Chemical glycobiology

• Elisa Fadda,
• Rachel Hevey,
• Benjamin Schumann and
• Ulrika Westerlind

Beilstein J. Org. Chem. 2025, 21, 8–9, doi:10.3762/bjoc.21.2

• of chemistry as being a catalyst to more than a century of glycobiology, with a profound and exciting vision for the future. Elisa Fadda, Rachel Hevey, Benjamin Schumann and Ulrika Westerlind Southampton, Basel, London, Umeå, November 2024

Synthesis, characterization, and photophysical properties of novel 9‑phenyl-9-phosphafluorene oxide derivatives

• Shuxian Qiu,
• Duan Dong,
• Jiahui Li,
• Huiting Wen,
• Jinpeng Li,
• Yu Yang,
• Shengxian Zhai and
• Xingyuan Gao

Beilstein J. Org. Chem. 2024, 20, 3299–3305, doi:10.3762/bjoc.20.274

• , TADF emitters containing the PhFlOP unit as an electron acceptor are still scarce. Meanwhile, the syntheses of the TADF emitters by the groups of Nishida and Wu both utilized palladium noble metal as a catalyst [31][32][33]. Therefore, it is of great significance to develop cost-effective synthetic

Synthesis of acenaphthylene-fused heteroarenes and polyoxygenated benzo[j]fluoranthenes via a Pd-catalyzed Suzuki–Miyaura/C–H arylation cascade

• Merve Yence,
• Dilgam Ahmadli,
• Damla Surmeli,
• Umut Mert Karacaoğlu,
• Sujit Pal and
• Yunus Emre Türkmen

Beilstein J. Org. Chem. 2024, 20, 3290–3298, doi:10.3762/bjoc.20.273

• )Cl2·CH2Cl2 was used with 5 mol % catalyst loading (Table 1, entry 1). Next, we examined whether different thiophene-3-ylboronic esters could also be used under the same reaction conditions. A variety of borylation methods are capable of providing different boronic esters, such as pinacol [44][45][46

Intramolecular C–H arylation of pyridine derivatives with a palladium catalyst for the synthesis of multiply fused heteroaromatic compounds

• Yuki Nakanishi,
• Shoichi Sugita,
• Kentaro Okano and
• Atsunori Mori

Beilstein J. Org. Chem. 2024, 20, 3256–3262, doi:10.3762/bjoc.20.269

• Abstract The C–H arylation of 2-quinolinecarboxyamide bearing a C–Br bond at the N-aryl moiety is carried out with a palladium catalyst. The reaction proceeds at the C–H bond on the pyridine ring adjacent to the amide group in the presence of 10 mol % Pd(OAc)2 at 110 °C to afford the cyclized product in 42

• conditions. We carried out the palladium-catalyzed intramolecular coupling reaction of precursor 1a under similar conditions [23], which afforded smooth reaction with phenanthroline bisamide, with 10 mol % of palladium acetate as a catalyst in the presence of potassium carbonate and tetra-n-butylammonium

• resulted in a decreased yield (27%) (Table 1, entries 4 and 5). It was found that increasing the amount of potassium carbonate to a three-fold excess improved the yield of 2a to 59% in the reaction at 110 °C shown in entry 6 of Table 1. Next, the effect of the ligand of the palladium catalyst was examined

Non-covalent organocatalyzed enantioselective cyclization reactions of α,β-unsaturated imines

• Sergio Torres-Oya and
• Mercedes Zurro

Beilstein J. Org. Chem. 2024, 20, 3221–3255, doi:10.3762/bjoc.20.268

• Michael addition product was obtained with low diastereoselectivity. The mechanism is described in Scheme 4: the bifunctional squaramide activates the azadiene through hydrogen bonding while the malononitrile is deprotonated by the tertiary amine present in the backbone of the catalyst, establishing

• the α-position led to the desired products albeit with unsatisfactory results. The bifunctional squaramide catalyst V has two functions; firstly it deprotonates the enolic form of the azlactone through the Brønsted-base moiety, and secondly it activates the 1-azadiene and enolate form of the

• % ee) when using thiourea VIII with a relatively low catalyst loading (Scheme 9). The authors also attempted to perform the reaction using acyclic azadienes and indene-derived azadiene instead of benzofuran-derived azadienes 11. However, in these cases, the reactions did not take place. The authors

Germanyl triazoles as a platform for CuAAC diversification and chemoselective orthogonal cross-coupling

• John M. Halford-McGuff,
• Thomas M. Richardson,
• Aidan P. McKay,
• Frederik Peschke,
• Glenn A. Burley and
• Allan J. B. Watson

Beilstein J. Org. Chem. 2024, 20, 3198–3204, doi:10.3762/bjoc.20.265

• ]. As such, the reaction has been used extensively throughout drug discovery [20][21], chemical biology [22][23], and materials science [24][25][26][27]. Orthogonal alkyne reactivity can also be observed under certain systems [28][29][30]. The reaction typically uses a Cu(II) pre-catalyst, which is

Synthesis of 2H-azirine-2,2-dicarboxylic acids and their derivatives

• Anastasiya V. Agafonova,
• Mikhail S. Novikov and
• Alexander F. Khlebnikov

Beilstein J. Org. Chem. 2024, 20, 3191–3197, doi:10.3762/bjoc.20.264

• -5-chloroisoxazoles [25][26][27] using anhydrous FeCl2 as a catalyst and carrying out the reaction in acetonitrile at rt for 2 h. After TLC showed the disappearance of the starting isoxazoles 1, the reaction mixture was treated with water and acids 6a–i were isolated in 64–98% yield. Isoxazole 1j did

Hypervalent iodine-mediated intramolecular alkene halocyclisation

• Charu Bansal,
• Oliver Ruggles,
• Albert C. Rowett and
• Alastair J. J. Lennox

Beilstein J. Org. Chem. 2024, 20, 3113–3133, doi:10.3762/bjoc.20.258

• aza-heterocycles were synthesised in good yields. The authors proposed a mechanism for the fluorocyclisation reactions (Scheme 6), which relies on the activation of the fluoro-iodane reagent 12 with the zinc catalyst. The activation enables better orbital overlap to occur with the π bond of the alkene

• from the styrenyl starting materials is stereoselective, giving the syn-diasteroisomer in high yields. A chiral iodoarene catalyst 16 was employed, along with a stoichiometric sacrificial oxidant, to give good to excellent levels of enantioselectivity. This elegant strategy led to a variety of β

• the oxyfluorination of alkenes in 2015 [31]. Under identical conditions to the aminofluorination using 1-fluoro-3,3-dimethylbenziodoxole (12) with Zn(BF4)2 catalyst, unsaturated alcohols were cyclised to fluorinated tetrahydropyrans 26 and oxepanes 28 (Scheme 12) in 1–2 hours in good yields. Gulder

Advances in the use of metal-free tetrapyrrolic macrocycles as catalysts

• Mandeep K. Chahal

Beilstein J. Org. Chem. 2024, 20, 3085–3112, doi:10.3762/bjoc.20.257

• interactions and accelerating aldol reactions. In the absence of a catalyst, no reaction between 2-(trimethylsilyloxy)furan (TMSOF, 13) and benzaldehyde (14) was observed, whereas all the tested macrocyclic compounds were found catalytically active, with 11 being the most efficient providing erythro/threo (15

• , with TBAI as a co-catalyst, up to 74% yields (Table 1). The inactivity of porphyrin 18 was attributed to the inaccessibility of the inner core imine due to its planar structure. The mechanism of the epoxide ring-opening reaction was elucidated by DFT calculations, which suggested that the macrocycle

• activates the Cu–Cl bond via chloride···calixpyrrole (N–H···Cl) hydrogen-bonding interactions toward the formation of the nitrene intermediate from chloramine-T (NaCl=NTs). Additionally, calix[4]pyrrole served as a phase-transfer catalyst in this reaction. Since chloramine-T had low solubility in

Enantioselective regiospecific addition of propargyltrichlorosilane to aldehydes catalyzed by biisoquinoline N,N’-dioxide

• Noble Brako,
• Sreerag Moorkkannur Narayanan,
• Amber Burns,
• Layla Auter,
• Valentino Cesiliano,
• Rajeev Prabhakar and
• Norito Takenaka

Beilstein J. Org. Chem. 2024, 20, 3069–3076, doi:10.3762/bjoc.20.255

• systematic catalyst structure–reactivity and selectivity relationship study. The observed catalyst structure–enantioselectivity relationship of the present allenylation reaction was found exactly opposite to that of the analogous allylation reaction. The method provided eleven α-allenic alcohols in 22–99

• enantioenriched form [11][12]. However, such metal/metalloid reagents and the corresponding metal catalyst-bound intermediates often equilibrate between possible regioisomeric forms and can undergo both, SE2 and SE2’ addition reactions, resulting in a mixture of homopropargylic alcohols and α-allenic alcohols [14

• stable allenyltrichlorosilane that affords undesired homopropargylic alcohols [35][36] (Scheme 2b). Furthermore, Iseki [35] and Nakajima [36] evaluated only one chiral catalyst in their independent studies (i.e., no catalyst structure–reactivity and selectivity relationship study). In this context, we

Cyclodextrin-based rotaxanes for polymer materials: challenge on simultaneous realization of inexpensive production and defined structures

• Yosuke Akae

Beilstein J. Org. Chem. 2024, 20, 3026–3049, doi:10.3762/bjoc.20.252

• , [3]rotaxane diol 10 was used as the initiator of the controlled ring-opening polymerization (ROP) of ε-caprolactone in the presence of a diphenyl phosphate catalyst to introduce the polyester main chain into the rotaxane framework; the successive end-capping reactions yielded macromolecular [3

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

• of allylic peroxidation 2, 4 and 5 were observed (Scheme 4) [24]. Similar transformations were reported later using CuCl as the catalyst [39]. Later, Gade with coauthors demonstrated the allylic peroxidation of cyclohexane with TBHP using the alkylperoxocobalt(III) complexes [Co(BPI)(OAc)(OO-t-Bu

• -t-Bu)2. Allylic peroxidation of 3-substituted prop-1-ene-1,3-diyldibenzenes 8 was performed with TBHP as the oxidant/peroxidation agent and with Cu2O as the catalyst [42] (Scheme 6). The proposed mechanism of peroxides 9 formation does not include peroxo–copper complexes and begins with the

• ) [51]. The corresponding peroxides 30 are enough stable under the reaction conditions and were isolated in high yields (Scheme 12). Flow-modification of the 2-oxoindole peroxidation method using nanoparticles of iron oxide as the catalyst was proposed [52]. The summarized proposed reaction pathway is

Recent advances in transition-metal-free arylation reactions involving hypervalent iodine salts

• Ritu Mamgain,
• Kokila Sakthivel and
• Fateh V. Singh

Beilstein J. Org. Chem. 2024, 20, 2891–2920, doi:10.3762/bjoc.20.243

• concentrate on various arylation reactions involving carbon and other heteroatoms, encompassing rearrangement reactions in the absence of any metal catalyst, and summarize advancements made in the last five years. Keywords: arylation reaction; diaryliodonium salts; electrophilic arylation reagent; metal-free

• formation of the Nu–Ar product and aryl iodide [21]. Second, the arylation can take place in the presence of a metal catalyst via oxidative addition, followed by reduction elimination [48][49]. Thirdly, it proceeds through a ligand-coupled arylation which involves a five-membered transition state to yield

• , C–C bond formation was reported by Chen and colleagues in 2020 via the arylation of vinyl pinacol boronates 23 by using diaryliodonium salts 16 to yield trans-arylvinylboronates 24 in the absence of a metal catalyst [62]. The optimized reaction conditions involve the reaction of substituted

Synthesis of pyrrole-fused dibenzoxazepine/dibenzothiazepine/triazolobenzodiazepine derivatives via isocyanide-based multicomponent reactions

• Marzieh Norouzi,
• Mohammad Taghi Nazeri,
• Ahmad Shaabani and
• Behrouz Notash

Beilstein J. Org. Chem. 2024, 20, 2870–2882, doi:10.3762/bjoc.20.241

• , and triazolobenzodiazepine under solvent- and catalyst-free conditions. Purposefully, this approach produced various bioactive scaffolds using environmentally friendly, mild, and simple conditions. Due to their bioactive moieties, these compounds with exclusive fluorescence properties may attract

• solvent- and catalyst-free conditions (Scheme 1d). Results and Discussion Synthesis Dibenzoxazepine as imine component, cyclohexyl isocyanide, and the gem-diactivated olefin (2-benzylidenemalononitrile) were selected as the starting materials to screen the reaction conditions (Scheme 2, Table 1). First

• isocyanides, gem-diactivated olefins, and cyclic imines (dibenzoxazepines, dibenzothiazepine, and triazolobenzodiazepine) under catalyst- and solvent-free conditions. Furthermore, the other advantages of this reaction include the manufacturing premium pharmaceutical scaffolds, a wide range of substrates

Mechanochemical difluoromethylations of ketones

• Jinbo Ke,
• Pit van Bonn and
• Carsten Bolm

Beilstein J. Org. Chem. 2024, 20, 2799–2805, doi:10.3762/bjoc.20.235

• sodium fluoride catalyst, with simple ketones, which resulted in the formation of difluoromethyl 2,2-difluorocyclopropyl ethers (Scheme 1B). Although the reactions worked well, it is also noteworthy that the use of TFDA as reagent, liberated fluoro(trimethyl)silane (TMSF), carbon dioxide, and ozone

C–C Coupling in sterically demanding porphyrin environments

• Liam Cribbin,
• Brendan Twamley,
• Nicolae Buga,
• John E. O’ Brien,
• Raphael Bühler,
• Roland A. Fischer and
• Mathias O. Senge

Beilstein J. Org. Chem. 2024, 20, 2784–2798, doi:10.3762/bjoc.20.234

• further substitution directly on the meso- or a meso-phenyl ortho/meta/para positions of a porphyrin, is the introduction of C–C bond forming chemistry. This is typically achieved using palladium and/or another transition-metal catalyst [20]. Sonagashira [21], Suzuki–Miyaura [22], Heck [23], Stille [24

• the Suzuki coupling began with investigating first the Suzuki reaction compatibility of boronic acid 14 with porphyrin 13. Porphyrin 13 and phenylboronic acid (14) were subjected to coupling at 85 °C for 48 hours using Pd2dba3/SPhos as a catalyst/ligand giving porphyrin 26 in a 32% yield, based on a

• [48], switching catalyst to Pd(PPh)3, and base to Na2CO3 (Table 1, entry 16) gave no product. Ultimately, an increased catalyst loading of 25 mol % per C–Br bond gave the desired porphyrin in a 16% yield when using Cs2CO3 as base. The synthesis of other heterocycle-appended dodecasubstituted

Access to optically active tetrafluoroethylenated amines based on [1,3]-proton shift reaction

• Yuta Kabumoto,
• Eiichiro Yoshimoto,
• Bing Xiaohuan,
• Masato Morita,
• Motohiro Yasui,
• Shigeyuki Yamada and
• Tsutomu Konno

Beilstein J. Org. Chem. 2024, 20, 2776–2783, doi:10.3762/bjoc.20.233

• published that the asymmetric conjugate addition of 4-methylphenylboronic acid towards (E)-5-bromo-4,4,5,5-tetrafluoro-1-phenyl-2-penten-1-one (8) in the presence of a rhodium catalyst coordinated with (S)-BINAP gave the corresponding Michael adduct 9 in 94% enantiomeric excess (reaction 2, Scheme 1) [22

• chlorides in the presence of a copper catalyst to afford the corresponding tetrafluoroethylenated ketones 19. The ketones were then condensed with (R)-1-phenylethylamine under the influence of TiCl4 [34][35] to prepare various optically active imines (R)-16 in high yields (Scheme 3). Based on the result of

Copper-catalyzed yne-allylic substitutions: concept and recent developments

• Shuang Yang and
• Xinqiang Fang

Beilstein J. Org. Chem. 2024, 20, 2739–2775, doi:10.3762/bjoc.20.232

• alkoxylation and alkylation products with the assistance of Lewis acid as co-catalyst (Scheme 9). Starting from four different racemic substrates, the same product 6g with 96% ee was obtained under standard conditions. This indicates that the reactions proceed through the same transition state and the

• stereocenter of the product is controlled by the catalyst. A single crystal of Cu(I) was investigated by X-ray and proved to be the dicopper complex, while the Cu(II) catalyst was revealed as mononuclear copper coordinated with two ligands. Further kinetic isotope experiments and nonlinear relationship studies

• demonstrated that the terminal alkyne unit is crucial for the process and the reactions using different isomers all proceed via the same intermediate. Nonlinear relationship experiments proved that the active catalyst is a mono-copper complex containing one ligand. A catalytic cycle is proposed in which copper

Synthesis of spiroindolenines through a one-pot multistep process mediated by visible light

• Francesco Gambuti,
• Jacopo Pizzorno,
• Chiara Lambruschini,
• Renata Riva and
• Lisa Moni

Beilstein J. Org. Chem. 2024, 20, 2722–2731, doi:10.3762/bjoc.20.230

• -pot multistep synthesis of unprecedent 2,3-diaminoindolenines using graphene oxide (GO) as heterogeneous catalyst [21]. The protocol involves the three-component Ugi (3C-Ugi) reaction between aldehydes, isocyanides and 2 equivalents of electron-rich anilines to give α-aminoamidines, which undergo a C

• ] 3. Based on our experience on the use of graphene oxide (GO) as heterogeneous catalyst to promote MCRs and subsequent C–N bond oxidation [16][21], we first investigated the GO-promoted oxidation of N-Ph-THIQ and the subsequent 3C Ugi reaction to give α-aminoamidine 2a. Applying the previously

• isocyanide without the presence of a catalyst. In order to establish the role of GO we carried out the 3C Ugi-type reaction starting from iminium ion 1a, freshly prepared by visible light irradiation in the presence of bromochloroform [28]. This protocol resulted quite convenient as can be conducted under

5th International Symposium on Synthesis and Catalysis (ISySyCat2023)

• Anthony J. Burke and
• Elisabete P. Carreiro

Beilstein J. Org. Chem. 2024, 20, 2704–2707, doi:10.3762/bjoc.20.227

• novel lipophilic cinchona squaramide organocatalyst. This organocatalyst was evaluated in a benchmark Michael addition of acetylacetone to trans-β-nitrostyrene, yielding the Michael adduct with high yield and enantioselectivity. The hydrophobic chain of the catalyst allowed the organocatalyst to be

• easily recovered by precipitation using polar solvents. This catalyst proved to be excellent for the preparation of (S)-baclofen on a gram scale, furnishing the main chiral intermediate in high yield and enantioselectivity. Furthermore, the catalyst was recycled over five cycles while maintaining its

Synthesis of fluoroalkenes and fluoroenynes via cross-coupling reactions using novel multihalogenated vinyl ethers

• Yukiko Karuo,
• Keita Hirata,
• Atsushi Tarui,
• Kazuyuki Sato,
• Kentaro Kawai and
• Masaaki Omote

Beilstein J. Org. Chem. 2024, 20, 2691–2703, doi:10.3762/bjoc.20.226

• First, we optimized the conditions of the Suzuki–Miyaura cross-coupling in reference to the report by Yang et al. (Table 1) [43]. Upon the treatment of multihalogenated vinyl ether 1a with phenylboronic acid 4a (1.3 equiv) and palladium diacetate (10 mol %) as a catalyst at 40 °C, Suzuki–Miyaura cross

• synthesized in 84% yield under reflux conditions (Table 1, entries 3 and 4). Next, we examined an effective catalyst for the cross-coupling. Reactions using palladium dichloride or bis(2,4-pentanedionato)palladium significantly reduced the yields of 2a (Table 1, entries 5 and 6, respectively). When an

• allylpalladium chloride dimer or bis(triphenylphosphine)palladium dichloride were used as catalyst, the reaction proceeded with the same yield as that in Table 1, entry 4 (entries 7 and 8). Utilizing palladium catalyst such as bis(triphenylphosphine)palladium dichloride, all these reactions could convert 1a into

Computational design for enantioselective CO₂ capture: asymmetric frustrated Lewis pairs in epoxide transformations

• Maxime Ferrer,
• Iñigo Iribarren,
• Tim Renningholtz,
• Ibon Alkorta and
• Cristina Trujillo

Beilstein J. Org. Chem. 2024, 20, 2668–2681, doi:10.3762/bjoc.20.224

• catalyst efficiency and selectivity in sustainable chemistry applications. Keywords: asymmetric catalysis; carbon dioxide; CO2; epoxide; frustrated Lewis pairs (FLPs); volcano plot; Introduction The field of frustrated Lewis pairs (FLPs) has flourished since their seminal discovery in 2006 by Stephan and

• H2 over CO2 becomes crucial for effective CO2 reduction [7]. Additionally, the strength of the interaction between the catalyst and the resulting system after hydride transfer presents a limitation. The formation of a robust LA–oxygen interaction may impede proton transfer to the basic oxygen atom

• catalyst [23][24][25]. Therefore, the stereochemical aspects of CO2 insertion into PO enabled by FLP catalysts should be investigated. To the best of our knowledge, only one paper has proposed an asymmetric approach to this reaction using a metal-based catalyst [23]. However, our approach differs

Transition-metal-free decarbonylation–oxidation of 3-arylbenzofuran-2(3H)-ones: access to 2-hydroxybenzophenones

• Bhaskar B. Dhotare,
• Seema V. Kanojia,
• Chahna K. Sakhiya,
• Amey Wadawale and
• Dibakar Goswami

Beilstein J. Org. Chem. 2024, 20, 2655–2667, doi:10.3762/bjoc.20.223

• (3H)-ones to 2-hydroxybenzophenones via decarbonylation–oxidation quickly and without the need of a transition-metal catalyst. Herein, a novel decarbonylation–oxidation method for 3-arylbenzofuran-2(3H)-ones has been developed for the synthesis of 2-hydroxybenzophenones via a transition-metal-free

• catalyst was essential for this reaction to happen at a higher temperature, and the products were obtained in negligible yields without the catalyst. Our protocol established that the reaction proceeds without the need for a transition-metal catalyst, as well as at a lower temperature. Additionally, the

The scent gland composition of the Mangshan pit viper, Protobothrops mangshanensis

• Jonas Holste,
• Paul Weldon,
• Donald Boyer and
• Stefan Schulz

Beilstein J. Org. Chem. 2024, 20, 2644–2654, doi:10.3762/bjoc.20.222

• concentrated under a stream of N2. Hydrogenation: The solvent of the natural extract (100 µL) was removed with a stream of N2 and taken up in pentane (100 µL) and a catalytic amount of Pd/C was added. The reaction was then stirred for 1 h under a H2 atmosphere. The catalyst was filtered and rinsed with pentane

Efficient modification of peroxydisulfate oxidation reactions of nitrogen-containing heterocycles 6-methyluracil and pyridine

• Alfiya R. Gimadieva,
• Yuliya Z. Khazimullina,
• Aigiza A. Gilimkhanova and
• Akhat G. Mustafin

Beilstein J. Org. Chem. 2024, 20, 2599–2607, doi:10.3762/bjoc.20.219

• use of catalysts reduced the duration of the oxidation reaction and significantly increased the yield of sulfate derivatives. In the presence of РсМ, the optimal duration for the oxidation reaction of MU (1) was found to be 4 hours. When the catalyst was not applied, the yield of MU-5-ammonium sulfate

• catalyst increasing by a factor of 10 in each successive experiment. As described in [13] PcFe(II), PcСo, and PcFe(III) exhibited the highest activity in oxidizing reactions of MU (1). Addition of these catalysts in the amount of 0.01–0.05 wt % increased the yield of MU-5-ammonium sulfate 2 to 82–95%. The

• maximum yield of compound 2, equal to 95%, was obtained when 0.05 wt % PcFe(II) was introduced into the reaction. However, on enhancing the catalyst's quantity to 0.1 wt %, the product yield decreased to 33–45%. Further increase in the quantity of catalyst led to a greater decline in the yield of MU-5