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

gem-Difluorination of carbon–carbon triple bonds using Brønsted acid/Bu₄NBF₄ or electrogenerated acid

• Mizuki Yamaguchi,
• Hiroki Shimao,
• Kengo Hamasaki,
• Keiji Nishiwaki,
• Shigenori Kashimura and
• Kouichi Matsumoto

Beilstein J. Org. Chem. 2024, 20, 2261–2269, doi:10.3762/bjoc.20.194

• solution of Bu4NBF4/CH2Cl2 containing substrates might also promote the same reactions (Figure 1, reaction 6, electrochemical method). Currently, electrochemistry can be regarded as a promising technique in organic synthesis, because heavy-metal reagents can be avoided for the oxidation or reduction of

Cell-free protein synthesis with technical additives – expanding the parameter space of in vitro gene expression

• Tabea Bartsch,
• Stephan Lütz and
• Katrin Rosenthal

Beilstein J. Org. Chem. 2024, 20, 2242–2253, doi:10.3762/bjoc.20.192

• a strong negative effect on the in vitro synthesis of sfGFP. Although the concentration of inorganic ions and osmolarity are close to physiological conditions at a concentration of 2% choline chloride, a reduction of sfGFP production to only 2% was measured for choline chloride/urea and 41% for

Electrochemical allylations in a deep eutectic solvent

• Sophia Taylor and
• Scott T. Handy

Beilstein J. Org. Chem. 2024, 20, 2217–2224, doi:10.3762/bjoc.20.189

• there are many reasons for this renewed interest, two major motivations are the unmatched control of oxidation or reduction potential that can be achieved and the environmentally friendly aspect of having electrons as the only consumed reagent. This latter reason is certainly an advantage in many cases

• product, although in this case, reduction of the nitro group to an amino group was observed and the resulting 4-aminobenzaldehyde is likely too electron-rich to undergo allylation. The use of other halides was also explored (Table 3). Switching to allyl chloride (Table 3, entry 2) did result in partial

• reducing the waste generated in these allylations. While non-sacrificial graphite electrodes had failed to result in any reaction, it seemed possible that the use of a catalytic amount of tin metal or a tin salt with graphite electrodes would result in a superior reaction due to in situ reduction and/or

Natural resorcylic lactones derived from alternariol

• Joachim Podlech

Beilstein J. Org. Chem. 2024, 20, 2171–2207, doi:10.3762/bjoc.20.187

• Graphis scripta var. pulverulenta, G. prunicola, and G. cognata [43][45][46][165]. Their structures were proposed based on NMR-spectroscopic investigations and were unambiguously confirmed by total syntheses [44][166]. Graphislactone A had already been obtained previously from the synthetic reduction of

• ring was isolated from Ulocladium botrytis [219] and Microsphaeropsis olivacea [167]. Its structure was unambiguously confirmed by NMR spectroscopy and by total syntheses [44][220]. Ulocladol is a tyrosine kinase (p56lck) inhibitor leading to a reduction of enzyme activity to 7% at 0.02 µg/µL) [219

• ] and from Talaromyces sp. [243]. It showed significant α-glucosidase inhibition with an IC50 value of 2.2 μM [244] and was a potent scavenger of DPPH and of nitrite [243]. Decarboxyaltenusin (50) was reported in 1974 to be obtained by chemical decarboxylation of altenusin (47) and by reduction of

Efficacy of radical reactions of isocyanides with heteroatom radicals in organic synthesis

• Akiya Ogawa and
• Yuki Yamamoto

Beilstein J. Org. Chem. 2024, 20, 2114–2128, doi:10.3762/bjoc.20.182

• radicals abstract hydrogen from the tin hydride or hydrosilane, and the reduction reaction proceeds with the concomitant formation of stannyl or silyl cyanide 15 as byproducts (Scheme 9a) [38][43]. In the presence of acrylonitrile, the formed alkyl radical can add to acrylonitrile, affording the addition

From perfluoroalkyl aryl sulfoxides to ortho thioethers

• Yang Li,
• Guillaume Dagousset,
• Emmanuel Magnier and
• Bruce Pégot

Beilstein J. Org. Chem. 2024, 20, 2108–2113, doi:10.3762/bjoc.20.181

• yield of 15%. The main product obtained was phenyl(trifluoromethyl)selane, a reduction product of the selenoxide. Despite a low yield, this result is encouraging because it is the first example of rearrangement with aryl trifluoromethyl selenoxide. We further investigated the generality of the reaction

• chain, and the alkyl chain linking the cyano functional groups. The [3,3]-sigmatropic rearrangement of perfluoroalkyl selenoxides needs to be optimized to improve the yield and decrease the amount of reduction product. The complete evaluation of the potential of these new compounds will be provided in

Understanding X-ray-induced isomerisation in photoswitchable surfactant assemblies

• Beatrice E. Jones,
• Camille Blayo,
• Jake L. Greenfield,
• Matthew J. Fuchter,
• Nathan Cowieson and
• Rachel C. Evans

Beilstein J. Org. Chem. 2024, 20, 2005–2015, doi:10.3762/bjoc.20.176

• , Supporting Information File 1). Fits to the data show a return to the cylindrical micelle morphology present in the E isomer, but with smaller dimensions of 98 Å length (cf. 136 Å in the E isomer), and radii of 13 and 15 Å in the polar and equatorial directions (Table 1). A similar reduction in micelle size

Harnessing the versatility of hydrazones through electrosynthetic oxidative transformations

• Aurélie Claraz

Beilstein J. Org. Chem. 2024, 20, 1988–2004, doi:10.3762/bjoc.20.175

• have been harnessed as valuable intermediates in Wolff–Kishner reduction reactions [12][13][14] or for the synthesis of various olefins via diazo or vinyllithium intermediates in the Bamford–Stevens reaction [15] and Shapiro reaction [16], respectively [17]. SAMP/RAMP ((S)/(R)-1-amino-2

• hydrazone and (ii) the ammonium cation would provide a performant proton source to counterbalance the overall process, thereby protecting the diazo product from cathodic reduction (akin to the conversion of 132 into 135 in Scheme 27). Based on these studies, the authors proposed the initial anodic formation

• + (E1/2(TAC2+/TAC+) = +1.3 V vs SCE). Subsequent SET between highly oxidizing photoexcited species TAC2+* (E1/2(TAC2+*/TAC+) = +3.3 V vs SCE) and 150 generated distonic species 151 by denitrogenation. After Wagner–Merweein shift, the resulting radical cation 152 would undergo SET reduction from an

Radical reactivity of antiaromatic Ni(II) norcorroles with azo radical initiators

• Siham Asyiqin Shafie,
• Ryo Nozawa,
• Hideaki Takano and
• Hiroshi Shinokubo

Beilstein J. Org. Chem. 2024, 20, 1967–1972, doi:10.3762/bjoc.20.172

• the electrophile [16][17][18]. In addition, C–C double bonds of the norcorrole skeleton outside the π-delocalization pathway exhibit a reactivity similar to an alkene to afford hydrogenated norcorroles by hydrogenation [19] or reduction with hydrazine [20] and [3 + 2]-cycloadducts with 1,3-dipoles [21

• CH2Cl2 were examined using cyclic voltammetry (Figure 4). Macrocycle 2a exhibited one reversible oxidation wave at 0.44 V and two reversible reduction waves at −0.85 V and −1.14 V. The electrochemical HOMO–LUMO gap of 2a is 1.29 V, which is larger than that of 1a (1.08 V) [2]. DFT calculations We next

1,2-Difluoroethylene (HFO-1132): synthesis and chemistry

• Liubov V. Sokolenko,
• Taras M. Sokolenko and
• Yurii L. Yagupolskii

Beilstein J. Org. Chem. 2024, 20, 1955–1966, doi:10.3762/bjoc.20.171

• -difluoroethylene was based on 1,2-dichloro-1,2-difluoroethane (HCFC-132) [48][49][50][51][52], prepared from 1,1,2,2-tetrachloro-1,2-difluoroethane (CFC-112) by reduction using lithium aluminum hydride [48][49][50][51] or photoreduction (Scheme 2) [51]. The resulting HCFC-132 reacted with zinc [47][49][52] or

Negishi-coupling-enabled synthesis of α-heteroaryl-α-amino acid building blocks for DNA-encoded chemical library applications

• Matteo Gasparetto,
• Balázs Fődi and
• Gellért Sipos

Beilstein J. Org. Chem. 2024, 20, 1922–1932, doi:10.3762/bjoc.20.168

• heteroaromatic halides. The reaction sequence utilizes a photochemically enhanced Negishi cross-coupling as a key step, followed by oximation and reduction. The prepared amino esters were validated for on-DNA reactivity via a reverse amidation–hydrolysis–reverse amidation protocol. Keywords: amino acids; DEL

• that α-heteroaryl acetates accessed through Negishi coupling can be used as key intermediates towards NCAs (Scheme 1c). Indeed, oximation of these motifs followed by reduction gave access to the desired NCAs. Results and Discussion Negishi cross-coupling step The Negishi reaction provides convenient

• amino group by reduction. We reasoned that increasing the sp2 fraction and the rigidity of the whole structure will lead to increased stability of these derivatives. The first exploratory attempts demonstrated the easy preparation and the high bench stability of the oxime derivatives, therefore we opted

Novel oxidative routes to N-arylpyridoindazolium salts

• Oleg A. Levitskiy,
• Yuri K. Grishin and
• Tatiana V. Magdesieva

Beilstein J. Org. Chem. 2024, 20, 1906–1913, doi:10.3762/bjoc.20.166

• −1.2V to −1.3 V region (Table 1). In case of S2, the second reduction peak corresponds to the reduction of the carbonyl group. Thus, the electrochemical window for the new salts exceeds 3.5 V; that makes their molten forms perspective for application as ionic liquids. As follows from Table 1, oxidation

• of the starting amines A1–A3 occurs at ca. 1–1.1 V vs Ag/AgCl, KCl(sat.). The electrochemical study of PIFA reduction showed a broad irreversible peak with the onset potential value of +0.93 V (vs Ag/AgCl, KCl(sat.)). Thus, it is sufficiently strong to perform oxidation of diarylamines A1–A3, as it

• direction of the potential sweep is changed after passing the first reduction peak of salt S2, the new peak appears at the potential of 0.89 V that completely coincides with the first oxidation peak of the amine precursor. The CV curve for the diarylamine, in its turn, exhibited (in the reverse scan after