Total syntheses of highly oxidative Ryania diterpenoids facilitated by innovations in synthetic strategies

• Zhi-Qi Cao,
• Jin-Bao Qiao and
• Yu-Ming Zhao

Beilstein J. Org. Chem. 2025, 21, 2553–2570, doi:10.3762/bjoc.21.198

• of (+)-ryanodol (4) in just 15 steps, highlighting the Pauson–Khand cyclization and a selenium dioxide-mediated selective oxidation as key transformations [48] (Scheme 7). To construct the multi-substituted five-membered ring in the target molecule, the authors strategically employed the Pauson–Khand

• overall synthetic efficiency. A further highlight of this work was the development of a selenium dioxide-mediated regioselective oxidation. Leveraging the existing chiral centers in the molecular framework, this strategy allowed for the simultaneous installation of the desired oxidation states at three

Catalytic enantioselective synthesis of selenium-containing atropisomers via C–Se bond formations

• Qi-Sen Gao,
• Zheng-Wei Wei and
• Zhi-Min Chen

Beilstein J. Org. Chem. 2025, 21, 2447–2455, doi:10.3762/bjoc.21.186

• enantioselective synthesis of atropisomers, and significant progress has been made in recent years. However, selenium-containing atropisomers have long remained underexplored as synthetic targets, and only in recent years have they begun to attract increasing attention from the community. Recently, several

• synthetic approaches for constructing selenium-containing atropisomers have been reported, such as C–H selenylation of arenes, selenosulfonylation of vinylidene o-quinone methides (VQM), and hydroselenation of alkynes. Nevertheless, a comprehensive review that systematically summarizes these advances is

• currently lacking. This review aims to provide an overview of recent developments in the catalytic enantioselective synthesis of selenium-containing atropisomers via C–Se bond formation. We hope this review will serve as a valuable reference for researchers interested in further exploring this area

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

• , was an efficient and straightforward protocol towards oxazoles. An electrochemical and selenium-catalyzed construction of 2,1-benzoxazole through cyclization of o-nitrophenylacetylene was achieved by Pan in 2021 (Scheme 14) [256]. After examining the reaction in details, the best conditions were

• a plausible reaction mechanism. Initially, the anodization of diphenyl diselenide produced phenylselenium radical A and selenium cation B, the single-electron transfer on the anode could also transformed A into B. Addition of B to 37a formed the intermediate C that underwent intramolecular

• nucleophilic cyclization to give D. The fracture of the N–O bond in D yielded E. Elimination of selenium cation A from E and the following cyclization afforded 38a. This transformation, combining selenium catalysis and organic electrosynthesis, proceeded smoothly at rt without external oxidants and metal

Aryl iodane-induced cascade arylation–1,2-silyl shift–heterocyclization of propargylsilanes under copper catalysis

• Rasma Kroņkalne,
• Rūdolfs Beļaunieks,
• Armands Sebris,
• Anatoly Mishnev and
• Māris Turks

Beilstein J. Org. Chem. 2025, 21, 1984–1994, doi:10.3762/bjoc.21.154

• have been induced by addition of external halogen or selenium electrophiles and Brønsted acids. This encouraged us to develop a methodology involving a copper-catalyzed terminal alkyne arylation of propargylsilanes by diaryl-λ3-iodanes, followed by 1,2-silyl shift and terminated by nucleophile addition

pH-Controlled isomerization kinetics of ortho-disubstituted benzamidines: E/Z isomerism and axial chirality

• Ryota Kimura,
• Satoshi Ichikawa and
• Akira Katsuyama

Beilstein J. Org. Chem. 2025, 21, 1568–1576, doi:10.3762/bjoc.21.120

• usefulness of the single-atom substitution strategy on DiBA. By replacing the oxygen atom of DiBA with a nitrogen atom (and thus NH), which has been shown to be photo-responsive when replaced with sulfur or selenium, the pH-responsive property was acquired. Such minimal changes in physical properties can be

Advances in nitrogen-containing helicenes: synthesis, chiroptical properties, and optoelectronic applications

• Meng Qiu,
• Jing Du,
• Nai-Te Yao,
• Xin-Yue Wang and
• Han-Yuan Gong

Beilstein J. Org. Chem. 2025, 21, 1422–1453, doi:10.3762/bjoc.21.106

• , or selenium enables spectral tuning across the visible to near-infrared range, improved photostability, and dual-state emissive behavior. In parallel, significant progress in synthetic methodologies – including enantioselective catalysis, electrochemical cyclizations, and multicomponent reaction

• helicenes. Particular attention is given to multi-heteroatom systems co-doped with elements such as boron, oxygen, sulfur, and selenium, highlighting their influence on CPL performance and structure–property relationships. We classify the nitrogen-doped helicenes into only N-containing helicenes, B,N

• two π-extended hetero[6]helicenes – 61a and 61b – incorporating thiadiazole and selenadiazole moieties, respectively [76]. Substitution of sulfur with selenium enhanced intermolecular interactions and led to a notable reduction in the optical bandgap, highlighting the effectiveness of heteroatom

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

• synthesis of various organophosphorus compounds through the formation of phosphorus–carbon, phosphorus–nitrogen, phosphorus–oxygen, phosphorus–sulfur, and phosphorus–selenium bonds. The impact of different electrodes is also discussed in this matter. Graphite, platinum, RVC, and nickel electrodes have been

• , phosphorus–sulfur, and phosphorus–selenium bonds. The impact of different electrodes is also discussed in this matter. Graphite, platinum, reticulated vitreous carbon (RVC), and nickel electrodes have been used extensively for the electrochemical synthesis of organophosphorus compounds. Review

• , followed by the iodination reaction of aromatic compounds (Scheme 31). In the next step, elemental selenium was inserted into the aryl iodide bond to form the aryl iodoselenide intermediate for forming the P–Se bond. Other electrochemical reactions of organophosphorus Li et al. [72] reported an

Multicomponent reactions driving the discovery and optimization of agents targeting central nervous system pathologies

• Lucía Campos-Prieto,
• Aitor García-Rey,
• Eddy Sotelo and
• Ana Mallo-Abreu

Beilstein J. Org. Chem. 2024, 20, 3151–3173, doi:10.3762/bjoc.20.261

• -directed and metabolic antioxidants have shown efficacy in AD mouse models, with ongoing trials for vitamin E and selenium [32]. Ugi reaction: As already mentioned, one of the main targets in AD treatment are cholinesterase ligands. In recent years, butyrylcholinesterase, an enzyme present in high

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

• red light irradiation [97]. Firstly, they evaluated the photoreductant role of metal-free macrocycles, H2TPP (18) and PPIX 78, in the red light-induced C–H arylation of different substrates such as furan, coumarin, thiol, pivalamide, aryl thiaether and the selenium equivalents. Use of both macrocycles

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

N-Glycosides of indigo, indirubin, and isoindigo: blue, red, and yellow sugars and their cancerostatic activity

• Peter Langer

Beilstein J. Org. Chem. 2024, 20, 2840–2869, doi:10.3762/bjoc.20.240

• represents a π-donor. Although nitrogen, as present in indirubins 17, is an even better donor than oxygen, the stability of the intramolecular hydrogen bond overrules this effect. Sulfur and selenium are very weak π-donors. It was not studied so far whether the E/Z ratio of indirubin derivatives can be

A review of recent advances in electrochemical and photoelectrochemical late-stage functionalization classified by anodic oxidation, cathodic reduction, and paired electrolysis

• Nian Li,
• Ruzal Sitdikov,
• Ajit Prabhakar Kale,
• Joost Steverlynck,
• Bo Li and
• Magnus Rueping

Beilstein J. Org. Chem. 2024, 20, 2500–2566, doi:10.3762/bjoc.20.214

• , showcasing 118 examples with good to high yields. The LSF of complex molecules, such as probenecid and estrone, highlighted the potential application of this method in the synthesis of selenium-containing drugs (Scheme 19). 1.1.3 Annulation. Annulation refers to the formation of rings, a process that

Phenylseleno trifluoromethoxylation of alkenes

• Clément Delobel,
• Armen Panossian,
• Gilles Hanquet,
• Frédéric R. Leroux,
• Fabien Toulgoat and
• Thierry Billard

Beilstein J. Org. Chem. 2024, 20, 2434–2441, doi:10.3762/bjoc.20.207

• developed an electrophilic phenylseleno trifluoromethoxylation of alkenes, which leads to β-selenylated trifluoromethoxylated compounds or, upon subsequent reduction, to the trifluoromethoxylated ones. Keywords: DNTFB; electrophilic addition; fluorine; selenium; trifluoromethoxy; Introduction Due to the

• ], electronic effects [17][18], and conformation [19][20][21]. Some trifluoromethoxylated molecules can be used as drugs in the treatment of various pathologies (Figure 1) [22][23][24][25][26][27][28][29]. On the other hand, despite its toxicity at higher doses, selenium is also an essential trace element in

• resulting from the substitution of the CF3O group by the trifluoroacetoxy group was then observed. The activation of a fluorine atom from the CF3O group by H+ could be envisaged, which would then trigger the selenium attack to release difluorophosgene and HF, thus generating an episelenonium, which would

Synthesis, electrochemical properties, and antioxidant activity of sterically hindered catechols with 1,3,4-oxadiazole, 1,2,4-triazole, thiazole or pyridine fragments

• Daria A. Burmistrova,
• Andrey Galustyan,
• Nadezhda P. Pomortseva,
• Kristina D. Pashaeva,
• Maxim V. Arsenyev,
• Oleg P. Demidov,
• Mikhail A. Kiskin,
• Andrey I. Poddel’sky,
• Nadezhda T. Berberova and
• Ivan V. Smolyaninov

Beilstein J. Org. Chem. 2024, 20, 2378–2391, doi:10.3762/bjoc.20.202

• heteroatoms (nitrogen, sulfur, selenium, tellurium, etc.) as well as redox-active functional groups allows one to vary significantly the biological activity of such compounds. Heterocyclic molecular blocks are widely used in medicinal chemistry [12]. Thiazole, oxadiazole, triazole, imidazole, and other

O,S,Se-containing Biginelli products based on cyclic β-ketosulfone and their postfunctionalization

• Kateryna V. Dil and
• Vitalii A. Palchykov

Beilstein J. Org. Chem. 2024, 20, 2143–2151, doi:10.3762/bjoc.20.184

• with up to 95% yield. The use of selenourea has been shown to give low yields of products (up to 33%). In fact, we have thus expanded the range of available selenium-containing DHPMs in addition to the work of other authors [33][34][35]. We also attempted to replace urea/thiourea/selenourea with N

• signals clearly corresponds to the heterocycles depicted above. Figure S8 (see Supporting Information File 1) shows 1H NMR spectra for Ph-substituted O,S,Se-DHPMs 2a,h,o. It can be seen from them that when going from oxygen to selenium (2h→2a→2o), the signals of both NH groups shift to down field (7.87

Synthesis of 4-functionalized pyrazoles via oxidative thio- or selenocyanation mediated by PhICl₂ and NH₄SCN/KSeCN

• Jialiang Wu,
• Haofeng Shi,
• Xuemin Li,
• Jiaxin He,
• Chen Zhang,
• Fengxia Sun and
• Yunfei Du

Beilstein J. Org. Chem. 2024, 20, 1453–1461, doi:10.3762/bjoc.20.128

• thioethers [27]. Likewise, selenocyanates can be used as versatile precursors for the synthesis of a variety of selenium-containing compounds [28][29][30][31][32]. As the S/SeCN-containing organic compounds play an important role in organic and medicinal chemistry, organic chemists have devoted a great deal

• to give (SeCN)2 [60]. Then, one selenium atom of (SeCN)2 nucleophilically attacks the iodine center in PhICl2 to generate intermediate A, which was further transformed into intermediate B by release of one molecule of iodobenzene. Next, the nucleophilic attack of chloride anion to the bivalent

• selenium center of intermediate B resulted in the formation of two molecules of Cl–SeCN. Subsequently, Cl–SeCN undergoes an electrophilic addition reaction with pyrazole 1 to give intermediate C, which, after deprotonative rearomatization affords the 4-selenocyanated pyrazole 3. Conclusion In conclusion

Synthetic applications of the Cannizzaro reaction

• Bhaskar Chatterjee,
• Dhananjoy Mondal and
• Smritilekha Bera

Beilstein J. Org. Chem. 2024, 20, 1376–1395, doi:10.3762/bjoc.20.120

• synthesized via the Cannizzaro reaction. Proposed catalytic cycle for the dehydrogenation of alcohols. Intramolecular Cannizzaro reaction of aryl glyoxal hydrates using TOX catalysts. Intramolecular Cannizzaro reaction of aryl methyl ketones using ytterbium triflate/selenium dioxide. Intramolecular Cannizzaro

Competing electrophilic substitution and oxidative polymerization of arylamines with selenium dioxide

• Vishnu Selladurai and
• Selvakumar Karuthapandi

Beilstein J. Org. Chem. 2024, 20, 1221–1235, doi:10.3762/bjoc.20.105

• , and methyl anthranilate, with selenium dioxide in acetonitrile. A systematic analysis of the reaction products with the help of 77Se NMR and single-crystal X-ray crystallography revealed that the reaction progress follows three major reaction pathways, electrophilic selenation, oxidative

• using SeO2 as an electrophile source in aromatic electrophilic substitution reactions. Keywords: arylamines; electrophilic substitution; oxamides: polymerization; selenium dioxide; Introduction Organoselenium compounds have received considerable attention due to interesting medicinal properties, such

• interest [12][13]. The various approaches used for selenation of aromatic compounds include directed lithiation [14][15], copper-catalyzed selenation [16][17][18], and aromatic nucleophilic substitution reactions [19][20][21][22]. Electrophilic selenium reagents (e.g., phenylselenenyl bromide) have often

Switchable molecular tweezers: design and applications

• Pablo Msellem,
• Maksym Dekthiarenko,
• Nihal Hadj Seyd and
• Guillaume Vives

Beilstein J. Org. Chem. 2024, 20, 504–539, doi:10.3762/bjoc.20.45

• using metal complexes as switching units (Figure 20). This concept named “weak link approach” (WLA) [78] uses square planar d8-transition metal complexes with two hemilabile bidentate ligands composed of a strong binding site (phosphorus) and a weaker one (generally sulfur, oxygen, selenium, or nitrogen

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

• thiepines were progressively isolated as a result of very diverse synthetic strategies [46][47][48][49], which were further applied to the preparation of stable selenepines and tellurepines [50][51][52][53]. Extrusion reactions from sulfur-, selenium- and tellurium-containing compounds have long been

• helical S- and Se-doped seco-HBCs 28b and 28c were thus obtained as racemic mixtures in three steps from dibenzoheteropines 23b and 23c in 45% and 18% overall yield, respectively. To evaluate the impact of the heteroatom oxidation state on reactivity, the sulfur and selenium oxides were next prepared via

• design of pentacene’s soluble precursor, as reported by Müllen and Herwig [14], is depicted in the top left. Valence isomerization of chalcogen heteropines and subsequent cheletropic extrusion in the case of sulfur, selenium and tellurium derivatives. Early example of phenanthrene synthesis via a

N-Sulfenylsuccinimide/phthalimide: an alternative sulfenylating reagent in organic transformations

• Fatemeh Doraghi,
• Seyedeh Pegah Aledavoud,
• Mehdi Ghanbarlou,
• Bagher Larijani and
• Mohammad Mahdavi

Beilstein J. Org. Chem. 2023, 19, 1471–1502, doi:10.3762/bjoc.19.106

• cyclization transformation involving activation of the electrophilic sulfur reagent by PhSePh with the assistance of TMSOTf to form transition state I. Intermediate II formed through capturing of sulfonium by selenium. Then, II reacted with 136 to give regioselective cyclic thiiranium ion III. Nucleophilic

Construction of hexabenzocoronene-based chiral nanographenes

• Ranran Li,
• Di Wang,
• Shengtao Li and
• Peng An

Beilstein J. Org. Chem. 2023, 19, 736–751, doi:10.3762/bjoc.19.54

• . And the derivative 16 was also synthesized by allylic oxidation of compound 15 using selenium dioxide. As helical chiral NGs, helicene 14 and its derivatives 15 and 16 showed highly distorted helical conformation and also exhibited a relatively high isomerization barrier (over 28.9 kcal/mol determined

Synthesis and reactivity of azole-based iodazinium salts

• Thomas J. Kuczmera,
• Annalena Dietz,
• Andreas Boelke and
• Boris J. Nachtsheim

Beilstein J. Org. Chem. 2023, 19, 317–324, doi:10.3762/bjoc.19.27

• phenotellurazine 7c were isolated in lower yields of 16% and 6%, likely due to undesired oxidations of selenium and tellurium [38]. Substitutions with nitrogen nucleophiles were performed, giving the N-phenylphenazine 8 in 26% yield [39][40] and the N-tosyl derivative 9 in 18% yield [41]. Anion exchange reactions

Combining the best of both worlds: radical-based divergent total synthesis

• Kyriaki Gennaiou,
• Antonios Kelesidis,
• Maria Kourgiantaki and
• Alexandros L. Zografos

Beilstein J. Org. Chem. 2023, 19, 1–26, doi:10.3762/bjoc.19.1

• drastically the radical stability, nucleophilicity, and selectivity of 139 [73]. Furnishing of the common scaffold 130 can be carried out via an attack of intermediates of this type (e.g., 139) on Michael acceptors. Tosyl group deprotection of 130, followed by selenium anhydride oxidation and catalytic

Dienophilic reactivity of 2-phosphaindolizines: a conceptual DFT investigation

• Nosheen Beig,
• Aarti Peswani and
• Raj Kumar Bansal

Beilstein J. Org. Chem. 2022, 18, 1217–1224, doi:10.3762/bjoc.18.127

• of 1-aza-2-phosphaindolizines 3 with DMB and isoprene occurred at rt, although slowly and were speeded up by the use of sulfur or selenium which oxidized the phosphorus atom of the initially formed product thereby pushing the reaction in the forward direction [14]. The difference in the reactivities