Surprising acidity for the methylene of 1,3-indenocorannulenes?

• Shi Liu,
• Märt Lõkov,
• Sofja Tshepelevitsh,
• Ivo Leito,
• Kim K. Baldridge and
• Jay S. Siegel

Beilstein J. Org. Chem. 2024, 20, 3144–3150, doi:10.3762/bjoc.20.260

• benzene [7][8]. Furthermore, the trend of pKa values for CpH, InH, and FlH correlates with the reduction of the aromatic stabilization energy for the anion across the series [1][2]. At first glance, this model supports the notion that the relative pKa values of cyclopentadienes embedded in polynuclear

Controlled oligomerization of [1.1.1]propellane through radical polarity matching: selective synthesis of SF₅- and CF₃SF₄-containing [2]staffanes

• Jón Atiba Buldt,
• Wang-Yeuk Kong,
• Yannick Kraemer,
• Masiel M. Belsuzarri,
• Ansh Hiten Patel,
• James C. Fettinger,
• Dean J. Tantillo and
• Cody Ross Pitts

Beilstein J. Org. Chem. 2024, 20, 3134–3143, doi:10.3762/bjoc.20.259

• -chloropyrimidyl-SF4Cl) was determined to be significantly less "electrophilic" than SF5Cl or CF3SF4Cl, consistent with a reduction in the radical polarity matching effect (see Supporting Information File 1 for details). This was difficult to predict or rationalize based on calculation of free energies of

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

• ring A (Scheme 2). The Pd(II) intermediate is oxidised by PhI(OPiv)2/AgF, forming Pd(IV). Formation of the product can occur either by reductive elimination by Pd(IV) or SN2 nucleophilic attack by fluorine with concomitant palladium reduction. Reductive elimination of the Pd(II) intermediate forms the

• . Substrates with a range of substituents on the alkyl chain were cyclised in good yields, yet introduction of substituents on the alkene led to a reduction of yield. The authors proposed a standard mechanism for the reaction (Scheme 23) in which PhI(OAc)2 activates the alkene, intramolecular attack of

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

• second-sphere interactions with a multipoint hydrogen-bonding pattern enhance CO2 reduction in organic solvents, improving stability, facilitating proton transfer, reducing energy barriers, and increasing selectivity [20]. Apart from advances in synthetic methodologies [2][21][22][23], the exploration of

• at β- and meso-positions, N-alkylation, arylation or protonation, interruption of the conjugated system, reduction/oxidation of the macrocycle and/or strapping of the macrocycle via covalent linkage of the meso- or β-pyrrole positions [22][53][54][55][56][57]. These alternations can significantly

• . Changes in the reduction or oxidation state can alter redox behavior, thereby affecting catalytic activity. For example, it has been reported that 2,3,5,7,8,10,12,13,15,17,18,20-dodecasubstituted free-base porphyrins and their mono/diprotonated derivatives are highly distorted with a good access to the

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

• propargyltrichlorosilane [35][36] (Scheme 2). Other notable asymmetric catalytic approaches to prepare α-allenic alcohols (R2 = H) include the Corey–Bakshi–Shibata reduction of allenyl ketones [37], enzymatic [38][39][40], non-enzymatic [41] kinetic resolution of racemic α-allenic alcohols, and asymmetric 1,4

Chemical structure metagenomics of microbial natural products: surveying nonribosomal peptides and beyond

• Thomas Ma and
• John Chu

Beilstein J. Org. Chem. 2024, 20, 3050–3060, doi:10.3762/bjoc.20.253

• ], requires the presence of a nucleophile at the β-position of the amino acid and occurs exclusively on select amino acids. Specifically, cyclodehydration of a serine or threonine (followed by oxidation or reduction) generates an oxazole, oxazoline, or oxazolidine moiety in the NRP backbone, and the analogous

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

• peroxides, oxaziridines, and their derived species are often applied as terminal oxidants [7][8]. The weakness of the O–O bond allows alkoxy radicals to form through homolysis or reduction [9]. The generated alkoxy radicals provide an accessible tool for selective radical cascades, where a variety of

• -scission [31][32], which can lead to side reactions. Some aspects of the rich metal–peroxide redox chemistry have been discussed in previous reviews [33]. Specifically, the radical functionalization of C–C bonds accessed through the transition metal-mediated reduction of organic peroxides has been covered

• peroxy derivatives 36 in good yields. Three possible ways were proposed: a) anodic oxidation of TBHP and formation of tert-butylperoxy radical; b) hydrogen reduction of TBHP forming H2O and the tert-butylperoxy radical; c) anodic oxidation of NO3 anion to NO3 radical which act as a mediator to form the

Synthesis of fluorinated acid-functionalized, electron-rich nickel porphyrins

• Mike Brockmann,
• Jonas Lobbel,
• Lara Unterriker and
• Rainer Herges

Beilstein J. Org. Chem. 2024, 20, 2954–2958, doi:10.3762/bjoc.20.248

• ]. Beyond their essential biological roles, porphyrins and their derivatives are employed in a number of applications, acting as catalysts in numerous reactions, including oxidation, reduction, and cycloaddition [6][7][8][9][10]. Particularly when electron-rich porphyrins act as reducing agents, e.g. in

The charge transport properties of dicyanomethylene-functionalised violanthrone derivatives

• Sondos A. J. Almahmoud,
• Joseph Cameron,
• Dylan Wilkinson,
• Michele Cariello,
• Claire Wilson,
• Alan A. Wiles,
• Peter J. Skabara and
• Graeme Cooke

Beilstein J. Org. Chem. 2024, 20, 2921–2930, doi:10.3762/bjoc.20.244

• the incorporation of the strong electron-withdrawing dicyanomethylene unit. The study suggested that 3b could be a potential n-type material for OPVs. The incorporation of two dicyanomethylene groups resulted in a material with strong electron affinity and low reduction potential of −0.56 V vs NHE

• frontier orbitals. Electrochemical studies The electrochemical properties of the dyes were investigated by square wave voltammetry (SWV) and cyclic voltammetry (CV) and the data are summarised in Table 1, with the plots shown in Figure 6. All the materials exhibit at least one reversible reduction and two

• exhibit a narrow HOMO–LUMO gap (1.46–1.47 eV), with a wide absorption range exceeding 800 nm compared to their previously reported precursors [30]. The electrochemical studies of the three materials show reversible oxidation and reduction waves with EA values that are in a similar range (from −3.70 to

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

• 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

• (Scheme 17) suggests that the reaction initiates with an SNAr at the ortho-carbon, forming a Meisenheimer complex I and a novel iodine(III) intermediate II. This type of reactivity is unprecedented, as past reactions between nucleophiles and diaryliodonium salts usually lead to a reduction of iodine(III

N-Glycosides of indigo, indirubin, and isoindigo: blue, red, and yellow sugars and their cancerostatic activity

• Peter Langer

Beilstein J. Org. Chem. 2024, 20, 2840–2869, doi:10.3762/bjoc.20.240

• -glycoside 11a (Scheme 7) [20]. Debenzylation gave product 11b which was transformed to akashin A (11c) by reduction of the azide to the amine in the presence of propane-1,3-dithiol and subsequent debenzoylation. Akashin A was transformed to akashins B and C by acetylation and reaction with diacetyl

• most common non-melanoma skin cancer. In collaboration with Jürgen Eberle and his team, the activity of E-β-46b, E-β-46e, and E-β-46k in four CSCC cell lines were investigated [49]. High activities were observed for SCL-I, SCL-II, SCC-12, and SCC-13 cell lines with up to 80% reduction of cell

• proliferation, 60% reduction of cell viability and 30% induced apoptosis at a 10 μM level. Like in case of the studies mentioned above, apoptosis was further increased in combination with TRAIL. Induction of reactive oxygen species were again mandatory for these effects to be observed. In fact, apoptosis was

Investigation of a bimetallic terbium(III)/copper(II) chemosensor for the detection of aqueous hydrogen sulfide

• Parvathy Mini,
• Michael R. Grace,
• Genevieve H. Dennison and
• Kellie L. Tuck

Beilstein J. Org. Chem. 2024, 20, 2818–2826, doi:10.3762/bjoc.20.237

• equivalents (25 μM) were added (Figure S3 in Supporting Information File 1). The addition of 5 equivalents of Cu2+ ions led to 70% reduction in the luminescence signal, though complete quenching of luminescence could not be achieved, even with additional Cu2+ ions. However, as greater than 50% of emission

Synthesis of benzo[f]quinazoline-1,3(2H,4H)-diones

• Ruben Manuel Figueira de Abreu,
• Peter Ehlers and
• Peter Langer

Beilstein J. Org. Chem. 2024, 20, 2708–2719, doi:10.3762/bjoc.20.228

• the yield could be improved to 99% by increasing the reaction time to 4 hours (Table 1, entry 4), while reduction of the amount of acid resulted in a drop of the yield to 85%. With the optimised conditions in hand, the scope of the cycloisomerisation was studied and the products 5a, 5d, and 5f–i were

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

• Suzuki couplings and the reduction of the thiazole moiety to 2,3-dihydro[1,3]thiazolo[4,5-b]pyridines, a crucial intermediate, using BH3⋅NH3 and tris(pentafluorophenyl)borane as a Lewis acid, followed by treatment with formic acid. Gillie et al. reported the synthesis of a laterally fused N-heterocyclic

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

• alkenes [10][11], they have since found applications in catalysis [12][13]. Among the first catalytic uses of FLPs were the hydrogenation of unsaturated compounds [12][14] and the reduction of CO2 using H2 as a reductant [7][15][16][17]. FLPs have become an attractive avenue for the reduction of CO2

• 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

• ]. One study reported a reaction involving the asymmetric reduction of ketones using an achiral borane, denoted as B(p-HC6F4)3, paired with a chiral oxazoline, as depicted in Scheme 3 [28]. Remarkably, in this study, these FLPs demonstrated the capability to achieve high conversion rates and enantiomeric

Applications of microscopy and small angle scattering techniques for the characterisation of supramolecular gels

• Connor R. M. MacDonald and
• Emily R. Draper

Beilstein J. Org. Chem. 2024, 20, 2608–2634, doi:10.3762/bjoc.20.220

A review of recent advances in electrochemical and photoelectrochemical late-stage functionalization classified by anodic oxidation, cathodic reduction, and paired electrolysis

• Nian Li,
• Ruzal Sitdikov,
• Ajit Prabhakar Kale,
• Joost Steverlynck,
• Bo Li and
• Magnus Rueping

Beilstein J. Org. Chem. 2024, 20, 2500–2566, doi:10.3762/bjoc.20.214

• pharmaceutical drugs and natural products. We classify these advancements into three types: anodic oxidation, cathodic reduction, and paired electrolysis (Figure 1). This review considers direct electrolysis (oxidation or reduction), mediator-induced electrolysis, and metal-catalyzed and photocatalyzed

• carbocation intermediate, which rearomatizes through proton loss. Concurrently, the cathodic reduction of the generated protons produces H2. In addition to (hetero)aromatic groups, alkene scaffolds also underwent this reaction (Scheme 3). In the same year, the Lei group [10] extended the electrochemical C(sp2

• cathodic reduction and to prevent the reoxidation of the reduced SO2 at the anode, a divided cell setup is required (Scheme 12). C–H bond halogenation: Aryl and alkyl halides are important synthetic building blocks for cross-coupling reactions as well as bioactive molecules with applications in

Photoredox-catalyzed intramolecular nucleophilic amidation of alkenes with β-lactams

• Valentina Giraldi,
• Giandomenico Magagnano,
• Daria Giacomini,
• Pier Giorgio Cozzi and
• Andrea Gualandi

Beilstein J. Org. Chem. 2024, 20, 2461–2468, doi:10.3762/bjoc.20.210

• as final product, characterized by significant ring strain [59]. Under light irradiation, PhSSPh is in equilibrium with the corresponding thiyl radical, which is subsequently reduced to thiophenolate by PC•, originating from the reduction of *PC+. The reduction potential of PhS−/PhS• (Epred = +0.45 V

Synthesis and conformational analysis of pyran inter-halide analogues of ᴅ-talose

• Olivier Lessard,
• Mathilde Grosset-Magagne,
• Paul A. Johnson and
• Denis Giguère

Beilstein J. Org. Chem. 2024, 20, 2442–2454, doi:10.3762/bjoc.20.208

• halogenated analogues. There are reductions in the C1–C2–C3–C4 torsion angles for the halogenated pyrans as compared to compound 18 (–56.58°) (Table 3, entry 4). The decrease depends on the size of the halogen at C4 (F: –49.4°; Cl: –46.9°; Br: –46.5°; I: –46°). There is also a reduction in the C2–C3–C4–C5

Phenylseleno trifluoromethoxylation of alkenes

• Clément Delobel,
• Armen Panossian,
• Gilles Hanquet,
• Frédéric R. Leroux,
• Fabien Toulgoat and
• Thierry Billard

Beilstein J. Org. Chem. 2024, 20, 2434–2441, doi:10.3762/bjoc.20.207

• developed an electrophilic phenylseleno trifluoromethoxylation of alkenes, which leads to β-selenylated trifluoromethoxylated compounds or, upon subsequent reduction, to the trifluoromethoxylated ones. Keywords: DNTFB; electrophilic addition; fluorine; selenium; trifluoromethoxy; Introduction Due to the

• of the oxidative conditions used (mCPBA [75], H2O2 [75], selectfluor®/H2O [76], SO2Cl2/NaHCO3 (aq) [77][78]), in most cases a complex mixture was observed and no corresponding vinylic compound was detected by NMR. The phenylselenyl moiety could also undergo radical reduction to produce

Efficient one-step synthesis of diarylacetic acids by electrochemical direct carboxylation of diarylmethanol compounds in DMSO

• Hisanori Senboku and
• Mizuki Hayama

Beilstein J. Org. Chem. 2024, 20, 2392–2400, doi:10.3762/bjoc.20.203

• diarylacetic acids from diarylmethanol species and carbon dioxide without transformation of the hydroxy group into appropriate leaving groups, such as halides and esters including carbonates. Keywords: C(sp3)–O bond cleavage; diarylacetic acid; diarylmethanol; electrochemical reduction; fixation of carbon

• dioxide; Introduction Electrochemical reduction of benzyl alcohol derivatives can induce reductive cleavage of a C(sp3)–O bond [1] at the benzylic position to generate the corresponding benzylic anion species. This protocol has been frequently applied to electrochemical carboxylation [2][3][4][5][6][7][8

• ][9][10][11], yielding phenylacetic acids. For example, Troupel et al. successfully performed electrochemical reduction of benzyl ethers and several esters such as acetate, trifluoroacetate, benzoate, and dibenzyl carbonate derived from benzyl alcohols, including 1-phenylethanol compounds, in the

Synthesis, electrochemical properties, and antioxidant activity of sterically hindered catechols with 1,3,4-oxadiazole, 1,2,4-triazole, thiazole or pyridine fragments

• Daria A. Burmistrova,
• Andrey Galustyan,
• Nadezhda P. Pomortseva,
• Kristina D. Pashaeva,
• Maxim V. Arsenyev,
• Oleg P. Demidov,
• Mikhail A. Kiskin,
• Andrey I. Poddel’sky,
• Nadezhda T. Berberova and
• Ivan V. Smolyaninov

Beilstein J. Org. Chem. 2024, 20, 2378–2391, doi:10.3762/bjoc.20.202

• reaches 51%). Besides, the current value of the second peak remains unchanged. In the cathodic region, a one-electron quasi-reversible peak is displayed (Epc = −0.58 V). This process corresponds to the reduction of o-benzoquinone to o-benzosemiquinone. During electrolysis, the color of the solution

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

• scale (Scheme 27). Thus, the hydrolysis of the N=CPh2 group in the N-morpholinyl product 129 with hydroxylamine hydrochloride afforded the deprotected homoallylic amine 133 in a 99% yield without need for chromatographical purification. In a separate experiment, the sequential reduction of the N

• -morpholinyl amido and benzophenone imino groups with LiAlH4 and NaBH4 afforded the corresponding syn-2-benzyl-1,3-amino alcohol 134 in 83% yield. In the case of the dimethylamide derivative, deprotection of benzophenone imine 128 with NH2OH·HCl followed by the LiAlH4 reduction gave rise to chiral syn-2-benzyl

Hydrogen-bond activation enables aziridination of unactivated olefins with simple iminoiodinanes

• Phong Thai,
• Lauv Patel,
• Diyasha Manna and
• David C. Powers

Beilstein J. Org. Chem. 2024, 20, 2305–2312, doi:10.3762/bjoc.20.197

• −1.52 V, respectively. The titration showed a saturation point at 25 µL of HFIP (6.0 equiv with respect to 2c), at which the CV of 2c showed an Epr = –1.47 V and –1.52 mA current. Overall, the addition of HFIP results in a 250 mV shift in the reduction of 2c. The increased facility of reduction is

Deuterated reagents in multicomponent reactions to afford deuterium-labeled products

• Kevin Schofield,
• Shayna Maddern,
• Yueteng Zhang,
• Grace E. Mastin,
• Rachel Knight,
• Wei Wang,
• James Galligan and
• Christopher Hulme

Beilstein J. Org. Chem. 2024, 20, 2270–2279, doi:10.3762/bjoc.20.195

• production or external purchase and have progressed along the value chain to the clinic and full approval [5]. Literature inspection reveals that an established common method to prepare deuterated benzylic isonitriles is reduction of a nitrile in the presence of a deuterium source (Scheme 1) [16][17][18