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

• shift, while the emission band of 4j was slightly red-shifted. The N,N-dimethylaminophenyl-substituted compounds 4k and 4l showed the strongest bathochromic shifts of the emission spectra, which might be due to the occurrence of donor–acceptor interactions between the electron-deficient uracil and the

• amino group. The corresponding fluorescence quantum yields were also strongly affected by the substitution pattern of the pyrrolouracils. Compounds 4k and 4l show very high fluorescence quantum yields of 83% and 71%, respectively, what might be reasoned by the strong donor ability of the NMe2-functional

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

• overcoming scalability challenges in quantum technologies. Despite their potential, achieving high luminescence quantum yields has largely been limited to donor-functionalized monoradicals, and a detailed understanding of the luminescent behavior of open-shell organic molecules remains elusive. This review

• radicals has seen new impetus during the last decade, stimulated by the development of highly efficient electroluminescent devices based on donor-functionalized TTM radicals [7][8][9][10][11][12][13]. Today, new derivatives of donor-functionalized triarylmethyl radicals are being synthesized with enhanced

• ][14]. While first examples of radical emitters in light-emitting diodes (LEDs) only delivered around 12% internal quantum efficiency [7], representing no improvement compared to conventional emitters, optimization of the donor-functionalized TTM radical and of the device geometry quickly allowed

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

• Katy Medrano-Uribe Jorge Humbrias-Martin Luca Dell'Amico Department of Chemical Sciences, University of Padova, Via Francesco Marzolo 1, 35131, Padova, Italy 10.3762/bjoc.21.76 Abstract Since the discovery of donor–acceptor (D–A) type molecules in the field of materials science, they have found

• demonstrate that these simple D–A structures exhibit promising photocatalytic properties, comparable to those of more complex D–A–D systems. Keywords: donor–acceptor system; photocatalyst design; photoredox catalysis; organic photocatalyst; Introduction In recent years, photocatalysis has emerged as a

• –properties dependence to modulate its optical and photoredox properties [4]. For instance, molecules with donor–acceptor (D–A) structures, classically used as OLED emitters, have gained relevance by finding alternative applications in the field of photocatalysis [5]. In this type of structure, the electron

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

• attention due to their modular hydrogen bond donor/acceptor profile that can be tuned by varying the nitrogen position and the degree of unsaturation as well as by fusion with other rings [3]. Benzodiazepines, which contain a seven-membered diazepine core fused to a benzene ring, are recognized as

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

• species Int-44. This reactive intermediate then engages with a Ti(IV)-enolate complex through radical recombination, ultimately delivering 2-aza-bicyclo[3.1.1]heptene (BCHepe) while regenerating the Ti(III) catalyst to complete the catalytic cycle. (2) Scandium-catalyzed pathway: Activation of the donor

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

• studies by the groups of Akiyama and Terada in 2004 [14][15], many excellent results have been achieved by applying BINOL-derived phosphoric acids, which can act as proton donor and acceptor [16][17][18][19], possessing both Brønsted acid and Lewis base character [20]. Substantial effort has been invested

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

• )cyanophenylacetonitrile, called HBC [7]. This typical push–pull fluorophore uses a dialkylamino group as the electron donor and a cyano group as the electron acceptor, while the connecting conjugating system has been varied to obtain a series of derivatives covering a broad spectral range (Scheme 1) [7][12]. All of these

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

• polar C–F bonds at the end of an alkyl chain, is that the terminal C–H bond also becomes polarised. In the case of the difluoromethyl group, the terminal hydrogen bears a partial positive charge and is able to act as a H-bond donor (II, Figure 2). This can influence the conformation of the molecule if

• there is a H-bond acceptor suitably positioned elsewhere in the molecule (e.g., 4 vs 5, Figure 2) [15][16][17]. The ability of the difluoromethyl group to serve as a H-bond donor has also proven to be useful for optimising drug–target interactions [18][19][20], but since that application does not

• which has potentially useful chameleonic polarity (and also lipophilic H-bond-donor ability). Progressing to the trifluoromethyl system (45, Figure 6): now there is an even stronger tendency for the fluorinated group to be oriented orthogonal to the aryl plane [80]. This can be explained by two factors

Photochemically assisted synthesis of phenacenes fluorinated at the terminal benzene rings and their electronic spectra

• Yuuki Ishii,
• Minoru Yamaji,
• Fumito Tani,
• Kenta Goto,
• Yoshihiro Kubozono and
• Hideki Okamoto

Beilstein J. Org. Chem. 2025, 21, 670–679, doi:10.3762/bjoc.21.53

• molecules displayed high hole mobility [20][21][22][23][24][25][26] and imide-fused phenacenes served as n-type organic semiconductors [27]. It was also disclosed that donor–acceptor-type phenacenes provided environment-dependent fluorophores showing solvatochromic fluorescence behavior [28][29]. Because

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

• the light, the lamp wattage, and diverse photocatalysts or mechanisms (e.g., energy transfer, photoredox, or electron-donor/electron-acceptor photoinduced electron transfer) might all be brought to bear on controlling the DAR. In addition to the DAR, homogeneity for conjugation at specific sites using

Study of the interaction of 2H-furo[3,2-b]pyran-2-ones with nitrogen-containing nucleophiles

• Constantine V. Milyutin,
• Andrey N. Komogortsev and
• Boris V. Lichitsky

Beilstein J. Org. Chem. 2025, 21, 556–563, doi:10.3762/bjoc.21.44

•  4). The suggested method allows one to utilize arylhydrazines both with donor and acceptor substituents in the aromatic ring. Besides that, heterocyclic hydrazines also can be used in the considered transformation. In addition, we have tried to carry out the process under investigation with

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

• of its unique interaction in organic synthesis. Chiral halonium salts have been found to have strong halogen-bonding-donor abilities and work as powerful asymmetric catalysts. Recently, we have developed binaphthyl-based chiral halonium salts and applied them in several enantioselective reactions

Deep-blue emitting 9,10-bis(perfluorobenzyl)anthracene

• Long K. San,
• Sebastian Balser,
• Brian J. Reeves,
• Tyler T. Clikeman,
• Yu-Sheng Chen,
• Steven H. Strauss and
• Olga V. Boltalina

Beilstein J. Org. Chem. 2025, 21, 515–525, doi:10.3762/bjoc.21.39

• used to achieve higher yields [27]. Even in the absence of a transition-metal-based photosensitizer, a recent study showed that perfluoroalkylation using perfluoroalkyl iodides (RFI) could be carried out by activation of the RF–I bonds by formation of electron donor–electron acceptor complexes with an

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

• observed in dilute solutions because of the formation of aggregates perturbing electronic transitions [51][52][53]. Moreover, at high concentrations, the formation of electron donor–acceptor (EDA) complexes [54] or exciplexes is expected to be favored, and the effect of mechanical forces on these is worth

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

• constriction (ground-state destabilization) are also possible [140][168][169][170]. The metals can sometimes participate in redox catalysis [171], and may be stabilized by the cage structure [160][172][173][174]. The organic part of the MOC has also been levied as a hydrogen-bond donor to activate an

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

• glycosylation. Conventional glycosylation involves the ‘nucleophilic substitution’ of the leaving group at the sp3 anomeric centre of the donor moiety with a suitable carbohydrate or non-carbohydrate-based aglycon with the help of an electrophilic promoter to form the equatorial glycoside 7 or the axial

• group participation (NGP)’ [70], while involvement of protecting groups in the far, distal or remote position in the glycosyl donor is often termed as ‘remote group participation’ or ‘long distance participation’ [71]. While neighbouring group participation is a much established reaction pathway, there

• as the participating group facilitating the formation of a 1,2-trans glycoside (Scheme 2). In general, the cleavage of the activated anomeric leaving group of the glycosyl donor 9 leads to the formation of an electron-deficient oxocarbenium ion 10. The participating vicinal acyl group interacts with

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

• of the DCA, photodegraded species issued from DCA or DCA•−/substract donor–acceptor complex is debated (Scheme 4b). Nevertheless, the authors underline that the key feature of these transformations is going through the consecutive absorption of two red-light photons which enhances the photoredox

• case a palladium porphyrin complex is used as photocatalyst and a coumarin derivative is used as NO donor when the irradiation is carried out at λ = 630 nm. NO is released in a photoredox catalytic process and both reaction partners are covalently bound in a block copolymer which forms micelles. This

Streamlined modular synthesis of saframycin substructure via copper-catalyzed three-component assembly and gold-promoted 6-endo cyclization

• Asahi Kanno,
• Ryo Tanifuji,
• Satoshi Yoshida,
• Sota Sato,
• Saori Maki-Yonekura,
• Kiyofumi Takaba,
• Jungmin Kang,
• Kensuke Tono,
• Koji Yonekura and
• Hiroki Oguri

Beilstein J. Org. Chem. 2025, 21, 226–233, doi:10.3762/bjoc.21.14

• three base pairs, predominantly 5’-GGC-3’ and 5’-GGG-3’ [12][13]. Notably, a bis-phenol type unnatural analog 3, composed of the C5 deoxy A-ring bearing a phenolic hydroxy group at C8, presumably as a HB donor upon interaction with nucleic acids, exhibits superior DNA alkylation capability compared to

Quantifying the ability of the CF₂H group as a hydrogen bond donor

• Matthew E. Paolella,
• Daniel S. Honeycutt,
• Bradley M. Lipka,
• Jacob M. Goldberg and
• Fang Wang

Beilstein J. Org. Chem. 2025, 21, 189–199, doi:10.3762/bjoc.21.11

• group can act as a hydrogen bond donor, serving as a potential surrogate for OH or SH groups but with a weaker hydrogen bond donation ability. Here, we describe a series of CF2H group-containing moieties that facilitate hydrogen bond interactions. We survey hydrogen bond donation ability using several

• (CF2H); fluorine; hydrogen bond donors; hydrogen bond strength; Introduction Hydrogen bonding interactions are ubiquitous non-covalent forces in chemistry and biology [1][2][3][4]. In canonical hydrogen bond (HB) donor–acceptor pairs, the donor typically comprises an electronegative heteroatom, such as

• by hydrogen bond acidity [47][48] which is derived from the 1H NMR chemical shift difference of a given proton in DMSO-d6 and CDCl3, the CF2H group is generally a stronger donor than the methyl group but substantially weaker than the OH or amide NH groups [19][20]. These results collectively indicate

Recent advances in organocatalytic atroposelective reactions

• Henrich Szabados and
• Radovan Šebesta

Beilstein J. Org. Chem. 2025, 21, 55–121, doi:10.3762/bjoc.21.6

• heteroannulation [50]. The SPINOL-derived chiral phosphoric acid C26 catalyzed the formation of axially chiral products 81 from diarylketones 79a–f and ketoesters 80a–c (Scheme 26). The substrate scope contained a broad range of substituents, including electron-donor groups and whole benzene rings. The authors

• significantly high yields. The CPA organocatalyst activates quinones with an acceptor hydrogen bond while indole acts as hydrogen-bond donor. On the other hand, a hydroxy group of hydroxyindole becomes a hydrogen donor and the iminoquinone nitrogen represents an acceptor to the hydrogen from the CPA, resulting

• cases. High yields and remarkable enantiomeric purities were achieved with all prepared products (119, 121, and 124). The proposed reaction pathway indicates the asymmetric conjugated addition from 2-naphthylamine, stabilized by a donor hydrogen bond to the organocatalyst, towards the o-naphthoquinone

Synthesis, characterization, and photophysical properties of novel 9‑phenyl-9-phosphafluorene oxide derivatives

• Shuxian Qiu,
• Duan Dong,
• Jiahui Li,
• Huiting Wen,
• Jinpeng Li,
• Yu Yang,
• Shengxian Zhai and
• Xingyuan Gao

Beilstein J. Org. Chem. 2024, 20, 3299–3305, doi:10.3762/bjoc.20.274

• studies, revealing that their photophysical behavior can be affected by the different substituents in the donor carbazole group. Keywords: carbazole; D−A−D type; noble-metal-free system; 9‑phenyl-9-phosphafluorene oxide; photophysical properties; Introduction π-Conjugated molecular materials containing

• recent years, and they are mostly based on purely organic electron donor−electron acceptor (D−A) or D−A−D systems with significant intramolecular charge transfer interactions for frontier molecular orbital separation [28][29][30]. Due to the electron-accepting properties, PhFlOP can clearly act as an

• access to PhFlOP-based TADF emitters. Additionally, the design of TADF emitters with the PhFlOP acceptor moiety and the carbazole donor moiety is lacking structural diversity. Herein, we present a 5-step synthesis of several novel D−A−D-type PhFlOP derivatives with substituted carbazole groups as donors

Synthesis of acenaphthylene-fused heteroarenes and polyoxygenated benzo[j]fluoranthenes via a Pd-catalyzed Suzuki–Miyaura/C–H arylation cascade

• Merve Yence,
• Dilgam Ahmadli,
• Damla Surmeli,
• Umut Mert Karacaoğlu,
• Sujit Pal and
• Yunus Emre Türkmen

Beilstein J. Org. Chem. 2024, 20, 3290–3298, doi:10.3762/bjoc.20.273

• -catalyzed annulation reaction between bromo-chloronaphthalene dicarboximides 6 and heteroarylboronic esters that enabled the syntheses of acenaphthylene-fused thiophene and indole derivatives 7 having donor-acceptor units (Scheme 1a) [40]. In 2021, Jin and co-workers developed an elegant Pd-catalyzed

Giese-type alkylation of dehydroalanine derivatives via silane-mediated alkyl bromide activation

• Perry van der Heide,
• Michele Retini,
• Fabiola Fanini,
• Giovanni Piersanti,
• Francesco Secci,
• Daniele Mazzarella,
• Timothy Noël and
• Alberto Luridiana

Beilstein J. Org. Chem. 2024, 20, 3274–3280, doi:10.3762/bjoc.20.271

• photochemistry has introduced new ways of generating radicals like photoredox catalysis and via electron donor–acceptor (EDA) complexes [10][11][12][13]. These advances, coupled with modern electrochemical methods, chemical reactor engineering and light emitting diodes (LED), have eliminated the need for thermal

Synthesis of extended fluorinated tripeptides based on the tetrahydropyridazine scaffold

• Thierry Milcent,
• Pascal Retailleau,
• Benoit Crousse and
• Sandrine Ongeri

Beilstein J. Org. Chem. 2024, 20, 3174–3181, doi:10.3762/bjoc.20.262

• has become an essential structural motif in medicinal chemistry due to its hydrogen-bond donor capacity, its lipophilic character, and as a bioisostere for alcohol, thiol, or amine groups [16][17][18][19]. Thus, the contribution of fluorinated compounds to pharmaceuticals has been crucial for more

Advances in the use of metal-free tetrapyrrolic macrocycles as catalysts

• Mandeep K. Chahal

Beilstein J. Org. Chem. 2024, 20, 3085–3112, doi:10.3762/bjoc.20.257

• porphyrin macrocycle contains two Ns and two NHs (from two pyrrolenine and two pyrrole units), both of which can act as supramolecular H-bond donor and acceptors and can promote metal-free catalysis. Additionally, due to their synthetic versatility, these macrocycles can be further functionalized to add

• concluded that both the presence of hydrogen-bond donor moieties (pyrrolic –NH groups) and a basic β-substituent are necessary to make the compound catalytically active. Further, authors have performed 1H NMR binding and kinetic studies and suggested that the reaction mechanism involves a simultaneous

• -free meso-tetra(pentafluorophenyl)porphyrin (67) as a HER electrocatalyst using TsOH (p-toluenesulfonic acid) as a proton donor in THF [111]. Macrocycle 67 undergoes two reversible one-electron reductions at E1/2 = −1.14 V and −1.54 V yielding radical anion [67]˙− and a dianion species [67]2−. Upon