Copper catalysis: a constantly evolving field

• Elena Fernández and
• Jaesook Yun

Beilstein J. Org. Chem. 2025, 21, 1477–1479, doi:10.3762/bjoc.21.109

• process of 4,4-dichloro-2-butenoic acid derivatives and bis(pinacolato)diboron is described [10]. The transformations feature excellent chemo-, regio-, and diastereoselectivities, and the resulting products are highly functionalized. Due to this, they were considered as versatile building blocks for the

Microwave-enhanced additive-free C–H amination of benzoxazoles catalysed by supported copper

• Andrei Paraschiv,
• Valentina Maruzzo,
• Filippo Pettazzi,
• Stefano Magliocco,
• Paolo Inaudi,
• Daria Brambilla,
• Gloria Berlier,
• Giancarlo Cravotto and
• Katia Martina

Beilstein J. Org. Chem. 2025, 21, 1462–1476, doi:10.3762/bjoc.21.108

• pharmaceutical activity and their importance within the materials sciences [1][2]. 2-Aminobenzoxazoles, in particular, are important building blocks in the development of new bioactive compounds that can be useful as therapeutic agents with antibacterial [3], antiviral, antifungal [4], anticancer [5][6][7] and

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

• . Water is used as a pressure transmitting medium that has relatively low compressibility, readily available, and non-toxic. Results and Discussion HHP-assisted synthesis of 1,3-dihydrobenzimidazoles Heterocycles are extremely versatile compounds and are used as building blocks for fine chemicals and

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

• stable isosteric replacements for gem-dimethyl and carbonyl groups. This work reviews possible synthetic strategies towards these strained heterocycles, covering both de novo constructions of the 4-membered ring as well as derivatisations of oxetane building blocks, then reactivity of oxetanes in terms

• transformations of 3-oxetanone leading to advanced oxetane building blocks. In chapter 3, we review the reactivity of oxetanes with regards to ring openings and ring expansions including both symmetric and enantioselective variants. Finally, chapter 4 covers isolations, biological activities and total syntheses

• approach to these derivatives can proceed through functionalisations of readily available oxetane-containing building blocks. The most versatile precursor of these building blocks is 3-oxetanone (133) which was first recognised by Carreira and colleagues (Scheme 34). Besides describing its possible

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

• crucial for fine-tuning their properties. An alternative is the bottom-up approach where various nanographenes are synthesized form smaller building blocks via classical organic synthesis. This strategy enables precise control over the structure and topology, leading to the development of a vast array of

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

• , Kanazawa, 920-1192, Japan 10.3762/bjoc.21.95 Abstract Development of three-dimensional (3D) building blocks is a key to change tight molecular assemblies of rigid π-conjugated planes into organic functional materials endowed with molecular-size cavities. To increase the diversity of available 3D building

• moderate flexibility at the same time. Therefore, the monoformyl products are good precursors for soft materials which show molecular-size cavities and require desymmetrized building blocks. As a proof of concept, methylene-alternating copolymers were prepared by reduction to corresponding alcohols

• storage and transport [27][28][29]. Further progress in such unique organic materials largely depends on the exploitation of 3D π-building blocks. However, the variety of building blocks are limited to a few families such as tetraphenylmethane and triptycene [30][31][32][33][34][35][36][37][38][39

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

• important role as building blocks for peptide synthesis [1][2][3][4][5], as organocatalysts [6][7][8][9][10] and as enzyme inhibitors [4][11][12][13]. The incorporation of such amino acids into peptides can, for example, influence peptide conformation, the binding affinity to receptors [14], as well as

• -inducing properties in peptides [22][23][24]. Furthermore, derivatives of pipecolic acid are known for their bioactivity as secondary metabolites [25][26][27] and for being building blocks for piperidine alkaloids [28] with a variety of uses. Results and Discussion Addressing specific positions in the ring

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

• -containing five-membered saturated heterocycles. They are not only useful building blocks for the synthesis of biologically active compounds [1], for example, side-chain precursor of paclitaxel [2], but also widely exist in some pharmaceuticals [3][4], such as antibacterial agents of Gram-positive organisms

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

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

• principles, tandem reactions or annulations can be designed to efficiently access N-heterocycles. As the enamides are also easily accessible via condensations, applications of these nitrogen-containing building blocks in the synthesis of N-heterocycles are synthetically straightforward. When applied properly

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

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

• to obtain non-epimerized diastereomers of the resulting pyrazolodiazepine 18 as the major reaction products. Conclusion We have developed a straightforward, diversity-oriented approach for the synthesis of a novel pyrazolo[1,5-a][1,4]diazepine scaffold starting from readily available building blocks

Cu–Bpin-mediated dimerization of 4,4-dichloro-2-butenoic acid derivatives enables the synthesis of densely functionalized cyclopropanes

• Patricia Gómez-Roibás,
• Andrea Chaves-Pouso and
• Martín Fañanás-Mastral

Beilstein J. Org. Chem. 2025, 21, 877–883, doi:10.3762/bjoc.21.71

• versatile building blocks for the stereoselective synthesis of chlorocyclopropanes. Keywords: chlorocyclopropanes; copper; cyclization; 4,4-dichloro-2-butenoic acid derivatives; dimerization; Introduction In the last years our group has been focused on the development of catalytic methodologies for the

Orthogonal photoswitching of heterobivalent azobenzene glycoclusters: the effect of glycoligand orientation in bacterial adhesion

• Leon M. Friedrich and
• Thisbe K. Lindhorst

Beilstein J. Org. Chem. 2025, 21, 736–748, doi:10.3762/bjoc.21.57

• and tested to investigate the details of carbohydrate recognition [1][2][3][4][5][6][7]. It has turned out that carbohydrate–lectin interactions are orchestrated by a multitude of structural parameters. In addition to the configurational characteristics of specific carbohydrate building blocks, homo

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

• the corresponding parent phenacenes PIC, FUL, and 7PHEN to reveal the effects of the fluorination at the terminal rings. Results and Discussion Synthesis of F8-phenacenes The synthetic routes to building blocks 10, 13, and 15 and those to the desired F8PIC, F8FUL, and F87PHEN are respectively shown in

• state. The orange and blue sites, respectively, indicate negative and positive regions (−0.02 ≈ 0.02 hartree). Synthesis of building blocks 10, 13, and 15. Reagents and conditions: a) NaBH4, MeOH, THF, reflux; b) PBr3, reflux; c) N-methylmorpholine-N-oxide, THF, reflux; d) ethylene glycol, p-TsOH

Asymmetric synthesis of fluorinated derivatives of aromatic and γ-branched amino acids via a chiral Ni(II) complex

• Maurizio Iannuzzi,
• Thomas Hohmann,
• Michael Dyrks,
• Kilian Haoues,
• Katarzyna Salamon-Krokosz and
• Beate Koksch

Beilstein J. Org. Chem. 2025, 21, 659–669, doi:10.3762/bjoc.21.52

• Maurizio Iannuzzi Thomas Hohmann Michael Dyrks Kilian Haoues Katarzyna Salamon-Krokosz Beate Koksch Institute of Chemistry and Biochemistry, Freie Universität Berlin, Arnimallee 20, 14195 Berlin, Germany 10.3762/bjoc.21.52 Abstract Fluorinated amino acids are essential building blocks in the

• -natural amino acids are pivotal in protein engineering and drug development. Over 30% of approved small‑molecule drugs today contain non‑canonical amino acid building blocks [1][2]. In peptide and protein engineering, non‑natural amino acids significantly increase the respective range of tools used to

• hydrophobicity, alter the folding properties, and improve cell permeability [3][4][5]. Despite the evidence that unnatural amino acids play a significant role in the mentioned areas, synthesizing these building blocks can still be a major challenge [6]. A potent strategy in this regard is the utilization of

Sequential two-step, one-pot microwave-assisted Urech synthesis of 5-monosubstituted hydantoins from L-amino acids in water

• Wei-Jin Chang,
• Sook Yee Liew,
• Thomas Kurz and
• Siow-Ping Tan

Beilstein J. Org. Chem. 2025, 21, 596–600, doi:10.3762/bjoc.21.46

• ]. Furthermore, several methods for hydantoin synthesis have been reported. The modified Bucherer–Bergs reaction using nitriles or methyleneaziridines with organometallic reagents gave moderate yields of 40–77% and 48–75%, respectively [7][8]. Amino acids remain key building blocks, with approaches involving

• reagents in the procedures mentioned above. Amino acids can be procured from natural sources by enzymatic synthesis [21], as well as synthetically accessed from aldehyde building blocks via the Strecker synthesis [22], making them attractive starting materials for hydantoin synthesis. Results and

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

• controlling the formation of undesired byproducts during its reactions. This review explores alternative C1-building blocks that serve as surrogates for formaldehyde, aiming to mitigate some of the challenges associated with its use in multicomponent reactions. By identifying these alternatives, toxicity

• devoted to dimethyl sulfoxide, dihalomethanes, hexamethylene tetramine, and glyoxylates as C1-building blocks, substituting formaldehyde. Review Methanol as a source of formaldehyde There are several reports on the use of alcohols under oxidative conditions as aldehyde surrogates in Ugi and Passerini

• et al. developed a three-component Mannich-type reaction under oxidative and catalytic conditions that allows the coupling of aryl ketones 18 and saccharine (19) using DMSO as the solvent and the source for a methylene bridge linking the two building blocks (Scheme 15) [49]. Following this strategy

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

• macrolactamisation [21]. The syntheses of required unit A [28], C [29][30], and D [31] building blocks were accomplished as described previously. tert-Butyl-protected leucic acid 14 and Fmoc-β-aminopivalic acid (15) were connected by Steglich esterification (Scheme 2) and after cleavage of the tert-butyl ester group

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

• inductive methylation [24]. To research further the bioactivity of the pheromone, herein, we report an effective synthesis of the aggregation pheromone of T. castaneum, which uses the cheap (R)- and (S)-2-methyloxirane as chiral sources, connects two chiral building blocks through Li2CuCl4-catalyzed

• ]. 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

• the aggregation pheromone (4R,8S)-1, (4S,8R)-1, and (4S,8S)-1 were prepared through Li2CuCl4-catalyzed coupling and oxidation with RuCl3/NaIO4 from chiral building blocks (R)-10, (S)-10, (R)-11 and (S)-11, which were characterized by NMR spectroscopy and HRMS. Conclusion In summary, we have achieved a

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

• substitution. Substituents such as halogen atoms must be introduced into the N-acetyl diazocine structure during the synthesis of the building blocks. In the present work we start from mono- and dihalogenated N-acetyl diazocine 2–4 (Figure 2) and focus on the further derivatization via cross-coupling reactions

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

• glycochemists. The protecting building blocks on the glycosides contribute significantly in attaining the required stereochemistry of the resulting glycosides. Strategic installation of suitable protecting groups in the C-2 position, vicinal to the anomeric carbon, renders neighbouring group participation

• huge interest in the study of ‘Glycomics’ or ‘Carbohydrate Chemistry.’ These truly elevated the recognition of carbohydrates from being mere building blocks to a frontier research topic towards the development of drugs and pharmaceuticals [12][13], diagnostic tools [14], artificial sweeteners [15

• are various studies both supporting and refuting the concept of long-distance participation of building blocks. We will first give an overview of how neighbouring group participation of different protecting groups affects the stereochemistry of the glycoside bonds followed by the role of the same

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

• ; Introduction 1,2-Benzoquinones represent unique building blocks for various classes of heterocyclic systems. Their structure depends on the reactivity of the initial heterocycles and 1,2-benzoquinones, as well as on the reaction conditions. In the series of 2-methylquinolines [1], 2-methylquinoxalines [2], 2

Molecular diversity of the reactions of MBH carbonates of isatins and various nucleophiles

• Zi-Ying Xiao,
• Jing Sun and
• Chao-Guo Yan

Beilstein J. Org. Chem. 2025, 21, 286–295, doi:10.3762/bjoc.21.21

• have made them to become valuable building blocks in organic synthesis. Nucleophilic additions or spiroannulation of the highly reactive carbonyl group at the C-3 position of isatins have various fascinating applications in organic synthesis, which allowed transformation of isatins into various

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

• coupling of alkyne 8, THIQ segment 9, and benzaldehyde would enable convergent assembly of the building blocks to produce 10 [43][44][45][46]. Removal of the cyclic acetal in 10 followed by Strecker-type conversion leading to an α-amino nitrile would enable tandem intramolecular cyclization with phenol to