Synthesis and photoinduced switching properties of C₇-heteroatom containing push–pull norbornadiene derivatives

• Daniel Krappmann and
• Andreas Hirsch

Beilstein J. Org. Chem. 2025, 21, 807–816, doi:10.3762/bjoc.21.64

• corresponding to either N-NBD2 and N-UnS2. Addition of the previously used CoII-catalyst POR did not result in regeneration of the parent N-NBD2 species strongly excluding the presence of N-QC2. Given the challenges in generating heterocyclic QC derivatives – successfully achieved only for oxa derivatives – the

• from the respective QC derivative was accomplished by addition of a CoII-porphyrin catalyst. For the nitrogen containing NBDs N-NBD1 and N-NBD2 photoinduced generation of an unidentified species was observed, followed by complete photodecomposition upon extended irradiation. The formation of N-QC2 was

• absorption maximum and onset was observed for the heterocyclic derivatives in relation to their isocyclic analogues. Basic principle of the NBD to QC conversion and vice versa. The bridge-atom at position 7 was varied to carbon, oxygen or nitrogen. The back-conversion induced via heat or a catalyst can

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

• centers [30][31][32][33]. Herein, we report a mild and efficient method for the regio- and (E)-stereoselective formal hydrocyanation of di- and trisubstituted allenes. Using DIBAL-H as the hydride source and TsCN as a readily available and bench-stable cyanating agent in the presence of a copper catalyst

• , the hydride addition of DIBAL-H to allene 1a catalyzed by 5 mol % IPrCuCl as the optimal catalyst selectively generated the allylaluminum intermediate 2a with >98% conversion [30]. Subsequent addition of one equivalent of TsCN to 2a in a single vessel at room temperature proceeded regioselectively

• , achieving yields of 93% and 87%, respectively. When the catalyst loading was reduced to 3 mol % for the reaction of allene 4b, the hydroalumination did not reach full conversion even with an extended reaction time (6 h vs 3 h). As a result, the incomplete hydroalumination led to a side reaction between the

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

• . Studies showed that a Mn catalyst is critical for synthesizing derivatives of phenanthridine-based diarylphosphine oxides. The reaction yield decreased in the absence of the ligand, and eliminating both the ligand and manganese salt suppressed the reaction. Moreover, a slight decrease in the reaction

• derivatives of glycine with diarylphosphine oxide (R2P(O)–H) for the synthesis of 1-aminoalkylphosphine oxides without the use of any transition metal catalyst or external oxidant. In this conversion, 1-aminoalkylphosphine oxides were formed in an undivided cell using a carbon electrode as the anode and

• dialkyl phosphonates at carbon and platinum electrodes as the anode and cathode in the presence of a silver catalyst in a divided cell (Scheme 3). According to the report, the silver catalyst is central to the coupling reaction. The study of the effect of alternating current (a.c.) electrolysis parameters

New advances in asymmetric organocatalysis II

• Radovan Šebesta

Beilstein J. Org. Chem. 2025, 21, 766–769, doi:10.3762/bjoc.21.60

• prominent Hayashi–Jørgensen catalyst. This prolinol silyl ether was independently discovered by the respective Hayashi and Jørgensen research teams in 2005 [13][14]. Interestingly, the use of prolinol alkyl ethers for asymmetric Michael additions, although at the time added in a stoichiometric manner, has

• ]. The enantioselective addition of propargyltrichlorosilane to aldehydes was studied by Prabhakar, Takenaka, and co-workers. This transformation was catalyzed by a biisoquinoline N,N’-dioxide catalyst, which acted as a chiral Lewis base [26]. Torres-Oya and Zurro reviewed the recent developments in

• organocatalytic cycloaddition reactions of unsaturated imines. A broad variety of activation modes, as well as catalyst structures, was covered and found to be useful in affording a diverse array of chiral N-heterocycles [27]. In my group, we recently became interested in atroposelective catalytic syntheses

Development and mechanistic studies of calcium–BINOL phosphate-catalyzed hydrocyanation of hydrazones

• Carola Tortora,
• Christian A. Fischer,
• Sascha Kohlbauer,
• Alexandru Zamfir,
• Gerd M. Ballmann,
• Jürgen Pahl,
• Sjoerd Harder and
• Svetlana B. Tsogoeva

Beilstein J. Org. Chem. 2025, 21, 755–765, doi:10.3762/bjoc.21.59

• . Trimethylsilyl cyanide (TMSCN) has been used as a sacrificial cyanide source. We found that isocyanide (rather than cyanide) is a preferred coordination to calcium during the catalytic cycle, while the active catalyst prefers a side-on coordination of cyanide. The configuration-determining step is a

• hydrocyanation via a calcium isocyanide complex, whereas the rate-limiting step is that which recovers the calcium catalyst and replaces the TMS-bound product from the catalyst. While our experimental data demonstrate enantioselectivity values as high as 89% under certain conditions, the overall

• enantioselectivity achieved with the calcium catalyst remains modest, mainly due to competing pathways for the Z- and E-hydrazone isomers leading to opposite enantiomers. The experimental results confirm these computational proposals. Keywords: asymmetric synthesis; calcium–BINOL phosphate catalysis; hydrocyanation

Copper-catalyzed domino cyclization of anilines and cyclobutanone oxime: a scalable and versatile route to spirotetrahydroquinoline derivatives

• Qingqing Jiang,
• Xinyi Lei,
• Pan Gao and
• Yu Yuan

Beilstein J. Org. Chem. 2025, 21, 749–754, doi:10.3762/bjoc.21.58

• into tetrahydroquinoline (THQ)-based 6-6-4-membered ring systems through a combination of nucleophilic addition and borate-mediated [2 + 2] photocycloaddition, offering a catalyst-free approach to construct conformationally constrained 2D/3D frameworks with high functional group compatibility and

• ) trifluoroacetate (Cu(TFA)2) as the catalyst (20 mol %) under ambient air at 80 °C for 12 hours; the product 3aa was isolated by chromatographic purification (Table 1, entry 1). The use of other solvents, including acetonitrile (MeCN), tetrahydrofuran (THF), toluene, acetone and methanol (MeOH), resulted in

• significantly lower yields of 3aa (Table 1, entry 2). Replacing the Cu(TFA)2 catalyst with other copper sources, such as cuprous chloride (CuCl), cuprous thiocyanate (CuSCN), copper bromide (CuBr2), copper trifluoromethanesulfonate (Cu(OTf)2), and copper powder resulted in diminished reaction efficiency (Table

Synthesis of HBC fluorophores with an electrophilic handle for covalent attachment to Pepper RNA

• Raphael Bereiter and
• Ronald Micura

Beilstein J. Org. Chem. 2025, 21, 727–735, doi:10.3762/bjoc.21.56

• intention was to provide an RNA pulldown tool where the RNA of interest tagged with the Pepper aptamer becomes covalently attached to the fluorophore, which in turn can be biotinylated via a catalyst-free inverse-electron-demand Diels–Alder reaction (IEDDA) [11]. Thereby, the entire process is easily

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

Recent advances in allylation of chiral secondary alkylcopper species

• Minjae Kim,
• Gwanggyun Kim,
• Doyoon Kim,
• Jun Hee Lee and
• Seung Hwan Cho

Beilstein J. Org. Chem. 2025, 21, 639–658, doi:10.3762/bjoc.21.51

• including s-BuLi, n-BuLi, and PhLi. The optimized protocol, employing CuCN as a catalyst, enabled efficient coupling between t-BuLi-activated complexes 10 and allylic halides 11, furnishing products 12 with complete retention of stereochemistry and high yields (Scheme 7). The method's versatility and

• excellent enantioselectivity, although in moderate yield. Notably, the presence of a chloride anion in the reaction mixture proved crucial for high enantioselectivity, leading to the discovery that a 1:1 complex of copper(I) chloride and (S,S)-Ph-BPE (L1) could serve as an optimal catalyst system. Further

• optimization revealed LiOt-Bu and diphenyl phosphate as the optimal metal alkoxide and leaving group, delivering the desired product 32 in high yield and high enantioselectivity at room temperature with only 2 mol % catalyst loading. The scope of this transformation proved to be remarkably broad. In addition

Photocatalyzed elaboration of antibody-based bioconjugates

• Marine Le Stum,
• Eugénie Romero and
• Gary A. Molander

Beilstein J. Org. Chem. 2025, 21, 616–629, doi:10.3762/bjoc.21.49

• decision-making [6][7]. Antibody–oligonucleotide conjugates, antibody–enzyme conjugates, antibody–polymer conjugates, antibody–nanomaterial conjugates, antibody–catalyst conjugates, and antibodies involved in protein degradation also play critical roles in biomedical research and therapies [2]. In whatever

• transformations is a strong electrophile that can react with Tyr, for instance, if such an amino acid is located near the reactive site. In addition, command of the DAR might have some limits, as the distance between the catalyst and the mAbs is not well defined, meaning that the photoredox reaction might not

• available and inexpensive Ru(bpy)3, along with a water-soluble, air- and moisture-stable Ni(dabpy)Br2 catalyst. Moreover, they demonstrated that this system works efficiently in aqueous conditions, making it highly suitable for applications involving antibodies. These characteristics make the method highly

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

• ] with which a wide range of aromatic and aliphatic disubstituted alkynes were reactive, resulting in a greater diversity of quinolines II. In both cases, regardless of the catalyst used, the MCR tolerates a wide variety of anilines that have either electron-donating or electron-withdrawing groups with

• derivatives are isolated as side-products. Interestingly, when Liu et al. [40] modified this reaction by using a copper(II) catalyst under aerobic oxidative conditions, the regioisomers III (2-arylquinolines) were obtained (Scheme 9). To rationalize this singular result, the authors proposed a mechanism in

• DMSO (Scheme 12) [45]. In this case, the reaction works well under metal-free conditions using iodine as the catalyst. Remarkably, the activation of DMSO was accomplished using Selectfluor, and in this case, DMSO is the source of a C-1 unit. It is important to note that the reaction could be performed

Asymmetric synthesis of β-amino cyanoesters with contiguous tetrasubstituted carbon centers by halogen-bonding catalysis with chiral halonium salt

• Yasushi Yoshida,
• Maho Aono,
• Takashi Mino and
• Masami Sakamoto

Beilstein J. Org. Chem. 2025, 21, 547–555, doi:10.3762/bjoc.21.43

• catalysis (Figure 2c). Results and Discussion Chiral halonium salts 9a–c were prepared according to our previously reported methods [33]. The Mannich reaction of ketimine 7a and cyanoester 16a was selected as a benchmark, and catalyst screening was conducted (Scheme 1). The reaction was carried out with 1.0

• product was obtained in moderate diastereo- and enantioselectivity, however, chloronium salt 9c did not show significant catalytic activity, and the product was formed in nearly the same yield as that obtained without a catalyst with low stereoselectivity. From these observations, bromonium salt 9a was

• , the reaction catalyzed by only 1 mol % of iodonium salt 9b provided the opposite diastereomer of 17a as the major product compared with that without a catalyst, which revealed the high catalytic activity of our catalyst. Further reaction conditions optimization was conducted using 9a as a catalyst

Vinylogous functionalization of 4-alkylidene-5-aminopyrazoles with methyl trifluoropyruvates

• Judit Hostalet-Romero,
• Laura Carceller-Ferrer,
• Gonzalo Blay,
• Amparo Sanz-Marco,
• José R. Pedro and
• Carlos Vila

Beilstein J. Org. Chem. 2025, 21, 533–540, doi:10.3762/bjoc.21.41

• [32]. Then, we increased the reaction scale to 0.2 mmol and obtained similar results (Table 1, entry 13). At this point, we decided to explore the use of a bifunctional organocatalyst in order to improve the yield. When squaramide SQ-1 was used as a catalyst, we observed a similar yield and

• diastereoselectivity after 24 h of reaction (61% yield and 7:1 dr, Table 1, entry 14). By lowering the reaction temperature to 50 °C using the same catalyst (Table 1, entry 15), the yield of the reaction increased slightly to 73% in 24 hours. Disappointingly, the bifunctional thiourea THIO-1 gave a lower yield and

• . Considering the high diastereoselectivity observed both in the presence and absence of the squaramide catalyst, we propose a plausible mechanism (Scheme 3) that involves hydrogen bonding activation of the methyl trifluoropyruvate by the NH₂ group of the aminopyrazole. This interaction directs the attack 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

• , HOAt, N,N-dimethylformamide 0 °C for 2 h and at rt for 20 min, 11%; f) Grubbs II catalyst, CH2Cl2, reflux, 3 h, 84%; g) TFA, H2O, CH2Cl2, 0 °C to rt, 5 h, 91%. EDC·HCl = 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride; DMAP = 4-(dimethylamino)pyridine; TFA = trifluoroacetic acid; HOAt = 1

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

• [23]. Nevertheless, the arylation of monohalogenated N-acetyl diazocines via Stille coupling in our case gave unsatisfying results (Table 2). Reactions with tetrakis(triphenylphosphine)palladium(0) as catalyst resulted in no product 7 formation. Bis(tri-tert-butylphosphine)palladium(0) as catalyst

Organocatalytic kinetic resolution of 1,5-dicarbonyl compounds through a retro-Michael reaction

• James Guevara-Pulido,
• Fernando González-Pérez,
• José M. Andrés and
• Rafael Pedrosa

Beilstein J. Org. Chem. 2025, 21, 473–482, doi:10.3762/bjoc.21.34

• low catalyst loadings and mild reaction conditions. This research focuses on the kinetic resolution of 1,5-dicarbonyl compounds using a retro-Michael reaction, co-catalyzed at room temperature with 20 mol % of the Jørgensen–Hayashi catalyst and PNBA. The study highlights the importance of conducting

• chromatography [1]. Sometime later, kinetic resolution (KR) emerged. This method is based on the different reaction rates of each enantiomer in a racemic mixture when they are reacted with a reagent, a chiral catalyst, or an enzyme. This process results in obtaining the less reactive enantioenriched enantiomer

• processes with low catalyst loading. It involves the kinetic resolution of alcohols, amines, and esters using chiral phosphoric acids [6][7][8][9][10][11][12][13] and sulfoximines with enals using chiral N-heterocyclic carbene (NHC) catalysts [14]. Additionally, these processes have been conducted using

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

• % yield, albeit after 72 h of irradiation. This experiment proved that 4.2 can be used in a sub-stoichiometric way, in fact acting as a catalyst. More recently, based on their previous approach via manual grinding (Scheme 2) [64], MacGillivray and co-workers adopted the vortex grinding method to enable

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

• polarization (enthalpic) (Figure 1). Organization, the control of the position(s) and orientation(s) of reacting molecules, has been achieved historically in supramolecular chemistry using “pre-organized” catalyst designs (vide infra). More recently, organization has been mooted by List as a unifying concept

• across many fields of selective catalysis under the term confinement [3], a term borrowed from heterogeneous catalysis. Polarization can be understood as the catalyst providing an electrostatic environment that works to stabilize electron redistribution. Since all reactions redistribute electrons, and

• work simply by bringing substrates arbitrarily close to a potentially reactive group [99][100]. One rare but important exception is Breslow’s use of two tethered cyclodextrins to locate hydrophobic ester substrates next to a metal ion. Breslow’s catalyst accelerates the hydrolysis of esters and

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

• sections. Similarly, Pertel and co-workers also demonstrated the use of 2-(2,2,2-trichloroethoxy)-2-oxazoline glycosyl donor 22 (Scheme 4) which could be used for stereo- and regioselective glycosylations using extremely mild conditions [94] and requiring low concentrations of the catalyst. In this case

Synthesis of new condensed naphthoquinone, pyran and pyrimidine furancarboxylates

• Kirill A. Gomonov,
• Vasilii V. Pelipko,
• Igor A. Litvinov,
• Ilya A. Pilipenko,
• Anna M. Stepanova,
• Nikolai A. Lapatin,
• Ruslan I. Baichurin and
• Sergei V. Makarenko

Beilstein J. Org. Chem. 2025, 21, 340–347, doi:10.3762/bjoc.21.24

• ]. In addition, we have previously demonstrated the effective use of alkyl 3-bromo-3-nitroacrylates in the preparation of condensed furancarboxylates using potassium acetate as a catalyst [28][29][30]. The present study is aimed at developing methods for the synthesis of a wide range of condensed

Red light excitation: illuminating photocatalysis in a new spectrum

• Lucas Fortier,
• Corentin Lefebvre and
• Norbert Hoffmann

Beilstein J. Org. Chem. 2025, 21, 296–326, doi:10.3762/bjoc.21.22

• diverse catalyst types and applications. The first section is dedicated to metal-based photocatalysts. Complexes involving metals such as osmium and ruthenium, have dominated red-light photoredox catalysis because of their ability to absorb low-energy photons and sustain redox cycles via stable excited

• of side reactions. This latter advantage has been notably exploited in the case of ring-closing olefin metathesis reactions, where Weizmann et al. utilized the photothermal response of plasmons from gold nanoparticles to activate the catalyst [17]. This approach contrasts with the work of Rovis et al

• in continuous-flow conditions. This performance is particularly notable given that the reaction was carried out using sub-part-per-million loadings of the catalyst (0.003 mol %), a stark contrast to traditional systems, which often require higher concentrations of heavy metals. Unlike classical

Three-component reactions of conjugated dienes, CH acids and formaldehyde under diffusion mixing conditions

• Dmitry E. Shybanov,
• Maxim E. Kukushkin,
• Eugene V. Babaev,
• Nikolai V. Zyk and
• Elena K. Beloglazkina

Beilstein J. Org. Chem. 2025, 21, 262–269, doi:10.3762/bjoc.21.18

• characteristic triplets at 5.76 and 2.77 ppm (J = 7.0 Hz). Compound 3 was also formed in almost quantitative yield in acetonitrile within one day in the presence of ʟ-proline (Table 1, entry 10), which is an effective catalyst for crotonic condensation [22]. Since the reaction of diketone 1 in the presence and

• an important role; the presence of the condensation catalyst ʟ-proline accelerated the absorption of formaldehyde vapors by the reaction mixture. Carrying out the same reaction in the absence of a catalyst in CDCl3 and subsequent 1H NMR spectroscopy analysis showed that the mixture contained 42% of

• adducts of the Diels–Alder (i.e., I) and the hetero-Diels–Alder reaction (i.e., II), or adducts resulting from the addition of a second equivalent of CH acid to the crotonic condensation product (i.e., III). Apparently ʟ-proline played an essential role as catalyst in this three-component reaction. Using

Synthesis of disulfides and 3-sulfenylchromones from sodium sulfinates catalyzed by TBAI

• Zhenlei Zhang,
• Ying Wang,
• Xingxing Pan,
• Manqi Zhang,
• Wei Zhao,
• Meng Li and
• Hao Zhang

Beilstein J. Org. Chem. 2025, 21, 253–261, doi:10.3762/bjoc.21.17

• -toluenesulfinate as the model substrate and tetrabutylammonium iodide (TBAI) as the catalyst, the results are listed in Table 1. Various acids were tested to assess their effect on the reaction (Table 1, entries 1–5). From the results, it could be concluded that, in the presence of strong acids, all afforded the

• been further decreased, in the end, 0.5 mL of DMF was used because of the solubility of the reagents. Increasing the amount of catalyst to 20 mol % resulted in a significant increase in the yield, but further increases did not significantly change the yield (Table 1, entries 14 and 15). A decrease in

• reaction temperature resulted in a significant decrease in the yield (Table 1, entry 16) and at 80 °C no desired product, but only thiosulfonate was formed (Table 1, entry 17). The reaction did not proceed in the absence of acid or catalyst (Table 1, entries 18 and 19). Compared to TBAI, other iodized

Visible-light-promoted radical cyclisation of unactivated alkenes in benzimidazoles: synthesis of difluoromethyl- and aryldifluoromethyl-substituted polycyclic imidazoles

• Yujun Pang,
• Jinglan Yan,
• Nawaf Al-Maharik,
• Qian Zhang,
• Zeguo Fang and
• Dong Li

Beilstein J. Org. Chem. 2025, 21, 234–241, doi:10.3762/bjoc.21.15

• CF2HCO2H or PhCF2COOH, along with benzimidazoles bearing unactivated alkenes and PhI(OAc)2 as substrates, and proceeded without the need of any base, metal catalyst, photocatalyst or additive. In total, 24 examples were examined, and all of them successfully underwent cyclization reaction to produce the

• with CF2HCOOH or PhCF2COOH, and PIDA under additive-, base-, and metal catalyst-free conditions (Scheme 1b). Results and Discussion Initially, 1-(pent-4-en-1-yl)-1H-benzo[d]imidazole (1a), CF2HCOOH, and PIDA were chosen as the template substrates for this radical difluoromethylation and cyclization

• tricyclic and bicyclic imidazoles under additive-, base-, and metal catalyst-free conditions utilizing difluoroacetic acid and α,α-difluorobenzeneacetic acid as the readily available fluorine sources. The significant advantages of this approach, including its environmental friendliness and cost

Dioxazolones as electrophilic amide sources in copper-catalyzed and -mediated transformations

• Seungmin Lee,
• Minsuk Kim,
• Hyewon Han and
• Jongwoo Son

Beilstein J. Org. Chem. 2025, 21, 200–216, doi:10.3762/bjoc.21.12

• , the Chang group elegantly unveiled a protocol for an enantioselective C–N bond formation, introducing δ-lactams from dioxazolones using a copper(I) catalyst and a chiral BOX ligand [74]. As shown in Scheme 2, dioxazolones containing aryl and heteroaryl groups were converted into the corresponding

• ) nitrenoid intermediate INT-7. Subsequent nitrene insertion, protodemetalation, and intramolecular cyclization furnish the desired 1,2,4-triazole. 1.3 Three-component formation of N-acyl amidines In 2019, N-acyl amidines were prepared from dioxazolones using a copper catalyst with terminal alkynes and

• dioxazolone bearing a phenyl group showed no reactivity toward benzoyl amidine under the optimized reaction conditions. Instead, the authors employed a less bulky copper iodide catalyst in the absence of phosphine, successfully affording aryloyl amidine 10f. Furthermore, the electron-rich ethynylanisole