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

• stereoretentive coupling at C2 with aryl bromide 86, yielding 88 as a single diastereomer. Manipulation of the protecting group of 88 arrived at lycoplatyrine A (89). Notably, 87 and related α-hydroxy-β-lactams were obtained via Norrish–Yang cyclization of the corresponding neat α-keto amides in the solid state

• under blue LED irradiation. Solid-state reactions differ from solution-phase processes due to restraints on molecular motions imposed by the crystal lattice, thereby avoiding side reactions caused by unrestricted molecular motions in solution [41]. It has also been demonstrated that for crystalline 1,2

• undergoes SET to form a zwitterion as an intermediate step prior to cyclization [35][43][44]. It is noted that such molecular motions (rotations) are possible in solution but prevented by crystal-lattice restraints in the solid state [37]. In this synthesis, Sarpong et al. utilized the Norrish–Yang reaction

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

• along with comparator H2 as solid-state sequestrants for a panel of five dyes (methylene blue, methylene violet, acridine orange, rhodamine 6G, and methyl violet 6B). We find that catechol-walled H2 (OH substituents) is a superior sequestrant compared to G2W1–G2W4 (OMe substituents). X-ray crystal

• violet removal efficiency using triphenylene-walled G2W1. Design, synthesis and characterization of G2W1–G2W4 The sequestration of large planar aromatic dyes from aqueous solution into the solid state requires water-insoluble hosts that possess complementary molecular recognition surfaces. Previously, we

• larger aromatic walls in the form of triphenylene walls. To ensure that the targeted hosts display low aqueous solubility required for solid state sequestrants, we exchanged the O(CH2)3SO3Na groups for OMe groups. Accordingly, we targeted the preparation of W1 and W2 (Scheme 1) which contain large π

A m-quaterphenyl probe for absolute configurational assignments of primary and secondary amines

• Yuka Takeuchi,
• Mutsumi Kobayashi,
• Yuuka Gotoh,
• Mari Ikeda,
• Yoichi Habata,
• Tomohiko Shirai and
• Shunsuke Kuwahara

Beilstein J. Org. Chem. 2025, 21, 2211–2219, doi:10.3762/bjoc.21.168

• described above, the C6–C1–C1'–C6' dihedral angles in all conformers of (S)-3a–g and (R)-3h were approximately constant (plus or minus ca. 42 degree). The range of distribution of the angles was also small, ranging from +39.8 to +43.9 degrees, or −40.2 to −45.8 degrees (Figure 5). In the solid state of (S

Solar thermal fuels: azobenzene as a cyclic photon–heat transduction platform

• Jie Yan,
• Shaodong Sun,
• Minghao Wang and
• Si Wu

Beilstein J. Org. Chem. 2025, 21, 2036–2047, doi:10.3762/bjoc.21.159

• monomer to 103 min for the polymer. Linear azobenzene polymer solar thermal fuels Linear azobenzene polymers possess excellent processability and serve as ideal solid-state matrices for photoisomerization [49][50][51][52][53][54][55][56][57], making them suitable candidates for solar thermal fuels

• visible light under sunlight irradiation [59], achieving a solar efficiency of 0.4% and a solid-state isomerization efficiency of 72.7% (Figure 5b). Feng and co-workers reported the synthesis of three azopyridine polymers (ortho-, meta-, and para-) [60], with the m-azopyridine polymer exhibiting a

• azobenzene derivatives [82][83][84][85][86][87][88]. From an energy charging perspective, some solvent-free systems store energy in the solid state [89] or via photoinduced solid–liquid phase transitions [61][69][74], which occur because the melting temperature (Tm) of trans-azobenzene is above room

Understanding the origin of stereoselectivity in the photochemical denitrogenation of 2,3-diazabicyclo[2.2.1]heptene and its derivatives with non-adiabatic molecular dynamics

• Leticia A. Gomes and
• Steven A. Lopez

Beilstein J. Org. Chem. 2025, 21, 2007–2020, doi:10.3762/bjoc.21.156

• ][68][69][70][71][72][73][74][75][76][77][78] mechanisms of cyclic azoalkenes have been studied with experimental and computational techniques for more than six decades, in solution [51][55][59][60][61][64][67][69][70][73][74][75][76][78][79], gas phase [50][55][62][64][65], and solid state [60][63

Systematic pore lipophilization to enhance the efficiency of an amine-based MOF catalyst in the solvent-free Knoevenagel reaction

• Pricilla Matseketsa,
• Margret Kumbirayi Ruwimbo Pagare and
• Tendai Gadzikwa

Beilstein J. Org. Chem. 2025, 21, 1854–1863, doi:10.3762/bjoc.21.144

• functional groups are isolated together in confined space [7][8][9]. In the solid state, the generation of such multifunctional cavities has been pursued upon nanoporous scaffolds that include polymers of intrinsic microporosity (PIMs) [10][11][12][13], mesoporous silica materials (MSMs) [14][15][16][17

Photoswitches beyond azobenzene: a beginner’s guide

• Michela Marcon,
• Christoph Haag and
• Burkhard König

Beilstein J. Org. Chem. 2025, 21, 1808–1853, doi:10.3762/bjoc.21.143

• ) [112]. Examples The Aprahamian group reported hydrazone 121, which is emissive in its Z-isomer. The fluorescence can be switched on and off by irradiation with 442 nm and 340 nm, respectively (Scheme 37) [114]. The photophysical and emissive properties were also maintained in bovine serum, in the solid

• state, and in the presence of glutathione, opening the possibility for applications in a biological environment. Some interesting isatin-based arylhydrazones were reported [115][116][117]. Compound 122H is a P-type hydrazone photoswitch. The addition of tetrabutylammonium fluoride (TBAF) deprotonates

3,3'-Linked BINOL macrocycles: optimized synthesis of crown ethers featuring one or two BINOL units

• Somayyeh Kheirjou,
• Jan Riebe,
• Maike Thiele,
• Christoph Wölper and
• Jochen Niemeyer

Beilstein J. Org. Chem. 2025, 21, 1719–1729, doi:10.3762/bjoc.21.134

• bistosylates 85/6/7/8 (1.0 equiv), Cs2CO3 (2.0 equiv), CH3CN, 80 °C. Molecular structure of macrocycle (R)-Me-M16 in the solid state (hydrogen atoms are omitted for clarity and thermal ellipsoids are set at the 60% probability level). The ethylene glycol chain is partially disordered, only one component is

• : Experimental procedures and characterization data of new compounds. Supporting Information File 4: Crystallographic Information File (CIF) for the solid-state structure of (R)-Me-M16. Funding J.N. would like to thank the Deutsche Forschungsgemeinschaft DFG (project NI1273/2-2, project NI1273/5-1 and

Continuous-flow-enabled intensification in nitration processes: a review of technological developments and practical applications over the past decade

• Feng Zhou,
• Chuansong Duanmu,
• Yanxing Li,
• Jin Li,
• Haiqing Xu,
• Pan Wang and
• Kai Zhu

Beilstein J. Org. Chem. 2025, 21, 1678–1699, doi:10.3762/bjoc.21.132

• nitration systems (Figure 4b). A significant proportion of nitration substrates are in the solid state, necessitating solvent-mediated dissolution to achieve practical operability in continuous-flow configurations. The common solvents used in nitration reactions include sulfuric acid (24%), dichloromethane

Synthesis of an aza[5]helicene-incorporated macrocyclic heteroarene via oxidation of an o-phenylene-pyrrole-thiophene icosamer

• Yusuke Matsuo,
• Aoi Nakagawa,
• Shu Seki and
• Takayuki Tanaka

Beilstein J. Org. Chem. 2025, 21, 1561–1567, doi:10.3762/bjoc.21.119

• and 8.98 ppm and five doublet signals due to the heterole β-protons in the range of 6.7–5.8 ppm, along with o-phenylene protons around 7 ppm. Single crystals suitable for X-ray diffraction analysis were obtained from a mixture of acetone/n-hexane and the solid-state structure was successfully

• aza[5]helicene-incorporated macrocyclic structure (Figure 4). In the solid-state, the distance between the two aza[5]helicene moieties was found to be 3.185 Å, closely consistent with the DFT-optimized value of 3.136 Å (see Supporting Information File 1). The average dihedral angles between the o

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

• hydrogelator [25], photoregulation of DNA nanosystems [26], in controlling surface wettability [27], and in solar energy conversion [28]. Considering these advantages, we synthesized C3 symmetric tripodal azopyrazole-based derivatives having a trimesoyl core and aroylazole connections as a solid-state

• switchable probe for light-driven reversible printing and erasing applications [29]. Besides exhibiting excellent photoswitching in solution phase, the tripodal photoswitches exhibit extended half-life of the ZZZ isomer in the solid-state as well [22][29]. The overall efficiency of the molecular switch could

• surface at ambient conditions. The fluorine substitution is chosen in FNAAP for its better photoisomerization efficiency (in solution as well as in solid state) and higher molecular stability [29]. Possible photoisomers of FNAAP, EEE, EEZ, EZZ and ZZZ are shown in Figure 1. FNAAP molecules assemble into

Wittig reaction of cyclobisbiphenylenecarbonyl

• Taito Moribe,
• Junichiro Hirano,
• Hideaki Takano,
• Hiroshi Shinokubo and
• Norihito Fukui

Beilstein J. Org. Chem. 2025, 21, 1454–1461, doi:10.3762/bjoc.21.107

• reaction of CBBC 1 with methylenetriphenylphosphorane furnished two (exocyclic olefin)-containing macrocycles 3 and 5 as well as an internally functionalized DBC derivative 4. Compounds 3 and 5 adopt a bathtub-like conformation in the solid state. In solution, both figure-eight and bathtub conformations

Advances in nitrogen-containing helicenes: synthesis, chiroptical properties, and optoelectronic applications

• Meng Qiu,
• Jing Du,
• Nai-Te Yao,
• Xin-Yue Wang and
• Han-Yuan Gong

Beilstein J. Org. Chem. 2025, 21, 1422–1453, doi:10.3762/bjoc.21.106

• long-wavelength optical and chiroptical properties [35] (Table 6). In the solid state, 21c emitted in the far-red region at 641 nm (ΦF = 0.10) and demonstrated CPL with |glum| = 2.04 × 10−4. In solution, 21c showed a strong absorption band at 560 nm and a high ФF value of 0.86 at 583 nm, yielding a

• reported azabora[6]helicenes 45a and 45b [60]. However, their enantiomers could not be isolated due to low racemization barriers. The F- and Ph-coordinated derivatives displayed moderate PLQYs in solution (0.26 and 0.18, respectively), which dropped markedly in the solid state (0.02 and 0.04) owing to

• fluorescence in the solid state. The |gabs| in the visible region increase systematically with helical length, reaching values as high as ≈10−2 for compounds 54b and 54c – among the highest reported to date – highlighting their strong potential in chiral optoelectronic applications (Table 18). In 2023, the

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

• largely gone unnoticed as an activation method for organic synthesis. A large number of applications have been reported in solid state, homogeneous and heterogeneous systems to prepare inorganic compounds and materials [7][8][9]. In contrast, high pressure organic chemistry, or HHP-initiated organic

Optimized synthesis of aroyl-S,N-ketene acetals by omission of solubilizing alcohol cosolvents

• Julius Krenzer and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2025, 21, 1201–1206, doi:10.3762/bjoc.21.97

• ; condensation; Einhorn-type acylation; 2-methyl N-benzyl benzothiazolium salts; Introduction Aroyl-S,N-ketene acetals, in particular N-benzyl derivatives 1, are very short donor–acceptor chromophores that have recently found a renaissance due to their peculiar intense solid-state emission and significant turn

Gold extraction at the molecular level using α- and β-cyclodextrins

• Susana Santos Braga

Beilstein J. Org. Chem. 2025, 21, 1116–1125, doi:10.3762/bjoc.21.89

• stripping from activated carbon using α-cyclodextrin. J. Am. Chem. Soc. 2021, 143, 1984–1992. Copyright 2020 American Chemical Society. This content is not subject to CC BY 4.0. Solid-state structure of the complex 2β-CD·HAuBr4·DBC. (a) Capped-stick and space-filling representation of different views of 2β

Supramolecular assembly of hypervalent iodine macrocycles and alkali metals

• Krishna Pandey,
• Lucas X. Orton,
• Grayson Venus,
• Waseem A. Hussain,
• Toby Woods,
• Lichang Wang and
• Kyle N. Plunkett

Beilstein J. Org. Chem. 2025, 21, 1095–1103, doi:10.3762/bjoc.21.87

• at Urbana-Champaign, Urbana, IL, 61801, United States 10.3762/bjoc.21.87 Abstract This study explores the solution- and solid-state assembly of phenylalanine-based hypervalent iodine macrocycles (HIMs) with lithium and sodium cations. The metal cation binding of HIMs was evaluated by addition of

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

Unraveling cooperative interactions between complexed ions in dual-host strategy for cesium salt separation

• Zhihua Liu,
• Ya-Zhi Chen,
• Ji Wang,
• Qingling Nie,
• Wei Zhao and
• Biao Wu

Beilstein J. Org. Chem. 2025, 21, 845–853, doi:10.3762/bjoc.21.68

• displays higher hydration energy than that of sulfate, and the tetrahedral shape of sulfate anion matches the pseudo-tetrahedral cavity of the folded hexaurea receptor [30]. Secondly, for Cs+ cations, two types of Cs+ binding are shown in the solid state. Two type-(I) cesium cations are found to be

• six Cs–O ion-dipole interactions (2.9 Å and 3.2 Å). These intermolecular interactions of Cs+ cations with18-crown-6 and hexaurea receptors help to form 3D framework in the solid state (Supporting Information File 1, Figure S2), which may reinforce cooperative interactions between complexed Cs+ and

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

• systematically red-shifted by ca. 3–5 nm compared to those of the corresponding parent phenacenes. The vibrational progressions of the absorption and fluorescence bands were little affected by the fluorination in the solution phase. In the solid state, the absorption band of F8-phenacenes appeared in the similar

• significantly affects their electronic features as well as molecular and crystalline structures [30][31][32]. For example, the fluorination of oligoacene frameworks manipulates their electronic properties as well as their solid-state packing motifs [33][34][35][36]. The most pronounced example is that pentacene

• processes contributing to the low fluorescence quantum yield of the F8-phenacenes (cf. Table 1). Because fluorescence behavior in the solid state reflects molecular alignment and intermolecular interactions in the crystals, solid-state fluorescence of the F8-phenacenes was investigated. We observed

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

• -purity color and improved stability, has been observed. OLED materials have attracted considerable research because they found commercial uses for flat panel displays and solid-state lighting applications. Currently, the design of efficient and highly stable blue fluorescent emitters remains a challenge

• for material scientists [12][13][14]. One of the structural features favorable for an efficient anthracene-based blue emitter is the introduction of bulky substituents in the 9 and 10 positions, which results in a solid-state packing with limited π–π intermolecular interactions, which, in turn, tends

• ANTH and the –C6F5 group might provide the desired spatial isolation of the ANTH (and other PAH) cores, and result in enhanced photoluminescence by disrupting close π–π stacking in the solid state. In addition, air- and photostability might also be improved due to the steric and electronic properties

Unprecedented visible light-initiated topochemical [2 + 2] cycloaddition in a functionalized bimane dye

• Metodej Dvoracek,
• Brendan Twamley,
• Mathias O. Senge and
• Mikhail A. Filatov

Beilstein J. Org. Chem. 2025, 21, 500–509, doi:10.3762/bjoc.21.37

• solid state, which are highly dependent on molecular packing. The concept of topochemical reactions was first introduced by Kohlschütter in 1919 [1], and topochemical polymerizations were systematically studied by Schmidt and co-workers in the 1960s and 1970s [2][3][4]. Schmidt's pioneering work

• primarily focused on [2 + 2] photocycloaddition in the solid state, making it one of the earliest known examples of topochemical polymerization and a valuable method for synthesizing substituted cyclobutanes [5]. These solid-state reactions are highly influenced by the arrangement of monomers within the

• Figure 2b. We hypothesized that this reaction occurred in the solid state, and further investigations confirmed this. To validate our findings, we employed single-crystal X-ray diffraction, which revealed the packing mode in the crystal and identified any photoproducts formed. Two additional compounds

Photomechanochemistry: harnessing mechanical forces to enhance photochemical reactions

• Francesco Mele,
• Ana M. Constantin,
• Andrea Porcheddu,
• Raimondo Maggi,
• Giovanni Maestri,
• Nicola Della Ca’ and
• Luca Capaldo

Beilstein J. Org. Chem. 2025, 21, 458–472, doi:10.3762/bjoc.21.33

• mechanochemistry holds potential for unique opportunities for substrate activation while adopting an environmentally benign emerging technology (Figure 2, top). For example, it is well known that molecules in the solid state (or in very high concentration) often exhibit photophysical behaviors distinct from those

• light energy and mechanical forces have been integrated through the years, either in a combined or sequential manner. Our goal is not to provide an exhaustive review on photomechanochemistry [34][42][55], nor a detailed explanation of solid-state photochemistry [56][57], but rather to capture a snapshot

• studied to get insights into the impact of light energy onto crystals [60][61]. In the following, we describe selected examples with an emphasis on the role of manual grinding in improving irradiation. Mechanochemistry is a linchpin in topochemical solid-state reactions, where the correct molecular

Beyond symmetric self-assembly and effective molarity: unlocking functional enzyme mimics with robust organic cages

• Keith G. Andrews

Beilstein J. Org. Chem. 2025, 21, 421–443, doi:10.3762/bjoc.21.30

• therefore can be subjected to automated and high-throughput crystallization studies and, with Szczypiński, Slater, Cooper and co-workers, we were able to isolate all five calculated lowest-energy conformers of cage 1 in the solid state (see crystal cavity heights marked under conformers in Figure 9A) [40

• , screening for particularly stable assemblies [405][411] screens out cages with the taut, dynamic properties found in biological systems [100][146][395][401][412]. Therefore, despite the apparent similarity between porous organic cages (solid state) and robust organic cages (solution state), current leading

Antibiofilm and cytotoxic metabolites from the entomopathogenic fungus Samsoniella aurantia

• Rita Toshe,
• Syeda J. Khalid,
• Blondelle Matio Kemkuignou,
• Esteban Charria-Girón,
• Paul Eckhardt,
• Birthe Sandargo,
• Kunlapat Nuchthien,
• J. Jennifer Luangsa-ard,
• Till Opatz,
• Hedda Schrey,
• Sherif S. Ebada and
• Marc Stadler

Beilstein J. Org. Chem. 2025, 21, 327–339, doi:10.3762/bjoc.21.23

• 10.3762/bjoc.21.23 Abstract During the course of our studies on the secondary metabolism of rare, hitherto untapped Thai insect-associated fungi, the ethyl acetate (EtOAc) extract derived from solid-state cultivation of Samsoniella aurantia on rice afforded one previously undescribed tetramic acid