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Search for "B" in Full Text gives 3138 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.

High-pressure activation for the solvent- and catalyst-free syntheses of heterocycles, pharmaceuticals and esters

  • Kelsey Plasse,
  • Valerie Wright,
  • Guoshu Xie,
  • R. Bernadett Vlocskó,
  • Alexander Lazarev and
  • Béla Török

Beilstein J. Org. Chem. 2025, 21, 1374–1387, doi:10.3762/bjoc.21.102

Graphical Abstract
  • reactions were carried out at 80 °C and at (a) 3.8 kbar, 1 h, (b) 2.8 kbar, 30 × 1 min cycles, (c) 2.8 kbar, 40 × 1 min cycles. The yields were determined by GC. High pressure-initiated large scale syntheses of N-aryl- and N-alkylpyrroles at about 100 g scale. Optimization of the HHP-initiated synthesis of
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Published 02 Jul 2025

Oxetanes: formation, reactivity and total syntheses of natural products

  • Peter Gabko,
  • Martin Kalník and
  • Maroš Bella

Beilstein J. Org. Chem. 2025, 21, 1324–1373, doi:10.3762/bjoc.21.101

Graphical Abstract
  • ], oxetanocin A [22], oxetin [23], merrilactone A [24], dictyoxetane [25] and mitrephorone A [26], which were isolated by 2005, but the collection is still being expanded and more recent additions include dichrocephone B from 2013 [27], compositacin D from 2017 [28], hawaiienol A from 2018 [29] or dendroterpene
  • categorised into 6 synthetic strategies as depicted in Scheme 1: a) C–O bond-forming cyclisations, b) C–C bond-forming cyclisations, c) [2 + 2] cycloadditions between carbonyls and alkenes, d) ring expansions, e) ring contractions and f) O–H insertions. In the following subchapters, these strategies will be
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Published 27 Jun 2025

Recent advances in amidyl radical-mediated photocatalytic direct intermolecular hydrogen atom transfer

  • Hao-Sen Wang,
  • Lin Li,
  • Xin Chen,
  • Jian-Li Wu,
  • Kai Sun,
  • Xiao-Lan Chen,
  • Ling-Bo Qu and
  • Bing Yu

Beilstein J. Org. Chem. 2025, 21, 1306–1323, doi:10.3762/bjoc.21.100

Graphical Abstract
  • transfer (HAT) in photocatalytic reactions. These radicals display exceptional selectivity and efficiency in abstracting hydrogen atoms from C–H, Si–H, B–H, and Ge–H, positioning them as invaluable tools in synthetic chemistry. This review summarizes the latest advancements in the photocatalyzed generation
  • and the relatively green chemistry of generating amidyl radicals. Amidyl radicals offer several advantages that enhance their applicability in organic synthesis: 1) The BDE of amidyl N–H bond is more than 105 kcal/mol, relative to the bond (C–H, Si–H, B–H, and Ge–H) which BDE is lower than 100 kcal
  • amidyl radicals from HRP: (a) direct single-electron oxidation of amide HRP in the presence of photocatalyst and a base via a proton-coupled electron transfer (PCET) process by the cleavage of the N–H bond; (b) single-electron reduction of HRP catalyzed by photocatalyst via a single-electron transfer
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Published 27 Jun 2025

Recent advances and future challenges in the bottom-up synthesis of azulene-embedded nanographenes

  • Bartłomiej Pigulski

Beilstein J. Org. Chem. 2025, 21, 1272–1305, doi:10.3762/bjoc.21.99

Graphical Abstract
  • antiaromatic character of the pentagon, in contrast to pristine azulene. This results in a significantly red-shifted optical absorption at 997 nm. Therefore, compound 24 should be considered a formally antiaromatic extended indeno[1,2-b]fluorene, rather than a ‘true’ extended azulene. Similarly, Müllen and co
  • with a low singlet−triplet gap. Nanographene 26, which also contains the indeno[1,2-b]fluorene structural motif, displays an extremely narrow energy gap of 0.27 eV and exhibits a pronounced open-shell biradical character, with biradical character index close to 1 (y0 = 0.92). Very recently, a similar
  • products containing either two (63) or four azulene subunits (64). Analysis of NICS values revealed that the formally antiaromatic character indeno[1,2-b]fluorene units remain dominant in fused PAHs 63 and 64 resulting also in a biradical character. Considering these factors, PAHs 63 and 64 should be
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Published 26 Jun 2025

Recent advances in oxidative radical difunctionalization of N-arylacrylamides enabled by carbon radical reagents

  • Jiangfei Chen,
  • Yi-Lin Qu,
  • Ming Yuan,
  • Xiang-Mei Wu,
  • Heng-Pei Jiang,
  • Ying Fu and
  • Shengrong Guo

Beilstein J. Org. Chem. 2025, 21, 1207–1271, doi:10.3762/bjoc.21.98

Graphical Abstract
  • radical A. This is followed by the conversion of a substrate containing C(sp3)–H bonds adjacent to an oxygen atom into an alkyl radical intermediate B. The alkyl radical intermediate then adds to the C=C bond of N-arylacrylamide, generating a second alkyl radical intermediate C, which undergoes
  • . This alkyl radical then adds across the C–C double bond in the enyne, forming an alkyl radical intermediate B, which reacts with the C–C triple bond to generate a vinyl radical intermediate C. Depending on the substitution effect at the 3-position of the acrylamide moiety, the intermediate undergoes
  • -determining step. Based on these results, a detailed mechanism was proposed (Scheme 10) in which a copper-assisted homolysis of DCP generates a cumyloxyl radical A, which initiates the formation of an imidoyl radical B from the isocyanide. This radical then undergoes homolytic cleavage to yield an alkyl
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Published 24 Jun 2025

Optimized synthesis of aroyl-S,N-ketene acetals by omission of solubilizing alcohol cosolvents

  • Julius Krenzer and
  • Thomas J. J. Müller

Beilstein J. Org. Chem. 2025, 21, 1201–1206, doi:10.3762/bjoc.21.97

Graphical Abstract
  • chlorides 2 and 2-methyl-N-benzylbenzothiazolium salts 3 in 1,4-dioxane as a solvent at room temp for 0.5 to 1 h produces representative aroyl-S,N-ketene acetals 1 in mostly excellent yield (Scheme 3). For comparison, the yields of the products 1 under standard (A) and new modified (B) conditions are listed
  • in Table 1. The yield of compounds 1 after flash chromatography on silica gel under modified conditions (B) are significantly higher than under standard conditions (A). The results demonstrate the broad applicability of the optimized reaction conditions. Acid chlorides with electron-withdrawing (-CN
  • ) and will be applied in future sequences for the generation of (hetero)aroyl-S,N-ketene acetals. Experimental Synthesis of compound 1i according to conditions B (typical procedure): 4-Fluorobenzoyl chloride (2e, 0.590 mL, 4.99 mmol, 1.00 equiv) and benzothiazolium salt 3a (1.76 g, 5.50 mmol, 1.10 equiv
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Published 20 Jun 2025

Synthesis of β-ketophosphonates through aerobic copper(II)-mediated phosphorylation of enol acetates

  • Alexander S. Budnikov,
  • Igor B. Krylov,
  • Fedor K. Monin,
  • Valentina M. Merkulova,
  • Alexey I. Ilovaisky,
  • Liu Yan,
  • Bing Yu and
  • Alexander O. Terent’ev

Beilstein J. Org. Chem. 2025, 21, 1192–1200, doi:10.3762/bjoc.21.96

Graphical Abstract
  • Alexander S. Budnikov Igor B. Krylov Fedor K. Monin Valentina M. Merkulova Alexey I. Ilovaisky Liu Yan Bing Yu Alexander O. Terent'ev N. D. Zelinsky Institute of Organic Chemistry of the Russian Academy of Sciences, 47 Leninsky prosp., 119991 Moscow, Russian Federation M. V. Lomonosov Moscow State
  • radicals and product 3 can be described by several pathways. The direct oxidation of 2 by Cu(II) A leads to the formation of P-centered radical E and Cu(I) B. Under air atmosphere, the formed Cu(I) species B can react with molecular oxygen resulting in the formation of peroxycopper intermediate C [75][76
  • hydroperoxide transfer from copper complex D with the formation of intermediate H and, therefore, regenerating Cu(I) B. Alternatively, the latter can be formed by oxidation of benzylic radical G with the formation of carbocation I. However, given that in the absence of oxygen the β-ketophosphonate was formed
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Published 20 Jun 2025

Selective monoformylation of naphthalene-fused propellanes for methylene-alternating copolymers

  • Kenichi Kato,
  • Tatsuki Hiroi,
  • Seina Okada,
  • Shunsuke Ohtani and
  • Tomoki Ogoshi

Beilstein J. Org. Chem. 2025, 21, 1183–1191, doi:10.3762/bjoc.21.95

Graphical Abstract
  • electrophilic functionalization. a) Synthesis of methylene-alternating copolymers of fully π-fused propellanes. DCE, 1,2-dichloroethane. b) 1H NMR (500 MHz, top) and 13C (126 MHz, bottom) NMR spectra of [4.3.3]_CH2OH and [4.3.3]_linear in CDCl3 at room temperature. Gas adsorption (filled circles) and desorption
  • (open circles) isotherms of [3.3.3]_oligo (dark red), [3.3.3]_linear (red), [3.3.3]_branch (orange), [4.3.3]_oligo (purple), [4.3.3]_linear (blue), and [4.3.3]_branch (green). a) CO2 at 298 K and b) N2 at 77 K. Formylation of naphthalene-fused propellanes. Properties of methylene-alternating
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Published 18 Jun 2025

Enhancing chemical synthesis planning: automated quantum mechanics-based regioselectivity prediction for C–H activation with directing groups

  • Julius Seumer,
  • Nicolai Ree and
  • Jan H. Jensen

Beilstein J. Org. Chem. 2025, 21, 1171–1182, doi:10.3762/bjoc.21.94

Graphical Abstract
  • SMARTS pattern match than highlighted in Tomberg and colleagues [9]. The matching SMARTS pattern from Tomberg et al. [9] is shown in (a), whereas our algorithm resulted in the match shown in (b). An example highlighting the difficulties in prioritizing the SMARTS patterns. All three patterns match the
  • black cross. B: Distribution of correct (green), semi-correct (yellow), and wrong (red) predictions for the same molecules, evaluated with an energy threshold of 1.0 kcal·mol−1. Molecules with five potential reaction sites that are predicted wrong by the QM workflow. The experimentally observed and
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Published 16 Jun 2025

A multicomponent reaction-initiated synthesis of imidazopyridine-fused isoquinolinones

  • Ashutosh Nath,
  • John Mark Awad and
  • Wei Zhang

Beilstein J. Org. Chem. 2025, 21, 1161–1169, doi:10.3762/bjoc.21.92

Graphical Abstract
  • reaction followed by the cleavage of the alkyl group to give intermediate II as a free amine. Annulation of II with CDI gave product B which is an HIV reverse transcriptase inhibitor (Scheme 1B) [17]. We have reported a three-component [3 + 2] cycloaddition followed by IMDA reaction for making heterocyclic
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Published 13 Jun 2025

Synthetic approach to borrelidin fragments: focus on key intermediates

  • Yudhi Dwi Kurniawan,
  • Zetryana Puteri Tachrim,
  • Teni Ernawati,
  • Faris Hermawan,
  • Ima Nurasiyah and
  • Muhammad Alfin Sulmantara

Beilstein J. Org. Chem. 2025, 21, 1135–1160, doi:10.3762/bjoc.21.91

Graphical Abstract
  • derivatives named alphabetically starting from the original borrelidin 1, designated as borrelidin A (Table 1, entry 1). A rare nitrile moiety at C12 of the macrolide ring in borrelidin A is present in most members of the borrelidin family (Table 1, entries 4, 5, 7–11, 13–16, and 18), except for borrelidin B
  • , N-acetylborrelidin B, borrelidin CR2, borrelidin I, and borrelidin N (Table 1, entries 2, 3, 6, 12, and 17). Borrelidin B (Table 1, entry 2), a tetrahydroborrelidin derivative with an aminomethyl group instead of the nitrile in position 12 of the macrolide, was isolated from the marine-derived
  • Streptomyces sp. RL09-241-NTF-B strain [17]. The discovery of borrelidin B, along with the novel introduction of an N-acetyl group in borrelidin B (N-acetylborrelidin B, Table 1, entry 3), expanded the borrelidin family. N-Acetylborrelidin B was obtained from Streptomyces mutabilis sp. MII [18], a marine
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Published 12 Jun 2025

Investigations of amination reactions on an antimalarial 1,2,4-triazolo[4,3-a]pyrazine scaffold

  • Henry S. T. Smith,
  • Ben Giuliani,
  • Kanchana Wijesekera,
  • Kah Yean Lum,
  • Sandra Duffy,
  • Aaron Lock,
  • Jonathan M. White,
  • Vicky M. Avery and
  • Rohan A. Davis

Beilstein J. Org. Chem. 2025, 21, 1126–1134, doi:10.3762/bjoc.21.90

Graphical Abstract
  • C20H2635ClN6NaO2, 439.1620; found, 439.1616. (A) Position numbering on the pyrazine ring of 1,2,4-triazolo[4,3-a]pyrazine. (B) Illustration of ipso- and tele-substitution products for reactions of nucleophiles with 5-halogenated 1,2,4-triazolo[4,3-a]pyrazine, where X = halogen and Nuc = nucleophile. Key COSY
  • (–), HMBC (→) and ROESY (↔) correlations for compound 2. Thermal ellipsoid plot of compound 2. Thermal ellipsoid plots for compounds 7 (A), 10 (B) and 15 (C). Treatment of 1 with phenethylamine (PEA) under two different reaction conditions, (i) or (ii), gave 2 in 70% and 82% yield, respectively. Reagents
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Published 10 Jun 2025

Gold extraction at the molecular level using α- and β-cyclodextrins

  • Susana Santos Braga

Beilstein J. Org. Chem. 2025, 21, 1116–1125, doi:10.3762/bjoc.21.89

Graphical Abstract
  • -CD·HAuBr4·DBC, showing the packing mode and dimensions of the complex. (b) Capped-stick and space-filling representation of the β-CD channels extending along the c-axis, which are occupied by alternating DBC and [AuBr4]− anions. Solvent molecules and hydrogen atoms have been omitted for the sake of clarity
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Published 06 Jun 2025

A versatile route towards 6-arylpipecolic acids

  • Erich Gebel,
  • Cornelia Göcke,
  • Carolin Gruner and
  • Norbert Sewald

Beilstein J. Org. Chem. 2025, 21, 1104–1115, doi:10.3762/bjoc.21.88

Graphical Abstract
  • broad doublets instead of double-doublets (Figure 2a,b). The lack of a second coupling constant indicates a conformation in between a chair and a boat with a dihedral angle ϕ near 90°, which is necessary for a coupling constant to be around 0 Hz. Half-chair or twist-boat conformations are well known for
  • -S) and 3J(H2,H3,pro-R). Therefore, a half-chair conformation with ϕ(H2,H3,pro-S) = 90° and ϕ(H6,H5,pro-R) = 270° resulting in 3J(H2,H3,pro-S) = 3J(H6,H5,pro-R) ≈ 0 Hz and 3J(H2,H3,pro-R) = 5.0 Hz as well as 3J(H6,H5,pro-S) = 5.7 Hz (as shown in Figure 2a,b) would be the most suitable explanation
  • for H2 and H6. 1H NMR spectra with both signal sets for the chair and half-chair configuration as well as Newman projection for both protons H2 and H6 with corresponding dihedral angles ϕ for a) (2R,6S)-9, b) saponification product (2R,6S)-10. 1H NMR spectra with signal set for the chair configuration
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Published 04 Jun 2025

Supramolecular assembly of hypervalent iodine macrocycles and alkali metals

  • Krishna Pandey,
  • Lucas X. Orton,
  • Grayson Venus,
  • Waseem A. Hussain,
  • Toby Woods,
  • Lichang Wang and
  • Kyle N. Plunkett

Beilstein J. Org. Chem. 2025, 21, 1095–1103, doi:10.3762/bjoc.21.87

Graphical Abstract
  • help assemble higher order supramolecular hypervalent iodine macrocycles [16][17][18]. Examples of hypervalent iodine macrocycles (HIMs) include those synthesized by Ochiai [16], Tykwinski and Zhdankin [17], and our group’s extension of those works (Figure 1A and B) [18][19]. The main driving force for
  • 7.750 ppm (compound 1, proton b, Figure 3A) shifting upfield and the multiplet at 7.60 ppm (protons c and d, Figure 3A) shifting downfield and merging into a single multiplet when approximately 1:1 ratio of HIM to salt was added as shown in Figure 4. Additional titration data are provided in Supporting
  • macrocycle and not to the electrophilic, yet oxygen-rich, core of the macrocycle. (A) Our previous work: Assembly and disassembly of phenylalanine hypervalent iodine macrocycles (Phe HIM) through anion coordination. (B) Another work on π-extended hypervalent iodine macrocycle and their supramolecular
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Published 30 May 2025

Salen–scandium(III) complex-catalyzed asymmetric (3 + 2) annulation of aziridines and aldehydes

  • Linqiang Wang and
  • Jiaxi Xu

Beilstein J. Org. Chem. 2025, 21, 1087–1094, doi:10.3762/bjoc.21.86

Graphical Abstract
  • carboxylate groups followed by a ring opening of the aziridine ring, forming azomethine ylide intermediates A. The intermediates A further undergo a [2 + 3] annulation (or cycloaddition) with aldehydes 2 through endo transition state TS to generate intermediates B, which release products 3 with regeneration
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Published 28 May 2025

Recent advances in synthetic approaches for bioactive cinnamic acid derivatives

  • Betty A. Kustiana,
  • Galuh Widiyarti and
  • Teni Ernawati

Beilstein J. Org. Chem. 2025, 21, 1031–1086, doi:10.3762/bjoc.21.85

Graphical Abstract
  • vinylphenylboronic acid to synthesize the solid-supported phenylboronic acid catalyst (cat 1) which was used to convert cinnamic acid (7) to its corresponding amide 12 in moderate yield. The reaction involves dicarboxylate complex 135 formed through Lewis acid B–O=C interaction (Scheme 41A) [23]. The catalyst could
  • be reused multiple times without significant loss of activity. Using B(C6F5)3 as catalyst, Wu and co-workers (2021) developed a borane-catalyzed Fischer esterification of cinnamic acids with methanol to afford the corresponding methyl cinnamates 136 and 137 via (C6F5)3B–O=C interaction (138) (Scheme
  • -branched (L/B) selectivity of >20:1. The reaction involves the formation of palladium hydride (Pd–H) 270 as the key species followed by alkyne and CO insertion reactions via 271 and 272 (Scheme 68A) [116]. On the one hand, Jia and co-workers (2021) utilized environmentally benign water as the hydrogen
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Published 28 May 2025

Biobased carbon dots as photoreductants – an investigation by using triarylsulfonium salts

  • Valentina Benazzi,
  • Arianna Bini,
  • Ilaria Bertuol,
  • Mariangela Novello,
  • Federica Baldi,
  • Matteo Hoch,
  • Alvise Perosa and
  • Stefano Protti

Beilstein J. Org. Chem. 2025, 21, 1024–1030, doi:10.3762/bjoc.21.84

Graphical Abstract
  • solution was examined, for solubility reasons. a) CDs-mediated 1,2-difunctionalization of alkenes by alkyl halides R–Y and b) light-driven reduction of triarylsulfonium salts in the presence of CDs. Carbon dots tested in this project and their main (photo)physical characteristics. Emission parameters for
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Published 26 May 2025

Synthesis of pyrrolo[3,2-d]pyrimidine-2,4(3H)-diones by domino C–N coupling/hydroamination reactions

  • Ruben Manuel Figueira de Abreu,
  • Robin Tiedemann,
  • Peter Ehlers and
  • Peter Langer

Beilstein J. Org. Chem. 2025, 21, 1010–1017, doi:10.3762/bjoc.21.82

Graphical Abstract
  • instance, deazapurines represent heterocyclic fused pyrimidine bases which have found special attention, due to their widespread occurrence in natural alkaloids exhibiting various biological properties. For example, cadeguomycin (A), tubercidin (B), and toyocamycin (C) show antibiotic properties, while
  • activities. Development of drugs based on pyrrolopyrimidines: A: Cadeguomycin. B: Tubercidin. C: Toyocamycin. D: Batzelladine A. E: Sangivamycin. F: Pemetrexed. G: Immucillin H. H: TAK-285 (tyrosine kinase inhibitor). UV–vis absorption (left) and emission (right, λex = 300 nm) spectra of compounds 4a, 4j, 4k
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Published 22 May 2025

Recent total synthesis of natural products leveraging a strategy of enamide cyclization

  • Chun-Yu Mi,
  • Jia-Yuan Zhai and
  • Xiao-Ming Zhang

Beilstein J. Org. Chem. 2025, 21, 999–1009, doi:10.3762/bjoc.21.81

Graphical Abstract
  • cephalotaxine, cephalezomine H, (−)-cephalotaxine, (−)-cephalotine B, (−)-fortuneicyclidin A, (−)-fortuneicyclidin B, and (−)-cephalocyclidin A. Unlike enamines, tertiary enamides can participate in cyclization reactions initial as nucleophiles, and upon protonation, alkenylation, or alkylation, the resultant
  • a fragmentation process for the total synthesis of (−)-phlegmariurine B. A one-pot epoxidation/nucleophilic epoxide opening introduced both a hydroxy group and a chloride across the cyclopentene, producing 14 in 57% yield. After oxidation of alcohol 14 to ketone 15, the Mukaiyama hydration then
  • triggered a Grob fragmentation process of hemiaminal 16 and afforded the imide compound 17. Final regioselective reduction of one of the two carbonyls on the imide completed the synthesis of (−)-phlegmariurine B. Annulation Total syntheses of cephalotaxine and cephalezomine H The [2 + 3] annulation of
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Published 22 May 2025

On the photoluminescence in triarylmethyl-centered mono-, di-, and multiradicals

  • Daniel Straub,
  • Markus Gross,
  • Mona E. Arnold,
  • Julia Zolg and
  • Alexander J. C. Kuehne

Beilstein J. Org. Chem. 2025, 21, 964–998, doi:10.3762/bjoc.21.80

Graphical Abstract
  • -shifted and reduced in ϕ compared to TTM-Cz (cf. compounds 31 and 33 in Figure 8a and b). Higher generations (G3TTM, G4TTM) exhibit hypsochromically shifted emission maxima compared to the G2TTM and increased ϕ (52% and 63% respectively (in cyclohexane)) (see Figure 10). This effect can be explained by
  • extension of the Cz donor structure to benzocarbazole (BCz) and dibenzocarbazole (DbCz) follows the trend of the above described three-state model (see Figure 11). However, further extension to aza[7]helicenes also leads to contradiction with the model (cf. compounds 35 and 36 in Figure 8a and b). The ϕs of
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Published 21 May 2025

Harnessing tethered nitreniums for diastereoselective amino-sulfonoxylation of alkenes

  • Shyam Sathyamoorthi,
  • Appasaheb K. Nirpal,
  • Dnyaneshwar A. Gorve and
  • Steven P. Kelley

Beilstein J. Org. Chem. 2025, 21, 947–954, doi:10.3762/bjoc.21.78

Graphical Abstract
  • disulfonoxylation [2] and alkene amino-trifluoroacetoxylation [4], we hypothesized that treatment of (E)-hex-3-en-1-yl methoxycarbamate with a mixture of an I(III) oxidant and a sulfonic acid would lead to the formation of amino-sulfonoxylated product. We were thus very pleased to observe 59% of desired product B
  • using a combination of 1 equivalent of commercially available 1-acetoxy-1,2-benziodoxol-3-(1H)-one (CAS [1829-26-1]) and 1 equivalent of methanesulfonic acid (MsOH) (Table 1, entry 1). Increasing the equivalents of both reagents to 1.5 completely consumed starting material and delivered product B in an
  • excellent yield of 73% (Table 1, entry 2). A similar yield was achieved by using 1.5 equivalents of commercially available PhI(OH)(OMs) (CAS [105551-42-6]) (Table 1, entry 3). With these conditions, adding exogenous MsOH was not necessary. Reasonable amounts of product B could also be obtained with 1
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Published 19 May 2025

Study of tribenzo[b,d,f]azepine as donor in D–A photocatalysts

  • Katy Medrano-Uribe,
  • Jorge Humbrías-Martín and
  • Luca Dell’Amico

Beilstein J. Org. Chem. 2025, 21, 935–944, doi:10.3762/bjoc.21.76

Graphical Abstract
  • nitrogen donors have gained increasing attention for their use as photoredox catalysts. This study introduces a new family of D–A molecules by exploring various sulfur-based acceptors and nitrogen donors, including a novel tribenzo[b,d,f]azepine (TBA) unit and 5H-dibenz[b,f]azepine (IMD). Our findings
  • -donating strength. The development of stronger donors to enhance luminescence remains a key area of research [20][21][22]. Recently, azepine-based analogs, such as tribenzo[b,d,f]azepine (TBA, a), have been explored due to their photoluminescence properties [23][24][25][26][27]. This antiaromatic core
  • offers unique features, including twisted structures, reduced π–π stacking, and enhanced reverse intersystem crossing rates, becoming a better donor compared to fully planar compounds as carbazole (c). Similarly, 5H-dibenz[b,f]azepine (IMD, b) has been incorporated into D–A–D structures, showing
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Published 14 May 2025

A convergent synthetic approach to the tetracyclic core framework of khayanolide-type limonoids

  • Zhiyang Zhang,
  • Jialei Hu,
  • Hanfeng Ding,
  • Li Zhang and
  • Peirong Rao

Beilstein J. Org. Chem. 2025, 21, 926–934, doi:10.3762/bjoc.21.75

Graphical Abstract
  • simultaneously installing the hydroxy group at C30. The latter intermediate could in turn be derived from dienone 11 by an AcOH-interrupted Nazarov cyclization [32][33][34], thereby establishing the B ring with the desired all-cis stereochemical configuration, including the quaternary carbon at C10 and the
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Published 12 May 2025

Silver(I) triflate-catalyzed post-Ugi synthesis of pyrazolodiazepines

  • Muhammad Hasan,
  • Anatoly A. Peshkov,
  • Syed Anis Ali Shah,
  • Andrey Belyaev,
  • Chang-Keun Lim,
  • Shunyi Wang and
  • Vsevolod A. Peshkov

Beilstein J. Org. Chem. 2025, 21, 915–925, doi:10.3762/bjoc.21.74

Graphical Abstract
  • activated alkyne in an endo-dig fashion, forming a 7-membered ring. The resulting intermediate B undergoes proton transfer from the second pyrazole nitrogen to the vinyl silver moiety yielding pyrazolo[1,5-a][1,4]diazepine 16a and regenerating the silver catalyst. Methylation of either pyrazole nitrogen
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Published 08 May 2025
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