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Search for "LED" in Full Text gives 2030 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.
Oxetanes: formation, reactivity and total syntheses of natural products
Beilstein J. Org. Chem. 2025, 21, 1324–1373, doi:10.3762/bjoc.21.101
- alkenes and high diastereocontrol (dr ≥ 80:20) was achieved for trisubstituted ones. Switching the bromonium activator to the iodonium analogue only led to a lower yield. This haloetherification method was further expanded by McLaughlin and Roberts in 2022 who reported a convenient two-step sequence
Recent advances in amidyl radical-mediated photocatalytic direct intermolecular hydrogen atom transfer
Beilstein J. Org. Chem. 2025, 21, 1306–1323, doi:10.3762/bjoc.21.100
- feasibility of the reactions but has also led to the establishment of a comprehensive platform for C–H functionalization through the introduction of the highly versatile xanthyl functional group. In 2016, Alexanian’s group successfully implemented a method for the direct xanthylation of C–H bonds with high
Recent advances and future challenges in the bottom-up synthesis of azulene-embedded nanographenes
Beilstein J. Org. Chem. 2025, 21, 1272–1305, doi:10.3762/bjoc.21.99
- co-workers reported the oxidation of partially saturated precursor 23 using DDQ, which led to the isolation of PAH 24 in 50% yield which contains two formal azulene units (Scheme 4) [39]. However, compound 24 was found to possess a biradical structure (biradical character index, y0 = 0.49) with
- oxidation of precursor 41 using DDQ which led to a mixture of azulene-embedded PAHs 42–44 (Scheme 7) [48]. Contorted PAHs 42–44 containing two azulene subunits, were formed through a single-step cyclopentannulation and cycloheptannulation process. The cyclodehydrogenation reaction was accompanied by further
- ring expansion for 2,2’-di(arylethynyl)biphenyls 53a–f [54]. The platinum-catalysed reaction led to a series of azulenophenanthrens 54a–f in yields ranging from 40% to 80%. A similar strategy was employed very recently in the synthesis of azulene-embedded isomers of linear acenes (Scheme 9) by Zhang
Recent advances in oxidative radical difunctionalization of N-arylacrylamides enabled by carbon radical reagents
Beilstein J. Org. Chem. 2025, 21, 1207–1271, doi:10.3762/bjoc.21.98
- -substituents induced steric hindrance effects that led to lower yields. To gain further insight into the mechanism, several control experiments were performed. The results indicated that an iminoxyl radical is generated as the initiator of the reaction (Scheme 6). Initially, TBHP undergoes homolytic cleavage
- radical-mediated process. The necessity of Cp2Fe and Y(OTf)3 for the reaction was also confirmed, as the absence of either catalyst led to a dramatic decrease in product yield. These findings highlighted the critical role of electrochemically generated carbon-centered radicals in driving the cyclization
- with α-aminoalkyl radicals generated from tertiary arylamines using photoredox catalysis (Scheme 13) [9]. In this system, Ir[dF(CF3)ppy]2(dtbbpy)PF6 was used as a photosensitizer to trigger the α-C–H activation of N,N-dimethylaniline, generating an alkyl radical under 30 W blue LED (454 nm) irradiation
Synthesis of β-ketophosphonates through aerobic copper(II)-mediated phosphorylation of enol acetates
Beilstein J. Org. Chem. 2025, 21, 1192–1200, doi:10.3762/bjoc.21.96
- produced by the oxidation of PH-reagents by copper(II)-containing species. Employing anhydrous CuSO4 instead of the pentahydrate led to a dramatic phosphorylation yield drop from 70 to <5%. It seems that the ligand environment of copper is very important for the effective reaction: other Cu(II) and Cu(I
Selective monoformylation of naphthalene-fused propellanes for methylene-alternating copolymers
Beilstein J. Org. Chem. 2025, 21, 1183–1191, doi:10.3762/bjoc.21.95
- Supporting Information File 1). Despite several trials, the reactions led to complicated mixtures owing to decomposition and debromination or predominant recovery of the starting material, respectively. Then, we turned our attention to electrophilic formylation. Vilsmeier–Haack [61] and Duff [62] reactions
- led to recovery of starting material or a complicated mixture probably owing to the modestly electron-rich and sterically demanding naphthalene α-positions (Table S202, entries 1–3, Supporting Information File 1). By contrast, a combination of dichloromethyl methyl ether and TiCl4 (Rieche reaction
Synthetic approach to borrelidin fragments: focus on key intermediates
Beilstein J. Org. Chem. 2025, 21, 1135–1160, doi:10.3762/bjoc.21.91
- a marine or hypersaline environment natural products library to identify potent drugs, a putatively novel metabolite co-produced with borrelidin was discovered, expanding the potential for new borrelidin derivatives. This led to the formation of the so-called “borrelidin family” (Table 1), with
- failure may have been due to the low reactivity of sulfones 27 and ent-27 under the reaction conditions. Additionally, treating ent-42 with excess tert-butyllithium to form the corresponding lithiated derivative and reacting it with epoxide 23a, both with or without BF3·OEt2, also led to unsatisfying
- epoxides 23b and 23a with the non-protected variant 23c, and reacting it with sulfone 27 after pre-complexation with Ti(OiPr)4, again led only to decomposition. Given the unsatisfying results, Uguen and co-workers replaced the epoxides 23a–c to monoethers 46a and 46b, derived from trans-2,3-epoxy-1,4
Gold extraction at the molecular level using α- and β-cyclodextrins
Beilstein J. Org. Chem. 2025, 21, 1116–1125, doi:10.3762/bjoc.21.89
- , led to the quick formation of co-precipitates when added to aqueous solutions of β-CD and KAuBr4 (both at 5 mM): dibutyl carbitol, isopropyl ether, chloroform, dichloromethane, hexane, benzene, and toluene [51]. The most effective one was dibutyl carbitol (DBC), which caused 99.7% precipitation when
A versatile route towards 6-arylpipecolic acids
Beilstein J. Org. Chem. 2025, 21, 1104–1115, doi:10.3762/bjoc.21.88
- to reduce the arylated N-formyl enamine moiety in 3 remained unsuccessful. We also aimed at improving conversion and yield by first testing different bases and catalysts [42][43]. DMF, a well-established solvent for cross-coupling reactions, led to lower degradation of the bromide 2 compared to other
Supramolecular assembly of hypervalent iodine macrocycles and alkali metals
Beilstein J. Org. Chem. 2025, 21, 1095–1103, doi:10.3762/bjoc.21.87
- investigate the association of HIMs with metal cations. NMR titration of HIM 1 with LiBArF20 led to distinct shifting of signals with the successive addition of salt. Figure 4 shows a titration of 1 with increasing equivalents of LiBArF20. The most dramatic changes included the aromatic proton multiplet at
Recent advances in synthetic approaches for bioactive cinnamic acid derivatives
Beilstein J. Org. Chem. 2025, 21, 1031–1086, doi:10.3762/bjoc.21.85
- other hand, Fan and co-workers (2020) prepared α-amidoketone 71 by employing vinyl azide and cinnamic acid (7) in good yield via cascade reaction (Scheme 23B) [58]. The thermal decomposition of the azide led to the generation of the reactive azirine intermediate 72. Moreover, Li and co-workers (2020
- ion 105 formation via its reaction with acetonitrile. Kokotos and co-workers (2023) prepared Weinreb amide 107 mediated by sunlight or LED 370 nm from cinnamic acid (7) via light-activated DMAP 108, leading to electrophilic iminium 109 formation (Scheme 33) [28]. On the other hand, Gilmour and co
Pd-Catalyzed asymmetric allylic amination with isatin using a P,olefin-type chiral ligand with C–N bond axial chirality
Beilstein J. Org. Chem. 2025, 21, 1018–1023, doi:10.3762/bjoc.21.83
- (Table 1, entry 5). Other potassium salts such as K3PO4 led to a low yield of the product (Table 1, entry 6). Meanwhile, when Na3PO4 was tested, the yield decreased, but the enantioselectivity improved to 88% ee (Table 1, entry 7). With Na3PO4 as the optimum base, which showed the highest
- in good yield, although with slightly decreased enantioselectivity. The introduction of the chloro group at the same position led to a moderate yield for (S)-13d, while the enantioselectivity remained high. In contrast, the reaction with the isatin derivative bearing a nitro group at the 5-position
- yields with high enantioselectivities. Conversely, the isatin derivative bearing a methoxy group at the 6-position led to a decreased yield for (S)-13j, though the enantioselectivity remained high. Additionally, we tested the reaction using an isatin derivative with a chloro group at the 7-position and
Synthesis of pyrrolo[3,2-d]pyrimidine-2,4(3H)-diones by domino C–N coupling/hydroamination reactions
Beilstein J. Org. Chem. 2025, 21, 1010–1017, doi:10.3762/bjoc.21.82
- absorption band. With respect to the phenyl group attached to the pyrrole nitrogen, the presence of the electron-withdrawing CF3 group led to a slight hypsochromic shift (4j). In the case of compound 4l, containing a 4-trifluoromethylphenyl group attached to the nitrogen, no significant shift of the
- wavelengths. However, this shoulder was less distinct for compounds 4m and 4j and not detectable for 4k and 4l, containing the N,N-dimethylaminophenyl group. In contrast to the absorption spectra, in the case of the emission spectra, the presence of a thienyl substituent (compound 4m) led to a hypsochromic
- . Electron-donating N,N-dimethylaminophenyl substituents led to bathochromically shifted absorption and emission spectra accompanied by strongly elevated fluorescence quantum yields (up to 83%). Further studies will be devoted to the synthesis of novel polycyclic uracil derivatives with potential biological
Recent total synthesis of natural products leveraging a strategy of enamide cyclization
Beilstein J. Org. Chem. 2025, 21, 999–1009, doi:10.3762/bjoc.21.81
- the terminal alkene and the conformational strain of forming a bridge[3.2.1]bicycle might be responsible for a selective 6-exo-trig cyclization. From tricyclic compound 4, anti-Markovnikov oxidation catalyzed by palladium led to the formation of aldehyde 5. When treated with p-TsOH, the intramolecular
Studies on the syntheses of β-carboline alkaloids brevicarine and brevicolline
Beilstein J. Org. Chem. 2025, 21, 955–963, doi:10.3762/bjoc.21.79
- salt for further confirming their structures. A new synthesis of the related alkaloid brevicolline was also attempted from the same intermediate. However, after successful coupling of β-carboline with N-methylpyrrole, the trials to saturate the pyrrole ring under various conditions led to unexpected
- , versatile key triflate intermediate 3, which allowed the introduction of substituents attached by a C–C bond to position 4 of the β-carboline scaffold by cross-coupling reactions. Sonogashira reaction of compound 3 with N-(3-butynyl)phthalimide (4) led to coupled compound 5. Cleavage of the phthalimide
Study of tribenzo[b,d,f]azepine as donor in D–A photocatalysts
Beilstein J. Org. Chem. 2025, 21, 935–944, doi:10.3762/bjoc.21.76
- previously reported by Zysman-Colman and co-workers [19]. Compound 5d showed the best performance with a 27% calculated NMR yield (20%, isolated yield) (Table 3, entry 3), while the azepine derivatives 5a and 5b led the transformation at 13 and 8%, respectively (Table 3, entries 1 and 2). However, these
A convergent synthetic approach to the tetracyclic core framework of khayanolide-type limonoids
Beilstein J. Org. Chem. 2025, 21, 926–934, doi:10.3762/bjoc.21.75
- .) of 24 led only to epimerization at C10 or slow decomposition of the starting material (see Supporting Information File 1, Table S1). Pleasingly, treating 24 with HMDS and TMSI regioselectively generated the expected TMS enol ether [46], which underwent a Li/Si exchange in the presence of MeLi
- stage was set for the construction of the target skeleton through a 1,2-addition (Scheme 4). Preliminary trials to generate organometallic species via Li/I exchange under various conditions (n-BuLi, t-BuLi, or t-BuLi in combination with CeCl3 or MgBr2) led to rapid decomposition, likely due to inherent
- Nazarov cyclization under a variety of conditions (Table 1). Initial trials under acid-mediated Nazarov conditions (AlCl3, BF3·Et2O and Me2AlCl) led to complete decomposition, while the exposure to AcOH resulted in recovery of the starting material (Table 1, entries 1–4). Recognizing the limitations of
Silver(I) triflate-catalyzed post-Ugi synthesis of pyrazolodiazepines
Beilstein J. Org. Chem. 2025, 21, 915–925, doi:10.3762/bjoc.21.74
- reduction with LiAlH₄, which led to a further decrease in the degree of unsaturation of the pyrazolodiazepine core, while the more sterically hindered exocyclic amide moiety remained intact. However, both reactions were accompanied by partial epimerization, and careful kinetic control was therefore required
Cu–Bpin-mediated dimerization of 4,4-dichloro-2-butenoic acid derivatives enables the synthesis of densely functionalized cyclopropanes
Beilstein J. Org. Chem. 2025, 21, 877–883, doi:10.3762/bjoc.21.71
- bearing aromatic and aliphatic substituents efficiently provided the allylboration product (Scheme 1a), the use of ester derivative 1 under same reaction conditions led to the formation of an unexpected product arising from the coupling of two dichloride molecules with no alkyne incorporation (Scheme 1b
- , entry 2), although the use of sub-stoichiometric amounts led to a significant decrease in reaction yield (Table 1, entry 3). We also tried to reduce the amount of base, but this caused a drop in the reaction efficiency (Table 1, entry 4). Evaluation of different bases demonstrated the important role of
- the base metal cation. Gratifyingly, we observed that the use of LiOt-Bu led to the formation of product 2 as a single diastereomer (Table 1, entry 5). A slightly lower diastereoselectivity was observed when KOt-Bu was used, which also gave rise to 2 in diminished yield (Table 1, entry 6). The nature
Data accessibility in the chemical sciences: an analysis of recent practice in organic chemistry journals
Beilstein J. Org. Chem. 2025, 21, 864–876, doi:10.3762/bjoc.21.70
- exist in several disciplines. For example: the ‘Bermuda Principles’ in genomics [4][5], the Omics Discovery Index in biomedical science [6], access to sky survey data in astronomy [7], and commitments to data sharing in Earth and environmental sciences [8]. Sharing has led to the development of tools
- primary data were not deposited in a public repository (Figure 5a). Except for one example from Synthesis, data of any type had only been shared to a public repository when published in one of the four ACS journals. 95% of these used Figshare [40], (Figure 5b), and this is entirely publisher-led behavior
- article cited or linked?’ assesses if it is possible to trace data back to the original publication where the methods used to generate those data are described. 76% of primary data had a citation, however, publisher-led copying of SI files to Figshare positively distorts this proportion, as the repository
Light-enabled intramolecular [2 + 2] cycloaddition via photoactivation of simple alkenylboronic esters
Beilstein J. Org. Chem. 2025, 21, 854–863, doi:10.3762/bjoc.21.69
- state catalyst are not operational (see Supporting Information File 1 for full details), providing support for an EnT mechanism, while exposing the Z-isomer (Z)-1a to the model reaction conditions, led to the generation of a similar photostationary state equilibrium of isomers, characteristic of an EnT
Unraveling cooperative interactions between complexed ions in dual-host strategy for cesium salt separation
Beilstein J. Org. Chem. 2025, 21, 845–853, doi:10.3762/bjoc.21.68
- cations within a single molecule, have facilitated advancements in ion-pair recognition. This progress has led to the development of ion separation utilizing ion-pair receptors [16][17][18][19][20], which eliminate the need for auxiliary reagents to balance overall charges compared to the use of
- ]. According to our previous results, the binding affinity of L with chloride, sulfate and phosphate is determined to be 2.2 × 102 M−1, 9.9 × 104 M−1, and 3.8 × 106 M−1, respectively (in DMSO) [31]. Such strong anion binding affinity has led to selective extraction of sulfate and phosphate from basic aqueous
Chitosan-supported CuI-catalyzed cascade reaction of 2-halobenzoic acids and amidines for the synthesis of quinazolinones
Beilstein J. Org. Chem. 2025, 21, 839–844, doi:10.3762/bjoc.21.67
- nonprotonated solvents such as THF and toluene were used, the yields were relatively low (Table 1, entries 1 and 2, 39 and 27% yields), indicating poor catalytic activity in these solvents. In contrast, using proton solvents (MeOH, iPrOH and H2O) led to improved yields (Table 1, entries 3−5, 51−60% yields
Substituent effects in N-acetylated phenylazopyrazole photoswitches
Beilstein J. Org. Chem. 2025, 21, 830–838, doi:10.3762/bjoc.21.66
- * transition, while the weaker n→π* band shows absorption maxima in the range of 410–451 nm in CH3CN. The introduction of methyl and acyl groups on one nitrogen of the pyrazole ring led to a hyperchromic effect and a minor bathochromic shift. Also, the introduction of an EDG or EWG on the R position led to
- hyperchromic effects compared for NH- and NMe-PAP-H. Photochemical isomerization Upon irradiation with a 365 nm LED (exemplarily displayed for NMe-PAP-CN in Figure 2), we observed a decrease of the π→π* band for the E isomers. Simultaneously the π→π* bands around 253–369 nm and the n→π* bands around 426–457
- , while for NMe-PAP-CN 146 nm and for NH-PAP-CN 102 nm are found. Subsequent illumination with a 445 nm LED led to the formation of the E isomer, which is accompanied by an increase of its π→π* band until reaching the PSS445. However, judging from the intensity of the E isomers’ π→π* band, the
Synthesis and photoinduced switching properties of C7-heteroatom containing push–pull norbornadiene derivatives
Beilstein J. Org. Chem. 2025, 21, 807–816, doi:10.3762/bjoc.21.64
- ) derivatives. Push–pull substitution on the 2 and 3 position as well as introduction of oxygen or nitrogen at position 7 of the NBD scaffold have led to the development of a new family of photoswitches. We studied the potential conversion of norbornadiene to quadricyclane (QC) isomers. As main investigation
- explored. For instance, incorporation of a C2H4 moiety into the bridge led to the formation of [2.2.2]-bicyclooctadiene derivatives with increased storage capacities but significantly reduced half-lifes compared to analogues NBD derivatives [23][24]. Additionally, introduction of one or more heteroatoms at
- observed π–π* absorption from λπ–π* = 294 nm to 298 nm was found. Prolonged irradiation up to 660 s led to a complete change in the overall absorption properties with maxima at λ = 348 nm and 297 nm and an absorption shoulder at λ = 228 nm suggesting photodecomposition. Next, NMR monitoring of the
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