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

• catechol moiety were detected. The yields of the target sulfoxides ranged from 42% to 89%. Compounds 3–6 were prepared and characterized as described previously (3, 4, and 6 [23], 5 [42]). The structures of new thioethers 1, 2, 7 and sulfoxides 1a–7a were confirmed by the spectral methods IR-, 1H NMR, 13C

• 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

• spectroscopic data. In the IR spectra of the sulfoxides, bands corresponding to the stretching vibrations of hydrogen-bonded OH groups are observed. For compounds 2a–4a, 6a, and 7a, a single broad band appears in the region of 3223–3465 cm−1, whereas for 1a and 5a, two bands are fixed at 3418/3368 cm−1 and 3276

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

• :1 isatin-to-diamine ratio provides the diiminoisatin, whereas a 1:2 ratio leads to the formation of a highly symmetric bis-spirooxindole scaffold. The new spirocyclic product was fully characterized by HRMS, IR and extensive 1D/2D NMR analysis, and its structure was unequivocally established by

• aromatic pattern of the isatin core. The IR spectrum showed a strong imine C=N band at 1610 cm−1, and the absence of the C-3 carbonyl stretching band confirmed complete condensation. The 13C NMR spectrum revealed multiple sets of closely related signals, consistent with the presence of three C=N

• and HMBC experiments were used for signal assignment. Chemical shifts (δ) are expressed in ppm and coupling constants (J) in hertz (Hz). Chemical shifts are reported using CD3OD or DMSO-d6 as internal reference. IR spectra were recorded with a Bruker Alpha spectrometer using a single reflection ATR

Synthesis and biological evaluation of new brassinosteroid analogs with C-22 benzoate function

• María Núñez,
• Camila Escobar,
• Mario Párraga,
• Mauricio Soto,
• Luis Espinoza-Catalán,
• Katy Díaz and
• Andrés F. Olea

Beilstein J. Org. Chem. 2026, 22, 753–762, doi:10.3762/bjoc.22.57

• be possible to evaluate the contribution of different functions attached to ring A. Thus, herein the synthesis of analogs 17–22, starting from the precursor 16, is described. All compounds have been fully characterized by spectroscopic techniques (IR, 1D, 2D NMR and HRMS). The biological activities

• %). All compounds have been characterized by IR, NMR (1D and 2D) and HRMS spectroscopy techniques (see Supporting Information File 1, Figures S1–S30). Thus, in the 1H NMR spectrum of compound 23, the presence of signals at δ = 7.91 ppm (2H, d, J = 8.1 Hz) and 7.21 ppm (2H, d, J = 8.1 Hz) are assigned to

Photoorganocatalytic trifluoromethylation of (het)arenes in green conditions

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

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

• trifluoromethyl-substituted compounds. Over the past decade, numerous photocatalytic protocols for the trifluoromethylation of arenes and heteroarenes have been developed, including approaches employing microflow techniques [6]. These transformations utilize a broad spectrum of catalysts, ranging from Ru- and Ir

• approaches can be regarded as among the most environmentally sustainable methods for trifluoromethylation. MacMillan and co-workers reported the photochemical trifluoromethylation of arenes and heteroarenes using Ru- and Ir-based photocatalysts together with trifluoromethanesulfonyl chloride (TfCl) in the

• for the photochemical trifluoromethylation of (hetero)arenes using an Ir-based photocatalyst under blue-light irradiation (Scheme 1c) [16]. Although these approaches employed inexpensive CF3 sources, they relied on costly noble-metal catalysts with loadings of up to 3 mol %. Moreover, all of these

Hydrogen production from formic acid catalyzed by NHC–Cu complexes

• Orlando Santoro and
• Catherine S. J. Cazin

Beilstein J. Org. Chem. 2026, 22, 620–627, doi:10.3762/bjoc.22.48

• from its dehydrogenation could be recycled by hydrogenation to methanol or formic acid [8][9][10]. The catalytic FA dehydrogenation has been mediated using several transition metals [11][12][13][14]. In this context, noble metals such as Ru [15][16][17][18][19][20][21][22][23], Ir [24][25][26][27][28

• [46]. Nevertheless, these systems still show inferior performance compared to Fe [33], Ru [15], and Ir [28], allowing for TOFs of up to 105 h−1. Conclusion The production of hydrogen from formic acid catalyzed by NHC–Cu complexes was investigated. The reaction in the presence of PhSiH3 led to the

Experimental and DFT studies on the regioselective methanolysis of 5-azido-9-oxabicyclo[6.1.0]nonan-4-yl 4-nitrobenzoate isomers

• İlknur Polat,
• Selçuk Eşsiz and
• Emine Salamci

Beilstein J. Org. Chem. 2026, 22, 547–556, doi:10.3762/bjoc.22.40

• to design pharmacological tools in the future. Experimental General information Melting points are uncorrected. Infrared spectra were obtained from solution in 0.1 mm cells or KBr pellets on an FT-IR Mattson 1000 instrument. The 1H and 13C NMR spectra were recorded on 400 (100) MHz Varian or 400 (100

• , 30.7, 30.3, 23.8, 23.3; IR (cm−1): 3013, 2940, 2621, 2515, 2099, 1725, 1527, 1272, 1117, 1103; HRESIMS (m/z): [M+ + Na] calcd for C15H16N4O4, 339.1069; found, 339.1063. Epoxidation of the azidobenzoate 8 with m-CPBA The azidobenzoate 8 (1.00 g, 3.16 mmol) was dissolved in CH2Cl2 (70 mL) and cooled to

• , 21.2; IR: 2951, 2621, 2102, 1772, 1727, 1528, 1272, 1237, 1020, 719; HRESIMS (m/z): [M+ + Na] calcd for C17H19ClN4O6, 433.0891; found, 433.0884. (1S*,2S*,5S*,6S*)-5-Acetoxy-2-azido-6-chlorocyclooctyl 4-nitrobenzoate (11): 1H NMR (400 MHz, CDCl3) δ 8.36–8.24 (m, 4H, aromatic), 5.23–5.09 (m, 1H, H-1 and

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

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

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

• showed that the quadricyclane 2f0,3 was formed almost quantitatively as the photoproduct (>95%) (see Supporting Information File 1, Figure S11). The photosensitized reaction in the presence of Ir(ppy)3 also afforded quadricyclane 2f0,3 in almost quantitative yield (>95%), as shown by 1H NMR spectroscopy

• (see Supporting Information File 1, Figure S10). The photosensitized reaction in the presence of Ir(ppy)3 or 1-butyl-7,8-dimethoxy-3-methylalloxazin (4) as an alternative catalyst [44][45] with λex = 405 nm (LED) was investigated by in situ 1H NMR spectroscopy. In both cases, the photoreaction was

• ]. According to the results of the photosensitized reaction, the triplet state energy of the norbornadiene 1f is higher than that of norbornadiene 1b (2.08 eV) [50], as the sensitized photocycloaddition only took place with the photocatalyst Ir(ppy)3 (2.52 eV) [51] and with flavine (2.28 eV) [52]. In contrast

Design, synthesis and biological evaluation of 2,5-diaryloxazolo[4,5-d]pyrimidin-7-ylamines as selective cytotoxic agents against HeLa cells

• Maryna V. Kachaeva,
• Agnieszka B. Olejniczak,
• Marta Denel-Bobrowska,
• Victor V. Zhirnov,
• Yevheniia S. Velihina,
• Stepan G. Pilyo and
• Volodymyr S. Brovarets

Beilstein J. Org. Chem. 2026, 22, 390–398, doi:10.3762/bjoc.22.27

• Analytique, Université d’Orléans, Pôle de chimierue de Chartres, BP 6759, 45067 Orléans Cedex 2, France 10.3762/bjoc.22.27 Abstract Nine novel functionalized 2,5-diaryloxazolo[4,5-d]pyrimidin-7-ylamines were designed, synthesized and characterized using 1H, 13C NMR, IR spectroscopy, elemental analysis, and

• cyclocondensation products – [1,3]oxazolo[4,5-d]pyrimidines. Subsequent reaction with phosphoryl chloride in the presence of N,N-dimethylaniline converted these intermediates into 2,5-diaryl-7-chloro[1,3]oxazolo[4,5-d]pyrimidines II. The structures of compounds 1–9 were proven and confirmed by 1H and 13C NMR, IR

• spectroscopy, LC–MS and elemental analysis (Supporting Information File 1, Figures S1–S36). The IR spectra of compounds 1–5 showed the presence of NH absorption bands in the range 3381–2936 cm−1, OH at 3396 cm−1 (compound 9), and C=O at 1601–1610 cm−1 (compounds 6-8). Cytotoxic potency of the compounds 1–9

Synthesis of tricyclic fused pyrrolidine nitroxides from 2-alkynylpyrrolidine-1-oxyls

• Mark M. Gulman,
• Yuliya F. Polienko,
• Sofia Yu. Trakhininа,
• Yuri V. Gatilov,
• Tatyana V. Rybalova,
• Sergey A. Dobrynin and
• Igor A. Kirilyuk

Beilstein J. Org. Chem. 2026, 22, 344–351, doi:10.3762/bjoc.22.22

• presence of DIPEA in chloroform under reflux (Scheme 2). These conditions ensured complete conversion in 30 minutes. The IR spectra of nitroxides 3a–f exhibit intense absorption bands in the ranges of 1354–1358 cm−1 and 1174–1178 cm−1, corresponding to the asymmetric and symmetric vibrations of the

• isolated from the reaction mixtures in each case. The IR spectra of the isolated compounds 4a–f showed characteristic absorption bands to the azido group vibrations at 2100–2116 cm−1. Absorption bands in the ranges of 1410–1420 cm−1 and 1170–1190 cm−1 were also observed, which can be assigned to the out-of

• catalytic system comprising PPh3, CuI, and Pd(PPh3)2Cl2. This procedure afforded alkynones 6a,b in the yields of 75% and 44%, respectively (Scheme 3). In the IR spectra of 6a,b intense bands were observed at 2212–2214 and 1645–1647 cm−1, assigned to vibrations of the triple bond, and the conjugated carbonyl

Streptoquinolines A and B, new antibacterial meroterpenoids produced by Streptomyces sp. TMPU-A0679

• Akiho Yagi,
• Hitomi Tomura,
• Ami Konno and
• Ryuji Uchida

Beilstein J. Org. Chem. 2026, 22, 185–191, doi:10.3762/bjoc.22.12

• preparative HPLC, yielding streptoquinolines A (1, 7.50 mg) and B (2, 8.05 mg). The physicochemical properties of 1 and 2 are summarized in Table 1. Compounds 1 and 2 showed characteristic absorption maxima at 200–202, 214, 231–234, 312, and 349–350 nm in UV spectra. Common IR absorption bands at 3414–3427

Design and synthesis of an axially chiral platinum(II) complex and its CPL properties in PMMA matrix

• Daiki Tauchi,
• Sota Ogura,
• Misa Sakura,
• Kazunori Tsubaki and
• Masashi Hasegawa

Beilstein J. Org. Chem. 2026, 22, 143–150, doi:10.3762/bjoc.22.7

•  4b). The dissymmetry factor is defined as follows: glum = 2ΔI/I = 2(IL – IR)/(IL + IR), where IL and IR denote the luminescence intensities of left- and right-handed circularly polarized luminescence, respectively. The measured dissymmetry factor |glum| was 0.4 × 10−3 (at 558 nm), which is within the

• , Exactive Plus Orbitrap mass spectrometer for electrospray ionization (ESI). IR spectra were measured using a FT/IR-4600 spectrometer with KBr pellets. UV–vis absorption spectra of CH2Cl2 solutions (1.0 × 10−5 M) were recorded with a JASCO V-560 UV–vis spectrometer. Photoluminescence spectra of CH2Cl2

• Hz, 2H), 7.45 (d, J = 8.8 Hz, 2H), 7.36 (dd, J = 1.6, 8.4 Hz, 2H), 7.202–7.198 (m, 2H), 3.74 (s, 6H), 0.17 (s, 18H); 13C NMR (100 MHz, CDCl3) δ 155.5, 133.7, 129.4, 128.9, 128.7, 128, 126.7, 121, 119.1, 114.7, 106.1, 94.2, 56.6, 0.05; IR (KBr) νmax: 3058, 1774, 1409, 1191, 1152, 969, 698, 553, 431 cm

Highly electrophilic, gem- and spiro-activated trichloromethylnitrocyclopropanes: synthesis and structure

• Ilia A. Pilipenko,
• Mikhail V. Grigoriev,
• Olga Yu. Ozerova,
• Igor A. Litvinov,
• Darya V. Spiridonova,
• Aleksander V. Vasilyev and
• Sergey V. Makarenko

Beilstein J. Org. Chem. 2026, 22, 123–130, doi:10.3762/bjoc.22.5

• conditions. The reaction is carried out either in tetrahydrofuran in the presence of triethylamine or in methanol in the presence of fused potassium acetate. The structures of the isolated individual products were characterized by 1H and 13C NMR, IR spectroscopy, mass spectrometry, and confirmed by single

• (1H), 100.53 MHz (13C) in CDCl3 using residual signals of the nondeuterated solvent (δH 7.26, δC 77.16) as the references. The vibrational spectra were measured on a Shimadzu IR-Prestige-21 Fourier-transform IR spectrometer in KBr pellets over 400–4000 cm−1 range (resolution was 2 cm−1). Mass spectra

• the structure are shown in Table S1 in Supporting Information File 1. Supporting Information File 14: General synthetic procedures, characterization data and copies of IR spectra, 1H-13C{1H}, 1H-1H dqfCOSY, 1H-1H NOESY, 1H-13C HMQC, 1H-13C HMBC NMR spectra of all synthesized compounds, and

Total synthesis of natural products based on hydrogenation of aromatic rings

• Haoxiang Wu and
• Xiangbing Qi

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

• in the presence of metal catalysts including Pd or Ir and different ligands. In 2021 and 2022, Wang and co-workers reported two impressive hydroboration–hydrogenation reactions catalyzed by FLP (triarylphenylborane) that reduced pyridine compounds 11 or 15 to dihydropyridine compounds 12 or chiral

• stereoselective synthesis of 157, which strategically combined a Pd-catalyzed pyridine C–H acylation and an Ir-catalyzed asymmetric hydrogenation of the aromatic core [92]. The synthesis began with the coupling of trisubstituted benzene 158 and 2-substituted pyridine 159, furnishing the bicyclic intermediate 160

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

• Hiroshige Ogawa and
• Hugh Nakamura

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

• hydrogen atom from 1,4-cyclohexadiene to furnish the alcohol product. The active species Cp2ZrIII(OTf) is then regenerated via single-electron transfer (SET) from the Ir photocatalyst. Notably, the addition of thiourea 26 significantly improved the regioselectivity in this reaction. According to NMR

• regioselectivity. In a related study, Ota and Yamaguchi et al. reported the regioselective ring-opening of oxetanes using zirconocene catalysis (Scheme 6) [21]. Treatment of oxetane 27 with zirconocene in the presence of an Ir-photoredox catalyst led to ring opening via the less substituted radical intermediate

• the strong affinity of zirconium for halogens, they developed a catalytic system to address this issue. Treatment of alkyl chloride 34 with zirconocene bistosylate in the presence of an Ir-photoredox catalyst promoted halogen atom transfer to generate alkyl radical 35. This radical then abstracted a

Sustainable electrochemical synthesis of aliphatic nitro-NNO-azoxy compounds employing ammonium dinitramide and their in vitro evaluation as potential nitric oxide donors and fungicides

• Alexander S. Budnikov,
• Nikita E. Leonov,
• Michael S. Klenov,
• Andrey A. Kulikov,
• Igor B. Krylov,
• Timofey A. Kudryashev,
• Aleksandr M. Churakov,
• Alexander O. Terent’ev and
• Vladimir A. Tartakovsky

Beilstein J. Org. Chem. 2025, 21, 2739–2754, doi:10.3762/bjoc.21.211

• delta (δ) units, parts per million (ppm) downfield from internal TMS (1H, 13C) or external CH3NO2 (14N negative values of δN correspond to upfield shifts). The IR spectra were recorded with a Bruker ALPHA-T spectrometer in the range of 400–4000 cm−1 (resolution 2 cm−1) as pellets with KBr or as a thin

• washed with CH2Cl2 (3 × 20 mL). The combined organic phase was washed with H2O (20 mL) and brine (20 mL), dried over Na2SO4, and the solvent was removed in vacuo. The yields of 2a were determined with the use of 1H NMR spectroscopy using 1,1,2,2-tetrachloroethane as an internal standard. NMR and IR

Competitive cyclization of ethyl trifluoroacetoacetate and methyl ketones with 1,3-diamino-2-propanol into hydrogenated oxazolo- and pyrimido-condensed pyridones

• Svetlana O. Kushch,
• Marina V. Goryaeva,
• Yanina V. Burgart,
• Marina A. Ezhikova,
• Mikhail I. Kodess,
• Pavel A. Slepukhin,
• Alexandrina S. Volobueva,
• Vladimir V. Zarubaev and
• Victor I. Saloutin

Beilstein J. Org. Chem. 2025, 21, 2716–2729, doi:10.3762/bjoc.21.209

• octahydropyrido[1,2-a]pyrimidinones 4a–d and hexahydrooxazolo[3,2-a]pyridones 5a–c was determined by IR, 1H, 19F, 13C NMR spectroscopy, two-dimensional NMR experiments, and X-ray diffraction analysis (XRD). The IR spectra of octahydropyrido[1,2-a]pyrimidinones 4a–d are characterized by reduced vibrational

• frequencies of the carbonyl function (ν 1633–1593 cm−1) and N–H, O–H groups (ν 3435–3126 cm−1), which indicates their participation in the hydrogen bond formation [67]. On the other hand, the IR spectra of hexahydrooxazolo[3,2-a]pyridones 5a–c contain intense absorption bands of the C=O function at ν 1652

• . Supporting Information Supporting Information File 16: General synthetic procedures, characterization data, XRD analysis data and copies of 1H, 19F, 13C NMR spectra, IR spectra, HRMS spectra of all synthesized compounds. Acknowledgements Analytical studies were carried out using the equipment of the Center

Tandem hydrothiocyanation/cyclization of CF₃-iminopropargyl alcohols with NaSCN in the presence of AcOH

• Ruslan S. Shulgin,
• Ol’ga G. Volostnykh,
• Anton V. Stepanov,
• Igor’ A. Ushakov,
• Alexander V. Vashchenko and
• Olesya A. Shemyakina

Beilstein J. Org. Chem. 2025, 21, 2694–2702, doi:10.3762/bjoc.21.207

• . Results and Discussion We commenced our investigation using CF3-subsituted iminopropargyl alcohol 1a and NaSCN as model substrates. The completion of the reaction was monitored using IR spectroscopy to observe the disappearance of the band at 2219 cm−1 (–C≡C–). It was found that CF3-iminopropargyl alcohol

• internal reference at 20–25 °C. IR spectra were measured on a Bruker Vertex-70 instrument in thin layer, films or KВr pellets. Microanalyses were performed on a Flash 2000 elemental analyzer. Melting points were determined using a Kofler micro hot stage. Mass spectra were recorded on a GCMSQP5050A

• available starting materials were used without further purification. CF3/n-C3F7-substituted iminopropargyl alcohols 1 were prepared according to published methods [31][32]. The structures of synthesized products have been proven by 1H, 13C and 2D (1Н,13С HMBC) NMR, 19F NMR techniques, as well as IR spectra

Recent advancements in the synthesis of Veratrum alkaloids

• Morwenna Mögel,
• David Berger and
• Philipp Heretsch

Beilstein J. Org. Chem. 2025, 21, 2657–2693, doi:10.3762/bjoc.21.206

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

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

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

• standard open 40 μL aluminum pan under 50 mL/min nitrogen atmosphere. IR spectra were obtained on a Bruker ALPHA FT-IR spectrometer in KBr pellets or in neat. NMR spectra were recorded at 295 K on a Bruker Avance III HD 600 (600 and 150 MHz for 1H and 13C NMR spectra, respectively) spectrometer equipped

• (thickness of the stationary phase: 30 mm, eluent: DCM). After evaporation of the solvent, the residue was triturated with Et2O (50 mL) to give pure 7 (25.30 g, 84%) as colorless crystals. Mp 223‒225 °C (CH3CN/EtOH 1:1 (v/v)); IR (KBr): 1638, 1604, 1574, 1501, 1354, 1300, 1175, 1063, 854 cm−1; 1H NMR (600

• chromatography (short aluminum oxide column, eluent: heptane/DCM 1:1, DCM) and isomer 8 (0.62 g, 2%) was isolated as pale yellow crystals. Mp 254‒256 °C (CH3CN); IR (KBr): 1665, 1485, 1344, 1111, 1061, 859 cm−1; 1H NMR (500 MHz, CDCl3): 7.96 (d, 4J = 2.0 Hz, 1H), 7.94 (d, 3J = 8.6 Hz, 1H), 7.63 (dd, 4J = 2.1 Hz

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

• inconsistency made it challenging to rely on NMR as the primary method for confirming the structure of the expected products. To overcome this limitation, other analytical techniques, such as mass spectrometry and infrared (IR) spectroscopy, were employed. These methods successfully corroborated the formation

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

• presence of NHC (20 mol %), 4CzIPN (2 mol %) under mild conditions, producing corresponding unsymmetrical ketone derivatives 8 in up to 95% yield. An Ir-based photocatalyst was initially selected because its excited state is a strong oxidant (E1/2[Ir*III/II] = +1.21 V). Although 4-ethylanisole exhibits a

• higher oxidation potential (E1/2 = +1.52 V). This reaction was examined using different solvents, and it was found that toluene and 1,4-dioxane gave low yields (4–5% yield). Under blue LED irradiation, Ir-based PC is photoexcited, and its excited state is reductively quenched by the electron-rich arene

• substrate 7, generating the aryl radical cation C along with the formation of corresponding radical anion of the photocatalyst (PC•–). The reduction potentials are (E1/2(P/P•–) = –1.37V vs SCE for [Ir(dF(CF₃)ppy)₂(dtbbpy)]PF₆ and –1.21V vs SCE for 4CzIPN as an organophotocatalyst. This method permits the C

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

• formation of unique radical intermediates [9][10]. We previously demonstrated the Ir-catalyzed [2 + 2] cyclization/retro-Mannich reaction of a tryptamine-substituted cyclopentenone F, which led to the formation of indoline J (Figure 1b) [15]. Unlike other reported methods [16][17][18], the PET reaction of F

• construction of the tetracyclic core of Aspidosperma alkaloids. Our method involves an Ir-catalyzed PET reaction of K for the stereoselective formation of the cis-configured BC bicyclic core with an all-carbon quaternary center [25][26]. Computational studies suggest that the observed tandem PET reaction of K

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

• performed using silica gel (60 F254, Merck, Darmstadt, Germany) plates. Melting points were recorded using a Büchi melting point B-540 apparatus (Büchi Labortechnik AG in Flawil, Switzerland). The IR spectra were measured by Spectrum Two FT-IR spectrometer (PerkinElmer, Massachusetts, USA). The NMR spectra

Comparative analysis of complanadine A total syntheses

• Reem Al-Ahmad and
• Mingji Dai

Beilstein J. Org. Chem. 2025, 21, 2334–2344, doi:10.3762/bjoc.21.178

• with an Ir-catalyzed regioselective C–H borylation developed simultaneously by Ishiyama, Miyaura, Hartwig, and co-workers and Smith and co-workers [26][27]. First, the triflate group of 33 was removed by a Pd-catalyzed reduction with ammonium formate as the reducing reagent. The resulting Boc-protected

• lycodine 34 underwent Ir-catalyzed C3–H borylation mainly guided by steric factors to provide boronic ester 35 in 75% yield. With the boronic ester handle at the C3 position, the subsequent Suzuki–Miyaura cross coupling between 35 and 33 occurred smoothly to deliver pseudo-dimer 36, which upon acidic

• . With optically active 51 in hand, its extra ketone functionality was reduced via thioacetalization (51 → 52) and radical reduction (52 → 53) to provide 53, a diverging point to access C–H arylation partners 54 and 55. mCPBA oxidation of 53 afforded pyridine N-oxide 54. The Ir-catalyzed C–H borylation

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

• 82, followed by dehydrogenation, delivered compound 83 in 49% yield over three steps. Pyridone 83 could be funneled into pyridine 85 through O-triflation followed by Pd-catalyzed reductive detriflation. Ir-catalyzed meta-selective C–H borylation of 85, followed by bromodeborylation of the pyridine