Insoluble methylene-bridged glycoluril dimers as sequestrants for dyes

• Suvenika Perera,
• Peter Y. Zavalij and
• Lyle Isaacs

Beilstein J. Org. Chem. 2025, 21, 2302–2314, doi:10.3762/bjoc.21.176

• textile, leather, paint, plastic, cosmetics, pharmaceuticals, and food industries [4]. It has been estimated that about 7 × 106 tons of dyes (e.g., methylene blue, rhodamine B, methyl orange, Congo red, disperse violet 26, methyl red, crystal violet) are produced annually worldwide [5]. Many dyes are

• accord with the depicted C2v-symmetric structures. Figure 3 shows the 1H NMR spectra recorded for G2W1–G2W4 in DMSO-d6 at 400 MHz. As expected, all four hosts display two singlets for the equatorial CH3 groups (a, b), two pairs of doublets for the diastereotopic CH2 groups (c,c’ and d,d’) in the expected

• crystal structures by X-ray diffraction methods. Figure 5a shows a cross-eyed stereoview of one molecule of G2W3 in the crystal. Crystals of G2W3 are monoclinic with the P21/c space group (a/Å = 10.0768(9); b/Å = 13.4198(11); c/Å = 32.411(3); α/° = 90, β/° = 98.135(3), γ/° = 90). As has been observed

Halogenated butyrolactones from the biomass-derived synthon levoglucosenone

• Johannes Puschnig,
• Martyn Jevric and
• Ben W. Greatrex

Beilstein J. Org. Chem. 2025, 21, 2297–2301, doi:10.3762/bjoc.21.175

• -derived bioactives. Preparation of chlorinated and brominated lactones 8a,b and 11a,b. Preparation of fluorinated lactone 14. Fluorination of LGO (5) and conversion to lactone 17. Trifluoromethylation of 9a,b and 15 and subsequent Baeyer–Villiger oxidation. Supporting Information Supporting Information

Enantioselective radical chemistry: a bright future ahead

• Anna C. Renner,
• Sagar S. Thorat,
• Hariharaputhiran Subramanian and
• Mukund P. Sibi

Beilstein J. Org. Chem. 2025, 21, 2283–2296, doi:10.3762/bjoc.21.174

• obviating the need for both enantiomers of the ligand. Although chiral Lewis acid-mediated radical reactions were groundbreaking, they suffered from major disadvantages: (a) high catalyst loadings (stoichiometric or sub-stoichiometric), (b) large amounts of the radical initiator, (c) the need for a large

• diazoester 24 to furnish a Co(III)-bonded α-ester radical (α-Co(III)-ester radical) with extrusion of nitrogen was proposed by the authors. Further steps include (a) 5-exo cyclization by α-Co(III)-ester radical and (b) homolytic substitution at the carbon atom by 3-exo-tet-cyclization to generate bicyclic

• generation (A) and general types of radical reactions (B). Chiral catalysis in enantioselective radical chemistry [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37]. Diastereo- and enantioselective additions of nucleophilic radicals to N-enoyloxazolidinone

Pathway economy in cyclization of 1,n-enynes

• Hezhen Han,
• Wenjie Mao,
• Bin Lin,
• Maosheng Cheng,
• Lu Yang and
• Yongxiang Liu

Beilstein J. Org. Chem. 2025, 21, 2260–2282, doi:10.3762/bjoc.21.173

•  2, path b). In the following years, Liu and co-workers discovered that the protonation of intermediate 2 triggered its conversion to intermediate 3, which subsequently underwent oxidation with oxygen, resulting in the generation of an indenone skeleton 6 [9]. This tunability achieved efficient and

• (THF) was used as solvent, the proton elimination and protodeauration led to the formation of dihydrophenanthrene 12 due to solvent effects (Scheme 3, path b). This pathway-controlled approach for the syntheses of phenanthrenes complemented the established protocols. In 2020, Mutra et al. achieved a

• preferentially initiated 6-endo-trig cyclization, affording iodinated homoallylic alcohol piperidines 15 (Scheme 4, path a). Conversely, cyclopropane-annulated pyrrolidines 17 were constructed using methanol as solvent through hydroxyl radical-mediated 5-exo-trig cyclization pathway (Scheme 4, path b). This

Research towards selective inhibition of the CLK3 kinase

• Vinay Kumar Singh,
• Frédéric Justaud,
• Dabbugoddu Brahmaiah,
• Nangunoori Sampath Kumar,
• Blandine Baratte,
• Thomas Robert,
• Stéphane Bach,
• Chada Raji Reddy,
• Nicolas Levoin and
• René L. Grée

Beilstein J. Org. Chem. 2025, 21, 2250–2259, doi:10.3762/bjoc.21.172

• , Khudwadhar, Gulaothi, Bulandshahr, Uttar Pradesh-203408, India Chemveda Life Sciences India Pvt. Ltd., B-11/1, IDA Uppal, Hyderabad-500039, Telangana, India Sorbonne Université, CNRS, FR 2424, Plateforme de criblage KISSf (Kinase Inhibitor Specialized Screening facility), Station Biologique de Roscoff, CS

• series of molecules: the ones without chlorine in meta position on this group (series a) and the others which kept this chlorine, like in DB18 (series b). These syntheses are reported in Scheme 2. A Suzuki-type Pd-catalyzed coupling of 7a with 4-(methoxycarbonyl)phenylboronic acid dimethyl ester (8) gave

• present in DYRK kinases. Nevertheless, by highlighting the role of the lysine 241, the present work paves the way towards the long-term goal of getting more potent and selective inhibitors of this understudied CLK3 kinase. A) Sequence of amino acids in CLK3 as compared to the three other CLKs; B

A chiral LC–MS strategy for stereochemical assignment of natural products sharing a 3-methylpent-4-en-2-ol moiety in their terminal structures

• Rei Suo,
• Raku Irie,
• Hinako Nakayama,
• Yuta Ishimaru,
• Yuya Akama,
• Masato Oikawa and
• Shiro Itoi

Beilstein J. Org. Chem. 2025, 21, 2243–2249, doi:10.3762/bjoc.21.171

• analysis, and computational methods have been widely used. For example, the absolute configuration of chaetomugilin B [19] was determined by X-ray crystallography, while that of capsulactone (1) was established through density functional theory (DFT)-based simulations of NMR chemical shifts and electronic

• . (a) Synthetic (2S,3S)-8, (2S,3R)-9, (2R,3R)-10, and (2R,3S)-11 and (b) C9–C12 fragment 7 derived from 1. (A) General strategy for the preparation of the fragment from an MPO-containing natural product. (B) Synthesis of esters 4–6, each as a mixture of four stereoisomers. Preparation of the C9–C12

Pd-catalyzed dehydrogenative arylation of arylhydrazines to access non-symmetric azobenzenes, including tetra-ortho derivatives

• Loris Geminiani,
• Kathrin Junge,
• Matthias Beller and
• Jean-François Soulé

Beilstein J. Org. Chem. 2025, 21, 2234–2242, doi:10.3762/bjoc.21.170

• )–aryl intermediate (B). Subsequently, ligand exchange occurs, generating hydrazido complexes C and C'. When bulky substituents are present on the phosphine ligand and/or (both) coupling partner(s) has ortho-substituent(s), the hydrazido complex C, chelating on the terminal nitrogen, is preferentially

• azobenzenes; b) previous Pd-catalyzed methods for the synthesis of non-symmetric azobenzenes; c) this work: Pd-catalyzed dehydrogenative C–N coupling of arylhydrazine. a) Proposed catalytic cycle for the one-pot palladium-catalyzed dehydrogenative C–N coupling for the synthesis of azobenzene from

• arylhydrazine and aryl bromide. b) Proposed chemical pathway for azobenzene synthesis, including side-product formation as determined by GC/MS analysis. Scope of aryl bromides in palladium-catalyzed dehydrogenative C–N coupling with phenylhydrazine (1a). aUsing 2 equiv of 1a. Scope of arylhydrazines in

Thiadiazino-indole, thiadiazino-carbazole and benzothiadiazino-carbazole dioxides: synthesis, physicochemical and early ADME characterization of representatives of new tri-, tetra- and pentacyclic ring systems and their intermediates

• Gyöngyvér Pusztai,
• László Poszávácz,
• Anna Vincze,
• András Marton,
• Ahmed Qasim Abdulhussein,
• Judit Halász,
• András Dancsó,
• Gyula Simig,
• György Tibor Balogh and
• Balázs Volk

Beilstein J. Org. Chem. 2025, 21, 2220–2233, doi:10.3762/bjoc.21.169

• -1,2,3-benzothiadiazine 1,1-dioxide (4b), both described in our earlier publication [8]. Treatment of compounds 4a,b with hydrazine monohydrate afforded 8-hydrazino derivatives 5a,b as suitable starting materials for the construction of the indole structural element of compounds 3 by Fischer indole

• hydrazino derivatives 5a,b with ketones 6a–e in the presence of bismuth nitrate pentahydrate catalyst in refluxing methanol with good to excellent yields (method A, step 1). As regards cis–trans isomerism, compounds (E)-7a and (E)-7f were isolated in high yields (94% and 84%, respectively), however, in the

• conditions. Finally, we were able to achieve the Fischer cyclization of compounds 7a–j by using p-toluenesulfonic acid monohydrate as catalyst in boiling toluene (method A, step 2) [26][27]. On the other hand, the one-pot synthesis of target compounds 3a–j starting from hydrazino derivatives 5a,b was

A m-quaterphenyl probe for absolute configurational assignments of primary and secondary amines

• Yuka Takeuchi,
• Mutsumi Kobayashi,
• Yuuka Gotoh,
• Mari Ikeda,
• Yoichi Habata,
• Tomohiko Shirai and
• Shunsuke Kuwahara

Beilstein J. Org. Chem. 2025, 21, 2211–2219, doi:10.3762/bjoc.21.168

• of all local minima employing DFT at the B3LYP/6-31G* level of theory [47]. Four low-energy conformers of (S)-3a were identified within 10.0 kJ/mol (Figure 3). Among them, conformers A and D exhibited an M twist between the long axes of the biphenyl chromophores, whereas conformers B and C displayed

• 293 K, the population of the P and M conformers were determined. CD and UV spectra of (a) tertiary amines (S)-2a–e and (b) quaternary ammonium salts (S)-2f,g and (R)-2h (2.0 × 10−4 M in CH3CN, 293 K). Schematic representation of the preferred conformation of (S)-2a. Four major conformers of (S)-3a

Synthesis of triazolo- and tetrazolo-fused 1,4-benzodiazepines via one-pot Ugi–azide and Cu-free click reactions

• Xiaoming Ma,
• Zijie Gao,
• Jiawei Niu,
• Wentao Shao,
• Shenghu Yan,
• Sai Zhang and
• Wei Zhang

Beilstein J. Org. Chem. 2025, 21, 2202–2210, doi:10.3762/bjoc.21.167

• methods for the synthesis of tetrazoles [25][26][27][28], the Ugi–azide reaction is a good approach for constructing 1,5-disubstituted-tetrazoles (1,5-DS-T) [29][30][31]. This scaffold can be subsequently linked to 1,2,3-triazole [32], 4H-chromen-4-one [33], pyrrolo[3,4-b]indolizine [34], and other

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

• systematically. According to different types of five-membered rings, the electrochemical construction of five-membered rings from alkynes are mainly classified into the following categories: (a) construction of indoles, (b) construction of isoindolinones and indolizines, (c) construction of oxazoles and

• ] generated [Cp2Fe]+ along with cathodic reduction of MeOH to H2 and MeO− acting as a base. Deprotonation of 1a using MeO− produced the anion A, which underwent single-electron transfer (SET) with [Cp2Fe]+ to give the nitrogen-centered radical B with regeneration of [Cp2Fe] [164][165][166][167][168][169][170

• ][171][172]. Then, the 6-exo-dig cyclization of B obtained the vinyl radical C [173] that proceeded cyclization with the aryl species to form the radical D. Eventually, the rearomatization of D by eliminating one proton along with electron afforded 2a. This protocol, proceeding smoothly without noble

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

• asymmetric hydrogenation process of α-hydroxy ketones opens up a new pathway for the production of chiral terminal 1,2-diols (Scheme 23) [98]. Kini and Mathews reported the synthesis of novel oxazole derivatives such as 6-(substituted benzylidene)-2-methylthiazolo[2,3-b]oxazol-5(6H)-one by reacting 1

• % yield (Scheme 42, path b) [131]. 5-Acetamido-2(5Н)-furanone is obtained in 20–40% yield when acetamide reacts with 5-bromo- or 5-ethoxy-2(5H)-furanone [132][133][134][135], while 5-acetamido-2(5Н)-furanone and 5-benzoylamido-2(5H)-furanone were obtained in 48% and 55% yield, respectively, by reaction of

• phosphorus oxide catalyst (VPO), furoic acid was also found to be a key intermediate (Scheme 44, route b) [149]. A photocatalytic access to succinic anhydride from furoic acid using catalytic porphyrin H2TPP in the presence of O2 and light was also reported [150]. Yang and Lv reported the oxidation of

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

• the presence of Fe(dpm)3/Ph(iPrO)SiH2 proceeded smoothly to furnish the tetracyclic product 39 in 56% yield with 2.5:1 ratio. Finally, removal of the acetonide and the Bn protecting group completed the total synthesis of (+)-aplysiasecosterol A (6). Total synthesis of (+)-cyrneine A, (−)-cyrneine B

• ][26][27][28][29][30]. In 2018, the group of Han accomplished the total synthesis of (+)-cyrneine A (7), (−)-cyrneine B (9), (−)-glaucopine C (10), and (+)-allocyathin B2 (8) by a collective manner [31]. In their synthetic route, an enzyme-catalyzed desymmetric enantioselective reduction of 1,3

• (Scheme 3) [31][32]. Oxidation state adjustment of 48 led to the ketone 49. Starting from this common intermediate, firstly, base-promoted double bond migration and oxidation at the γ-position gave tertiary alcohol 50. Deprotection of acetyl in 50 followed by selective oxidation delivered (−)-cyrneine B

Multicomponent reactions IV

• Thomas J. J. Müller and
• Valentyn A. Chebanov

Beilstein J. Org. Chem. 2025, 21, 2082–2084, doi:10.3762/bjoc.21.163

• , September 2025 Number of publications by year on multicomponent and one-pot reactions (A) and multicomponent reactions alone (B) accessed by Web of Science on June 16, 2025.

Further elaboration of the stereodivergent approach to chaetominine-type alkaloids: synthesis of the reported structures of aspera chaetominines A and B and revised structure of aspera chaetominine B

• Jin-Fang Lü,
• Jiang-Feng Wu,
• Jian-Liang Ye and
• Pei-Qiang Huang

Beilstein J. Org. Chem. 2025, 21, 2072–2081, doi:10.3762/bjoc.21.162

• reported structures of alkaloids aspera chaetominines A and B have been synthesized. Moreover, the four-step synthesis of the reported structure of aspera chaetominine B generated another diastereomer that was converted in one-pot to (–)-isochaetominine C, which turned out to be the revised structure of

• aspera chaetominine B. Keywords: epoxidation; selective epimerization; stereodivergent synthesis; structural revision; tandem reaction; Introduction In contemporary organic chemistry, due to the widespread application of modern separation and analytical techniques, the structural elucidation and

• endophytic fungus from the liverwort Heteroscyphus tener (Steph.) Schiffn. [30]; (–)-versiquinazoline H (9), isolated from the gorgonian (Pseudopterogorgia sp.)-derived fungus Aspergillus versicolor LZD-14-1 [31]; as well as 5) aspera chaetominines A and B (12 and 13), isolated from marine sponge associated

Discovery of cytotoxic indolo[1,2-c]quinazoline derivatives through scaffold-based design

• Daniil V. Khabarov,
• Valeria A. Litvinova,
• Lyubov G. Dezhenkova,
• Dmitry N. Kaluzhny,
• Alexander S. Tikhomirov and
• Andrey E. Shchekotikhin

Beilstein J. Org. Chem. 2025, 21, 2062–2071, doi:10.3762/bjoc.21.161

• Daniil V. Khabarov Valeria A. Litvinova Lyubov G. Dezhenkova Dmitry N. Kaluzhny Alexander S. Tikhomirov Andrey E. Shchekotikhin Gause Institute of New Antibiotics, 11 B. Pirogovskaya Street, Moscow 119021, Russia Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 32 Vavilov

• [2,1-b]quinazoline-6,12-dione) and its derivatives are particularly noteworthy as they demonstrate multiple biological activities, including antibacterial, antitumor, antifungal, antiviral, anti-inflammatory, antileishmanial, antiplasmodial, etc. [18][19]. The structurally isomeric class – pyrimido

Bioinspired total syntheses of natural products: a personal adventure

• Zhengyi Qin,
• Yuting Yang,
• Nuran Yan,
• Xinyu Liang,
• Zhiyu Zhang,
• Yaxuan Duan,
• Huilin Li and
• Xuegong She

Beilstein J. Org. Chem. 2025, 21, 2048–2061, doi:10.3762/bjoc.21.160

• proposal is that toussaintine C was isolated as a racemic mixture, and sarglamides A and B are derived from one enantiomer of toussaintine C while sarglamides C–E are derived from the other one. The Diels–Alder cycloadditions are basically proceeded through endo-selectivity. The isopropyl group in α

Solar thermal fuels: azobenzene as a cyclic photon–heat transduction platform

• Jie Yan,
• Shaodong Sun,
• Minghao Wang and
• Si Wu

Beilstein J. Org. Chem. 2025, 21, 2036–2047, doi:10.3762/bjoc.21.159

• energy-storage capacity of solar thermal fuels“, Nature Chemistry, vol. 6, pages 441–447, published by Springer Nature, 2014, reproduced with permission from SNCSC). This content is not subject to CC BY 4.0. (b) RGO templating. Figure 3b was used with permission of The Royal Society of Chemistry, from

• subject to CC BY 4.0. (b) Schematic illustration of diacetylene monomer photopolymerization and the conjugated polydiacetylene structure. Figure 4b was redrawn from [47]. (c) Photoisomerization of a conjugated azobenzene polymer with a carbazole backbone. Figure 4c was redrawn from [48]. Linear azobenzene

• Wiley and Sons. Copyright © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. This content is not subject to CC BY 4.0. (b) Structure of the UV–vis solar-thermal cell. Figure 5b was adapted from [59], A. K. Saydjari et al., “Spanning the Solar Spectrum: Azopolymer Solar Thermal Fuels for Simultaneous UV

Switchable pathways of multicomponent heterocyclizations of 5-amino-1,2,4-triazoles with salicylaldehydes and pyruvic acid

• Yana I. Sakhno,
• Oleksander V. Buravov,
• Kostyantyn Yu. Yurkov,
• Anastasia Yu. Andryushchenko,
• Svitlana V. Shishkina and
• Valentyn A. Chebanov

Beilstein J. Org. Chem. 2025, 21, 2030–2035, doi:10.3762/bjoc.21.158

• -triazoles, salicylaldehydes, and pyruvic acid were studied under different reaction conditions. In particular, it was found that the three-component reaction of an equimolar mixture of 5-amino-3-methylthio(methoxy)-1,2,4-triazole 1a,b, salicylaldehydes 2a–f, and pyruvic acid (3) under conventional heating

• -aminotriazoles 1a,b having pronounced electron-donating substituents (methylthio- and methoxy groups). On the other hand, the MCR of the reagents 1a, 2a–c and 3 under ultrasonic irradiation for 2 h at room temperature (25 °C) (Scheme 3) afforded a mixture of 5-(2-hydroxyphenyl)-2-(methylthio)-7-((3-(methylthio

α-Ketoglutaric acid in Ugi reactions and Ugi/aza-Wittig tandem reactions

• Vladyslav O. Honcharov,
• Yana I. Sakhno,
• Olena H. Shvets,
• Vyacheslav E. Saraev,
• Svitlana V. Shishkina,
• Tetyana V. Shcherbakova and
• Valentyn A. Chebanov

Beilstein J. Org. Chem. 2025, 21, 2021–2029, doi:10.3762/bjoc.21.157

• -methylisoxazol-3-yl)-5-oxo-2,5-dihydro-1H-pyrrol-3-yl]acetic acids II (Scheme 1, pathway B). Subsequently, a four-component Ugi reaction of compounds II with temperature-controlled formation of diastereomers of peptidomimetics III was also studied [52]. Taking into account all mentioned above, this work is

• isocyanide (4) in a molar ratio of 1:2:2:2 in MeOH and subsequent stirring at a temperature of 45 °C for 24 hours led to the formation of N1,N5-bis(2-(tert-butylamino)-1-(4-chlorophenyl)-2-oxoethyl)-N1,N5-bis(4-chlorophenyl)-2-oxopentanediamide (6a) in 55% yield (Scheme 2, pathway B; Table 2). Compounds 5

• prepare new quinoxalinone derivatives, we studied a tandem combination of Ugi/aza-Wittig reactions involving α-ketoglutaric acid and o-azidoanilines. First, 5-((2-arylazido)(1-aryl-2-(tert-butylamino)-2-oxoethyl)amino)-4,5-dioxopentanoic acids 8a,b,d,f–h were synthesized by the reaction of KGA (1

Understanding the origin of stereoselectivity in the photochemical denitrogenation of 2,3-diazabicyclo[2.2.1]heptene and its derivatives with non-adiabatic molecular dynamics

• Leticia A. Gomes and
• Steven A. Lopez

Beilstein J. Org. Chem. 2025, 21, 2007–2020, doi:10.3762/bjoc.21.156

• isosurface is 0.001. Absorption spectra and geometric overlays corresponding to Wigner-sampled geometries of 1 (a), 3 (b), and 5 (c) with XMS-CASPT2(8,9)/ANO-S-VDZP. Minimum energy path using XMS-CASPT2(8,9)/ANO-S-VDZP for 1 (a), 3 (b), and 5 (c). The dots on the graphs correspond to the S0 (black), S1 (red

• depicted. σCN bonds plotted against each other for 1 (b), 3 (c), and 5 (d). The solid multicolor lines on each plot show the bond lengths over time, and the dots represent the S1/S0 surface hopping points for each trajectory. (a) Geometrical parameters. Plots show trajectories for a 1 ps NAMD simulation

• with CASSCF (8,9)/ANO-S-VDZP, monitoring C–C-bond formation, H–C–C–C dihedral angle, and relative energy for 1 (b), 3 (c), and 5 (d). The energy is relative to the lowest total energy of each trajectory. The red trajectories return to reactant, the green trajectories form retained housane, the blue

Measuring the stereogenic remoteness in non-central chirality: a stereocontrol connectivity index for asymmetric reactions

• Ivan Keng Wee On,
• Yu Kun Choo,
• Sambhav Baid and
• Ye Zhu

Beilstein J. Org. Chem. 2025, 21, 1995–2006, doi:10.3762/bjoc.21.155

• molecule is characterized by the absence of mirror planes and centers of inversion. Central chirality arises when four distinct substituents (a, b, c, and d) are arranged tetrahedrally around a central atom (Scheme 1A). Non-central chirality – such as axial and planar chirality – are becoming increasingly

• can be generated from achiral starting substrates by various means that assemble the four distinct substituents (a, b, c, and d) (Scheme 1D). In the case of central chirality, the differentiating substituents are often directly attached to the newly formed stereocenter. By contrast, for non-central

• chirality, the pairs of substituents (a and b, c and d) are separated in space because the stereogenic scaffolds span multiple atoms. Consequently, bond cleavage and formation occur at positions that are distant from the stereogenic elements and remote from the actual points of differentiation among the

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

• an internal nucleophile (O-, N-) and reductive elimination affords the arylated product 8 and regenerates the Cu(I) catalyst. The added base (B:) traps the H+, generated in this catalytic cycle. In the case of tert-butyl esters (7: R = COOt-Bu) an equivalent of isobutylene gas is released as a side

• mmol/mL. bNo reaction at 60 and 120 °C. cSame result at 120 °C. Synthesis of lactone and pyrrolidine derivatives. Conditions: ac7e = 0.1 mmol/mL. bReaction conditions modifications: a) 1.2 equiv I-1, CuCl (5 mol %), 60 °C, 3 h, c7f = 0.3 mmol/mL; b) 3.0 equiv I-1, CuCl (10 mol %), 70 °C, 3 h, c7g = 0.1

Photochemical reduction of acylimidazolium salts

• Michael Jakob,
• Nick Bechler,
• Hassan Abdelwahab,
• Fabian Weber,
• Janos Wasternack,
• Leonardo Kleebauer,
• Jan P. Götze and
• Matthew N. Hopkinson

Beilstein J. Org. Chem. 2025, 21, 1973–1983, doi:10.3762/bjoc.21.153

• suitably electrophilic substrate at the carboxylic acid oxidation level provides an acylazolium species B, which typically reacts directly with nucleophiles or may first be transformed into the corresponding enolate derivative. Regardless of the individual pathway, NHC-catalyzed reactions of this type

• offer many synthetic advantages while the wide availability of chiral NHCs can also allow for high levels of enantioselectivity. As effective enamine and active ester derivatives, Breslow and acylazolium intermediates A and B typically react via classical two-electron polar mechanisms, however, recent

• applications, are underway in our laboratory. (a) Combining N-heterocyclic carbene (NHC) organocatalysis with photoredox catalysis for radical–radical coupling reactions. (b) This work: light-mediated reduction of acylimidazolium species 1 with the tertiary amine DIPEA or the simple silane HSiEt3. Initial test

Asymmetric total synthesis of tricyclic prostaglandin D2 metabolite methyl ester via oxidative radical cyclization

• Miao Xiao,
• Liuyang Pu,
• Qiaoli Shang,
• Lei Zhu and
• Jun Huang

Beilstein J. Org. Chem. 2025, 21, 1964–1972, doi:10.3762/bjoc.21.152

• synthetically challenging because of the tricyclic ring system, spiroketal moiety (B, C-ring), and instability arising from dehydration of the hydroxy groups. Prior approaches to (±)-4 have shown the feasibility of accessing this target molecule. Blair [7] and Sulikowski [8] reported the total synthesis of