Synthetic study of vic-bromination of diarylacetylenes, easy purification and separation

• Akane Togo,
• Hiyono Suzuki,
• Yuto Akai,
• Makoto Matsumoto,
• Yoshinori Suzuma,
• Hidehiko Kodama and
• Kouichi Matsumoto

Beilstein J. Org. Chem. 2026, 22, 795–802, doi:10.3762/bjoc.22.61

• scope and limitations by using various diarylacetylenes bearing the substituents on the benzene ring at para-position. The results were summarized in Table 2. Depending on the product's characteristics, either heptane or methanol was used for purification and separation. The reaction of 1,2-di-p

• ). Poor selectivity as shown in entries 1 and 2 might be due to the stability of the intermediate. In the cases of Table 2, entries 3–6 residues such as MeO, F, Br and CN as the substituent at para position of the benzene ring in 1d–g, the selectivity of E and Z and the isolated yield of the E isomer

• seemed to be good. In the case of unsymmetrical diarylacetylene, 1-(tert-butyl)-4-((4-fluorophenyl)ethynyl)benzene (1h) was tested and the corresponding E-2h was isolated and purified with MeOH. E-2h was obtained in 41% yield (Table 2, entry 7). A gram-scale synthesis of E-2a and Z-2a from 1a was

Halogenated azobenzene acrylates: from efficient solution photoswitching to stable solid-state photochromic materials

• Martina Vachtlová,
• Michaela Fecková,
• Vítězslav Zima,
• Jan Podlesný,
• Milan Klikar,
• Oldřich Pytela,
• Patrik Pařík,
• Jakub Opršal,
• Eliška Juhaňáková,
• Veronika Chrtová and
• Filip Bureš

Beilstein J. Org. Chem. 2026, 22, 782–794, doi:10.3762/bjoc.22.60

• angle between both benzene ring planes denoted as ϕE/Z has been employed to judge planarity of both isomers (see Supporting Information File 1, Table S1). The monosubstituted E-isomers are nearly planar (ϕE = 168–180°), while the disubstituted E-isomers are rather twisted with ϕE =122–146°. The

Preparation of 3-(alkylamino)imidazo[1,2-a]pyridine-2-carbaldehydes via Kornblum oxidation and unexpected ring-opening reactions of the corresponding alcohols under oxidative conditions

• Sandile J. Mkhize,
• Memory Zimuwandeyi,
• Manuel A. Fernandes,
• Amanda L. Rousseau and
• Moira L. Bode

Beilstein J. Org. Chem. 2026, 22, 763–770, doi:10.3762/bjoc.22.58

• torsional flexibility which might maintain activity against the viral mutants. The plan was to increase compound flexibility through introduction of a bridging nitrogen atom between the imidazopyridine ring and the benzene ring of the original compounds such as 5. Initially, it was envisaged that chemotype

Harnessing light energy with molecules

• Grace G. D. Han,
• Mogens Brøndsted Nielsen and
• Hermann A. Wegner

Beilstein J. Org. Chem. 2026, 22, 680–682, doi:10.3762/bjoc.22.52

• trisNBD-benzene, overcoming the signal overlap that limits conventional 1H NMR analysis. Further, the consequences on the absorption properties, photoisomerization, and QC lifetime were studied. In another article by Krappmann and Hirsch [6], the implications of replacing the methylene bridge of the NBD

Photoorganocatalytic trifluoromethylation of (het)arenes in green conditions

• Egor N. Boronin,
• Svetlana E. Kaurkina,
• Milena M. Svetlakova,
• Anton S. Bolshakov,
• Maxim V. Arsenyev,
• Vasilii F. Otvagin,
• Alexey Yu. Fedorov,
• Timothy Noël and
• Alexander V. Nyuchev

Beilstein J. Org. Chem. 2026, 22, 662–671, doi:10.3762/bjoc.22.50

• ); unreactive substrates are shown in Supporting Information File 1, Schemes S4 and S5. Benzene, toluene, tert-butylbenzene, biphenyl, naphthalene, o-xylene, and durene afforded the corresponding products 2–8 in moderate yields. In contrast, mesitylene, a less electron-enriched substrate than durene, gave

• CF3 radical, is an endothermic process. The subsequent attack of the electrophilic CF3 radical on the benzene ring, accompanied by its oxidation, proceeds through exothermic steps. The proton transfer to the solvent constitutes the most favorable step, resulting in an overall free energy change (ΔG

• ) of −17.8 kcal mol−1 for the catalytic cycle, thereby confirming the energetic feasibility of the proposed mechanism (Scheme 4). Furthermore, the scope analysis revealed that trifluoromethylation of benzene proceeds less efficiently than the corresponding reaction with TMB. We therefore hypothesized

Advantages of PROTACs in achieving selective degradation of homologous protein families

• Luxi Yang,
• Xinfei Mao,
• Jingyi Zhang,
• Jing Shu,
• Wenhai Huang,
• Xiaowu Dong,
• Yinqiao Chen and
• Mingfei Wu

Beilstein J. Org. Chem. 2026, 22, 628–661, doi:10.3762/bjoc.22.49

Kinetic resolution of racemic planar-chiral vinylcymantrenes by molybdenum-catalyzed asymmetric metathesis dimerization

• Haruna Imazu,
• Hitoshi Izu,
• Yasuhiro Ohki and
• Masamichi Ogasawara

Beilstein J. Org. Chem. 2026, 22, 568–574, doi:10.3762/bjoc.22.42

• benzene at the indicated temperature in the presence of an appropriate chiral Mo-precatalyst (10 mol %), which was generated in situ from the Mo-precursor, (pyrrolyl)2Mo(=CHCMe2Ph)(=N-C6H3-2,6-iPr2) [36], and an axially chiral biphenol ligand. The chiral Mo/(R)-L1 precatalyst [21] facilitated the

Melifoliox B, a novel phloroglucin derivative isolated from Melicope barbigera (Rutaceae) and synthesis of new oxidation products from melifoliones A and B

• Horst Weber,
• Kim-Thao Tran-Cong,
• Bernhard Mayer,
• Guido J. Reiss,
• Iryna S. Konovalova,
• Marc S. Appelhans,
• Kenneth R. Wood and
• Claus M. Passreiter

Beilstein J. Org. Chem. 2026, 22, 535–546, doi:10.3762/bjoc.22.39

• information for a better understanding of the NMR spectra. In contrast to the planar benzene ring of melifoliones, the para quinol ring in 4 adopts a flat but rigid boat conformation. However, the sp3-hybridized C-10b leads to greater flexibility of the whole molecule. Therefore, it is easier for the

Get a better glimpse on sequential photoreactions of trisnorbornadienes with ¹⁹F NMR spectroscopy

• Julian Felix Maria Hebborn,
• Ben Eric Merten,
• Thomas Paululat and
• Heiko Ihmels

Beilstein J. Org. Chem. 2026, 22, 527–534, doi:10.3762/bjoc.22.38

• benzene (see Supporting Information File 1, Figure S1). The absorption spectra have essentially the same key features, specifically absorption maxima at around 209 nm, 240 nm, and 273 nm, with a long-wavelength absorption onset at 350 nm. Both maxima and onset absorptions are hypsochromically shifted

• sensitized photocycloaddition reaction [48] A solution of the norbornadiene (4.02–25.0 mg, 10.0–62.1 mmol) and the sensitizer Ir(ppy)3 or [Ru(phen)3](PF6)2 (5–10 mol %) in deaerated benzene or MeCN was irradiated with light (λex = 420 or 520 nm) for 0.5–3 h. The solvent was removed under reduced pressure at

• benzene (4 mL) was irradiated with λex = 420 nm at rt for 3 h. The product was obtained as an opaque viscous liquid (24.6 mg, 61.1 µmol, >95%). 1H NMR (500 MHz, CDCl3) δ 1.54–1.57 (m, 1H), 1.67 (ddd, 3J = 6.0 Hz, 3J = 4.5 Hz, 3J = 2.2 Hz, 1H), 1.73–1.78 (m, 1H), 1.84–1.89 (m, 1H), 2.10 (dt, 2J = 11.1 Hz

Modern synthetic pathways towards eribulin and its subunits

• Sebastian Dominik Graf

Beilstein J. Org. Chem. 2026, 22, 495–526, doi:10.3762/bjoc.22.37

Recent advances in the stereoselective synthesis of distal biaxially chiral molecules

• Fanxing Zhou,
• Chen Zhang,
• Lingyu Sun,
• Yiyun Fang,
• Siming Zheng,
• Lina Hu,
• Mengyang Shen,
• Zhen Zhao,
• Wei Xu,
• Yunqiang Sun and
• Zi-Qiang Rong

Beilstein J. Org. Chem. 2026, 22, 461–479, doi:10.3762/bjoc.22.34

• carboxylic acid derivatives (Scheme 2b) [43]. They revealed that ortho-alkoxy substitution on the benzene-derived alkyne markedly enhanced both reactivity and enantioselectivity, while incorporation of a naphthyl substituent into the diyne enabled access to remote biaxially chiral molecules. Subsequent

A facile and practical method for the synthesis of trans-(±)-taxifolin and its derivatives via Darzens reaction

• Bo Peng,
• Panpan Yang,
• Maaz Khan,
• Xiaotong Lin,
• Jiang Wu,
• Peng Fu and
• Qingqing Wu

Beilstein J. Org. Chem. 2026, 22, 443–450, doi:10.3762/bjoc.22.31

• (Supporting Information File 1, Table S1, entries 3–5, and 7). When NaHCO3 was used as an additive to neutralize HBr in the reaction mixture that was responsible for the cleavage of MOM, bromination with PTT was also unsuccessful in that the bromination occurred at the benzene ring and MOM was partially

• . The stereochemical outcome of the Darzens reaction may produce the α,β-epoxycarbonyl products with either the substituents on the same side or opposite side of the epoxy functionality, i.e., as cis/trans isomers. In this work, the α,β-epoxycarbonyl product contains bulky multiple-substituted benzene

Synthesis and stereochemical analysis of dynamic planar chiral oxa[7]orthocyclophene

• Yukiho Hashimoto,
• Yuuya Kawasaki,
• Kazunobu Igawa and
• Katsuhiko Tomooka

Beilstein J. Org. Chem. 2026, 22, 436–442, doi:10.3762/bjoc.22.30

• X-ray crystallographic analysis was performed (CCDC 2513894). The solid-state structure of 1ac shows that the phenyl group on the E-alkene is directed antiparallel to the fused benzene ring. The dihedral angle of the alkene moiety (∠C4–C5–C6–C7) of 1ac is 146.4°, which is distorted by 33.6° from an

Cone p-aminocalix[4]arenes enriched with ‘clickable’ alkyne or azide functionalities

• Ilia Korniltsev,
• Vasily Bazhenov,
• Alexander Gorbunov,
• Dmitry Cheshkov,
• Stanislav Bezzubov,
• Vladimir Kovalev and
• Ivan Vatsouro

Beilstein J. Org. Chem. 2026, 22, 399–415, doi:10.3762/bjoc.22.28

• complexation processes were obtained in these cases either; adding excess salt to solutions of these calixarenes in CDCl3 or in CDCl3/benzene-d6 mixtures resulted in the formation of insoluble precipitates containing the entire portions of the hosts, thus indicating a complexation process but the

Dialkylaminoalkylation of β-ketosulfones via ring-opening of 3-sulfonylpyrrolidines

• Evgeny M. Buev,
• Alexander V. Pavlushin,
• Vladimir S. Moshkin and
• Vyacheslav Y. Sosnovskikh

Beilstein J. Org. Chem. 2026, 22, 383–389, doi:10.3762/bjoc.22.26

• results. Refluxing a mixture of ketosulfone 1, a two-fold excesses of N-methylglycine and paraformaldehyde in benzene with a Dean–Stark trap for 4 h yields incomplete conversion of the substrate (Scheme 1, product 2a, 60%). However, we did not observe the resinification of the reaction media and hence we

Electrosynthetic access to unsymmetrical oxaza[8]helicenes with high chiral stability and strong circularly polarized luminescence (CPL)

• Tin Zar Aye,
• Rubal Sharma,
• Muthu Karuppasamy,
• Daiya Suzuki,
• Haruka Nakajima,
• Yoshitane Imai,
• Mitsuhiro Arisawa,
• Mohamed S. H. Salem and
• Shinobu Takizawa

Beilstein J. Org. Chem. 2026, 22, 372–382, doi:10.3762/bjoc.22.25

• attributed to magnetic coupling between the face-to-face terminal rings, in line with the Johnson–Bovey model, given the inter-ring distances of approximately 3.75–3.79 Å [59]. On the other hand, the aromaticity of the pyrrole rings (A and A′) and benzene rings G and G′ in 5a and 5b decreases, which can be

• resulting plots show a clockwise diatropic current along the fused heterocycles and benzene rings, in agreement with the ring-current patterns reported for other helicene scaffolds [27] (Figure 2B). Enantiomerization barriers of oxaza[7]helicenes To investigate the enantiomerization (P/M) barriers of oxaza

Ring contraction and ring expansion reactions in terpenoid biosynthesis and their application to total synthesis

• Nicolas Kratena,
• Nicolas Heinzig and
• Peter Gärtner

Beilstein J. Org. Chem. 2026, 22, 289–343, doi:10.3762/bjoc.22.21

• 4-membered ring (see Scheme 23B). Finally, acetal formation on the novel carbaldehyde furnished the structure of pepluacetal (89). An interesting example for both the ring expansion and contraction of benzene rings in nature was unveiled during investigations into the biosynthesis of xenovulene A

• natural product liphagal (104). A ring contraction from 6→5 was suggested for the biosynthesis of taiwaniaquinol natural products and is depicted in Scheme 27 [151][152][153][154][155][156]. The precursor to this family of natural products, 6,7-dehydroferruginol (107), is oxidised both at the benzene core

Arene activation via π-bond localization: concepts and opportunities

• Paul Meiners,
• Julian J. Melder and
• Tobias Morack

Beilstein J. Org. Chem. 2026, 22, 257–273, doi:10.3762/bjoc.22.19

• ; Introduction Aromaticity has intrigued chemists since Michael Faraday’s isolation of benzene in 1825, marking the beginning of a concept that has shaped much of modern chemical thinking [1][2]. Despite its fundamental importance, aromaticity remains an abstract notion [3]. It is central to understanding

• molecular structure and reactivity, yet it cannot be measured directly [4]. This inherent elusiveness contributed to decades of debate over the structure of benzene, the prototypical aromatic molecule, until August Kekulé proposed his venerable representation: a six-membered carbon ring with alternating

• single and double bonds (Figure 1A) [5]. However, despite its strength in representing a planar cyclic arrangement of tetravalent carbon atoms, this formalism fails to accurately depict the observed reactivity, structure, and stability of benzene. It implies three rapidly equilibrating, localized double

A mild and atom-efficient four-component cascade strategy for the construction of biologically relevant 4-hydroxyquinolin-2(1H)-one derivatives

• Dmitrii A. Grishin,
• Kseniia I. Sharkovskaia,
• Ilya G. Kolmakov,
• Daria A. Ipatova,
• Rostislav A. Petrov,
• Nikolai D. Dagaev,
• Dmitry A. Skvortsov,
• Maria G. Khrenova,
• Valeriy V. Andreychev,
• Sergei A. Evteev,
• Yan A. Ivanenkov,
• Roman L. Antipin,
• Olga А. Dontsova and
• Elena K. Beloglazkina

Beilstein J. Org. Chem. 2026, 22, 244–256, doi:10.3762/bjoc.22.18

• isopropanol as the solvent under the established conditions. This resulted in a mixture of the open-chain isopropyl ester and the corresponding cyclic product, with the latter predominating. When a mixture of isopropanol and benzene (1:1.5) was employed as the solvent, no isopropyl ester was formed

Configuration–packing synergy enabling integrated crystalline-state RTP and amorphous-state TADF

• Ruiyan Wang and
• Yunan Wu

Beilstein J. Org. Chem. 2026, 22, 224–236, doi:10.3762/bjoc.22.16

• -tris(1-phenyl-1H-benzoimidazol-2-yl)benzene, is the electron-transport material, and CBP – 4,4′-N,N′-dicarbazolebiphenyl is used as the host material mixed with 1 to form the emissive layer. As illustrated in Figure 9a, the electroluminescence peak of the fabricated OLED is observed at 533 nm. This

Total synthesis of natural products based on hydrogenation of aromatic rings

• Haoxiang Wu and
• Xiangbing Qi

Beilstein J. Org. Chem. 2026, 22, 88–122, doi:10.3762/bjoc.22.4

• mutually compatible, and rationalized facial selectivity through insights from asymmetric styrene hydrogenation. In 2024, Glorius and co-workers developed a chemoselective hydrogenation strategy capable of selectively reducing benzene rings in the presence of pyridine rings (Scheme 4) [47]. Supported by

• hydrogenation of the polycyclic aromatic compound PyBQ to PyBTHQ using this catalyst in HFIP (Scheme 5) [50]. Under the optimized conditions, only the heteroaromatic part of quinoline was reduced selectively, while the benzene ring and pyridine remained unchanged. In 2020, Beller and co-workers used a manganese

• 53 while retaining the benzene ring structure using an iridium catalyst to selectively hydrogenate indoles and benzofurans (Scheme 7) [59]. The hydrogenated products were obtained in 90% yield with 98% ee on average. In 2024, Yin and co-workers reported an innovative palladium-catalyzed asymmetric

Advances in Zr-mediated radical transformations and applications to total synthesis

• Hiroshige Ogawa and
• Hugh Nakamura

Beilstein J. Org. Chem. 2026, 22, 71–87, doi:10.3762/bjoc.22.3

• available materials, in benzene afforded the Zr(RCNN)2 complex 18. Investigation of the photoredox properties of the synthesized complex revealed trends similar to those of known photosensitizers, suggesting its potential utility as a photosensitizer [15]. Accordingly, the Zr(MeCNN)2 complex was employed as

Synthesis and applications of alkenyl chlorides (vinyl chlorides): a review

• Daniel S. Müller

Beilstein J. Org. Chem. 2026, 22, 1–63, doi:10.3762/bjoc.22.1

• vary widely across the literature, with solvents ranging from neat conditions to cyclohexane, hexanes, toluene, benzene, carbon tetrachloride, dichloromethane, and diethyl ether. Reaction temperatures span from −10 °C to 100 °C. The first detailed investigation of this transformation was reported by

• Kagan and co-workers [48], who demonstrated that the reaction of acetophenone (1) with PCl5 in refluxing benzene affords a complex product mixture (Scheme 2). A second, very detailed investigation of this reaction was presented by Jung and Kwon [49]. Focusing on the synthesis of efavirenz (21), a potent

Synthesis of new tetra- and pentacyclic, methylenedioxy- and ethylenedioxy-substituted derivatives of the dibenzo[c,f][1,2]thiazepine ring system

• Gábor Berecz,
• András Dancsó,
• Mária Tóthné Lauritz,
• Loránd Kiss,
• Gyula Simig and
• Balázs Volk

Beilstein J. Org. Chem. 2025, 21, 2645–2656, doi:10.3762/bjoc.21.205

• Group, Magyar tudósok krt. 2, H-1117 Budapest, Hungary 10.3762/bjoc.21.205 Abstract New tetra- and pentacyclic derivatives of the dibenzo[c,f][1,2]thiazepine ring system have been synthesized. The target compounds contain methylenedioxy or ethylenedioxy substituents linked to the benzene ring. The key

Ni-promoted reductive cyclization cascade enables a total synthesis of (+)-aglacin B

• Si-Chen Yao,
• Jing-Si Cao,
• Jian Xiao,
• Ya-Wen Wang and
• Yu Peng

Beilstein J. Org. Chem. 2025, 21, 2548–2552, doi:10.3762/bjoc.21.197

• followed by reaction with CH(OMe)3 afforded acetal 17, which was then subjected to a CH2Cl2 solution of TMSOTf and iPr2NEt. A mixture of enol methyl ethers 18 were thus produced by an elimination reaction. Eventually, a site-selective bromination of the double bond over the electron-rich benzene rings with