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

• in situ nitro reduction using Mn powder to afford the amide intermediate 42. The acid halide once again was applied for cinnamic acid amidation. Xiao and co-workers (2021) performed a transesterification and aminolysis of the tert-butyl ester 43 simply by using PCl3 through in situ generation of the

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

•  1 for CD-a-N-BB). Light-mediated reduction of triarylsulfonium salts. At this point, a Stern–Volmer analysis in the presence of tri-p-tolylsulfonium triflate (1b) as the model substrate was employed to quantify the quenching rate coefficient (Kq), in order to determine the interaction between the

• (whose EREDonset value were in the range −1.60 and −1.92 V vs Ag/AgCl, a set comparable to that reported in the literature for fac-Ir(ppy) [37], which was effectively used in the photoredox-catalyzed reduction of sulfonium salts [29]) and derivatives 1a–d (EAr3S+/Ar3S• = −1.35 to −1.46 V vs Ag/AgCl; see

• Supporting Information File 1 for further information). The obtained results highlighted the feasibility of the reduction process, thus, a nitrogen-saturated solution of 1a–d (0.1 M) in THF/H2O 1:1 in the presence of the CDs was irradiated at 427 nm for 24 h and the photolyzed solution analyzed. As

Pd-Catalyzed asymmetric allylic amination with isatin using a P,olefin-type chiral ligand with C–N bond axial chirality

• Natsume Akimoto,
• Kaho Takaya,
• Yoshio Kasashima,
• Kohei Watanabe,
• Yasushi Yoshida and
• Takashi Mino

Beilstein J. Org. Chem. 2025, 21, 1018–1023, doi:10.3762/bjoc.21.83

• reaction with nucleophilic lithium amide from n-propylamine, the reduction of phosphine oxide 9 by trichlorosilane/triethylamine, and the N-acylation of 10 with cinnamoyl chloride in three steps (Scheme 1). We also analyzed amide compound 7 by HPLC analysis using a chiral stationary phase column with a CD

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

• absorption was observed as compared to compound 4k containing a 4-tolyl group. However, the presence of a CF3 group resulted in a reduction of the extinction coefficient of the absorption band. The emission spectrum of 4a consisted of a strong emission band at 377 nm with a weak shoulder expiring to higher

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

• aldol condensation of 5 provided the tetracyclic α,β-unsaturated enone 6 in 57% yield. Subsequent catalytic hydrogenation using Pd/C conditions delivered the hydrogen to the alkene from the less hindered face, producing ketone 7 with high diastereoselectivity. Final reduction of both the amide and

• a regioselective manner. From tetracyclic compound 11, a one-pot facial and regioselective hydroboration/amide reduction followed by oxidation produced (+)-lycoposerramine Q, which was then converted to (+)-fawcettidine by Ley oxidation. Alternatively, hydroboration of 11 in mild conditions without

• the reduction of amide-generated ketone 12 after a subsequent Dess–Martin oxidation. Upon treatment of 12 with Co(acac)2 and PhSiH3 in iPrOH at 80 °C, the Mukaiyama hydration of enamide delivered hemiaminal 13. Despite the incorrect configuration of the newly formed hydroxy group, it is considered

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

• stabilized and a remarkably high ϕ of 91% can be recorded. This high value is explained by a reduction of the non-radiative pathways by inclusion of the 3I-PTM into the rigid 3I-PTM-H crystal, and a charge transfer (CT) from the high bandgap 3I-PTM-H matrix to the 3I-PTM radical, which is further supported

• Table 2). Analysis of the Huang-Rhys factors delivered that the meta-chlorinated phenyl units do indeed restrict the rotation of the donor. Moreover, the reduction of the LE character of the D1-excited state and a reduction of coupled vibrational modes in the regime from 1000–2000 cm−1 seem to decrease

• reduction in energy from weak to strong CT in Figure 9) [62][71]. The bell shape of the ϕ dependency on the donor strength could be explained by employing a three-state model, in which one assumes that the excitation of the donor-functionalized TTM radical occurs adiabatically into an LE state, followed by

Studies on the syntheses of β-carboline alkaloids brevicarine and brevicolline

• Benedek Batizi,
• Patrik Pollák,
• András Dancsó,
• Péter Keglevich,
• Gyula Simig,
• Balázs Volk and
• Mátyás Milen

Beilstein J. Org. Chem. 2025, 21, 955–963, doi:10.3762/bjoc.21.79

• reactions: reduction of ring A of the β-carboline skeleton or trifluoroethylation of the pyrrole moiety occurred, leading to interesting and potentially useful derivatives. Keywords: alkaloid; β-carboline; Carex brevicollis DC; cross-coupling reaction; trifluoroethylation; Introduction Carex brevicollis

• group with methylhydrazine afforded butynylamine derivative 6. Cyclization of the latter to dihydropyrrole 7 and subsequent reduction resulted in compound 8, which was N-methylated to give racemic brevicolline ((±)-1). The natural product (S)-brevicolline ((S)-1) was finally obtained by chiral

• synthesis of brevicarine (2) (Scheme 5) started with the known synthesis of 5 from 3, followed by catalytic reduction of the triple bond of phthaloyl intermediate 5 to give compound 24. Removal of the phthalimide group with methylamine resulted in amine 25. Alternatively, the removal of the phthaloyl moiety

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

• showed a better performance in comparison with the D–A–D compound 3 (Table 3, entry 7). Furthermore, we obtained pleasing outcomes when we tried the photocatalyzed reductive pinacol coupling of benzaldehyde (15), as reported by Rueping [38]. In this methodology, the reduction of compound 15 is

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

• -unsaturated aldehyde and synthesized from 26 via a four-step transformation sequence, including deketalization, reduction, silylation of the primary alcohol and oxidation of the secondary alcohol. For the disconnection of the C2–C7 bond, a two-step protocol involving Rubottom oxidation and PIDA-promoted

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

• ]. In 2015, García-Valverde and co-workers described an alternative synthesis of benzo[e][1,4]diazepines 6, exploring the nitro group of 2-nitrobenzoic acid as a masked amino group. The release was achieved through the post-Ugi reduction of the nitro group with SnCl2 triggering concomitant

• 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

Recent advances in controllable/divergent synthesis

• Jilei Cao,
• Leiyang Bai and
• Xuefeng Jiang

Beilstein J. Org. Chem. 2025, 21, 890–914, doi:10.3762/bjoc.21.73

• )–H functionalization/thiolation to deliver indane-fused pyrrolidines 43 in excellent yields (up to 92%). Strikingly, switching the solvent to acetonitrile completely suppresses carbene formation under identical conditions, redirecting the pathway toward an unconventional diazo reduction wherein aryl

• barrierless thiyl radical addition and intersystem crossing (ISC) to furnish the final product. In contrast, acetonitrile’s polar aprotic environment destabilizes the carbene pathway, favoring direct reduction of the diazo moiety via electron transfer from the thiol. This solvent-gated selectivity underscores

Regioselective formal hydrocyanation of allenes: synthesis of β,γ-unsaturated nitriles with α-all-carbon quaternary centers

• Seeun Lim,
• Teresa Kim and
• Yunmi Lee

Beilstein J. Org. Chem. 2025, 21, 800–806, doi:10.3762/bjoc.21.63

• % yield under basic conditions using sodium hydroxide and tert-butanol. The reduction of nitrile 3q with lithium aluminum hydride generated amine 7 in an 85% yield, whereas the selective hydrogenation of the alkene moiety of 3q using a Pd/C catalyst in a H2 gas environment smoothly produced product 8 in a

Recent advances in the electrochemical synthesis of organophosphorus compounds

• Babak Kaboudin,
• Milad Behroozi,
• Sepideh Sadighi and
• Fatemeh Asgharzadeh

Beilstein J. Org. Chem. 2025, 21, 770–797, doi:10.3762/bjoc.21.61

• . Electricity can perform the oxidation and reduction process by exchanging electrons on the electrode surface in a region called the double layer (DL) [12]. Unlike traditional methods that require high temperature, pressure, and external oxidants, electrochemistry is an efficient and energy-saving approach

• . They consist of two electrodes – anode (where oxidation occurs) and cathode (where reduction occurs) – immersed in an electrolyte. Galvanic cell The redox reaction occurs spontaneously in these cells, converting chemical energy into electrical energy. The potential difference between the two electrodes

• reduction occur in separate compartments, separated by a diaphragm or salt bridge, to prevent reactant mixing and improve efficiency (e.g., Daniel cell). However, in undivided cells, both reactions occur in a single compartment without separation, resulting in a more straightforward design but potentially

Origami with small molecules: exploiting the C–F bond as a conformational tool

• Patrick Ryan,
• Ramsha Iftikhar and
• Luke Hunter

Beilstein J. Org. Chem. 2025, 21, 680–716, doi:10.3762/bjoc.21.54

• reduction of the H-bond-donor acidity of the hydroxy group of 58. (See section 6, which focuses on carbonyl compounds, for a further explanation of the predicted conformation of 58.) Finally, two structural variations on the hydroxy group should be mentioned. First, if the hydroxy group is acylated (i.e

Entry to 2-aminoprolines via electrochemical decarboxylative amidation of N‑acetylamino malonic acid monoesters

• Olesja Koleda,
• Janis Sadauskis,
• Darja Antonenko,
• Edvards Janis Treijs,
• Raivis Davis Steberis and
• Edgars Suna

Beilstein J. Org. Chem. 2025, 21, 630–638, doi:10.3762/bjoc.21.50

• amount of water was reduced from 33% to 17% (Table 1, entry 8 vs entry 7), an observation that might be useful for substrates of low aqueous solubility. However, further reduction of water amount to 5 equivalents completely inhibited the anodic oxidation of 9a, and only traces of the desired 6a were

• undesired cathodic reduction. Indeed, trace amounts of 2-aminoproline derivative 6g (<4%) could be obtained by replacing SS as the cathode material with platinum that has a low overpotential for hydrogen evolution reaction [14]. To avoid the undesired cathodic reduction of the nitro group, the electrolysis

• under Pd-catalyzed hydrogenolysis afforded diamino acid ester 14 (75% yield) that was likely formed by ring-opening of the unstable N-unprotected 2-aminoproline followed by the reduction of the open-chain imine tautomer. Likewise, the open-chain amino alcohol 15 was formed also upon the reduction of the

Formaldehyde surrogates in multicomponent reactions

• Cecilia I. Attorresi,
• Javier A. Ramírez and
• Bernhard Westermann

Beilstein J. Org. Chem. 2025, 21, 564–595, doi:10.3762/bjoc.21.45

• implementation often implies fewer purification steps to achieve the target molecules, leading to a reduction of waste, when compared to traditional “step by step” synthesis. Another advantage of MCRs is that by selecting appropriate starting materials, follow-up functionalization by, e.g., post-cyclization of

Cryptophycin unit B analogues

• Thomas Schachtsiek,
• Jona Voss,
• Maren Hamsen,
• Beate Neumann,
• Hans-Georg Stammler and
• Norbert Sewald

Beilstein J. Org. Chem. 2025, 21, 526–532, doi:10.3762/bjoc.21.40

• formation and N-Boc-protection [24] provided nitroarene 5 in 40% yield over three steps. Reduction of the nitro group was performed with Pd/C and hydrogen to obtain aniline 6 in 98% yield, which served as a precursor for mono- and dimethylated unit B derivatives 7 and 8, respectively. While dimethylaniline

Synthesis of the aggregation pheromone of Tribolium castaneum

• Biyu An,
• Xueyang Wang,
• Ao Jiao,
• Qinghua Bian and
• Jiangchun Zhong

Beilstein J. Org. Chem. 2025, 21, 510–514, doi:10.3762/bjoc.21.38

• -amine reduction and tosylation from diethyl (S)-2-(hex-5-en-2-yl)malonate ((S)-6). The stereocenter in geminal ester (S)-6 could be derived from (R)-2-methyloxirane ((R)-2) via a ring-opening reaction and a stereospecific inversion of the chiral secondary tosylate (R)-5. Following the similar procedure

• , geminal acid (S)-7 was decarboxylated with DMSO to yield chiral acid (S)-8 [33], followed by TiCl4-catalyzed reduction with ammonia-borane to obtain the chiral alkenyl alcohol (S)-9 [34]. The final tosylation with p-tosyl chloride provided (S)-3-methylhept-6-en-1-yl 4-methylbenzenesulfonate ((S)-10) [29

• ]. Similarly, chiral tosylate (R)-10 could be prepared from (S)-2-methyloxirane ((S)-2) through the ring-opening reaction, tosylation, stereospecific inversion, hydrolysis, decarboxylation, reduction, and second tosylation (Scheme 3). With two the chiral building blocks (R)-10 and (S)-10 in hand, we next

Synthesis of N-acetyl diazocine derivatives via cross-coupling reaction

• Thomas Brandt,
• Pascal Lentes,
• Jeremy Rudtke,
• Michael Hösgen,
• Christian Näther and
• Rainer Herges

Beilstein J. Org. Chem. 2025, 21, 490–499, doi:10.3762/bjoc.21.36

• because the design of a photoswitchable agent usually starts with a known, non-switchable drug or a known biological molecule, which is already carefully "optimized" either by pharmaceutical industry or by nature. Hence, there is a high risk that any change in structure will also lead to a reduction in

• except the preparation of the aminoaniline building block tert-butyl (2-amino-5-bromophenyl)carbamate (5), which was prepared by Boc-protection of the 5-bromo-2-nitroaniline (6) and subsequent reduction of the nitro group (see Supporting Information File 1, section II.1). Cross-coupling reactions Stille

Synthesis of electrophile-tethered preQ₁ analogs for covalent attachment to preQ₁ RNA

• Laurin Flemmich and
• Ronald Micura

Beilstein J. Org. Chem. 2025, 21, 483–489, doi:10.3762/bjoc.21.35

• -diaminopyrimidin-4(3H)-one to afford preQ0 (7), as originally reported by Townsend et al. [30]. The next step, namely the reduction of the nitrile moiety by hydrogenation is critical and notoriously difficult due to the low reactivity of this group in preQ0 [26]. We solved this problem by applying strongly acidic

• -step synthesis of O6-methyl preQ1 (16, m6preQ1) [28]. The direct reduction of the precursor O6-methyl preQ0 (15, m6preQ0) was possible, eliminating the need for the previously introduced protection/solubility concept, which shortened the synthetic route to only four steps (Supporting Information File 1

• of the electrophile. We thus identified aldehydes 9 and 10 as suitable branching points, which were easily derivatized to their aminomethyl-modified preQ1 analogs by reductive amination (Scheme 3). Their syntheses by Raney-Ni reduction of nitriles 7 and 8, previously described by Gangjee and co

Photomechanochemistry: harnessing mechanical forces to enhance photochemical reactions

• Francesco Mele,
• Ana M. Constantin,
• Andrea Porcheddu,
• Raimondo Maggi,
• Giovanni Maestri,
• Nicola Della Ca’ and
• Luca Capaldo

Beilstein J. Org. Chem. 2025, 21, 458–472, doi:10.3762/bjoc.21.33

• , as a beam of light traverses through a solution, photons are quickly absorbed, resulting in abrupt reduction in light intensity. Thr Beer–Lambert law imposes the most stringent constraints from a practical point of view, mainly in terms of scalability. This requires highly diluted solutions, which in

• yield of 79%. Scanning electron microscopy (SEM) analysis revealed the deformation and reduction in size of SAOED particles upon milling. Interestingly, carbon determination experiments revealed that SAOED is quickly poisoned by organic matter, thus hampering recyclability. This can be to some extent

Electrochemical synthesis of cyclic biaryl λ³-bromanes from 2,2’-dibromobiphenyls

• Andrejs Savkins and
• Igors Sokolovs

Beilstein J. Org. Chem. 2025, 21, 451–457, doi:10.3762/bjoc.21.32

• extractive workup followed by reversed-phase chromatography and its structure was unambiguously confirmed by X-ray crystallography (Table 1, graphic). Gratifyingly, a two-fold increase in the yield was achieved by a slight reduction of the current density to j = 8 mA·cm−2 (entry 2 vs entry 1 in Table 1). A

• ) experiments (0.1 M TBA-BF4 in HFIP on a Pt disk electrode) revealed that the reduction current increases almost 4 times upon the addition of 5 mM 1a to the electrolyte (see Supporting Information File 1, Figure S1). At the same time, passing 6.0 F through a solution of 1a in 50 mM TBA-BF4/HFIP at j = 8 mA·cm

Beyond symmetric self-assembly and effective molarity: unlocking functional enzyme mimics with robust organic cages

• Keith G. Andrews

Beilstein J. Org. Chem. 2025, 21, 421–443, doi:10.3762/bjoc.21.30

• ][344][345], which show early promise for low-symmetry cavities with catalytic potential [42][43][44][340]. Notably, Otte has used semi-stepwise self-assembly via imine formation/reduction to access a robust organic cage with reduced-symmetry and internal functionality able to chelate a copper(I) ion

• , organocatalytic motifs, and functional triads in precise-enough ways to permit a new wave of enzyme model studies, this time to reveal details of electric field catalysis [99][417][438][439][440] and the elusive roles of enzyme dynamics [395][401][441]. Catalytic rate enhancements from a reduction in the Gibbs

The effect of neighbouring group participation and possible long range remote group participation in O-glycosylation

• Rituparna Das and
• Balaram Mukhopadhyay

Beilstein J. Org. Chem. 2025, 21, 369–406, doi:10.3762/bjoc.21.27

• used for glycosylation reactions in combination with the PIFA-TfOH reaction system. MeTetMe was particularly effective and could be orthogonally removed under Birch reduction conditions. Inference on neighbouring group participation Thus, we see that the electron-withdrawing groups like an ester

Synthesis, structure, ionochromic and cytotoxic properties of new 2-(indolin-2-yl)-1,3-tropolones

• Yurii A. Sayapin,
• Eugeny A. Gusakov,
• Inna O. Tupaeva,
• Alexander D. Dubonosov,
• Igor V. Dorogan,
• Valery V. Tkachev,
• Anna S. Goncharova,
• Gennady V. Shilov,
• Natalia S. Kuznetsova,
• Svetlana Y. Filippova,
• Tatyana A. Krasnikova,
• Yanis A. Boumber,
• Alexey Y. Maksimov,
• Sergey M. Aldoshin and
• Vladimir I. Minkin

Beilstein J. Org. Chem. 2025, 21, 358–368, doi:10.3762/bjoc.21.26

• equation formalism (IEFPCM) [38]. Biological experiments The MTT colorimetric test for cell viability assessment is based on the reduction by NADPH-H-dependent cellular oxidoreductase enzymes of the tetrazolium dye 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, which has yellow color, into