Novel macrocycles: from synthesis to supramolecular function

• Veronica Iuliano,
• Carmen Talotta,
• Margherita De Rosa,
• Paolo Della Sala,
• Konrad Tiefenbacher,
• Pablo Ballester and
• Carmine Gaeta

Beilstein J. Org. Chem. 2026, 22, 982–985, doi:10.3762/bjoc.22.76

• characterized by deep, biomimetic cavities capable of efficient guest encapsulation. Macrocycles have evolved well beyond academic model studies and are now involved in a broad range of applications spanning environmental remediation [17], biomedicine [18][19], sensing [20][21][22], catalysis [23][24][25], and

Electrochemical reduction of unsaturated carbon–carbon bonds via 3d transition-metal catalysis

• Geon Kang,
• Minki Jeon,
• Pooja Kumari Jat,
• Cheoljae Kim and
• Isaac Choi

Beilstein J. Org. Chem. 2026, 22, 955–981, doi:10.3762/bjoc.22.75

• provide effective approaches for promoting selective alkene hydrogenation. Electrochemical and 3d transition-metal catalysis Owing to the straightforwardness of the reductive chemical transformation, a plethora of synthetic approaches has been utilized, with recent efforts increasingly converging on 3d

• transition-metal catalysis [13][14][15][16][17][18] that enables cost-effective hydrogenation reactivity and electroorganic synthetic strategies [19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37] that employ externally applied potentials to achieve bond reduction with operational

• sustainability. First of all, the recent emergence of homogeneous 3d transition-metal catalysis has reshaped reductive methodologies, as these earth-abundant metals offer accessible redox manifolds and characteristic SET behavior that directly address the economic and environmental constraints of noble-metal

Synthesis of sterically shielded piperidine nitroxides via acid-catalyzed heterocyclization of β-aminoketone derivatives with ketones

• Mark M. Gulman,
• Yurii I. Glazachev and
• Sergey A. Dobrynin

Beilstein J. Org. Chem. 2026, 22, 948–954, doi:10.3762/bjoc.22.74

• in materials science and structural biology. The new heterocyclization strategy implies the construction of a 2,2,6-trisubstituted piperidine scaffold from β-aminoketone acetals and dialkyl ketones under acid catalysis. The resulting amines were oxidized to the corresponding ketonitrones and

Recent advances in copper-catalyzed direct hydroamination of alkenes with (hetero)aromatic amines

• Hyejeong Lee and
• Yunmi Lee

Beilstein J. Org. Chem. 2026, 22, 925–947, doi:10.3762/bjoc.22.73

• coordination behavior of these substrates render such transformations inherently challenging. Recently, copper catalysis has emerged as a versatile and practical platform for addressing these limitations. Owing to its redox flexibility and ligand tunability, copper facilitates multiple activation modes

• , and functional group tolerance. This review summarizes recent advances in the copper-catalyzed hydroamination of alkenes with (hetero)aromatic N–H nucleophiles, emphasizing the mechanistic paradigms and the factors governing selectivity. Keywords: aromatic amines; aza-Michael addition; Cu catalysis

• the direct hydroamination of alkenes using aromatic amines and aza-heterocyclic N–H nucleophiles under copper catalysis. The primary focus is on the mechanistic paradigms, Cu–amido pathways, Lewis acid activation, and carbon-radical manifolds, and on how these distinct activation modes translate into

Cascade transformation of 2-(diazoacetyl)-2H-azirines to 2-aroyl-3-hydroxy-1H-pyrroles via condensation with aromatic aldehydes

• Timur O. Zanakhov,
• Ekaterina E. Galenko,
• Mikhail S. Novikov and
• Alexander F. Khlebnikov

Beilstein J. Org. Chem. 2026, 22, 897–904, doi:10.3762/bjoc.22.70

• mixture was observed in the presence of AcOH, TfOH, TFAA, and BF3⋅Et2O. This is clearly due to the complex mechanism of formation of pyrrole 5a. The role of acid catalysis follows from the plausible mechanism of transformation of the bicyclic intermediate (1RR,3SR,6RR)-Phe-4 to pyrrole 5 shown in Scheme 4

Diastereodivergent electrophilic trapping of α-boryl lithium derivatives

• Tereza Pavlíčková,
• Noam Orbach and
• Ilan Marek

Beilstein J. Org. Chem. 2026, 22, 882–887, doi:10.3762/bjoc.22.68

• Tereza Pavlickova Noam Orbach Ilan Marek Schulich Faculty of Chemistry and the Resnick Sustainability Center for Catalysis, Technion – Israel Institute of Technology, Haifa, 3200009, Israel 10.3762/bjoc.22.68 Abstract α-Boryl carbanions are valuable organoboron intermediates, but controlling

Site-specific labelling of native peptides and proteins: chemical and enzymatic strategies

• Antonio Angelastro,
• Jonathan Bargh,
• Subhajit Guria,
• Victor Laserna and
• Louis Luk

Beilstein J. Org. Chem. 2026, 22, 857–881, doi:10.3762/bjoc.22.67

• , Gothenburg, 43183, Sweden Interdisciplinary Research Center, Division of Interdisciplinary Science, Institute for Radiation Sciences, The University of Osaka, 1-2 Machikaneyama-cho, Toyonaka 560-0043, Osaka, Japan School of Chemistry and Cardiff Catalysis Institute, Cardiff University Main Building, Park Pl

• highlight opportunities for innovation in next-generation native-sequence protein modification technologies. Keywords: affinity-guided chemistry; disulfide-rebridging; enzyme catalysis; glycan modifications; native-sequence; protein labelling; small-molecule modifications; terminal; Introduction Protein

• has led to the development of labelling techniques, wherein the C-terminal carboxylate can be functionalized via visible-light photoredox decarboxylative catalysis (Scheme 2d) [23]. Similarly, decarboxylative alkylation has been applied to complex proteomes to enable proteome-wide C-terminal profiling

The trans-influence in gold chemistry from a catalytic perspective

• Manfred Bochmann

Beilstein J. Org. Chem. 2026, 22, 838–856, doi:10.3762/bjoc.22.66

• Manfred Bochmann School of Chemistry, University of East Anglia, Norwich Research Park, NR4 7TJ, Norwich, United Kingdom 10.3762/bjoc.22.66 Abstract Gold catalysis has developed into an increasingly important method in organic synthesis. Especially the potential of gold(I,III) redox systems and

• recent mechanistic insights. Keywords: catalysis; gold; ligands; reaction mechanism; trans-influence; Introduction Gold catalysts have emerged as catalysts of choice in a multitude of organic transformations, not least due to their high functional group tolerance. Their applications have been widely

• and 3. This correlation proved to be of predictive value in the optimisation of product selectivity with as yet untested ligands [26]. Using kinetic competition experiments is a particularly sensitive method for assessing ligand effects in catalysis, since they are able to quantitatively reflect even

Knoevenagel condensation of 4,5- and 1,8-diazafluorenes

• Darya S. Cheshkina,
• Christina S. Becker,
• Alina A. Sonina and
• Maxim S. Kazantsev

Beilstein J. Org. Chem. 2026, 22, 803–812, doi:10.3762/bjoc.22.62

• malononitrile or acetonitrile derivatives [14][19][20]. However, the use of diazafluorenes as the methylene component in condensation reactions remains underexplored. These reactions can be carried out under basic [13][21], acidic [3][5] or Lewis acid catalysis [15][22], but the corresponding literature

• examples are scarce, especially for 1,8-diazafluorene. We have previously reported the condensation of 4,5-diazafluorene (1) with aromatic aldehydes and dialdehydes under ammonium acetate catalysis in acetic acid giving the corresponding products in good yields [5][23]. Remarkably, the only condensation of

Rongalite addition to dienones: diastereoselectivity in cyclic sulfone synthesis; stereochemical rationalization and prospects as a general conjugate nucleophile

• Melina Goga,
• Hao Zong,
• James Franco,
• Jazmine Prana,
• Rudolph Michel,
• Antonia Muro,
• Elana Rubin,
• Janet Brenya,
• Henk Eshuis and
• Magnus W. P. Bebbington

Beilstein J. Org. Chem. 2026, 22, 742–752, doi:10.3762/bjoc.22.56

• appears that there is scope for further development of Rongalite as a nucleophile in double intermolecular conjugate additions, but full realization of this goal is likely to require the intervention of catalysis. Suitable modes of activation might include well-chosen Lewis acids [46], hydrogen-bond

• donors [47] or, given the high solubility of Rongalite in water, phase-transfer catalysis [48]. Our earlier results indicate that tolerance of steric effects is greater in reactions with doubly electrophilic substrates that render the second conjugate addition intramolecular, justifying our choice of

• heterocycles and also those looking to use Rongalite as a source of nucleophilic sulfur in other transformations. We are currently examining extensions of this method and other sulfinate reaction development and catalysis. Rongalite as an equivalent of the unstable hyposulfite ion. Sulfone diastereomers 1a and

Synthesis of heterocycles based on azomethine ylides from α-amino acids (or amines) and carbonyl compounds

• Ekaterina V. Berezhnaya,
• Alexander I. Ponyaev,
• Vitali M. Boitsov and
• Alexander V. Stepakov

Beilstein J. Org. Chem. 2026, 22, 705–741, doi:10.3762/bjoc.22.55

• compounds; catalysis; (3 + 2) cycloaddition; decarboxylation; dipolarophiles; iminoesters; polycyclic compounds; spirocyclic compounds; stereoselectivity; Introduction The 1,3-dipolar cycloaddition is one of the most popular pericyclic reactions in organic synthesis, in which a dipole molecule interacts

• enones, which trigger a 1,3-dipolar cycloaddition via copper–ruthenium catalysis [54] (Scheme 15). Further reductive hydrogenation of ketopyrrolidines proceeds to form hydroxypyrrolidines 31 in high yields and excellent diastereo-/enantioselectivity. The reaction can be used with aldimine esters with

Synthesis of depressin, cryptomeridiol and 4-epi-cryptomeridiol enabled by a terpenoid chiral pool-producing platform

• Yao Kong,
• Tao Wang,
• Chen Wang,
• Pengcheng Zhang,
• Yuanning Liu,
• Kaibiao Wang,
• Fen Liu,
• Hongli Jia and
• Zhengren Xu

Beilstein J. Org. Chem. 2026, 22, 683–690, doi:10.3762/bjoc.22.53

• available by taking advantage of Nature’s logic for terpene synthesis, either via in vitro enzymatic catalysis [12], or via heterologous production. The toolbox of the terpenoid ‘chiral pool’ has been further expanded by integrating enzymatic catalysis, hence providing us with more flexibility to design the

Harnessing light energy with molecules

• Grace G. D. Han,
• Mogens Brøndsted Nielsen and
• Hermann A. Wegner

Beilstein J. Org. Chem. 2026, 22, 680–682, doi:10.3762/bjoc.22.52

• storage, catalysis, or controlled drug delivery. In the article by Venkataramani, Gopakumar, and co-workers [13], it is shown how a fluorinated tripodal N-functionalized arylazo-3,5-dimethylpyrazole derivative, self-assembled on a graphite surface, can be switched between eight states in a tunneling

• singlet-state photoredox catalyst in the sulfonylation/arylation of styrenes and as a triplet sensitizer in energy transfer catalysis. In addition to the photoredox contribution mentioned above, this thematic issue contains two publications on photochemical reactions beyond photoisomerizations. In the

Advantages of PROTACs in achieving selective degradation of homologous protein families

• Luxi Yang,
• Xinfei Mao,
• Jingyi Zhang,
• Jing Shu,
• Wenhai Huang,
• Xiaowu Dong,
• Yinqiao Chen and
• Mingfei Wu

Beilstein J. Org. Chem. 2026, 22, 628–661, doi:10.3762/bjoc.22.49

• proteins under the catalysis of a series of enzymes [112]. The ubiquitinated protein can be recognized explicitly by the proteasome to achieve degradation. The whole process requires the participation of three enzymes: ubiquitin-activating enzyme (E1), ubiquitin-conjugating enzymes (E2), and ubiquitin

Hydrogen production from formic acid catalyzed by NHC–Cu complexes

• Orlando Santoro and
• Catherine S. J. Cazin

Beilstein J. Org. Chem. 2026, 22, 620–627, doi:10.3762/bjoc.22.48

• equimolar mixture of H2 and CO2. The efficiency of the catalysis showed to be strongly dependent on the nature of the amine. Keywords: copper N-heterocyclic carbene; formic acid dehydrogenation; hydrogen storage; metal hydride; silanes; Introduction The discovery and utilization of alternative and

Regioselective approach to 5-arylsulfonylisoxazoles and their antimicrobial activity

• Artem S. Sazonov,
• Dmitry A. Vasilenko,
• Denis V. Porfiriev,
• Yuri K. Grishin,
• Rimma A. Gazzaeva,
• Alisa P. Chernyshova,
• Maxim A. Kryakvin,
• Anna A. Baranova,
• Vera A. Alferova and
• Elena B. Averina

Beilstein J. Org. Chem. 2026, 22, 592–602, doi:10.3762/bjoc.22.45

• nitrile oxides in cycloaddition reactions, complete control of regioselectivity without metal catalysis is not always achievable. Another problem with this method is the tendency of nitrile oxides to form dimers (furoxanes), which entails a decrease in the yield of isoxazoles. Due to dimerization, nitrile

Continuous-flow carbonyl hydrogenation under subatmospheric to atmospheric hydrogen pressure enabled by robust heterogeneous Pt–Fe catalysts

• Hiroyuki Miyamura,
• Ryosuke Kajiyama,
• Shun-ya Onozawa,
• Yoshihiro Kon and
• Shū Kobayashi

Beilstein J. Org. Chem. 2026, 22, 575–582, doi:10.3762/bjoc.22.43

• as functional materials and pharmaceuticals [1][2][3][4]. While stoichiometric reagents and catalytic methods are widely developed for this transformation, one of the most ideal methods is heterogeneous catalysis using molecular hydrogen as a reductant, which realizes 100% atom economy [5][6][7][8][9

• : Additional experimental details, materials, and methods including photographs of reactor systems, STEM-EDS images and XPS spectra of heterogeneous catalysts, and copies of 1H and 13C NMR spectra for isolated compounds. Acknowledgements H. M. also thanks the Joint Usage/Research Center for Catalysis

Melifoliox B, a novel phloroglucin derivative isolated from Melicope barbigera (Rutaceae) and synthesis of new oxidation products from melifoliones A and B

• Horst Weber,
• Kim-Thao Tran-Cong,
• Bernhard Mayer,
• Guido J. Reiss,
• Iryna S. Konovalova,
• Marc S. Appelhans,
• Kenneth R. Wood and
• Claus M. Passreiter

Beilstein J. Org. Chem. 2026, 22, 535–546, doi:10.3762/bjoc.22.39

• melifoliones should be synthesized first, to get enough quantity for oxidation to the corresponding quinols in a second experiment. Using the method of Wang and Lee [5], 1 could be prepared regio-specifically in good yield by heating phloroacetophenone and citral in DMF under catalysis of ethylenediammonium

Modern synthetic pathways towards eribulin and its subunits

• Sebastian Dominik Graf

Beilstein J. Org. Chem. 2026, 22, 495–526, doi:10.3762/bjoc.22.37

• aldehyde 104, which contains the necessary functional group pattern to be used as a building block for the assembly of 1. By the design of this novel synthetic pathway, Lee and co-workers showed that the commonly used NHK reaction involving dual chromium/nickel catalysis can be circumvented [86]. Here

Synthesis and uranyl(VI) extraction performance of a calix[4]pyrrole–tetrahydroxamic acid receptor

• Sara Karnib,
• Rana Baydoun,
• Wissam Zaidan,
• Nancy AlHaddad,
• Omar El Samad,
• Bilal Nsouli,
• Francine Cazier-Dennin and
• Pierre-Edouard Danjou

Beilstein J. Org. Chem. 2026, 22, 486–494, doi:10.3762/bjoc.22.36

• matrices for a broad range of applications [9]. Notable examples include catalysis, chromogenic sensors and fluorescent sensors, as well as heavy metals extraction [12][13][14][15][16]. One CP molecule that has attracted the attention of several research groups is the meso-tetra-methyltetrakis(4

Recent advances in the stereoselective synthesis of distal biaxially chiral molecules

• Fanxing Zhou,
• Chen Zhang,
• Lingyu Sun,
• Yiyun Fang,
• Siming Zheng,
• Lina Hu,
• Mengyang Shen,
• Zhen Zhao,
• Wei Xu,
• Yunqiang Sun and
• Zi-Qiang Rong

Beilstein J. Org. Chem. 2026, 22, 461–479, doi:10.3762/bjoc.22.34

• catalysis [26]. These molecules are widely found in natural products [27] and drugs, such as michellamines A and B [28], korupensamines A and B [29], diazonamide A [30], mastigophorene A [31], and the recently developed drug candidate BMS-986142 [32] (Figure 1). When a molecule contains two or more chiral

• axes, it constitutes a bi- or multiaxial chiral system, significantly increasing structural complexity and stereochemical diversity, which endows the molecules with unique functionalities and excellent performance in catalysis, pharmaceuticals [33], and materials science [34]. In 1989, Hayashi

• in catalysis, drug discovery, and functional materials. Review One-step construction of remote biaxial chiral molecules In recent years, the development of asymmetric catalytic methods, including both transition-metal catalysis and organocatalysis, has provided powerful tools for the one-step

Cone p-aminocalix[4]arenes enriched with ‘clickable’ alkyne or azide functionalities

• Ilia Korniltsev,
• Vasily Bazhenov,
• Alexander Gorbunov,
• Dmitry Cheshkov,
• Stanislav Bezzubov,
• Vladimir Kovalev and
• Ivan Vatsouro

Beilstein J. Org. Chem. 2026, 22, 399–415, doi:10.3762/bjoc.22.28

• excess benzyl azide or phenylacetylene, taken as representatives, under copper(I) catalysis, resulting in the narrow-rim triazolated macrocycles. By removing the Boc protecting groups and involving the free amino groups in reactions with p-tolyl isocyanate, a series of narrow-rim triazolated

• arrangement of the triazole N(3)-atoms relative to the calixarene core in compound 40. It was established previously, that p-tert-butylcalix[4]arene having two distal 2-azidoethyl groups at the narrow rim could not efficiently react with phenylacetylene under copper(I) catalysis unless a huge excess of Cu

Electrosynthetic access to unsymmetrical oxaza[8]helicenes with high chiral stability and strong circularly polarized luminescence (CPL)

• Tin Zar Aye,
• Rubal Sharma,
• Muthu Karuppasamy,
• Daiya Suzuki,
• Haruka Nakajima,
• Yoshitane Imai,
• Mitsuhiro Arisawa,
• Mohamed S. H. Salem and
• Shinobu Takizawa

Beilstein J. Org. Chem. 2026, 22, 372–382, doi:10.3762/bjoc.22.25

• -bromophenanthrene (1) via Buchwald–Hartwig amination with p-toluidine under Pd catalysis [55] – was subjected to phosphoric acid-mediated annulation with p-benzoquinone to give the hydroxycarbazole derivative 3 through a tandem Michael addition/ring-closure sequence. After rapid optimization of key parameters (see

Non-central chirality in organic chemistry

• Ken Tanaka and
• Naohiko Yoshikai

Beilstein J. Org. Chem. 2026, 22, 370–371, doi:10.3762/bjoc.22.24

• axial, planar, or helical chirality individually, often organized along specific molecular classes or application-driven themes such as asymmetric catalysis or chiral materials. In contrast, this Thematic Issue deliberately brings together diverse manifestations of non-central chirality under a single

Recent advances in the cleavage of non-activated amides

• Eun-Sol Choi and
• Hyo-Jun Lee

Beilstein J. Org. Chem. 2026, 22, 352–369, doi:10.3762/bjoc.22.23

• catalysis, electrophilic activation, strong base-counter-cation systems, and N-based activating groups that enable chemoselective bond cleavage. Together, these developments provide powerful tools for amide functionalization and offer new opportunities for efficient, practical, and selective syntheses

• substrate scope, mechanistic features, and unique advantages or limitations, with the goal of providing a comprehensive overview of current strategies and future opportunities for amide-bond manipulation. Review Transition-metal catalysis Various transition metals that function as Lewis acids have been

• ) Metal-free photoredox catalysis for cleavage of N-PMB anilide. Funding This study was supported by the Korea institute of Energy Technology Evaluation and Planning (KETEP) grant funded by the Korean Government (MCEE) (RS-2022-KP002707, Jeonbuk, regional Energy Cluster Training of Human resources) and