An undecacyclic carbon-centered hydrocarbon radical: synthesis and investigation

• Ali S. Acan,
• Johannes Werner and
• Joachim Podlech

Beilstein J. Org. Chem. 2026, 22, 1196–1204, doi:10.3762/bjoc.22.95

• ], numerous stable carbon-centered hydrocarbon radicals [22] have been synthesized and investigated. However, only a limited number of these radicals turned out to be stable towards air, moisture, and solvents, or showed resistance to dimerization (as in the formation of Gomberg’s dimer 2) or

• synthesized nonacyclic radicals 5 and 6 [46]. Herein, we report the synthesis and comprehensive characterization of a new CP-PAH radical 7 as a further rare example of a stable, carbon-centered radical with a further extended π system. Results and Discussion Synthesis The synthesis of radical 7 was initiated

• spin density is delocalized over the undecacylic framework, which accounts for the absence of resolved hyperfine structure. Nevertheless, pronounced Mulliken atomic spin densities (Figure 3) are calculated for the mesityl-substituted carbon atoms. Densities at the respective outer carbons C-16 and C-19

Triazole-based hybrid molecules in anticancer drug discovery: structural classes and mechanistic insights, 2014–2025

• Meena Bhandari,
• Akshi Goyal and
• Deepak Yadav

Beilstein J. Org. Chem. 2026, 22, 1168–1195, doi:10.3762/bjoc.22.94

• interest in therapeutic chemistry [21]. Triazoles are five-membered heterocycles with three nitrogen and two carbon atoms, existing in two isomeric forms, i.e., 1,2,3-triazole and 1,2,4-triazole (Figure 3) and several methods have been developed for their regioselective synthesis [22][23][24]. They have

• –coumarin hybrids tethered through a 1,2,3-triazole linker (24a,b and 25, Figure 7) showed promising cytotoxicity towards THP-1, COLO-205, and HCT-116 cancer cell lines with IC50 values ranging from 0.82 to 9.95 µM but displayed no significant effect on PC-3 cells. Importantly, the two-carbon spacer flanked

The surprising reaction of (chloro- and methanesulfonyloxy)(phenyl)methylphosphonates and –(phenyl)methylphosphine oxides with potassium diphenylphosphide followed by oxidation

• Zsuzsanna Szalai,
• Janka Bednárik,
• András Miskó,
• Angéla Takács,
• László Kőhidai,
• László Drahos and
• György Keglevich

Beilstein J. Org. Chem. 2026, 22, 1160–1167, doi:10.3762/bjoc.22.93

• to give the major product diethyl (diethoxyphosphonyl)(phenyl)methyl phosphate (6), and the minor species (diphenylphosphinoyl)(phenyl)methyl diphenylphosphinate (8a). The unstability of bis(>P(O)-functionalized hydroxymethylene derivatives, especially with a phenyl group on the central carbon atom

• series of compound family 8, the P-diphenyl derivative 8a and the bis(4-methylphenyl)-substituted 8e were the most potent. These results indicate that the strong activity does not require substitution at the aryl ring attached to the central carbon, since neither the electron-withdrawing chloro

A cascade synthesis of 2-aminothiochromones from 2-fluorophenyl ketone and thiocarbonyldiimidazole

• Kai Zhang,
• Haofan Shao,
• Kangjun Liao,
• Ying Xu,
• Shimei Du,
• Yanfang Zhao,
• Gang Li,
• Wenzhen Xu,
• Haihong Huang and
• Peng Li

Beilstein J. Org. Chem. 2026, 22, 1151–1159, doi:10.3762/bjoc.22.92

• bioactivity. In 2018, we reported a strategy for the construction of the 2-aminothiochromone scaffold with the aim of identifying antitubercular agents [27]. This approach involved the reaction of o-chloroacetophenone bearing an electron-withdrawing group with carbon disulfide to furnish the core scaffold

Construction of CF₂ moieties in FDA-approved drugs (2016–2025): industrial routes, mechanisms, and scale-up considerations

• Wenyan Yao,
• Huanhuan Zhang,
• Xiaolong Yang and
• Feng Liu

Beilstein J. Org. Chem. 2026, 22, 1122–1150, doi:10.3762/bjoc.22.91

• an inexpensive enzymatic process [8]), route a suffered from several scale-up issues: the use of OsO4 (highly toxic) and DAST (hazardous), the low fluorination yield, and a low overall yield of only 7% over ten steps. Route b [7] used compound 19, which contains an aldehyde group and a chiral carbon

• the carbon chain, affording 1-(perfluorohexyl)octane (11) in 57% yield on a 20 g scale [40]. In summary, C6F13X (X = Cl, Br, I) all are suitable substrates reacting with 1-octene to produce 1-(perfluorohexyl)octane. However, the iodo-substituted compound 69 has lower cost and is more suitable for

Discovery of sugarnitriles A and B, and structural reassignment of SF-2140, from a sugarcane endophytic actinomycete Amycolatopsis sp. JS-O27

• Qiuyun Li,
• Ying Liu,
• Baoyue Wei,
• Yu Sun,
• Di Mao,
• Yanmin Zou and
• Shan Lu

Beilstein J. Org. Chem. 2026, 22, 1114–1121, doi:10.3762/bjoc.22.90

• supported the presence of a pyrrole ring, and the HMBC correlations from H-2'' to C-3a indicated that the pyrrole ring is fused with a benzene ring at C-3a and C-7a to form an indole skeleton. The DEPT135 spectrum supported the assignment of C-1'' as a quaternary carbon, and the chemical shift of C-1'' (δC

• 119.6 ppm) was consistent with the reported data of a cyano carbon [34]. The 1H,1H COSY signals for H-1'/H-2'/H-3'/H-4'/H-5', accompanied by the HMBC correlations from H-5' to C-1' and C-3', established a glycosyl moiety. Finally, from the HMBC signals between H-1' and C-2, it was determined that the

• anomeric carbon (C-1') was connected to the indole ring through a heteroatom, revealing that compound 1 is an indole N-glycoside (Figure 2a). Further detailed analysis of the 2D NMR data of 1 indicated that the planar structure of 1 was identical to that of SF-2140 (Tables S1 and S2, Supporting Information

Rhodopyran, a carboxylated hexahydrocyclopenta[b]pyran from Rhodococcus

• Enjuro Harunari,
• Sara Fushimi and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2026, 22, 1107–1113, doi:10.3762/bjoc.22.89

• . The 13C NMR spectrum exhibited 14 signals, including two carbonyl carbons (δC 176.1, 170.6), four olefinic carbons (δC 142.9, 135.5, 130.2, 125.0), an oxygenated quaternary carbon (δC 75.6), an oxygenated methine (δC 77.2), and three methyl carbons (δC 24.3, 21.1, 17.9) (Table 1). The remaining carbon

• carboxyl group at C-4 was assigned by correlations from H-3 and H-4a to the carbonyl carbon C-11, and by correlations from H-3 and H-4a to C-4. Likewise, correlations from H-6α/H-6β and H-7 to C-12 positioned another carboxyl group at C-7. The linkage from C-5 to C-6 and the placement of Me-14 at C-5 were

• -cyclopenta[b]pyran-6-one core bearing a hydroxy group and an allyl side chain [19]. In contrast, rhodopyran (1) is a carboxylated hexahydrocyclopenta[b]pyran bearing two carboxyl groups and a 1-propenyl substituent, and therefore differs markedly from the diospentenols in carbon number, oxidation state, and

Controlled supramolecular assemblies of luminescent tridentate cyclometalated alkynylgold(III) amphiphiles in aqueous media

• Kelvin Sze-Yim Cai,
• Brian Boyan Liu and
• Franco King-Chi Leung

Beilstein J. Org. Chem. 2026, 22, 1097–1106, doi:10.3762/bjoc.22.88

• 20.0 °C at a rate of 1.0 °C/min. Transmission electron microscopy (TEM): TEM samples were prepared by depositing sample solutions (0.2 wt %, 10.0 μL) onto a carbon grid (Micro to Nano, EMR Carbon support film on copper, 400 square mesh) for 30 s. The sample solution was removed by blotting and

One-pot four-component sequential synthesis of S-alkyl dithiocarbamates using lipase as a biocatalyst

• Mansour Shahedi,
• Pargol Tahmasebi pour and
• Zohreh Habibi

Beilstein J. Org. Chem. 2026, 22, 1048–1056, doi:10.3762/bjoc.22.83

• , where they serve as antifungal and anticancer agents. As a result, their synthesis has garnered significant attention in recent years. In this study, we present an efficient one-pot four-component approach for the synthesis of these scaffolds, utilizing aldehydes, ethyl acetoacetate, carbon disulfide

• the development of efficient and diverse synthetic methodologies for S-alkyl dithiocarbamates remains crucial. The synthesis of S-alkyl dithiocarbamates is primarily achieved through multicomponent reactions [17][18] that involve primary or secondary amines, carbon disulfide (CS2), and electrophilic

• remains limited. Notable advances in this area include a 2020 study by Halimehjani et al. who employed a four-component strategy involving β-naphthol, formaldehyde, amines, and carbon disulfide in water as the solvent to synthesize these compounds (Scheme 1a) [25]. Also, in 2013, Azizi et al. demonstrated

Synthesis of novel 1,2,4-oxadiazole-isoxazoline hybrids and their in silico potential with adenosine receptors

• Pshtiwan S. Mohammed,
• Mohammed K. S. Dalo,
• Onur C. Yazıcı,
• Muhammet Yildirim and
• Akın Sağırlı

Beilstein J. Org. Chem. 2026, 22, 1033–1047, doi:10.3762/bjoc.22.82

• vinylic proton signals at around 6.5, 5.9, and 6.7 ppm and aromatic proton resonances in the range of 7.0–8.5 ppm in the ¹H NMR spectra, as well as characteristic oxadiazole ring C=N carbon signals at approximately 168 and 175 ppm in the ¹³C NMR spectra. Furthermore, it was found that the obtained

• compounds (7x-(S), 7x-(R), 7j-(S), 7aw-(S), 7aw-(R), 7ah-(S)) and reference (co-crystallized) ligand with A1 adenosine receptor. Green arrows: conventional hydrogen bonds; pink region: alkyl connections; light pink region: pi-alkyl connections; blue region: halogen interactions; light green region: carbon

Semisynthesis, characterisation, and antibacterial evaluation of a novel lecanoric acid-derived amide library

• Ethan D. Abbott,
• Sasha Hayes,
• Jonathan M. White,
• Bernd H. A. Rehm and
• Rohan A. Davis

Beilstein J. Org. Chem. 2026, 22, 1023–1032, doi:10.3762/bjoc.22.81

• methylene groups (δC 38.1, 37.1), one aliphatic methine carbon (δC 25.2), and one carbonyl carbon (δC 167.7). The presence of phenols in 6 was supported by a bathochromic shift of the UV spectrum upon addition of base (NaOH) [25][26]. One spin system was identified from the COSY spectrum, which was the

• diffractometer using Cu Kα radiation at 200.0(1) K using an Oxford Cryostream cooling device. The structures were solved by direct methods and difference Fourier synthesis [35]. Hydrogen atoms bound to the carbon atom were placed at their idealized positions and included in subsequent refinement cycles. The

Synthesis and optical resolution of 4,5-diaminohomoadamantane: a promising scaffold for chiral ligands and bioactive compounds

• Polina A. Man’kova,
• Vadim A. Shiryaev,
• Olga S. Podlipnova,
• Marat M. Khisyamov,
• Dmitry S. Nikerov,
• Alexander N. Reznikov and
• Yuri N. Klimochkin

Beilstein J. Org. Chem. 2026, 22, 1013–1022, doi:10.3762/bjoc.22.80

• analysis conditions could be identified. Therefore, a preliminary derivatization of diamine 8a′ was required, which was carried out by reactions with carbon disulfide [75] or benzil [77]. However, HPLC analysis was only successful for racemic 2,3-dihydropyrazine 17 (Scheme 6). For (4R,5R)-2,3

The role of spacer length and flexibility in peptide self-assembly

• Julian Link,
• Albin Lahu,
• Manfred Wagner,
• Tanja Weil and
• David Y. W. Ng

Beilstein J. Org. Chem. 2026, 22, 986–996, doi:10.3762/bjoc.22.77

• -cysteine-alanine (ICA) tripeptides containing carbon spacers of 6, 3, or 0 methylene units linking the peptide backbone to a hydrophobic naphthalene (Nap) π-block. Using complementary spectroscopic and microscopic techniques, we show that spacer length controls the balance between conformational

Novel macrocycles: from synthesis to supramolecular function

• Veronica Iuliano,
• Carmen Talotta,
• Margherita De Rosa,
• Paolo Della Sala,
• Konrad Tiefenbacher,
• Pablo Ballester and
• Carmine Gaeta

Beilstein J. Org. Chem. 2026, 22, 982–985, doi:10.3762/bjoc.22.76

• desymmetrized building blocks avoid the dense packing commonly observed in rigid planar systems. As a proof of concept, these precursors were converted into methylene-alternating copolymers that exhibit high solubility and measurable carbon dioxide adsorption, highlighting their potential for the development of

• versatile tools for the selective modulation of biologically relevant protein–protein interactions. The contributions collected in this thematic issue highlight the breadth and continued evolution of contemporary macrocyclic chemistry. From new ultracycle receptors to functional materials for carbon dioxide

Electrochemical reduction of unsaturated carbon–carbon bonds via 3d transition-metal catalysis

• Geon Kang,
• Minki Jeon,
• Pooja Kumari Jat,
• Cheoljae Kim and
• Isaac Choi

Beilstein J. Org. Chem. 2026, 22, 955–981, doi:10.3762/bjoc.22.75

• metal–alkenyl intermediate. In some cases, this organometallic species can further undergo chain walking, where iterative β-hydride elimination and reinsertion enable migration of the metal center along the carbon skeleton before product release, thereby allowing remote hydrogenation or positional

• through the combination of anodic iron salts and electrochemically generated silyl hydrides, actively participate in the reaction pathway (Scheme 2C) [91]. The authors proposed that the ring-opening product arises from β-carbon elimination of an intermediate generated via migratory insertion, followed by

• chemoselectivity that are difficult to achieve under classical HAT conditions. Substrates featuring a quaternary carbon adjacent to the alkyne exhibited diminished E/Z selectivity, which was tentatively attributed to increased steric hindrance surrounding the putative cobalt–alkene intermediate. Interestingly

Synthesis of sterically shielded piperidine nitroxides via acid-catalyzed heterocyclization of β-aminoketone derivatives with ketones

• Mark M. Gulman,
• Yurii I. Glazachev and
• Sergey A. Dobrynin

Beilstein J. Org. Chem. 2026, 22, 948–954, doi:10.3762/bjoc.22.74

• subsequent reaction with moderately basic organometallic reagents, such as 2-alkynyl- and 2-allylmagnesium halides, enables the facile introduction of diverse substituents, including those with functional groups. If necessary, the multiple carbon–carbon bonds in the side chain can be subjected to

• alkynyl- or allylmagnesium halides gave 2-alkynyl or 2-allyl-substituted nitroxides. Finally, carbon–carbon multiple bonds were removed via Pd-catalyzed hydrogenation and the nitroxide group was recovered by mild oxidation. This approach was used to prepare both symmetric 2,2,6,6-tetraethyl- and 2,2,6,6

• allyl derivative 7d, extensive signal overlap prevented rigorous simulation, but characteristic terminal vinyl protons at 5.83, 5.28, 5.27 ppm were clearly observed. Elemental analysis and HRMS data were in agreement with the proposed structures. Subsequent hydrogenation of the unsaturated carbon–carbon

Recent advances in copper-catalyzed direct hydroamination of alkenes with (hetero)aromatic amines

• Hyejeong Lee and
• Yunmi Lee

Beilstein J. Org. Chem. 2026, 22, 925–947, doi:10.3762/bjoc.22.73

• , tunable basicity, and directional hydrogen-bonding capabilities enable precise modulation of molecular recognition, biological activity, and physicochemical properties. Consequently, the efficient and selective construction of carbon–nitrogen (C–N) bonds embedded within aromatic nitrogen frameworks

• the direct hydroamination of alkenes using aromatic amines and aza-heterocyclic N–H nucleophiles under copper catalysis. The primary focus is on the mechanistic paradigms, Cu–amido pathways, Lewis acid activation, and carbon-radical manifolds, and on how these distinct activation modes translate into

• Michael acceptor. This coordination increased the electrophilicity of the β-carbon, facilitating nucleophilic attack. The reaction proceeded efficiently with various activated olefins 14, affording N-substituted products 15 in high yields with good regioselectivities. Notably, the catalytic role of copper

Palladium-catalyzed benzocyclization reactions of quinoline-2-carboxamides via sequential C–H/N–H functionalization

• Shoichi Sugita,
• Kentaro Okano and
• Atsunori Mori

Beilstein J. Org. Chem. 2026, 22, 905–914, doi:10.3762/bjoc.22.71

• metal affinity [9][10]. It is therefore expected that annulation of the amide moiety in quinoline-2-carboxamides would extend their functionality as biologically active structures, ligands, and extractants. Transition-metal-catalyzed coupling reactions are crucial for constructing carbon–carbon and

• carbon–heteroatom bonds. The classical coupling reactions, such as Kumada–Tamao–Corriu coupling [11][12][13], Sonogashira coupling [14][15], Negishi coupling [16][17], Migita–Kosugi–Stille coupling [18][19][20], Suzuki–Miyaura coupling [21][22], and Hiyama coupling [23][24] involve carbon–halogen and

• carbon–metal species (Scheme 1a). Fagnou and co-workers reported direct arylation reactions with palladium(II) acetate to synthesize biaryl compounds via concerted metalation–deprotonation (CMD; Scheme 1b) [25][26][27]. Buchwald, Hartwig, and co-workers explored carbon–nitrogen coupling reactions that

Chiral cyclopropenimine-catalyzed enantioselective Michael reactions of phenol and benzofuran-derived α,β-unsaturated pyrazolamides with benzophenone-imine of glycine esters

• Ya Bai,
• Xue-Ying Wang,
• Si-Kai Zhu,
• Yan-Ting Shen,
• Sheng-Yong Zhang and
• Ping-An Wang

Beilstein J. Org. Chem. 2026, 22, 888–896, doi:10.3762/bjoc.22.69

• -conformation and the absolute configurations of 7d’ was unambiguously assigned as 2S and 3S, this means that the benzophenone-imine group and bromophenoxymethyl group should be arranged on the same side of the longest carbon chain to be syn before lactamization, therefore, the absolute configuration of 6d’ was

Diastereodivergent electrophilic trapping of α-boryl lithium derivatives

• Tereza Pavlíčková,
• Noam Orbach and
• Ilan Marek

Beilstein J. Org. Chem. 2026, 22, 882–887, doi:10.3762/bjoc.22.68

• ; Introduction α-Boryl carbanions 1 (Scheme 1), also referred to as boron alkylidenes or borata alkenes, represent a fascinating class of organoboron intermediates characterized by the delocalization of electron density from the negatively charged carbon center toward the electron-deficient boron atom. This

The trans-influence in gold chemistry from a catalytic perspective

• Manfred Bochmann

Beilstein J. Org. Chem. 2026, 22, 838–856, doi:10.3762/bjoc.22.66

• trialkylphosphines, anionic carbon and hydride ligands. N- and O-lone pair donors (pyridine, water) are weak ligands. The following indicative series is typical for Pt(II), although there may be slight variations in the specific ordering depending on the complex type under investigation: CO, CN−, C2H4 > P(alkyl)3

• , while C^N^C and C^C^N ligand frameworks look like simple structural isomers, their reactivity and analysis of their bonding has shown that replacing the weak N(pyridine) donor by strongly donating anionic carbon leads to profound changes in gold orbital ordering, often with drastic consequences for

• chemical shifts [32][49][50][51][52]. Both neutral and cationic gold(III) hydride pincer complexes could be prepared. They fall into two categories: those of types 8–11 where the hydride ligand is trans to an N donor (shielding, negative δ shifts), and those where the hydride is trans to an anionic carbon

Unsymmetrical sulfoxides with sterically hindered catechol fragment: synthesis, structure, electrochemical properties, and antiradical activity

• Daria A. Burmistrova,
• Vasiliy A. Fokin,
• Oleg P. Demidov,
• Mikhail A. Kiskin,
• Maxim V. Arsenyev,
• Andrey I. Poddel’sky,
• Nadezhda T. Berberova and
• Ivan V. Smolyaninov

Beilstein J. Org. Chem. 2026, 22, 828–837, doi:10.3762/bjoc.22.65

• the sulfoxides, the signals of the carbon atoms bearing the OH groups are shifted downfield and appear at δ 148.4–150.0 ppm. The sulfinyl group also influences the signals of aliphatic carbon atoms. For example, in sulfoxide 1a, the signal of the secondary carbon in the isopropyl substituent is

• shifted downfield (δ 54.4 ppm) compared to the analogous carbon atom in thioether 1 (δ 41.9 ppm). These results indicate a pronounced electron-withdrawing effect of the sulfinyl group, as well as the presence of strong intra- and intermolecular O–H···O=S bonds, which is consistent with the IR

• supported by the oxidation potential data. As the number of carbon atoms in the aliphatic hydrocarbon substituents of sulfoxides increases, their activity in the DPPH test diminishes. Compounds 7 and 7a, which contain a naphthyl substituent, exhibit the highest IC50 values among the studied catechols

Total synthesis of the capsular polysaccharide repeating unit towards the development of a glycoconjugate vaccine against Klebsiella pneumoniae ST512

• Shuo Zhang,
• Ondřej Daněk and
• Peter H. Seeberger

Beilstein J. Org. Chem. 2026, 22, 821–827, doi:10.3762/bjoc.22.64

• followed by catalytic hydrogenation over palladium on carbon, affording disaccharide 21 in 47% yield over two steps. Similarly, trisaccharide 22, tetrasaccharide 23, and pentasaccharide 24 were prepared from intermediates 14, 15, and 17, respectively. The analogues 21–24, together with the repeating unit

Synthesis and structural elucidation of a novel bis-spirooxindole from isatin and ethylenediamine

• Irene Moreno-Gutiérrez,
• Josefa L. López-Martínez,
• Sonia Berenguel-Gómez,
• Irene Torres-García,
• Duane Choquesillo-Lazarte,
• Manuel Muñoz-Dorado,
• Miriam Álvarez-Corral and
• Ignacio Rodríguez-García

Beilstein J. Org. Chem. 2026, 22, 813–820, doi:10.3762/bjoc.22.63

• retained the four-signal pattern of isatin (H4', H5', H6', H7'), slightly shifted by the new structural environment. In the 13C NMR spectrum, the amide carbonyl appeared at δ 176.5 ppm, while a key quaternary carbon at δ 61.0 ppm (C3‘) – formerly the C-3 isatin carbonyl carbon – confirmed the formation of

Knoevenagel condensation of 4,5- and 1,8-diazafluorenes

• Darya S. Cheshkina,
• Christina S. Becker,
• Alina A. Sonina and
• Maxim S. Kazantsev

Beilstein J. Org. Chem. 2026, 22, 803–812, doi:10.3762/bjoc.22.62

• to the iminium cation occurs via the methylene carbon of the corresponding enamine tautomeric form 1B or 2B. Thus, this process is limited by the concentration of this form which is expected to be higher for 1,8-diazafluorene (2) due to the activation by the neighboring nitrogen atoms via the