Redox-active molecules as organocatalysts for selective oxidative transformations – an unperceived organocatalysis field

• Elena R. Lopat’eva,
• Igor B. Krylov,
• Dmitry A. Lapshin and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2022, 18, 1672–1695, doi:10.3762/bjoc.18.179

• organocatalyst forms hydrogen bonds with both H2O2 and cyclic ketones [66]. A chiral Brønsted acid was used as chirality source and activator of H2O2 for an asymmetric sulfoxidation reaction [67] (Scheme 4B). It is generally accepted that in asymmetric Brønsted acid catalysis the activation of both the

• , the acidic and basic sites of the catalyst are suggested to be involved in the activation of only hydrogen peroxide within a well-defined and deep chiral cavity. The enantioselective approach of sulfide to H2O2 is ensured by the sterically demanding structure of the catalyst. It should also be noted

• active oxidative agent. Asymmetric quaternary ammonium phase-transfer catalysts proved to be effective in the asymmetric nucleophilic epoxidation of electron-poor alkenes by hydroperoxides [70] and the asymmetric hydroxylation of enolizable carbonyl compounds employing O2 or H2O2 as terminal oxidants [71

Naphthalimide-phenothiazine dyads: effect of conformational flexibility and matching of the energy of the charge-transfer state and the localized triplet excited state on the thermally activated delayed fluorescence

• Kaiyue Ye,
• Liyuan Cao,
• Davita M. E. van Raamsdonk,
• Zhijia Wang,
• Jianzhang Zhao,
• Daniel Escudero and
• Denis Jacquemin

Beilstein J. Org. Chem. 2022, 18, 1435–1453, doi:10.3762/bjoc.18.149

• dissolved in glacial acetic acid (28 mL), H2O2 (8.2 mL, 30%, 6.5 mmol) was added dropwise. The mixture was stirred at 40 °C overnight. The mixture was poured into water and the pH of the mixture was brought to 7 with a saturated aqueous solution of Na2CO3. After cooling, water (20 mL) was added, and the

• optimized ground state geometries. An isovalue of 0.02 is used. Synthesis of the compoundsa. aKey: (a) phenothiazine, sodium tert-butoxide, dried toluene (TOL), tri-tert-butylphosphine tetrafluoroborate, Pd(OAc)2, 120 °C, 8 h, 93.1%; (b) H2O2 (30%), CH3COOH, 40 °C, 1 h, yield: 87.2%; (c) similar to step (a

Inductive heating and flow chemistry – a perfect synergy of emerging enabling technologies

• Conrad Kuhwald,
• Sibel Türkhan and
• Andreas Kirschning

Beilstein J. Org. Chem. 2022, 18, 688–706, doi:10.3762/bjoc.18.70

• ) [93]. Cyclohexanone (25) was mixed with conc. formic acid, and a mixture of H2O2 (30%)/HNO3 (65%) in a PTFE reactor at rt. This led to the formation of the cyclic triperoxide 91 in 48% (isolated) yield. Interestingly, the equilibrium favors the formation of the trimer 91 over the corresponding dimeric

Menadione: a platform and a target to valuable compounds synthesis

• Acácio S. de Souza,
• Ruan Carlos B. Ribeiro,
• Dora C. S. Costa,
• Fernanda P. Pauli,
• David R. Pinho,
• Matheus G. de Moraes,
• Fernando de C. da Silva,
• Luana da S. M. Forezi and
• Vitor F. Ferreira

Beilstein J. Org. Chem. 2022, 18, 381–419, doi:10.3762/bjoc.18.43

• •−), hydrogen peroxide (H2O2), hydroxyl radical (•OH), and hydroperoxyl radical (•OOH) (Figure 3) [35]. Additionally, the menadione semiquinone radical can participate in another redox cycle, such as, the Fenton reaction, also resulting in the production of hydroxyl and hydroperoxyl radicals (Figure 3) [39][40

• one of the most studied and used oxidants has been H2O2. Yamaguchi and co-workers described the oxidation of 16 with aqueous H2O2 in the presence of a palladium(II)-polystyrene sulfonic acid resin (Table 1, entry 4) [50]. According to the authors, in the absence of the catalysts, the oxidation took

• place slowly with 7.8% yield, meanwhile, Pd-catalysis improved the yield to 50–60% under otherwise identical conditions [50]. The approach described by the Adam’s group used H2O2 (85%) and methyltrioxorhenium(VII) (MTO) as the catalyst (Table 1, entry 5) [51][64]. Without the catalyst, the reaction

Recent advances and perspectives in ruthenium-catalyzed cyanation reactions

• Thaipparambil Aneeja,
• Cheriya Mukkolakkal Abdulla Afsina,
• Padinjare Veetil Saranya and
• Gopinathan Anilkumar

Beilstein J. Org. Chem. 2022, 18, 37–52, doi:10.3762/bjoc.18.4

• -immobilized ruthenium trichloride to catalyze the oxidative cyanation of tertiary amines [28]. The reaction was performed using 2 mol % of catalyst, 2.5 mmol H2O2, 1.2 mmol NaCN, and 1 mL CH3COOH in methanol at room temperature (Scheme 1). Better yields of the α-aminonitrile products were obtained for

• -41-2N-RuCl3) catalyzed oxidative cyanation of tertiary amines was achieved by Cai et al. [31]. The optimized conditions were MCM-41-2N-RuCl3 (5 mol %), NaCN (1.2 mmol), AcOH (6.0 mmol), H2O2 (2.5 mmol) in methanol at 60 °C under Ar atmosphere for 4 h (Scheme 6). The reaction proceeded smoothly for N

• group reported a novel synthetic pathway for the oxidative cyanation of tertiary amines using sodium cyanide [33]. The optimized conditions for this reaction included the use of 0.05 mmol of RuCl3 as the catalyst, 1.2 mmol of NaCN in acetic acid as the cyanide source and 2.5 mmol of H2O2 as the oxidant

Efficient N-arylation of 4-chloroquinazolines en route to novel 4-anilinoquinazolines as potential anticancer agents

• Rodolfo H. V. Nishimura,
• Thiago dos Santos,
• Valter E. Murie,
• Luciana C. Furtado,
• Leticia V. Costa-Lotufo and
• Giuliano C. Clososki

Beilstein J. Org. Chem. 2021, 17, 2968–2975, doi:10.3762/bjoc.17.206

• and 8b. Conditions: a) NBS, CH3CN, 30 min, 25 °C; b) H2O, H2O2, I2, 24 h, 50 °C. N-Arylation reactions using ortho-, meta-, and para-substituted primary anilines of type 14 followed by methylation of ortho-derivatives 15a–d, to obtain the desired 4-anilinoquinazolines of type 10. N-Arylation reactions

Highly stereocontrolled total synthesis of racemic codonopsinol B through isoxazolidine-4,5-diol vinylation

• Lukáš Ďurina,
• Anna Ďurinová,
• František Trejtnar,
• Ľuboš Janotka,
• Lucia Messingerová,
• Jana Doháňošová,
• Ján Moncol and
• Róbert Fischer

Beilstein J. Org. Chem. 2021, 17, 2781–2786, doi:10.3762/bjoc.17.188

• phosphotungstic heteropoly acid, a commercial heteropoly acid [29][30]. Under our optimized conditions in terms of amount of catalyst, reaction temperature, and organic co-solvent, the epoxidation of 11 with aqueous H2O2 (35 wt %) and 12WO3·H3PO4×H2O (1 mol %) at room temperature in ethyl acetate provided the

• %; (c) 12WO3·H3PO4×H2O, H2O2 (35 wt % in H2O), pyridine, ethyl acetate, rt, 48 h, 70%; (d) BF3·OEt2, CH2Cl2, 0 °C, 15 min, 69%; (e) H2 (1 atm), Pd(OH)2/C (5 wt %), MeOH, rt, 2 h, (±)-2, 71%; (f) H2 (1 atm), Pd(OH)2/C (5 wt %), MeOH, rt, 2 h; then formaldehyde (37 wt % in H2O), H2 (1 atm), Pd(OH)2/C (5

Synthesis of highly substituted fluorenones via metal-free TBHP-promoted oxidative cyclization of 2-(aminomethyl)biphenyls. Application to the total synthesis of nobilone

• Ilya A. P. Jourjine,
• Lukas Zeisel,
• Jürgen Krauß and
• Franz Bracher

Beilstein J. Org. Chem. 2021, 17, 2668–2679, doi:10.3762/bjoc.17.181

• secondary and tertiary amines, amides/lactams/carbamates, and nitrile. The test reactions were monitored by thin-layer chromatography (TLC) and, where deemed necessary, results were further verified by GC–MS. The reagents employed encompassed tritylium tetrafluoroborate [50], H2O2/HBr [42], ceric ammonium

• nitrate (CAN) [41], 2,2,6,6-tetramethylpiperidinyloxyl (TEMPO)/CuCl [51], K2S2O8 [36], dimethyl sulfoxide (DMSO)/O2 [52], PhI(OAc)2/benzoyl peroxide (BPO) [47], Dess-Martin periodinane, N-bromosuccinimide (NBS), N-hydroxyphthalimide (NHPI)/Co(OAc)2/O2 [53], H2O2/tetrabutylammonium iodide (TBAI) [43], CBr4

Cryogels: recent applications in 3D-bioprinting, injectable cryogels, drug delivery, and wound healing

• Luke O. Jones,
• Leah Williams,
• Tasmin Boam,
• Martin Kalmet,
• Chidubem Oguike and
• Fiona L. Hatton

Beilstein J. Org. Chem. 2021, 17, 2553–2569, doi:10.3762/bjoc.17.171

On the application of 3d metals for C–H activation toward bioactive compounds: The key step for the synthesis of silver bullets

• Renato L. Carvalho,
• Amanda S. de Miranda,
• Mateus P. Nunes,
• Roberto S. Gomes,
• Guilherme A. M. Jardim and
• Eufrânio N. da Silva Júnior

Beilstein J. Org. Chem. 2021, 17, 1849–1938, doi:10.3762/bjoc.17.126

• usually mediated by V(V) and V(IV)-oxo-peroxo complexes, which are produced in situ from vanadium-oxo and dioxo precatalysts in the presence of oxidants, such as H2O2, O2, and tert-butyl hydroperoxide (TBHP) [76][77][78][79][80][81][82]. Inorganic acids and chelating and non-chelating carboxylic acids

• derivatives. Using H2O2 as an oxidant agent, ketones and aldehydes were obtained from hydrocarbons with high yields (85–99%, Scheme 9B and 9C). Although the authors did not explore the biological effects of the obtained products, this class of molecules resembles the basic structure of several important

Manganese/bipyridine-catalyzed non-directed C(sp³)–H bromination using NBS and TMSN₃

• Kumar Sneh,
• Takeru Torigoe and
• Yoichiro Kuninobu

Beilstein J. Org. Chem. 2021, 17, 885–890, doi:10.3762/bjoc.17.74

• alcohols with HBr, PBr3, or other brominating reagents [7][8][9][10][11][12][13]. Direct C–H halogenation is one of the most efficient methods used for the synthesis of halogenated organic molecules. This direct method involves the reaction of an alkane with Br2, CBr4, or H2O2–HBr under photolysis or at

Synthesis of bis(aryloxy)fluoromethanes using a heterodihalocarbene strategy

• Carl Recsei and
• Yaniv Barda

Beilstein J. Org. Chem. 2021, 17, 813–818, doi:10.3762/bjoc.17.70

• %. Synthesis of 1. Reagents and conditions: (a) 1,3-dibromo-5,5-dimethylhydantoin, benzoyl peroxide, (CH2Cl)2, reflux, 4 h, 88%; (b) 5,5-dimethyl-3-(4H-isoxazolyl) carbamimidothioate·HCl, K2CO3, MeCN/H2O, 50 °C, 1.5 h, 73%; (c) H2O2, Na2WO4, MeCN/H2O, 45 °C, 1.5 d, 66%. Synthesis of 11–13. Reagents and

A new and efficient methodology for olefin epoxidation catalyzed by supported cobalt nanoparticles

• Lucía Rossi-Fernández,
• Viviana Dorn and
• Gabriel Radivoy

Beilstein J. Org. Chem. 2021, 17, 519–526, doi:10.3762/bjoc.17.46

• solvent (DMF, MeCN, ethyl acetate, DMSO, solvent free) on the activity and selectivity of the nanocatalysts has been noted [27][41][42][43][44]. Furthermore, all the reported methodologies use either molecular oxygen together with an aldehyde as a co-reductant, or only a “green” peroxide (H2O2, TBHP) as

• the CuNPs supported on MgO as catalyst, but a similar result to that obtained in DMF was observed (Table 1, entry 5). The use of H2O2 as co-oxidant improved the conversion of the starting styrene (1a) only for the CoNPs/MgO catalyst, but lead to low selectivity due to the formation of benzaldehyde and

¹⁹F NMR as a tool in chemical biology

• Diana Gimenez,
• Aoife Phelan,
• Cormac D. Murphy and
• Steven L. Cobb

Beilstein J. Org. Chem. 2021, 17, 293–318, doi:10.3762/bjoc.17.28

Recent progress in the synthesis of homotropane alkaloids adaline, euphococcinine and N-methyleuphococcinine

• Dimas J. P. Lima,
• Antonio E. G. Santana,
• Michael A. Birkett and
• Ricardo S. Porto

Beilstein J. Org. Chem. 2021, 17, 28–41, doi:10.3762/bjoc.17.4

• ) PCC, CH2Cl2, 70–72%. Synthesis (+)-euphococcinine (2). Reagents and conditions: i) H2O2, SeO2 (cat), acetone, rt, 88%; ii) 25, THF, −78 °C, 52% (67:33 diastereomeric mixture); iii) H2O2, FIEt+.ClO4 (cat.), MeOH, 0 °C, 55%; iv) AlCl3, CH2=CHCH2MgBr, THF, −78 °C, 54%; v) Ni2O3, CHCl3, rt, 54%; vi) Raney

• , −78 °C; then Comins’ reagent, 63%; v) Me2NHBH3, cat. Pd(PPh3)4, K2CO3, MeCN, 40 °C, 97%; vi) BH3.THF, then aq NaOH, H2O2, 31% (for (±)-40) and 39% (for (±)-41); vii) TPAP, NMO, 4 Å MS, CH2Cl2, 100%. Synthesis of (−)-adaline (1). Reagents and conditions: i) LiH2NBH3, THF, 40 °C, 88%; ii) TPAP, NMO

Anion exchange resins in phosphate form as versatile carriers for the reactions catalyzed by nucleoside phosphorylases

• Julia N. Artsemyeva,
• Ekaterina A. Remeeva,
• Tatiana N. Buravskaya,
• Irina D. Konstantinova,
• Roman S. Esipov,
• Anatoly I. Miroshnikov,
• Natalia M. Litvinko and
• Igor A. Mikhailopulo

Beilstein J. Org. Chem. 2020, 16, 2607–2622, doi:10.3762/bjoc.16.212

• -catalyzed oxidation of the hypoxanthine formed to uric acid [40] and H2O2, and the latter was converted to H2O and oxygen by catalase preventing thereby the reverse formation of the starting Ino. The Rib-1Pi (2Na+) was isolated from the reaction mixture in 74% yield (32 IU of PNP per 1 mmol of Ino; 50 mM Na

Synthesis of novel fluorinated building blocks via halofluorination and related reactions

• Attila Márió Remete,
• Tamás T. Novák,
• Melinda Nonn,
• Matti Haukka,
• Ferenc Fülöp and
• Loránd Kiss

Beilstein J. Org. Chem. 2020, 16, 2562–2575, doi:10.3762/bjoc.16.208

• (rac)-33 formed primarily (Scheme 22). A possible driving force of this reaction is the extended conjugation. Interestingly, the treatment of a mixture of (rac)-31 with H2O2/CF3COOH resulted in single allylic fluoride, (rac)-35 (Scheme 23). Unfortunately, the determination of the stereochemistry via

The B & B approach: Ball-milling conjugation of dextran with phenylboronic acid (PBA)-functionalized BODIPY

• Patrizia Andreozzi,
• Lorenza Tamberi,
• Elisamaria Tasca,
• Gina Elena Giacomazzo,
• Marta Martinez,
• Mirko Severi,
• Marco Marradi,
• Stefano Cicchi,
• Sergio Moya,
• Giacomo Biagiotti and
• Barbara Richichi

Beilstein J. Org. Chem. 2020, 16, 2272–2281, doi:10.3762/bjoc.16.188

• accurately weighted amount of each sample was treated with a microwave-assisted digestion (CEM MARS Xpress) using 1 mL of suprapure HNO3 obtained by sub-boiling distillation and 1 mL of suprapure H2O2. Each sample was thus diluted to 10 mL with Ultrapure water (UHQ), spiked with 0.5 ppm of Ge used as an

Synthetic approaches to bowl-shaped π-conjugated sumanene and its congeners

• Shakeel Alvi and
• Rashid Ali

Beilstein J. Org. Chem. 2020, 16, 2212–2259, doi:10.3762/bjoc.16.186

• generate the corresponding pyrazine-fused sumanene networks 169a–f and 170a–f in low-to-good yields (Scheme 44). As can be inspected from Scheme 45, oxidation of 155 and 160 with both oxone (potassium peroxymonosulfate) and H2O2 afforded the one-ring-opened product 177. Interestingly, when these compounds

• -7,7,8,8-tetracyanoquinodimethane (F4-TCNQ). On the other hand, when compounds 178 and 179 were reacted with oxidizing agents such as oxone and H2O2, selectively one benzene ring-cleaved products 180 and 181 were isolated (Scheme 46) [85]. Having the ring-opened products in hands, they were then subjected

One-pot synthesis of isosorbide from cellulose or lignocellulosic biomass: a challenge?

• Isaline Bonnin,
• Raphaël Mereau,
• Thierry Tassaing and
• Karine De Oliveira Vigier

Beilstein J. Org. Chem. 2020, 16, 1713–1721, doi:10.3762/bjoc.16.143

• 1.5 h in an ethanol/water (50:50) mixture at 210 °C, and ii) CIMV (Compagnie Industrielle de la Matière Végétale) technology, where wheat straw was treated during 3.5 h of acetic acid/formic acid/water (50:30:15 m/m/m) extraction at 105 °C and then in the presence of H2O2 and organic acids (peracetic

Heterogeneous photocatalysis in flow chemical reactors

• Christopher G. Thomson,
• Ai-Lan Lee and
• Filipe Vilela

Beilstein J. Org. Chem. 2020, 16, 1495–1549, doi:10.3762/bjoc.16.125

• used for the photocatalytic generation of H2O2, the degradation of methylene blue dye, and the reduction of nitrobenzene to aniline. Although it was an interesting and novel approach to efficiently irradiating HPCats, the report did not address the potential concerns with the heat dissipation from the

4-Hydroxy-3-methyl-2(1H)-quinolone, originally discovered from a Brassicaceae plant, produced by a soil bacterium of the genus Burkholderia sp.: determination of a preferred tautomer and antioxidant activity

• Dandan Li,
• Naoya Oku,
• Yukiko Shinozaki,
• Yoichi Kurokawa and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2020, 16, 1489–1494, doi:10.3762/bjoc.16.124

• caused biphasic separation of the mixture. Antimicrobial assay The antimicrobial activity was evaluated by the method described previously [16]. Antioxidant assay The antioxidant activity was evaluated by the method described in [41]. Briefly, luminol (10 μM), H2O2 (1000 μM), and vehicle solvent with or

Synthesis of 3-substituted isoxazolidin-4-ols using hydroboration–oxidation reactions of 4,5-unsubstituted 2,3-dihydroisoxazoles

• Lívia Dikošová,
• Júlia Laceková,
• Ondrej Záborský and
• Róbert Fischer

Beilstein J. Org. Chem. 2020, 16, 1313–1319, doi:10.3762/bjoc.16.112

• oxidation step, after the disappearance of the starting material, 10% aqueous NaOH and 35% aqueous H2O2 were added at 0 °C dropwise as slowly as possible. It turned out that a patient addition of both NaOH (aq) and H2O2 (aq) accompanied by intense cooling is a crucial part of the procedure, preventing the

• -substituted isoxazolidin-4-ols employing the hydroboration–oxidation reaction of 4,5-unsubstituted 2,3-dihydroisoxazoles with basic hydrogen peroxide. A patient addition of both NaOH (aq) and H2O2 (aq) accompanied by intense cooling was a crucial part of the procedure in terms of product yield. All

• ), a 10% solution of NaOH (7.5 mL) was added dropwise as slowly as possible at 0 °C, followed by a 35% solution of H2O2 (15 mL) added in a likewise manner. After 3 h of stirring at 0 °C (TLC, hexanes/EtOAc, 1:1), the reaction was diluted with EtOAc (30 mL). The organic layer was separated, washed with

Oxime radicals: generation, properties and application in organic synthesis

• Igor B. Krylov,
• Stanislav A. Paveliev,
• Alexander S. Budnikov and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2020, 16, 1234–1276, doi:10.3762/bjoc.16.107

• [46], Pb(OAc)4 [44][46][47][48][49][50][51], PbO2 [52], Mn(OAc)3 [46], KMnO4 [46], Ag2O [53], AgO [54], Horseradish peroxidase/H2O2 [55], metal-free oxidants PhI(OAc)2 [46], t-BuOOt-Bu [53] or quinones [56] under UV irradiation. Anodic oxidation was also reported [57]. The establishing of the self

Activated carbon as catalyst support: precursors, preparation, modification and characterization

• Melanie Iwanow,
• Tobias Gärtner,
• Volker Sieber and
• Burkhard König

Beilstein J. Org. Chem. 2020, 16, 1188–1202, doi:10.3762/bjoc.16.104

• of oxygen-containing surface groups can be influenced by treatment with different oxidants such as H2O2, HNO3, oxygen/ air, ozone or NaOCl. Thereby, the acidic or basic behavior and the resulting surface chemistry of the activated carbons are determined. Jaramillo et al. investigated the influence of

• different oxidizing reagents on the activated carbon materials prepared from cherry stones. Different amounts of oxygen functional groups were found on the surface of the materials depending on the oxidizing agents used: HNO3 > O3 > H2O2 > O2 (air). Mostly carboxyl groups were formed by the oxidative

• similar porosity, but different amounts of oxygen groups on the surface. They observed a decrease of the hydrophobicity of the carbon surface due to formation of acidic groups by oxidization with H2O2. This property change based on the increase of oxygen surface groups made the surface more accessible for