Chemoenzymatic synthesis of the cardenolide rhodexin A and its aglycone sarmentogenin

• Fuzhen Song,
• Mengmeng Zheng,
• Dongkai Wang,
• Xudong Qu and
• Qianghui Zhou

Beilstein J. Org. Chem. 2025, 21, 2637–2644, doi:10.3762/bjoc.21.204

• Sciences and Biotechnology, Zhangjiang Institute for Advanced Study, Shanghai Jiao Tong University, Shanghai, 200240, China 10.3762/bjoc.21.204 Abstract Herein, we report a concise chemoenzymatic synthesis of the cardenolide rhodexin A in 9 steps and the first protecting-group-free synthesis of its

• aglycone sarmentogenin in 7 steps from 17-deoxycortisone. The synthesis features a scalable enzymatic C14–H α-hydroxylation, a Bestmann ylide-enabled one-step construction of the butenolide motif, a late stage Mukaiyama hydration, and a stereoselective C11 carbonyl reduction. Keywords: cardiac glycosides

• ; C–H hydroxylation; chemoenzymatic synthesis; Mukaiyama hydration; protecting-group-free synthesis; Introduction Cardiac glycosides (CGs) are widely distributed natural products, generated by plants and amphibians [1]. Structurally, they are composed of an aglycone-steroidal moiety, an unsaturated

Thiazolidinones: novel insights from microwave synthesis, computational studies, and potentially bioactive hybrids

• Luan A. Martinho,
• Victor H. J. G. Praciano,
• Guilherme D. R. Matos,
• Claudia C. Gatto and
• Carlos Kleber Z. Andrade

Beilstein J. Org. Chem. 2025, 21, 2618–2636, doi:10.3762/bjoc.21.203

• different products were obtained), delivers excellent yields (up to 99%), and requires low catalyst loading (10 mol %). This new approach was successfully applied to the synthesis of eight novel imidazo[1,2-a]pyridine–thiazolidinone hybrids in good to excellent yields (66–99%). A spectroscopic study of

• ], antioxidant [34], cytotoxic [35], and antiproliferative [36]. The structures of these compounds allow the synthesis of a large collection of bioactive molecules due to their nucleophilic and electrophilic properties [37]. One of the forms of modifications is at the methylene group, particularly in the 5

• explored. One notable approach is the use of microwave irradiation. Microwave-assisted synthesis has proven effective in reducing reaction times and improving yields [59][60][61][62]. Herein, we report the synthesis of 5-arylidene derivatives from rhodanine or thiazolidine-2,4-dione via the Knoevenagel

Efficient solid-phase synthesis and structural characterization of segetalins A–H, J and K

• Liangyu Liu,
• Wanqiu Lu,
• Quanping Guo and
• Zhaoqing Xu

Beilstein J. Org. Chem. 2025, 21, 2612–2617, doi:10.3762/bjoc.21.202

• strategy for the total synthesis of segetalins A–H, J and K (1–10), bioactive cyclopeptides isolated from Vaccaria segetalis. Linear precursors were assembled on cost-effective 2-chlorotrityl chloride resin via Fmoc-SPPS, followed by PyBOP-mediated head-to-tail cyclization in DMF (10−3 M). After RP-HPLC

• scalable methodology overcomes limitations of prior syntheses, enabling biological evaluation. Keywords: Fmoc-solid-phase peptide synthesis (Fmoc-SPPS); head-to-tail cyclization; plant cyclopeptides; Vaccaria segetalis; Introduction Cyclopeptides have garnered significant research interest owing to their

• synthetic approaches have encountered significant challenges. Sonnet et al. reported the first total synthesis of segetalin A (1) via Sasrin resin-based SPPS, followed by cyclization under highly dilute conditions (10−4 M) with diphenylphosphoryl azide (DPPA) [17]. While successful, this approach suffers

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

• to SG not only by electrostatic interactions but also covalently, the BU1 synthesis is straightforward lacking difficult and time-consuming purification, and it is obtained in relatively high yield over 60%. Once BU1 was prepared, its covalent attachment on the surface of SG was achieved in two steps

• solution (10 mM) for 1 h or 3 × 15 min; experiments were done using 50 mg of SG-NHCO-BU1. Synthesis of SG-NHCO-BU1 and SG-BU1 materials based on covalently and non-covalently attached BU1 on the SG surface. Supporting Information Supporting Information File 4: Characterization of materials and additional

• experiments regarding anion uptake. Acknowledgements We thank Dr. Zdeněk Moravec for the TGA measurements and Dr. Arico Del Mauro for assistance with the BU1 synthesis. Funding The authors thank the RECETOX Research Infrastructure (LM2023069) financed by the Ministry of Education, Youth, and Sports, and the

Visible-light-driven NHC and organophotoredox dual catalysis for the synthesis of carbonyl compounds

• Vasudevan Dhayalan

Beilstein J. Org. Chem. 2025, 21, 2584–2603, doi:10.3762/bjoc.21.200

• ; NHC; organic photocatalyst; radicals; visible-light; Introduction Over the last ten years, NHC-catalyzed visible-light-promoted radical chemistry has been extensively developed for the cost-effective and practical synthesis of bioactive intermediates, pharmaceuticals, drugs, and natural products [1

• ]. The use of visible light as an energy source has significantly expanded the scope of organic molecule activation and its application in organic synthesis or medicinal chemistry [12], thereby driving the fast development of various photocatalytic transformations. Among these advances, dual catalysis

• carbenes (NHCs) with photocatalysts. The review encompasses transition-metal-based photocatalytic reactions for C–C and C–HA cross-coupling reactions involving various acyl fluorides, amides, aldehydes, carboxylic acids, and esters, highlighting their broad applications in organic synthesis and medicinal

Recent advances in total synthesis of illisimonin A

• Juan Huang and
• Ming Yang

Beilstein J. Org. Chem. 2025, 21, 2571–2583, doi:10.3762/bjoc.21.199

• , illisimonin A has garnered significant interest from the synthetic chemistry community. To date, five research groups have accomplished the total synthesis of illisimonin A. This review offers a comprehensive overview of its isolation, proposed biosynthetic pathway and the synthetic strategies employed in its

• total synthesis. Keywords: bioinspired synthesis; biosynthetic pathway; Illicium sesquiterpene; illisimonin A; total synthesis; Introduction The genus Illicium, the sole member of the family Illiciaceae, is a rich source of sesquiterpenoid natural products. To date, a wide variety of sesquiterpenes

• considerable interest from synthetic chemists. Although the intricate structures of this family have posed significant challenges to chemical synthesis, more than 30 total syntheses of Illicium sesquiterpenes have been reported until now [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22

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

• primary driving forces behind the advancement of organic synthetic chemistry. With rapidly evolving organic synthesis technologies, a diverse array of novel methods and sophisticated strategies continues to emerge. These approaches not only complement and synergize with one another but also significantly

• enhance synthetic efficiency, reduce costs, and provide robust solutions to challenges encountered in the synthesis of complex molecular architectures. Ryania diterpenes are natural products characterized by intricate structures and high oxidation states. Biological studies have revealed that the family

• focuses on reviewing the efficient application of ring-construction methods and synthetic strategies in the total synthesis of highly oxidized Ryania diterpenoid natural products, emphasizing the pivotal role of novel synthetic methods and strategic innovations. Keywords: natural products; Ryania

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

• Abstract The total synthesis of bioactive (+)-aglacin B was achieved. The key steps include an asymmetric conjugate addition reaction induced by a chiral auxiliary and a nickel-promoted reductive tandem cyclization of the elaborated β-bromo acetal, which led to the efficient construction of the

• the tropical rain forests of the Kalimantan region (Indonesia) [1][2]. These cyclic ether natural products belong to the typical aryltetralin lignans, which have already attracted broad attention from the synthetic community [3][4][5]. Zhu and co-workers disclosed a concise synthesis of (±)-aglacins B

• (2) and C (3), featuring a visible light-catalyzed radical cation cascade for the formation of the C8–C8′ and C2–C7′ bonds [6]. Subsequently, they improved the reaction conditions to achieve the racemic synthesis of aglacins A (1) and E (4) as well [7]. In 2021, the Gao group described the total

Rapid access to the core of malayamycin A by intramolecular dipolar cycloaddition

• Yilin Liu,
• Yuchen Yang,
• Chen Yang,
• Sha-Hua Huang,
• Jian Jin and
• Ran Hong

Beilstein J. Org. Chem. 2025, 21, 2542–2547, doi:10.3762/bjoc.21.196

• synthesis and structural determination of malaymycin A (1) as well as the subsequent design of structural analogues for biological evaluation [16][17][18][19][20]. Preliminary structure–activity relationship (SAR) studies revealed that fungicidal activity is highly dependent on the nature and

• target-oriented synthesis toward malayamycins remains to be complished and several steps need to be improved, the current strategy provides a reliable platform to access various uracil nucleosides and derivatives for developing potent fungicides. Selected natural uracil-containing nucleosides (the key

Synthesis and characterization of a isothiouronium-calix[4]arene derivative: self-assembly and anticancer activity

• Giuseppe Granata,
• Loredana Ferreri,
• Claudia Giovanna Leotta,
• Giovanni Mario Pitari and
• Grazia Maria Letizia Consoli

Beilstein J. Org. Chem. 2025, 21, 2535–2541, doi:10.3762/bjoc.21.195

• , and low toxicity make calixarene derivatives valuable drug candidates against cancer. The aim of the present study was the synthesis and characterization of a calix[4]arene derivative in which known anticancer isothiouronium groups were clustered on a calix[4]arene scaffold bearing long C12 alkyl

• anticancer activity. The synthesis and structural characterization of compound 3 were carried out, and its self-assembly behavior in aqueous medium was investigated using dynamic light scattering (DLS) and electrophoretic light scattering (ELS). The anticancer potential of compound 3 was assessed in human

• renal carcinoma cells (786O) and normal human fibroblasts (SW1), and the tumor cells selectivity was evaluated. To elucidate the role of the isothiouronium groups, antiproliferative effects were also estimated on calix[4]arene precursor 1 lacking these functional groups. Results and Discussion Synthesis

Pentacyclic aromatic heterocycles from Pd-catalyzed annulation of 1,5-diaryl-1,2,3-triazoles

• Kaylen D. Lathrum,
• Emily M. Hanneken,
• Katelyn R. Grzelak and
• James T. Fletcher

Beilstein J. Org. Chem. 2025, 21, 2524–2534, doi:10.3762/bjoc.21.194

• control compounds 37–42 (blue lines) in acetonitrile solvent. Synthesis of pentacyclic aromatic heterocycles from varying alkynes.a Synthesis of pentacyclic aromatic heterocycles from varying azides.a Summary of UV–vis absorbance/emission signals. Minimum inhibitory concentration assay results.a

Isoorotamide-based peptide nucleic acid nucleobases with extended linkers aimed at distal base recognition of adenosine in double helical RNA

• Grant D. Walby,
• Brandon R. Tessier,
• Tristan L. Mabee,
• Jennah M. Hoke,
• Hallie M. Bleam,
• Angelina Giglio-Tos,
• Emily E. Harding,
• Vladislavs Baskevics,
• Martins Katkevics,
• Eriks Rozners and
• James A. MacKay

Beilstein J. Org. Chem. 2025, 21, 2513–2523, doi:10.3762/bjoc.21.193

• Department of Chemistry, Ohio Wesleyan University, Delaware, OH, 43015, USA Department of Chemistry, Binghamton University, 4400 Vestal Parkway East, Binghamton, NY 13902, USA Latvian Institute of Organic Synthesis, Aizkraukles 21, Riga, LV-1006, Latvia 10.3762/bjoc.21.193 Abstract Non-coding ribonucleic

• regions of RNA. We herein report the synthesis and binding studies of new isoorotamide-based PNA monomers that target uridine–adenosine base pairs via a distal base recognition strategy. Monomers were designed with an arylisoorotamide core attached to a linker aimed at bypassing the uridine in a U–A pair

• , and it is easily prepared using well established peptide synthesis protocols, allowing for accessible incorporation of synthetic nucleobases [17][18]. With these advantages in mind, Rozners’ lab first demonstrated in 2010 that PNA not only binds favorably and quickly to RNA, but that it binds more

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

• Roman A. Irgashev Postovsky Institute of Organic Synthesis, Ural Branch of the Russian Academy of Sciences, Ekaterinburg, 620137, Russia 10.3762/bjoc.21.191 Abstract A versatile synthetic route to thieno[3,2-b]thiophenes was elaborated from dimethyl 3-nitrothiophene-2,5-dicarboxylate

• organic synthesis. A widely adopted strategy for building the TT scaffold involves the annulation of a second thiophene ring onto a suitably functionalized thiophene precursor. Most commonly, this approach starts from halogenated thiophenes such as 3-bromo- or 3-chlorothiophenes, which undergo subsequent

• -alkylation and base-promoted cyclization to form the 3-hydroxy-TT molecules (Scheme 2). Results and Discussion We began our study by investigating the reaction of dimethyl 3-nitrothiophene-2,5-dicarboxylate (1) with Na2S, inspired by Beck’s reported synthesis of 2-substituted-3-aminobenzo[b]thiophenes via

Palladium-catalyzed regioselective C1-selective nitration of carbazoles

• Vikash Kumar,
• Jyothis Dharaniyedath,
• Aiswarya T P,
• Sk Ariyan,
• Chitrothu Venkatesh and
• Parthasarathy Gandeepan

Beilstein J. Org. Chem. 2025, 21, 2479–2488, doi:10.3762/bjoc.21.190

• challenging due to the inherently higher reactivity at the C3/C6 positions. In this study, we report a palladium-catalyzed, directing group-assisted, regioselective C1–H nitration of carbazoles. The protocol features a removable directing group and is amenable to gram-scale synthesis. This strategy provides a

• attention has been devoted to the chemical synthesis of carbazole and its derivatives [9][10][11][12][13][14]. To access substituted carbazole cores for pharmacophores and functional materials, two main synthetic routes are: i) sequential multistep syntheses of selectively substituted carbazoles and ii

• ) functionalization of the carbazole core. Traditional approaches for constructing diversified carbazoles and derivatives are Fischer–Borsche synthesis [15][16], Graebe–Ullmann synthesis [17][18], cyclization of biaryl nitrenes–Cadogan synthesis [19], electrocyclic reactions [20][21], and others [22][23][24]. These

Synthesis of the tetracyclic skeleton of Aspidosperma alkaloids via PET-initiated cationic radical-derived interrupted [2 + 2]/retro-Mannich reaction

• Ru-Dong Liu,
• Jian-Yu Long,
• Zhi-Lin Song,
• Zhen Yang and
• Zhong-Chao Zhang

Beilstein J. Org. Chem. 2025, 21, 2470–2478, doi:10.3762/bjoc.21.189

• University, Liaoning Shenyang 110016, China 10.3762/bjoc.21.189 Abstract Natural products with topologically complex architectures are important sources in drug discovery. The pursuit of conciseness and efficiency in the total synthesis of natural products promotes continuous innovation and the development

• considerable attention in recent decades. Numerous approaches to natural product synthesis have been reported in which a photochemical transformation represents a key step [1][2][3]. In this context, the photochemical [2 + 2] cycloaddition and subsequent fragmentation of the resulting cyclobutane provides a

• current interest in the synthesis of complex natural products via photochemical reactions, we decided to achieve such an unusual bond cleavage (Figure 1a, path A) of cyclobutenone by generating a radical cation species via a PET reaction. The synthetic plan is shown in Figure 1c and includes a PET

Ex-situ generation of gaseous nitriles in two-chamber glassware for facile haloacetimidate synthesis

• Nikolai B. Akselvoll,
• Jonas T. Larsen and
• Christian M. Pedersen

Beilstein J. Org. Chem. 2025, 21, 2465–2469, doi:10.3762/bjoc.21.188

• .21.188 Abstract The synthesis of fluorinated haloacetimidates relies on the access to the corresponding fluoroacetonitriles, which are toxic gaseous molecules difficult to store and handle. In this work we develop a safe two-chamber method for the ex-situ generation of these reagents in one chamber and

• their subsequent reaction with O-nucleophiles in the second chamber. The method is easy to setup, control and gives access to new haloacetimidates under mild conditions, similar to the ones used for the synthesis of the more commonly used trichloroacetimidates. Keywords: gaseous reagents; glycosyl

• donor; haloacetimidates; haloacetonitrile; two-chamber reactor; Introduction Trifluoroacetonitrile is an electrophilic reagent that has seen a variety of uses, mostly for incorporating trifluoromethyl groups into organic compounds [1]. As an example it has been successfully utilized for the synthesis

The intramolecular stabilizing effects of O-benzoyl substituents as a driving force of the acid-promoted pyranoside-into-furanoside rearrangement

• Alexey G. Gerbst,
• Sofya P. Nikogosova,
• Darya A. Rastrepaeva,
• Dmitry A. Argunov,
• Vadim B. Krylov and
• Nikolay E. Nifantiev

Beilstein J. Org. Chem. 2025, 21, 2456–2464, doi:10.3762/bjoc.21.187

• .21.187 Abstract Furanoside derivatives are broadly present in the antigenic structures of pathogenic microorganisms and play a key role in their recognition by the host immune system. Despite the high demand for vaccine and diagnostic development, their chemical synthesis remains challenging. During the

• development of a new methodology for the synthesis of galactofuranoside building blocks, we encountered an unexpected predominance of the furanoside form in the equilibrium mixture of benzoylated β-galactosides. Since the furanoside form is typically less stable and is usually present only in minor amounts

• ] and vaccines [15][16][17][18]. That is why new efficient and stereoselective methods for the synthesis of both Galf-containing mono- and oligosaccharide derivatives are highly demanded. It is a well-known fact that galactofuranose form constitutes only 5% in water solution of unprotected ᴅ-galactose

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

• Qi-Sen Gao Zheng-Wei Wei Zhi-Min Chen State Key Laboratory of Synergistic Chem-Bio Synthesis, School of Chemistry and Chemical Engineering, Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs, Shanghai Jiao Tong University, Shanghai 200240, P. R. China 10.3762/bjoc.21.186 Abstract

• Atropisomers are not only prevalent in biologically active natural products and pharmaceuticals, but they have also garnered increasing attention for their effectiveness as ligands and catalysts in the field of catalytic asymmetric synthesis. Asymmetric catalysis serves as a key strategy for the

• 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

Transformation of the cyclohexane ring to the cyclopentane fragment of biologically active compounds

• Natalya Akhmetdinova,
• Ilgiz Biktagirov and
• Liliya Kh. Faizullina

Beilstein J. Org. Chem. 2025, 21, 2416–2446, doi:10.3762/bjoc.21.185

• contraction of six-membered cycles in the synthesis of functionalized cyclopentane/enones, which are biologically active compounds. The main synthetic methods of ring contraction (ozonolysis–aldol condensation, ozonolysis–Dieckmann reaction, Baeyer–Villiger cleavage–Dieckmann reaction) and rearrangements

• information. Keywords: biological activity; cyclopentane/enone; rearrangements; ring/cycle contractions; total synthesis; Introduction The functionalized cyclopentane/enone fragment is part of the structure of a large number of natural and synthetic biologically active compounds, including prostaglandins

• useful strategic transformations for the construction of carbocyclic and heterocyclic cyclopentanes. Six-membered carbocycles are convenient starting compounds for the synthesis of cyclopentanoids due to their widespread occurrence in nature and their synthetic availability. Undoubtedly, the development

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

• different sources [4][5]. In order to fulfil this requirement, a considerable number of green solvents of various classes have been developed for a range of applications, including the extraction of natural compounds [6][7][8][9], food analysis [10][11][12], pharmacology [13][14][15], and organic synthesis

• applications must persist. In the modern world, one of the main goals of an increasing number of chemists interested in the design and synthesis of versatile organic molecules is to develop atom-efficient, multicomponent, low-cost, and environmentally benign synthetic strategies for these molecules. In the

• the time- and labor-intensive nature of traditional multistep synthesis strategies. For instance, this methodology has been demonstrated to be highly advantageous in the synthesis of numerous pharmaceutical compounds, biological probes, insecticides, alkaloids, and other intricate natural compounds

An Fe(II)-catalyzed synthesis of spiro[indoline-3,2'-pyrrolidine] derivatives

• Elizaveta V. Gradova,
• Nikita A. Ozhegov,
• Roman O. Shcherbakov,
• Alexander G. Tkachenko,
• Larisa Y. Nesterova,
• Elena Y. Mendogralo and
• Maxim G. Uchuskin

Beilstein J. Org. Chem. 2025, 21, 2383–2388, doi:10.3762/bjoc.21.183

• activities, spiro[indoline-3,2'-pyrrolidines] have attracted substantial interest in medicinal chemistry, prompting the development of diverse synthetic strategies. Several methodologies have been reported for the synthesis of substituted spiro[indoline-3,2'-pyrrolidines] (Scheme 1), which can be broadly

• , a highly diastereoselective method for the synthesis of dihydrospiro[indoline-3,2'-pyrrole]-2-ones has been developed (Scheme 1, path a) [7]. This transformation proceeds via a Lewis acid-mediated conjugate addition of vinyl azides to electron-deficient alkenes, followed by denitrogenative

• e) [12]. The second category of synthetic methods relies on more accessible, non-pre-functionalized starting materials and stepwise assembly of the spirocyclic core. This strategy enables the synthesis of functionalized 3H-indoles, which can be further elaborated into structurally diverse products

Synthetic study toward vibralactone

• Liang Shi,
• Jiayi Song,
• Yiqing Li,
• Jia-Chen Li,
• Shuqi Li,
• Li Ren,
• Zhi-Yun Liu and
• Hong-Dong Hao

Beilstein J. Org. Chem. 2025, 21, 2376–2382, doi:10.3762/bjoc.21.182

• vibralactone, a potent inhibitor of pancreatic lipase, is reported. The synthesis of the challenging all-carbon quaternary center within the cyclopentene ring was achieved through intramolecular alkylidene carbene C–H insertion. Keywords: alkylidene carbene; C–H insertion; total synthesis; vibralactone

• ; Introduction β-Lactones have attracted continuous interest and have been widely utilized as key intermediates in the synthesis of natural products and polymers due to their innate ring strain [1][2][3][4][5][6]. Moreover, several natural products and their derivatives containing β-lactone as key structural

• and ClpP2 and it could be utilized as a probe to study the activity and structure of the ClpP1P2 complex from Listeria monocytogenes [25]. Previously, Snider and co-worker reported the first total synthesis of vibralactone (6) employing Birch reductive alkylation, intramolecular aldol reaction and

Conformational effects on iodide binding: a comparative study of flexible and rigid carbazole macrocyclic analogs

• Guang-Wei Zhang,
• Yong Zhang,
• Le Shi,
• Chuang Gao,
• Hong-Yu Li and
• Lei Xue

Beilstein J. Org. Chem. 2025, 21, 2369–2375, doi:10.3762/bjoc.21.181

• spectra of WDG (10 μM) in CHCl3, (c) Fluorescence spectra of PBG (10 μM) in CHCl3 (λex: 303 nm), (d) Fluorescence spectra of WDG (10 μM) in CHCl3 (λex: 303 nm). Synthesis routes of PBG and WDG. Supporting Information Supporting Information File 32: Additional experimental data. Funding The project was

Rotaxanes with integrated photoswitches: design principles, functional behavior, and emerging applications

• Jullyane Emi Matsushima,
• Khushbu,
• Zuliah Abdulsalam,
• Udyogi Navodya Kulathilaka Conthagamage and
• Víctor García-López

Beilstein J. Org. Chem. 2025, 21, 2345–2366, doi:10.3762/bjoc.21.179

• or upon irradiation with light at 280 nm. Azobenzene Azobenzene is one of the most widely utilized photoresponsive units in the design and synthesis of photoswitchable rotaxanes. These photoswitches undergo trans–cis isomerization and are classified as T-type, due to the thermal reversibility of the

• acridane photoswitch directly into a crown ether macrocycle [82]. However, the synthesis proceeded with very low yield, and the small amount of rotaxane obtained was immediately converted to the acridinium form during purification. Attempts to regenerate the acridane were unsuccessful. Nevertheless, the

Recent advances in Norrish–Yang cyclization and dicarbonyl photoredox reactions for natural product synthesis

• Peng-Xi Luo,
• Jin-Xuan Yang,
• Shao-Min Fu and
• Bo Liu

Beilstein J. Org. Chem. 2025, 21, 2315–2333, doi:10.3762/bjoc.21.177

• natural product synthesis. This review summarizes the latest advancements in these reactions for constructing terpenoids, alkaloids, and antibiotics. Through Norrish–Yang cyclization, dicarbonyls (e.g., 1,2-diketones and α-keto amides) can efficiently construct sterically hindered ring structures, which

• can further undergo ring-opening or rearrangement reaction to assemble complex molecular frameworks. Additionally, quinone photoredox reactions involving single-electron transfer (SET) processes provide novel strategies for the stereoselective synthesis of useful structures such as spiroketals. This

• synthesis of natural products but also establish a solid foundation for subsequent pharmaceutical investigations. Keywords: dicarbonyls; natural product; Norrish–Yang cyclization; photoredox; total synthesis; Introduction In the 1930s, Norrish documented the photodecomposition of aldehydes and ketones [1