Semisynthesis, characterisation, and antibacterial evaluation of a novel lecanoric acid-derived amide library

• Ethan D. Abbott,
• Sasha Hayes,
• Jonathan M. White,
• Bernd H. A. Rehm and
• Rohan A. Davis

Beilstein J. Org. Chem. 2026, 22, 1023–1032, doi:10.3762/bjoc.22.81

• isopentyl chain. The exchangeable proton δH 7.79 (1H, t, J = 5.6 Hz) indicated the existence of an amide moiety in 6, which showed strong COSY correlations to one of the methylenes [δH 3.17 (2H, dt, J = 5.6, 6.6 Hz)] of the isopentyl chain. Furthermore, the substitution position of the isopentyl chain to

Synthesis and optical resolution of 4,5-diaminohomoadamantane: a promising scaffold for chiral ligands and bioactive compounds

• Polina A. Man’kova,
• Vadim A. Shiryaev,
• Olga S. Podlipnova,
• Marat M. Khisyamov,
• Dmitry S. Nikerov,
• Alexander N. Reznikov and
• Yuri N. Klimochkin

Beilstein J. Org. Chem. 2026, 22, 1013–1022, doi:10.3762/bjoc.22.80

• for the synthesis of compound 2 from alcohol 1 using phosphoric acid, affording the target compound in high yield and purity. In the next step, chloronitrosation of alkene 2 led to α-chloroxime 3 in moderate yield. Substitution of chlorine in 3 with azido and benzylamino groups was then carried out to

Rh(III)-catalyzed chelation-assisted C–H activation/annulation of 2-arylimidazolines with cyclic diazo-1,3-dicarbonyl compounds: a novel approach to tetracyclic annulated derivatives of 2,3-dihydroimidazo[2,1-a]isoquinoline

• Ivan Lyutin,
• Grigory Kantin,
• Olga Bakulina and
• Dmitry Dar'in

Beilstein J. Org. Chem. 2026, 22, 997–1003, doi:10.3762/bjoc.22.78

• , as we were unable to find any published successful examples of Rh(III)-catalyzed chelation-assisted C–H activation/annulation with diazo compounds when such heterocyclic substrates were used as CH-components. Substitution at position 4 of the imidazoline ring with a methyl group resulted in the

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

• . The observed regioselectivity originates from through-space electronic communication between the naphthalene units, which suppresses multiple substitution pathways across the remaining framework. Owing to their defined three-dimensional shape and moderate conformational flexibility, the resulting

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

• strategy enables the trans-selective semireduction of unactivated internal alkynes, addressing a limitation in previous methods that typically rely on electronically biased substrates. Moreover, simple substitution of the proton source with HFIP-d1 or iPrOD-d1 enabled efficient trans-selective deuteration

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

• ester substituents. Notably, the reaction outcome was highly dependent on the reaction conditions. Although mild conditions favored C–N bond formation, high temperatures promoted alternative pathways, such as aromatic substitution, indicating that the C–N bond formation was reversible under Lewis acidic

Palladium-catalyzed benzocyclization reactions of quinoline-2-carboxamides via sequential C–H/N–H functionalization

• Shoichi Sugita,
• Kentaro Okano and
• Atsunori Mori

Beilstein J. Org. Chem. 2026, 22, 905–914, doi:10.3762/bjoc.22.71

• group in the C5 position, a similar substitution pattern was detected as for compound 3ad derived from 1-bromo-2-iodo-5-methylbenzene (2b). Additionally, during the coupling reaction carried out with 5-tert-butyl-1-bromo-2-iodobenzene, Int-1ad species was detected as a reaction intermediate, as

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

• engaging in diverse bond-forming processes, including C–C, C–O and C–N bond formations [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24]. Despite their growing utility, controlling the stereoselectivity in substitution reactions of α-boryl carbanions remains a formidable

• effects suggests that the adjacent stereocenter at C2 might play a key role in the conformational stability and the stereochemical outcome. We therefore set out to extend the scope of the transformation by probing how substitution at the C2 position of precursor 2 affects the diastereoselectivity of the

• confirmed due to the inability to obtain suitable crystals for X-ray analysis. In addition to the nucleophilic substitution of the boryl lithium species with R3SiCl, a small range of alternative electrophiles was examined (Scheme 3). Incorporation of a tin-based electrophile furnished stannane 6i in

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

• substitution → hydrolysis; Scheme 8) [79], laying the groundwork for ligase development [80][81]. Lysine residues are abundant and typically solvent-exposed [82], hyper-reactive variants have been reported, and have led to the development of tools such as “K-lock” [83][84][85]. Unfortunately, the reactivity

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

• the “trans-effect”, which describes the effect of a ligand L on the rate of substitution of another ligand in trans position, most prominently found in square-planar d8-complexes, notably those of platinum(II) [21]. This is a kinetic parameter and therefore combines ground-state energetics with the

Unsymmetrical sulfoxides with sterically hindered catechol fragment: synthesis, structure, electrochemical properties, and antiradical activity

• Daria A. Burmistrova,
• Vasiliy A. Fokin,
• Oleg P. Demidov,
• Mikhail A. Kiskin,
• Maxim V. Arsenyev,
• Andrey I. Poddel’sky,
• Nadezhda T. Berberova and
• Ivan V. Smolyaninov

Beilstein J. Org. Chem. 2026, 22, 828–837, doi:10.3762/bjoc.22.65

• thiol [22][23][24][25], through nucleophilic aromatic substitution on the catechol ring [26][27], or under electrochemical conditions [28][29][30][31][32]. A number of methods exist for the conversion of sulfides into sulfoxides, proceeding via either oxidative or non-oxidative pathways. The controlled

Synthesis and structural elucidation of a novel bis-spirooxindole from isatin and ethylenediamine

• Irene Moreno-Gutiérrez,
• Josefa L. López-Martínez,
• Sonia Berenguel-Gómez,
• Irene Torres-García,
• Duane Choquesillo-Lazarte,
• Manuel Muñoz-Dorado,
• Miriam Álvarez-Corral and
• Ignacio Rodríguez-García

Beilstein J. Org. Chem. 2026, 22, 813–820, doi:10.3762/bjoc.22.63

• ], reactions involving N-methylated ethylenediamines like 12 or 13 lead to spirocyclic products (14 and 15) [19]. These outcomes were rationalized through the involvement of imine and dipolarophilic intermediates (16 and 17), highlighting the sensitivity of the system to substitution at nitrogen. Furthermore

Halogenated azobenzene acrylates: from efficient solution photoswitching to stable solid-state photochromic materials

• Martina Vachtlová,
• Michaela Fecková,
• Vítězslav Zima,
• Jan Podlesný,
• Milan Klikar,
• Oldřich Pytela,
• Patrik Pařík,
• Jakub Opršal,
• Eliška Juhaňáková,
• Veronika Chrtová and
• Filip Bureš

Beilstein J. Org. Chem. 2026, 22, 782–794, doi:10.3762/bjoc.22.60

• halogenated azobenzene acrylate monomers bearing fluorine, chlorine or bromine substituents is reported. The monomers were prepared via a facile three-step synthetic route involving azo-coupling, O-alkylation and O-acylation. Apart from the steady electrochemical properties, halogen substitution proved to be

• diverse properties of various solid azobenzene polymeric systems. As an extension of these studies, we report herein a series of six novel azobenzene acrylate monomers 1a–f (Figure 1) structurally differing in the attached halogen atoms (F, Cl, and Br) at the positions 2 and 6. The described substitution

• Information File 1 for a complete list of analogous figures for all target azobenzenes 1a–f (Figures S24–35, S39–50, and S89–94). The DFT-calculated E/Z isomerization energies (ΔGE/Z) as a dependence of the substitution (Table S1 and Figure S52, Supporting Information File 1) indicates that ΔGE decreases when

Preparation of 3-(alkylamino)imidazo[1,2-a]pyridine-2-carbaldehydes via Kornblum oxidation and unexpected ring-opening reactions of the corresponding alcohols under oxidative conditions

• Sandile J. Mkhize,
• Memory Zimuwandeyi,
• Manuel A. Fernandes,
• Amanda L. Rousseau and
• Moira L. Bode

Beilstein J. Org. Chem. 2026, 22, 763–770, doi:10.3762/bjoc.22.58

• –99% using LiAlH4 reduction (Scheme 3). Unexpectedly, reduction of 13d and 13f led to the same compound, the dehalogenated derivative 17d in 96% and 51% yield, respectively, presumably through nucleophilic aromatic substitution [29]. Oxidation of alcohols 17a–d using pyridinium chlorochromate (PCC

Synthesis and biological evaluation of new brassinosteroid analogs with C-22 benzoate function

• María Núñez,
• Camila Escobar,
• Mario Párraga,
• Mauricio Soto,
• Luis Espinoza-Catalán,
• Katy Díaz and
• Andrés F. Olea

Beilstein J. Org. Chem. 2026, 22, 753–762, doi:10.3762/bjoc.22.57

• inhibition of root growth of Arabidopsis thaliana. The RLIT data is compared with those previously reported for two series of compounds having the same substitution pattern at C-22 but different structure in ring A. This comparison revealed that a 2α,3α-dihydroxy configuration is more active than a 3

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

• therefore more likely that steric effects in the transition state for the putative cyclization to give 8 are prohibitive. Indeed, we were unable to locate a transition state for this process computationally. In order to test the limits of the reaction with related substitution patterns in this process, we

• shift by a remarkable 1.0 ppm. Similarly, in the 13C NMR spectrum, the ortho-disubsituted ring produces 6 aromatic and 2 aliphatic signals, rather than the 4 aromatic and 1 aliphatic signals that would be expected given the symmetrical aromatic substitution pattern. These data indicate that the ortho

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

• of a product exhibiting reversed polarity (20). Conversely, when no α-aryl substitution is present, increased electron density remains at the C2 position, favoring the typical (3 + 2) cycloaddition pathway leading to product 19. In [48], the authors studied the reason for the complete change in

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

• . Systematic tuning of photochromic properties is the focus of several articles in this thematic issue. Kitagawa, Kobatake, and co-workers [15] studied the effect of the substitution position of aryl groups on the thermal back-reaction of azadiarylethene photoswitches. Simeth and co-workers [16] present a

Computational prediction of C–H hydricities and their use in predicting the regioselectivity of electron-rich C–H functionalisation reactions

• Rasmus M. Borup,
• Nicolai Ree and
• Jan H. Jensen

Beilstein J. Org. Chem. 2026, 22, 603–610, doi:10.3762/bjoc.22.46

• . These properties encompass the site of metabolism [25][27], the strengths of hydrogen bond donors and acceptors [28][29][30], the regioselectivity of electrophilic aromatic substitution reactions [10], C–H pKa values [3], and electro- and nucleophilicity [31]. Building on the methodology from Finkelmann

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

• nucleophilic aromatic substitution with thiophenols followed by oxidation with m-chloroperbenzoic acid (mCPBA). The scope of the reactions was explored, demonstrating high yields across a variety of functional groups and substituents. Optimized conditions enabled selective oxidation of thioaryl groups to

• as promising antimicrobial agents and provide new insights into their mechanism of action. Keywords: antimicrobial activity; aromatic nucleophilic substitution; isoxazoles; oxidation; sulfonylisoxazoles; Introduction The isoxazole ring represents an important building block for the synthesis of

• -sulfonylisoxazoles based on nucleophilic aromatic substitution of the nitro group in 3-EWG-5-nitroisoxazoles by treatment with thiophenols as S-nucleophiles and subsequent oxidation of the thioaryl group (Scheme 1, approach D). Previously, we reported that 3-EWG-5-nitroisoxazoles readily react with various N,O,S

Kinetic resolution of racemic planar-chiral vinylcymantrenes by molybdenum-catalyzed asymmetric metathesis dimerization

• Haruna Imazu,
• Hitoshi Izu,
• Yasuhiro Ohki and
• Masamichi Ogasawara

Beilstein J. Org. Chem. 2026, 22, 568–574, doi:10.3762/bjoc.22.42

• (I). Indeed, the Friedel–Crafts acetylation of cymantrene, a typical electrophilic aromatic substitution reaction, is much slower than that of ferrocene. Consequently, vinylcymantrenes are electron-deficient olefins and less reactive in olefin metathesis. For this reason, the present AMD/KR reactions

Get a better glimpse on sequential photoreactions of trisnorbornadienes with ¹⁹F NMR spectroscopy

• Julian Felix Maria Hebborn,
• Ben Eric Merten,
• Thomas Paululat and
• Heiko Ihmels

Beilstein J. Org. Chem. 2026, 22, 527–534, doi:10.3762/bjoc.22.38

• hindrance induced by the fluoro substituents in the ortho positions [54]. It should be noted that there is only very limited data available to compare the effect of the substitution pattern on the half-life of aryl-substituted norbornadienes to support this interpretation [55]. However, the effect of ortho

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

• –Kishi (NHK) coupling and Pd-mediated cyclization. Fragment 31 was synthesized from known precursor 28 [74] in 9 steps via MMTr-protection, replacement of the Bn- with TBDMS-protecting groups, hydroxylation of sulfone 29 to alcohol 30, tosylation, bromide substitution, acidic MMTr-cleavage and DMP

• )/Cr(II)-mediated coupling of 1-bromo-2-trimethylsilylethene, acidic cleavage of the remaining cyclohexylidene ring, TBDMS-protection of the three alcohol units and electrophilic substitution of the silyl moiety to afford vinyl iodide 103 was applied. Eventually, ester 103 was reduced to target

• formation of 252. Next, conditions reported by Kishi and co-workers were applied for the nucleophilic substitution of the chloride by the oxygen from the tetrahydrofuran ring towards 253 [94], before an adjacent secondary alcohol group reopened the bicyclic cationic intermediate. Cleavage of the TBDMS

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

• carboxylic acid derivatives (Scheme 2b) [43]. They revealed that ortho-alkoxy substitution on the benzene-derived alkyne markedly enhanced both reactivity and enantioselectivity, while incorporation of a naphthyl substituent into the diyne enabled access to remote biaxially chiral molecules. Subsequent

• first enantioselective C–H amination of arenes catalyzed by a chiral phosphoric acid. Thus, this nucleophilic aromatic substitution reaction not only enables the synthesis of compounds bearing two chiral N-aryl axes but also provides a viable alternative to metal-catalyzed C–N cross-coupling reactions

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

• substitution patterns were selected as the starting materials to enable further preparation of the respective mono-, di- and tetrapropargylated calix[4]arene tetraamines and their derivatives. The silylation of propargyl ethers 1–5 was first attempted using tert-butyldimethylsilyl chloride (TBSCl) and the

• conditions. In line with this, compounds 8–10 having less sterically hindered narrow-rim substitution patterns were found to be more resistant to side reactions during wide-rim nitration as well as to the target exhaustive nitration itself. These reactions required a higher nitric acid concentration of ≈2.5

• only the reaction time increased (Scheme 2). The 1D NMR spectra for the dinitrocalix[4]arenes 12 and 13 provided no definitive data on the substitution patterns at their wide-rims except for the presence of two nitro groups in the distal aromatic units. To localize the nitro groups in the structures of