 21, 2604–2611, doi:10.3762/bjoc.21.201

• was filtered and thoroughly washed with DMF, water and methanol in order to remove byproducts and unreacted BU1. After air-drying, SG-NHCO-BU1 was obtained. Preparation of SG-BU1 For the preparation of SG-BU1 with electrostatically bound BU1 on the surface of silica gel, a-SG (0.9 g) was suspended in

• DMF (15 mL) and BU1 (0.1 g), dissolved in a minimum amount of DMF, was added. The dispersion was mechanically shaken (180 rpm) at ambient temperature for 5.5 h. Afterwards, the dispersion was filtered, washed with DMF (5×) and methanol (5×) to remove unattached BU1. After air-drying in a hood

Assembly strategy for thieno[3,2-b]thiophenes via a disulfide intermediate derived from 3-nitrothiophene-2,5-dicarboxylate

• Roman A. Irgashev

Beilstein J. Org. Chem. 2025, 21, 2489–2497, doi:10.3762/bjoc.21.191

• visible region, and improved morphological stability [4][5][6]. Recent reports have shown that the development of alkyl-supported TT-based semiconductors has led to high-performance, air-stable OFETs [7], while integration of TT frameworks into donor–acceptor architectures has enabled the development of

The high potential of methyl laurate as a recyclable competitor to conventional toxic solvents in [3 + 2] cycloaddition reactions

• Ayhan Yıldırım and
• Mustafa Göker

Beilstein J. Org. Chem. 2025, 21, 2389–2415, doi:10.3762/bjoc.21.184

• chloroform and toluene do not pose a risk to 3 species (please see the green colored icons). In terms of environmental risk factors, the persistence of methyl laurate in soil, sediment and water, with the exception of air, is significantly lower than that of the other two solvents (values are calculated in

• of hexane and dried in open air. The resulting mixture of isomers was subjected to direct NMR analysis, without any additional purification or separation steps. Versatile compounds via cycloaddition reactions. a) Radar view of the physical properties of methyl laurate. b) Oral toxicity values of

Electrochemical cyclization of alkynes to construct five-membered nitrogen-heterocyclic rings

• Lifen Peng,
• Ting Wang,
• Zhiwen Yuan,
• Bin Li,
• Zilong Tang,
• Xirong Liu,
• Hui Li,
• Guofang Jiang,
• Chunling Zeng,
• Henry N. C. Wong and
• Xiao-Shui Peng

Beilstein J. Org. Chem. 2025, 21, 2173–2201, doi:10.3762/bjoc.21.166

• (0.3 mmol) and n-Bu4NBF4 (0.45 mmol), under electrolysis (Pt plate as electrodes, 5 mA) at air for 10 h. Electron-donating (Me, Et, t-Bu and OMe) or electron-withdrawing (Cl, Br and F) groups involved phenylacetylenes, 1-ethynylnaphthalene and 2-ethynylthiophene were tolerated well under these reaction

C2 to C6 biobased carbonyl platforms for fine chemistry

• Jingjing Jiang,
• Muhammad Noman Haider Tariq,
• Florence Popowycz,
• Yanlong Gu and
• Yves Queneau

Beilstein J. Org. Chem. 2025, 21, 2103–2172, doi:10.3762/bjoc.21.165

• a C1 building block for the N-formylation of secondary amines to formamides under catalyst-free conditions and air as oxidant. This method was applied to different aromatic and aliphatic (both cyclic and acyclic) amines (Scheme 3) [31]. Already in 1955, Parham and Reiff reported the synthesis and

The application of desymmetric enantioselective reduction of cyclic 1,3-dicarbonyl compounds in the total synthesis of terpenoid and alkaloid natural products

• Dong-Xing Tan and
• Fu-She Han

Beilstein J. Org. Chem. 2025, 21, 2085–2102, doi:10.3762/bjoc.21.164

• and aldehyde 37, which was prepared with 9 steps from commercially available (+)-citronellol, underwent a Reformatsky-type radical addition under the conditions of Et3B/air/Bu3SnH to deliver aldol product [16]. Dehydration of the secondary alcohol gave (E)-38. The HAT radical cyclization [17] of 38 in

Photoswitches beyond azobenzene: a beginner’s guide

• Michela Marcon,
• Christoph Haag and
• Burkhard König

Beilstein J. Org. Chem. 2025, 21, 1808–1853, doi:10.3762/bjoc.21.143

• , this form is not stable, and it easily undergoes irreversible oxidation under air to give phenanthrene (IV). This challenge was addressed by substituting the hydrogen atoms with methyl groups in 124-II. Moreover, the E–Z isomerisation could be avoided by adding a ring to the central double bond, thus

Fe-catalyzed efficient synthesis of 2,4- and 4-substituted quinolines via C(sp²)–C(sp²) bond scission of styrenes

• Prafull A. Jagtap,
• Manish M. Petkar,
• Vaishnavi R. Sawant and
• Bhalchandra M. Bhanage

Beilstein J. Org. Chem. 2025, 21, 1799–1807, doi:10.3762/bjoc.21.142

• [53]. In this work, the authors used a stoichiometric amount of Zn(OTf)3 as a Lewis acid catalyst and air as the oxidant for the reaction. Jana and colleagues demonstrated an atom-efficient pseudo-three-component C–H annulation reaction catalyzed by Yb and Cu, which involved nitrosoarenes and styrene

Formal synthesis of a selective estrogen receptor modulator with tetrahydrofluorenone structure using [3 + 2 + 1] cycloaddition of yne-vinylcyclopropanes and CO

• Jing Zhang,
• Guanyu Zhang,
• Hongxi Bai and
• Zhi-Xiang Yu

Beilstein J. Org. Chem. 2025, 21, 1639–1644, doi:10.3762/bjoc.21.127

• target Heck coupling, finding that using 1,4-dioxane as the solvent and 20 mol % PdCl2 as the catalyst, 11 could be obtained in 40% yield in the air. We tried by using more catalyst, or adding O2 (or CuCl2) as oxidant, but all these efforts did not give improved reaction yields (the reason for this was

Facile synthesis of hydantoin/1,2,4-oxadiazoline spiro-compounds via 1,3-dipolar cycloaddition of nitrile oxides to 5-iminohydantoins

• Juliana V. Petrova,
• Varvara T. Tkachenko,
• Victor A. Tafeenko,
• Anna S. Pestretsova,
• Vadim S. Pokrovsky,
• Maxim E. Kukushkin and
• Elena K. Beloglazkina

Beilstein J. Org. Chem. 2025, 21, 1552–1560, doi:10.3762/bjoc.21.118

• triethylamine solution was slowly added dropwise to the reaction mixture at 0 °C under an inert gas atmosphere to avoid moisture from the air (“classical” method). In another method, the base was inserted via diffusion of NEt3 into a solution containing the dipolarophile and dipole precursor (see Figure S1 in

General method for the synthesis of enaminones via photocatalysis

• Paula Pérez-Ramos,
• Raquel G. Soengas and
• Humberto Rodríguez-Solla

Beilstein J. Org. Chem. 2025, 21, 1535–1543, doi:10.3762/bjoc.21.116

• adduct 10 was identified using GC–MS (Figure S1, Supporting Information File 1). When the reaction was performed under air-equilibrated conditions, the intended product 9a was obtained in a 31% yield, indicating that air influenced the interaction between the Ni-catalyst and the α,β-unsaturated carbonyl

Ambident reactivity of enolizable 5-mercapto-1H-tetrazoles in trapping reactions with in situ-generated thiocarbonyl S-methanides derived from sterically crowded cycloaliphatic thioketones

• Grzegorz Mlostoń,
• Małgorzata Celeda,
• Marcin Palusiak,
• Heinz Heimgartner,
• Marta Denel-Bobrowska and
• Agnieszka B. Olejniczak

Beilstein J. Org. Chem. 2025, 21, 1508–1519, doi:10.3762/bjoc.21.113

• hours of cooling a colorless solid was separated. The crystalline material was filtered off and dried in the air at rt. 10-Thia-7,8-diazatrispiro[4.0.46.0.411.15]hexadec-7-en-16-one (2c): Yield: 910.0 mg (91%); mp 53‒55 °C (dec.); 1H NMR (CDCl3) δ 1.32–1.39 (m, 2H), 1.39–1.48 (m, 2H), 1.53–1.60 (m, 2H

Highly distinguishable isomeric states of a tripodal arylazopyrazole derivative on graphite through electron/hole-induced switching at ambient conditions

• Himani Malik,
• Sudha Devi,
• Debapriya Gupta,
• Ankit Kumar Gaur,
• Sugumar Venkataramani and
• Thiruvancheril G. Gopakumar

Beilstein J. Org. Chem. 2025, 21, 1496–1507, doi:10.3762/bjoc.21.112

• pyrolytic graphite (HOPG, ZYB grade from μMasch). Approximately 4 μL of solutions of FNAAP were drop-casted on the HOPG surface, dried (a few minutes) in ambient conditions, and AFM/STM studies were performed. Relative humidity (≈50%) and temperature (22–25 °C) of the room were controlled by an air

• green dashed lines. Two resonances are rotated by ≈120° and correspond to the major orientations of the domains in the 1D phase. Constant current STM topographs (300 pA, 0.3 V) of the FNAAP adlayer on HOPG (a, b) deposited from the corresponding ethanolic solution. Imaging is performed at the HOPG–air

Photoredox-catalyzed arylation of isonitriles by diaryliodonium salts towards benzamides

• Nadezhda M. Metalnikova,
• Nikita S. Antonkin,
• Tuan K. Nguyen,
• Natalia S. Soldatova,
• Alexander V. Nyuchev,
• Mikhail A. Kinzhalov and
• Pavel S. Postnikov

Beilstein J. Org. Chem. 2025, 21, 1480–1488, doi:10.3762/bjoc.21.110

• . Finally, control experiments without irradiation gave only traces of the benzamide 2aa showing no activation by the Ru complex at room temperature (Table 1, entry 24). An experiment conducted under an air atmosphere yielded only 9% of 2aa (Table 1, entry 25) indicating that the presence of atmospheric

Microwave-enhanced additive-free C–H amination of benzoxazoles catalysed by supported copper

• Andrei Paraschiv,
• Valentina Maruzzo,
• Filippo Pettazzi,
• Stefano Magliocco,
• Paolo Inaudi,
• Daria Brambilla,
• Gloria Berlier,
• Giancarlo Cravotto and
• Katia Martina

Beilstein J. Org. Chem. 2025, 21, 1462–1476, doi:10.3762/bjoc.21.108

• being applied when reacting amides to achieve their decarbonylation. In 2014, Cao et al. [47] reported the amination of benzoxazole with a secondary amine either in air or an O2 atmosphere, lowering the catalyst amount and the reaction temperature. In 2020, a study by De Vos and co-workers [48] focused

• temperature and gas pressure (up to 300 °C and 200 bar). The SynthWave reactor also allows multiple gases to be loaded, including both inert and reactive gases. As shown in Table 2, MW irradiation significantly reduced reaction times from 6 hours to 2 hours under atmospheric air conditions. At 60 °C with 20

• 13%, highlighting the importance of oxygen/air in the oxidative aromatisation of the benzoxazole ring. Reducing the reaction time to 1 hour or lowering the catalyst loading to 15 mol % resulted in decreased yields of 75% and 71%, respectively. The reaction was also carried out in Anton Paar equipment

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