Configuration–packing synergy enabling integrated crystalline-state RTP and amorphous-state TADF

• Ruiyan Wang and
• Yunan Wu

Beilstein J. Org. Chem. 2026, 22, 224–236, doi:10.3762/bjoc.22.16

• , the triplet exciton management and channel selectivity in different phases of PI-Cz 1 were systematically studied, validating the feasibility of “configuration-packing synergy” for controllable RTP–TADF switching within the same molecule. Results and Discussion Single crystals of 1 were successfully

Screwing the helical chirality through terminal peri-functionalization

• Devesh Chandra,
• Sachin and
• Upendra Sharma

Beilstein J. Org. Chem. 2026, 22, 205–212, doi:10.3762/bjoc.22.14

• -induced spin selectivity. These functionalities have great potential to transform in key areas such as drug discovery and modern diagnostic tools, as well as in distinct emerging fields like spintronics and optoelectronics [14]. Helicenes have found applications in chiral optoelectronics, i.e., as

Improved synthesis and physicochemical characterization of the selective serotonin 2A receptor agonist 25CN-NBOH

• Adrian G. Rossebø,
• Hannah G. Kolberg,
• Anders E. Tønder,
• Louise Kjaerulff,
• Poul Erik Hansen,
• Karla A. Frydenvang,
• Jesper Østergaard and
• Jesper L. Kristensen

Beilstein J. Org. Chem. 2026, 22, 175–184, doi:10.3762/bjoc.22.11

• efficacy [2]. Activation of the 5-HT2AR is thought to induce altered states of consciousness and suppress the default-mode network, a process hypothesized to underlie their clinical benefits [3]. However, classic psychedelics lack receptor selectivity, prompting efforts to develop more selective 5-HT2AR

Asymmetric Mannich reaction of aromatic imines with malonates in the presence of multifunctional catalysts

• Kadri Kriis,
• Harry Martõnov,
• Annette Miller,
• Mia Peterson,
• Ivar Järving and
• Tõnis Kanger

Beilstein J. Org. Chem. 2026, 22, 151–157, doi:10.3762/bjoc.22.8

• adduct in 83% ee (Table 1, entry 9). Replacing the five-membered pyrrolidine ring in the catalyst structure with the more flexible six-membered piperidine ring (catalyst H, Table 1, entry 13) reduced its selectivity slightly (78% ee). However, the catalyst derived from phenylglycine (catalyst F) or

• product in a slightly less enantioselective way (71% ee). When comparing the halogen bond donor properties of tetrafluoroiodophenyl and iodophenyl moieties, the latter is weaker as it is less electron-withdrawing. However, there is a very small difference between reactivity and selectivity for catalysts E

• the halogen bond is not essential for the stereoselectivity of the reaction, but the halogen atom has a beneficial effect on both reactivity and stereoselectivity. A comparative experiment using an imine with a para-toluenesulfonyl protecting group afforded the product in lower selectivity (Table 1

Symmetrical D–π–A–π–D indanone dyes: a new design for nonlinear optics and cyanide detection

• Ergin Keleş,
• Alberto Barsella,
• Nurgül Seferoğlu,
• Zeynel Seferoğlu and
• Burcu Aydıner

Beilstein J. Org. Chem. 2026, 22, 131–142, doi:10.3762/bjoc.22.6

• theory (DFT) methods. The dyes also exhibit chemosensor properties, showing selectivity for cyanide via a Michael addition mechanism that causes the disappearance of the ICT band, and a significant color change was observed in both organic and aqueous media. In addition, the interaction mechanism between

• photophysical properties of the dyes. The sensitivity/selectivity properties of the dyes to anions were investigated in DMSO and aqueous media, revealing that the dyes were selectively responsive only to cyanide anions. Changes after interactions were determined through absorption spectra and color changes

• also showed significant color changes with increasing polarity. Color changes of 2a; from purple to blue, 2b; blue to green, and 2c; pale orange to pale pink (Figure 2d). Dyes do not show any significant emission. Chemosensor properties Cyanide selectivity study The dyes 2a–c could have the ability to

Total synthesis of natural products based on hydrogenation of aromatic rings

• Haoxiang Wu and
• Xiangbing Qi

Beilstein J. Org. Chem. 2026, 22, 88–122, doi:10.3762/bjoc.22.4

• ]. Although oxidative dearomatization has been a widely studied and powerful approach in synthetic chemistry [21][26][27][28], researchers have gradually recognized its inherent limitations, including narrow substrate scope, poor selectivity, and low functional group compatibility. Under the circumstance of

• hydrogenation of aromatic rings The catalytic hydrogenation of arenes offers a powerful route to disrupt aromaticity and access synthetically valuable intermediates. However, its implementation in strategic synthesis has been hindered by the persistent challenge of controlling selectivity across diverse

• -art systems depend on expensive transition metals such as platinum, ruthenium, or palladium, inflating the cost of large-scale applications. In addition, precious-metal catalysts often display poor selectivity, while heteroatoms in heteroarenes – acting as Lewis bases – tend to coordinate to the metal

Advances in Zr-mediated radical transformations and applications to total synthesis

• Hiroshige Ogawa and
• Hugh Nakamura

Beilstein J. Org. Chem. 2026, 22, 71–87, doi:10.3762/bjoc.22.3

• benzylic position, giving the hydrogenated products with high site selectivity. Zr-catalyzed radical reaction in the total synthesis of complex natural products This section presents examples of zirconium-mediated reactions applied to the synthesis of complex molecules. For application in total synthesis

Reactivity umpolung of the cycloheptatriene core in hexa(methoxycarbonyl)cycloheptatriene

• Dmitry N. Platonov,
• Alexander Yu. Belyy,
• Rinat F. Salikov,
• Kirill S. Erokhin and
• Yury V. Tomilov

Beilstein J. Org. Chem. 2026, 22, 64–70, doi:10.3762/bjoc.22.2

• reactions mainly involve the initial electrophilic attack onto the α-position relative to the hydrogen atom. The selectivity is either due to the high stability of the α-nucleophilic conformer or due to the promotion by the adjacent ester group. Cascade reactions upon the target connection, if installed

• unavailability of other stable cycloheptatrienyl anions until recently, its derivatives were not expected to show high selectivity in reactions. Herein, we present the first examples of selective reactions of low-symmetry hexa(methoxycarbonyl)cycloheptatrienyl anion 2 [20] towards electrophiles. Additionally

• principle [38]. At least, the reaction times and conditions required for the alkylation reactions investigated, which proceed through an α-attack, indicate relatively high barriers. This in turn indicates that the selectivity observed in alkylation reactions (α-attack) is due to some stabilization of the

Synthesis and applications of alkenyl chlorides (vinyl chlorides): a review

• Daniel S. Müller

Beilstein J. Org. Chem. 2026, 22, 1–63, doi:10.3762/bjoc.22.1

• demonstrated that aromatic alkynes can undergo hydrochlorination with good selectivity for the mono-addition when a nitromethane/acetic acid solvent mixture is employed (Scheme 27) [96]. In contrast, selective monohydrochlorination is commonly observed for alkynes bearing coordinating substituents such as

• , aligned with the axis of the vacant orbital. In the case depicted in Scheme 40B, the face syn to the hydrogen is significantly more accessible than the face syn to the bulky tert-butyl group, accounting for the high E-selectivity observed. In contrast, alkyl groups with reduced steric demand led to

• of the reaction in which TiCl4 was employed in place of BCl3 (Scheme 43) [147]. Interestingly, this modification led to an improved E/Z ratio compared to the values reported by Melloni (compare selectivity for compound 219 in Scheme 38 and Scheme 41). The enhanced selectivity is likely attributable

Sustainable electrochemical synthesis of aliphatic nitro-NNO-azoxy compounds employing ammonium dinitramide and their in vitro evaluation as potential nitric oxide donors and fungicides

• Alexander S. Budnikov,
• Nikita E. Leonov,
• Michael S. Klenov,
• Andrey A. Kulikov,
• Igor B. Krylov,
• Timofey A. Kudryashev,
• Aleksandr M. Churakov,
• Alexander O. Terent’ev and
• Vladimir A. Tartakovsky

Beilstein J. Org. Chem. 2025, 21, 2739–2754, doi:10.3762/bjoc.21.211

• , electroorganic synthesis has become a powerful and reliable strategy for the functionalization of organic compounds under green and mild reaction conditions [36][37][38][39]. The control of selectivity through the variation of parameters such as current, voltage, electrolyte, electrodes, and the type of

• scalable and can be performed in an undivided cell under high current densities without a loss of selectivity. The use of ammonium dinitramide as a source of the [=N–NO2] group and an electrolyte eliminates the need for hazardous nitronium salts and allows the synthesis of nitro-NNO-azoxy compounds in a

Competitive cyclization of ethyl trifluoroacetoacetate and methyl ketones with 1,3-diamino-2-propanol into hydrogenated oxazolo- and pyrimido-condensed pyridones

• Svetlana O. Kushch,
• Marina V. Goryaeva,
• Yanina V. Burgart,
• Marina A. Ezhikova,
• Mikhail I. Kodess,
• Pavel A. Slepukhin,
• Alexandrina S. Volobueva,
• Vladimir V. Zarubaev and
• Victor I. Saloutin

Beilstein J. Org. Chem. 2025, 21, 2716–2729, doi:10.3762/bjoc.21.209

• triethylamine in 1,4-dioxane (Table 1, entry 9) did not affect the reaction course significantly. The use of conditions with catalysis by a combination of Bronsted acid and base (acetic acid, Et3N) contributed to a shift in the reaction selectivity towards octahydropyridopyrimidinones 4 (overall yield 71

• 5ctt (δF 79.74 ppm). All products were individually isolated by column chromatography. Carrying out these syntheses in 1,4-dioxane in the presence of acetic acid and triethylamine increased the selectivity for the formation of octahydropyrido[1,2-a]pyrimidinones 4 in the reactions with alkyl methyl

• influenza A/Puerto Rico/8/34 (H1N1) virus on the MDCK cell line using ribavirin as a reference (Table 5). Of all the tested compounds, octahydropyridopyrimidinone 4att (IC50 86 μM, SI = 13) showed moderate antiviral activity. However, the value of selectivity index (SI) did not exceed that of reference

Recent advancements in the synthesis of Veratrum alkaloids

• Morwenna Mögel,
• David Berger and
• Philipp Heretsch

Beilstein J. Org. Chem. 2025, 21, 2657–2693, doi:10.3762/bjoc.21.206

• afford cyclization of the E-ring. The obtained pyridinium species was directly reduced to reveal the piperidine moiety. The observed selectivity for hydrogenation from the α-side was attributed to the steric hindrance of the C20 axial tertiary TMS ether. The survival of the olefin in the D-ring was

Silica gel with covalently attached bambusuril macrocycle for dicyanoaurate sorption from water

• Michaela Šusterová and
• Vladimír Šindelář

Beilstein J. Org. Chem. 2025, 21, 2604–2611, doi:10.3762/bjoc.21.201

• leading not only to improved extraction effectivity but also to enhanced selectivity [2]. Anion extractants based on functionalized polystyrene or silica gel typically incorporate calixarenes [6] and their analogues, calixpyrroles [7][8], azacalixarene derivatives [9], or expanded porphyrin-like sapphyrin

• affected by its long aliphatic arms terminated with carboxylic groups, whose flexibility can enable intramolecular complexation competing for an anion binding [13]. Bambusurils are known to bind a wide range of anions with varying selectivity. Dicyanoaurate is particularly relevant to the gold mining

• industry, whereas dicyanoargentate is considered a contaminant in this context. To assess selectivity, we measured the sorption of dicyanoaurate from a 1 mM aqueous solution both in the absence and in the presence of an equimolar amount of dicyanoargentate. The measurements revealed that dicyanoaurate

Visible-light-driven NHC and organophotoredox dual catalysis for the synthesis of carbonyl compounds

• Vasudevan Dhayalan

Beilstein J. Org. Chem. 2025, 21, 2584–2603, doi:10.3762/bjoc.21.200

• production of ketone scaffolds, including drug moieties. The organocatalyzed acylation proceeds with excellent site selectivity and broad functional group tolerance of alkanes such as F, Cl, Br, I, CN, CF3, Me, and OMe. The reaction was achieved between acyl fluoride 4 and highly substituted alkane 7 in the

• para-selectivity observed in Friedel–Crafts acylation. The authors anticipate expanding this strategy to other reaction processes, allowing the efficient development of transformative synthetic methods, constructing new chemical spaces for drug discovery, and modifying bioactive molecules (Scheme 13

Recent advances in total synthesis of illisimonin A

• Juan Huang and
• Ming Yang

Beilstein J. Org. Chem. 2025, 21, 2571–2583, doi:10.3762/bjoc.21.199

• hydroxy group could be responsible for this reversal in selectivity. Dai’s asymmetric synthesis of (−)-illisimonin A In 2025, Dai and co-workers accomplished an asymmetric total synthesis of (−)-illisimonin A in 16 steps from (S)-carvone (67) using a pattern-recognition strategy and five sequential olefin

Total syntheses of highly oxidative Ryania diterpenoids facilitated by innovations in synthetic strategies

• Zhi-Qi Cao,
• Jin-Bao Qiao and
• Yu-Ming Zhao

Beilstein J. Org. Chem. 2025, 21, 2553–2570, doi:10.3762/bjoc.21.198

• atmosphere significantly suppressed side reactions, yielding the cyclized product in excellent yield and selectivity. This indicates that N-formylsaccharin, beyond acting as a CO-releasing agent, may function as a ligand in the catalytic cycle to regulate the palladium catalyst’s activity and stability

Synthesis and characterization of a isothiouronium-calix[4]arene derivative: self-assembly and anticancer activity

• Giuseppe Granata,
• Loredana Ferreri,
• Claudia Giovanna Leotta,
• Giovanni Mario Pitari and
• Grazia Maria Letizia Consoli

Beilstein J. Org. Chem. 2025, 21, 2535–2541, doi:10.3762/bjoc.21.195

• framework, these compounds offer the potential for enhanced therapeutic efficacy through a multivalency effect. Multivalency is a strategy employed by nature to improve selectivity, specificity, and avidity in molecular recognition events responsible for both physiological and pathological processes

• renal carcinoma cells (786O) and normal human fibroblasts (SW1), and the tumor cells selectivity was evaluated. To elucidate the role of the isothiouronium groups, antiproliferative effects were also estimated on calix[4]arene precursor 1 lacking these functional groups. Results and Discussion Synthesis

• , it is generally accepted that values higher than ±40 mV are associated with strong stability by repulsion, preventing further aggregation phenomena. Cytotoxicity and cancer cell selectivity Thiouronium-containing molecules can inhibit cancer cells, inducing apoptosis or necrosis, by different

Isoorotamide-based peptide nucleic acid nucleobases with extended linkers aimed at distal base recognition of adenosine in double helical RNA

• Grant D. Walby,
• Brandon R. Tessier,
• Tristan L. Mabee,
• Jennah M. Hoke,
• Hallie M. Bleam,
• Angelina Giglio-Tos,
• Emily E. Harding,
• Vladislavs Baskevics,
• Martins Katkevics,
• Eriks Rozners and
• James A. MacKay

Beilstein J. Org. Chem. 2025, 21, 2513–2523, doi:10.3762/bjoc.21.193

• M3R) [28] reported by us (Figure 2). Despite significant effort, most known extended nucleobases show only modest selectivity and/or can only be used for a single pyrimidine interruption without significant loss in binding affinity. Given the challenges outlined above, our group has approached the

• pyrimidine recognition problem with a threefold strategy (Figure 3). First, we aimed to focus primarily on U–A recognition due to the poor selectivity of E [30], the promiscuous behavior of S [31], and the synthetic advantages imparted by commercially available uracil derivatives that could be readily

• of connection to the PNA with the goal of U-recognition (Figure 3b). We first demonstrated that extended isoorotamide bases Io1–Io4 (Figure 4) recognize A–U base pairs with good selectivity and affinity [35]. Using Io4, this study highlighted the first example of a PNA with four consecutive extended

Catalytic enantioselective synthesis of selenium-containing atropisomers via C–Se bond formations

• Qi-Sen Gao,
• Zheng-Wei Wei and
• Zhi-Min Chen

Beilstein J. Org. Chem. 2025, 21, 2447–2455, doi:10.3762/bjoc.21.186

• participate in various types of asymmetric reactions, significantly improving the selectivity of reactions (Figure 1) [10][11][12][13][14]. Catalytic asymmetric synthesis is the main method to construct chiral organic selenium-containing compounds. Centrally chiral selenium-containing compounds can be

• catalytic performance. The developed catalytic system demonstrated high activity, excellent yields (mostly exceeding 85%), mild reaction conditions, broad functional group tolerance, as well as high regioselectivity, (E)-selectivity, and enantioselectivity (up to 99% ee). According to the kinetic study, the

Transformation of the cyclohexane ring to the cyclopentane fragment of biologically active compounds

• Natalya Akhmetdinova,
• Ilgiz Biktagirov and
• Liliya Kh. Faizullina

Beilstein J. Org. Chem. 2025, 21, 2416–2446, doi:10.3762/bjoc.21.185

• ], the mechanism and factors controlling the selectivity of the oxidative ring contraction in cyclic α-formyl ketones under the action of H2O2 were studied in detail. Due to their complex architecture and diverse biological activities, including antiviral, antitumor, antimalarial, and antifungal activity

• 30% and a selectivity of 70% at −100 °C (Scheme 21). 2.3 Wolff rearrangement The Wolff rearrangement is the transformation of α-diazoketones into acids or their derivatives through heating, catalysis, or UV irradiation in the presence of water, alcohols, ammonia, amines, etc. The Wolff rearrangement

• proceeded exclusively to the ring-contracted perhydrindanic ketone 205 in high to quantitative yields (Scheme 36). The authors suggest that the selectivity of the acid-induced rearrangement of epoxides 200 and 201, differing only by a single CH2 group, is influenced by the involvement of the lateral chain

The high potential of methyl laurate as a recyclable competitor to conventional toxic solvents in [3 + 2] cycloaddition reactions

• Ayhan Yıldırım and
• Mustafa Göker

Beilstein J. Org. Chem. 2025, 21, 2389–2415, doi:10.3762/bjoc.21.184

• using N-methyl,C-phenylnitrone and N-methylmaleimide [110]. Furthermore, although mono- and bifunctional N-methylnitrones exhibit higher cycloaddition reaction rates than their N-phenyl analogues, their impact on selectivity is diminished [111]. It is well established that nitrones prepared from

Conformational effects on iodide binding: a comparative study of flexible and rigid carbazole macrocyclic analogs

• Guang-Wei Zhang,
• Yong Zhang,
• Le Shi,
• Chuang Gao,
• Hong-Yu Li and
• Lei Xue

Beilstein J. Org. Chem. 2025, 21, 2369–2375, doi:10.3762/bjoc.21.181

• selective recognition. Balancing binding affinity and selectivity through precise conformational engineering remains a critical challenge [11]. Previous studies, such as those by Tian et al. [12], demonstrated selective binding in chiral assemblies via crown ether chain-length modulation. The dynamic

• , which provides a foundation for developing next-generation smart sensors with programmable anion selectivity. (a) partial 1H NMR spectrum of PBG in CDCl3 (400 MHz, CDCl3, 25 °C), (b) Partial 1H NMR spectrum of WDG in CDCl3 (400 MHz, CDCl3, 25 °C). (a) Partial 1H NMR spectra of PBG and TBAI at different

Rotaxanes with integrated photoswitches: design principles, functional behavior, and emerging applications

• Jullyane Emi Matsushima,
• Khushbu,
• Zuliah Abdulsalam,
• Udyogi Navodya Kulathilaka Conthagamage and
• Víctor García-López

Beilstein J. Org. Chem. 2025, 21, 2345–2366, doi:10.3762/bjoc.21.179

• macrocycle. By introducing stopper groups to prevent dethreading, the authors demonstrated that the photoisomerization of stiff-stilbene can reversibly modulate the chloride anion binding affinity of the system [95]. Due to its selectivity and light-controlled binding behavior, this system holds potential

Recent advances in Norrish–Yang cyclization and dicarbonyl photoredox reactions for natural product synthesis

• Peng-Xi Luo,
• Jin-Xuan Yang,
• Shao-Min Fu and
• Bo Liu

Beilstein J. Org. Chem. 2025, 21, 2315–2333, doi:10.3762/bjoc.21.177

• key late-stage step in this total synthesis, the Norrish–Yang photocyclization exhibits high chemoselectivity and efficiency. It regulates selectivity through C–H bond dissociation energy and restricted bond rotation, constructing a 6/6/4 fused ring system with three contiguous quaternary carbons

• . Moreover, the reaction can be performed on a 300 mg scale, balancing selectivity, efficiency, and practicality. 1.2 Synthetic study toward phainanoids Phainanoids are highly modified triterpenoids first isolated from Phyllanthus hainanensis by Yue's group [24][25]. Biologically, these molecules exhibit

• photophysical cycles and thereby enhances selectivity; and (2) promotion of subsequent ground-state processes [34][35]. In this work, the authors innovatively applied the Norrish–Yang reaction of p-benzoquinone to the synthesis of avarane-type meroterpenoids. Starting from the common precursor quinone, they

Insoluble methylene-bridged glycoluril dimers as sequestrants for dyes

• Suvenika Perera,
• Peter Y. Zavalij and
• Lyle Isaacs

Beilstein J. Org. Chem. 2025, 21, 2302–2314, doi:10.3762/bjoc.21.176

• ][37]. Previously, we showed that the water-soluble methylene-bridged glycoluril dimer (G2M2, Figure 1)-based host displayed highest affinity and selectivity for planar aromatic cations (e.g., dyes) [38]. Most recently, we synthesized a series of water-insoluble catechol-walled acyclic cucurbit[n]uril