A practical CO₂-mediated synthesis of 5,6-carboxylated silicon-rhodamines for targeted probe development

• Dongjie Hou,
• Shaowei Wu,
• Ning Xu,
• Pengjun Bao,
• Wenhao Jia,
• Qinglong Qiao and
• Zhaochao Xu

Beilstein J. Org. Chem. 2026, 22, 915–924, doi:10.3762/bjoc.22.72

• .22.72 Abstract Silicon-rhodamine (SiR) dyes are among the most important fluorophores for super-resolution imaging owing to their far-red emission, high photostability, and tunable lactone–zwitterion equilibrium. However, their broader application in targeted probe development has been limited by the

• facilitates the rapid development of targeted SiR probes. Keywords: carboxylation; CO2; fluorescent probes; silicon-rhodamine; super-resolution imaging; Introduction Rhodamine dyes, which enable fluorescence imaging in living cells – a powerful technique for studying biological systems in vivo [1][2] – have

• switching and fluorogenic responses, making rhodamines particularly valuable for advanced imaging beyond the optical diffraction limit [14][15][16][17][18][19]. Replacement of the conventional bridging oxygen atom with silicon shifts the emission of rhodamines from red to the far-red region (typically λem

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

• used to construct a light–heat responsive polyurethane actuator [15], a silicon-based liquid crystalline polyacrylate with photoinduced transition from the smectic mesophase to the isotropic phase [16], a drug delivery system capable to release the drug via E/Z isomerization induced by direct (UV) or

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

• −) attacks the silicon atom, while the polarized lithium atom (δ+) coordinates with the methoxy group as a Lewis acid, further removal of TMSF and LiOMe leads to the in situ formation of azomethine ylide, which then participates in cycloaddition with alkenes (Scheme 36) [79]. The decarboxylative route to

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

• silicon compounds was observed in all reactions (see Supporting Information File 1, Figure S3). Noteworthy, by replacing formic acid with acetic acid only 1 equivalent of hydrogen was released. The different reactivity towards the dehydrogenative coupling of the silyl carboxylate species can be due to

Pd-catalyzed dehydrogenative arylation of arylhydrazines to access non-symmetric azobenzenes, including tetra-ortho derivatives

• Loris Geminiani,
• Kathrin Junge,
• Matthias Beller and
• Jean-François Soulé

Beilstein J. Org. Chem. 2025, 21, 2234–2242, doi:10.3762/bjoc.21.170

• hydrazines. Their method involved a three-step process comprising Cu and Pd-catalyzed C–N bond formations followed by a dehydrogenative deprotection step (Figure 1b, top) [42]. This desymmetric approach was further employed by Oestreich and co-workers in 2022, who introduced silicon-masked diazenyl anions in

Bioinspired total syntheses of natural products: a personal adventure

• Zhengyi Qin,
• Yuting Yang,
• Nuran Yan,
• Xinyu Liang,
• Zhiyu Zhang,
• Yaxuan Duan,
• Huilin Li and
• Xuegong She

Beilstein J. Org. Chem. 2025, 21, 2048–2061, doi:10.3762/bjoc.21.160

• TBS protection in one pot. Oxidation of the primary alcohol using Swern oxidation gave the hydroxy aldehyde 3, which was activated with a formal silicon cation to trigger the Prins cyclization terminated by the tertiary alcohol, affording silylated bicycle 9 directly through the designed bioinspired

Aryl iodane-induced cascade arylation–1,2-silyl shift–heterocyclization of propargylsilanes under copper catalysis

• Rasma Kroņkalne,
• Rūdolfs Beļaunieks,
• Armands Sebris,
• Anatoly Mishnev and
• Māris Turks

Beilstein J. Org. Chem. 2025, 21, 1984–1994, doi:10.3762/bjoc.21.154

• , LV-1006, Riga, Latvia 10.3762/bjoc.21.154 Abstract A novel copper-catalyzed arylation strategy for propargylsilanes utilizing diaryl-λ3-iodanes has been developed, enabling a cascade sequence involving 1,2-silyl migration and heterocyclization. The β-silicon effect facilitates the formation of

• propargylsilane 7d halogenation–cyclization cascade and Suzuki–Miyaura cross-coupling in the second step [22]. Thus, we have developed a faster and palladium-free route towards tetrahydrofurans 8. The latter can still be modified further through silicon–halide exchange followed by cross-coupling chemistry as

• ) salt reacts with the diaryl-λ3-iodane (ArMesIY) to generate the strongly electrophilic arylcopper(III) species. The latter activates the propargylic system to induce the 1,2-silyl shift, producing the allylic cation intermediate Int-4, which is stabilized by the β-silicon effect. A following attack of

Photochemical reduction of acylimidazolium salts

• Michael Jakob,
• Nick Bechler,
• Hassan Abdelwahab,
• Fabian Weber,
• Janos Wasternack,
• Leonardo Kleebauer,
• Jan P. Götze and
• Matthew N. Hopkinson

Beilstein J. Org. Chem. 2025, 21, 1973–1983, doi:10.3762/bjoc.21.153

• an O-benzoylated intermediate species also being obtained under some conditions. Supported by TD-DFT studies, plausible reaction mechanisms for both processes were proposed. Moreover, further investigations employing silicon-containing additives allowed for an increase in the reduction yield beyond

Research progress on calixarene/pillararene-based controlled drug release systems

• Liu-Huan Yi,
• Jian Qin,
• Si-Ran Lu,
• Liu-Pan Yang,
• Li-Li Wang and
• Huan Yao

Beilstein J. Org. Chem. 2025, 21, 1757–1785, doi:10.3762/bjoc.21.139

• chiral ligand, which was modified on the upper rim of calixarene through hydrogen bonding. An azobenzene group was introduced as the photo-regulating part at the upper edge of calixarene. The alkyne at the lower edge of FC4AD was used to form self-assembled monolayers (SAMs) on a silicon surface through

Highly distinguishable isomeric states of a tripodal arylazopyrazole derivative on graphite through electron/hole-induced switching at ambient conditions

• Himani Malik,
• Sudha Devi,
• Debapriya Gupta,
• Ankit Kumar Gaur,
• Sugumar Venkataramani and
• Thiruvancheril G. Gopakumar

Beilstein J. Org. Chem. 2025, 21, 1496–1507, doi:10.3762/bjoc.21.112

• atomically precise write and read tool like an STM tip. Keywords: azo compounds; electron/hole-induced isomerization; isomerization; molecular switches; switching; Introduction Molecular electronic devices have been predicted to outperform silicon-based devices [1][2]. Reprogrammable arrays of molecular

• tapping mode and an ATM300 from RHK Technology, respectively. Aluminum-coated silicon cantilevers from Nanosensors (PPP-NCHR) were used as AFM probes. The force constant and resonance frequency of the cantilevers during the imaging were 30–34 N/m and ≈300 kHz, respectively. A Pt/Ir (80:20) tip was

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

• all yielded the expected products to some extent, no product formation was observed at the ambient pressure control reactions. Unlike water and a few elements (silicon, bismuth, gallium, etc.) that tend to form tetrahedral crystal lattices and exhibit lower density upon freezing, most organic

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

• a preparation of oxetanes via silicon-directed electrophilic cyclisation of homoallylic alcohols 49 (Scheme 12) [46]. The reaction was promoted by a bromonium cation and moderate to high yields of oxetanes 50 were obtained. The authors claim the reaction was diastereospecific for disubstituted

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

• was refluxed over sodium with benzophenone as an indicator and freshly distilled prior to use. Column chromatography was performed on silica gel (normal phase, 200–300 mesh) from Anhui Liangchen Silicon Material Co., Ltd. or basic aluminum oxide (pH 9–10) from Shanghai Titan Technology Co., Ltd

• . Petroleum ether (PE, 60–90 °C fraction) and ethyl acetate (EA) were used as eluent. Reactions were monitored by thin-layer chromatography (TLC) on GF254 silica gel plates (0.2 mm) from Anhui Liangchen Silicon Material Co., Ltd. The plates were visualized by UV light. 1H NMR (400 MHz) and 13C NMR (101 MHz

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

• imides and TMS-alkynes, enabling the rapid construction of S(VI)–C(sp2) or S(VI)–C(sp) bonds efficiently (Scheme 24) [55]. This linkage utilizes the high bond dissociation energy (BDE = 135 kcal/mol) of silicon–fluorine bonds, employing trifluoroborate as a fluorine transfer reagent to simultaneously

• cleave the S(VI)–F bond and activate the Si–C bond. DFT calculations indicate that the reaction proceeds via the formation of a difluoroborate phenylacetylene intermediate 94’’ by in situ generation from boron trifluoride etherate and silicon-protected phenylacetylene 94, which activates the S–F bond of

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

• the computational investigation, could not be isolated either – probably due to its high sensitivity to hydrolysis. However, a 2D 1H-15N NMR correlation spectrum showed no interactions of hydrogen nuclei in silicon-bound methyl groups and any of the nitrogens in the product. This led us to conclude

• that silicon is bound via the carbonyl oxygen in 12, as also shown by DFT computations. This is further corroborated by observation of a 13C NMR signal at 146 ppm for an sp2 carbon in the backbone of the product, which fits better for a C=N than a C=O bond. Recovery of the catalyst resting state 7 is

• achieved by reacting 11 with stoichiometric reagent TMSCN (8). This "reloads" calcium with cyanide and replaces TMS-bound isolated product 12 from the metal complex and in which silicon, rather than calcium, is bound to the carbonyl oxygen. The addition reaction itself is rather exothermic (Figure 3) and

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

• ; perfluorobenzylation; photochemistry; Introduction The revolution of small organic molecules in the semiconductor industry continues to progress, replacing some silicon and metal-based electronic components. Acenes, such as anthracene (ANTH) and its higher homologues, represent some of the most studied materials that

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

• hemoglobin, and silicon by selectively irradiating a specific area of the reaction medium with red light (660 nm) or blue light (456 nm), respectively (Scheme 2). The authors have demonstrated that this polymerization reaction proceeded much more efficiently under red light irradiation. Indeed, red light can

• %. Beyond their coordination with transition metals, phthalocyanin ligands also exhibit remarkable photoreactivity in supporting non-metallic central elements. Recent work by Amara et al. highlights the efficiency of silicon-based phthalocyanin complexes in red-light-driven photooxidation processes, marking

• a shift away from the reliance on traditional heavy-metal catalysts [38]. By utilizing silicon as a cheap, non-toxic, and abundantly available element, silicon-based phthalocyanin complex derivatives represent a more sustainable alternative to precious metal-based photocatalysts such as ruthenium or

Advances in radical peroxidation with hydroperoxides

• Oleg V. Bityukov,
• Pavel Yu. Serdyuchenko,
• Andrey S. Kirillov,
• Gennady I. Nikishin,
• Vera A. Vil’ and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2024, 20, 2959–3006, doi:10.3762/bjoc.20.249

Asymmetric organocatalytic synthesis of chiral homoallylic amines

• Nikolay S. Kondratyev and
• Andrei V. Malkov

Beilstein J. Org. Chem. 2024, 20, 2349–2377, doi:10.3762/bjoc.20.201

• excellent yields (77–91%) and excellent enantioselectivities (90–96%) on a millimolar scale (Scheme 13). It is worth noting the use of optimised minimal excess of allyltributyltin (65), which to some extent addresses the higher toxicity of trialkylstannanes compared to their silicon counterparts. The

Discovery of antimicrobial peptides clostrisin and cellulosin from Clostridium: insights into their structures, co-localized biosynthetic gene clusters, and antibiotic activity

• Moisés Alejandro Alejo Hernandez,
• Katia Pamela Villavicencio Sánchez,
• Rosendo Sánchez Morales,
• Karla Georgina Hernández-Magro Gil,
• David Silverio Moreno-Gutiérrez,
• Eddie Guillermo Sanchez-Rueda,
• Yanet Teresa-Cruz,
• Brian Choi,
• Armando Hernández Garcia,
• Alba Romero-Rodríguez,
• Oscar Juárez,
• Siseth Martínez-Caballero,
• Mario Figueroa and
• Corina-Diana Ceapă

Beilstein J. Org. Chem. 2024, 20, 1800–1816, doi:10.3762/bjoc.20.159

• performed using a Digital Instruments NanoScope V, acquiring 1024 samples per line with silicon nitride cantilevers possessing a nominal spring constant of 0.32 Nm−1 and a 0.8–1.0 Hz scan rate. Imaging was conducted at room temperature using the ScanAsyst™ air mode. Images were processed using NanoScope

Generation of alkyl and acyl radicals by visible-light photoredox catalysis: direct activation of C–O bonds in organic transformations

• Mithu Roy,
• Bitan Sardar,
• Itu Mallick and
• Dipankar Srimani

Beilstein J. Org. Chem. 2024, 20, 1348–1375, doi:10.3762/bjoc.20.119

• conventional metal hydrides, such as tin or silicon hydrides. The reaction mechanism is interesting since first, a Lewis acid–base adduct is generated by interaction of Et3N with a boron atom of bis(catecholato)diboron (B2cat2, 19). As a result, one of the catecholate ligands experiences an increase in

Two-fold addition reaction of silylene to C₆₀: structural and electronic properties of a bis-adduct

• Masahiro Kako,
• Masato Kai,
• Masanori Yasui,
• Michio Yamada,
• Yutaka Maeda and
• Takeshi Akasaka

Beilstein J. Org. Chem. 2024, 20, 1179–1188, doi:10.3762/bjoc.20.100

• 305-8577, Japan 10.3762/bjoc.20.100 Abstract The addition reaction of C60 with silylene 1, a silicon analog of carbene, yielded the corresponding bis-adduct 3. The structure of 3 was determined by single-crystal X-ray structure analysis, representing the first example of a crystal structure of a

• silicon analog of carbene, were described as providing silirane (silacyclopropane)-type 6,6-mono-adducts Dip2SiC60 (2, Scheme 1) and Dip2SiC70 [15][16]. Furthermore, bis-adducts (Dip2Si)2C60 and (Dip2Si)2C70 were obtained as byproducts, but no details of these bis-adducts have been clarified [15][16]. The

• results demonstrated that the electronic properties of product 2 were altered considerably compared to that of pristine C60 mainly because silicon atoms are less electronegative. Electron-donating effects of silyl groups in fullerene derivatives were also rationalized in terms of σ–π conjugations between

Perspectives on push–pull chromophores derived from click-type [2 + 2] cycloaddition–retroelectrocyclization reactions of electron-rich alkynes and electron-deficient alkenes

• Michio Yamada

Beilstein J. Org. Chem. 2024, 20, 125–154, doi:10.3762/bjoc.20.13

Multi-redox indenofluorene chromophores incorporating dithiafulvene donor and ene/enediyne acceptor units

• Christina Schøttler,
• Kasper Lund-Rasmussen,
• Line Broløs,
• Philip Vinterberg,
• Ema Bazikova,
• Viktor B. R. Pedersen and
• Mogens Brøndsted Nielsen

Beilstein J. Org. Chem. 2024, 20, 59–73, doi:10.3762/bjoc.20.8

• compound is shown below, in which the hydrogen atoms are omitted for clarity. Atoms are colored grey (carbon), white (hydrogen), brown (bromine), pale-yellow (silicon). Labels of bonds within five-membered ring. Synthesis of IF-DTF ketones 9–12 and dimer 13. Further functionalization of the IF-DTF ketone

Preparing a liquid crystalline dispersion of carbon nanotubes with high aspect ratio

• Keiko Kojima,
• Nodoka Kosugi,
• Hirokuni Jintoku,
• Kazufumi Kobashi and
• Toshiya Okazaki

Beilstein J. Org. Chem. 2024, 20, 52–58, doi:10.3762/bjoc.20.7

• flowing air (200 mL/min) at a ramping rate of 1 °C/min. The Raman and absorption spectra were obtained from DWCNT thin film on a silicon substrate. The DWCNT thin film was prepared using vacuum filtration. Raman measurements were conducted using a HORIBA T64000 532 nm laser, while far-infrared (FIR

• ) analysis (CPS Instruments, CPS 24000UHR (CR-39)). The shape and size of the DWCNTs in dispersion were observed by settling them on a silicon substrate, washed with acetone, and exposed to UV light for 20 minutes using an ozone cleaner (Meiwafosis, PC-450 plus) via dip-coating. The structures of DWCNTs were