New bio-nanocomposites based on iron oxides and polysaccharides applied to oxidation and alkylation reactions

• Daily Rodríguez-Padrón,
• Alina M. Balu,
• Antonio A. Romero and
• Rafael Luque

Beilstein J. Org. Chem. 2017, 13, 1982–1993, doi:10.3762/bjoc.13.194

• require stoichiometric amounts of inorganic oxidants, which are highly toxic and polluting. Aiming to minimize chemical waste in these catalytic processes, the scientific community is moving towards the use of clean oxidants ("green oxidants"), such as molecular oxygen or H2O2 [39]. Thus, the use of clean

Chiral phase-transfer catalysis in the asymmetric α-heterofunctionalization of prochiral nucleophiles

• Johannes Schörgenhumer,
• Maximilian Tiffner and
• Mario Waser

Beilstein J. Org. Chem. 2017, 13, 1753–1769, doi:10.3762/bjoc.13.170

• -transfer reactions is hydrogen peroxide (H2O2). Unfortunately, the direct use of this base-chemical under asymmetric organocatalysis turned out to be rather tricky for α-hydroxylation reactions. One recent report by the Ooi group overcame some of the limitations by using H2O2 in combination with

• cycloetherification reactions based on the use of in situ-generated chiral quaternary ammonium hypoiodite species. By using Maruoka-type catalysts B, which contain an iodide counter anion, in the presence of a simple oxidant like H2O2 they were able to generate a chiral hypoiodite species in situ, which then

The chemistry and biology of mycolactones

• Matthias Gehringer and
• Karl-Heinz Altmann

Beilstein J. Org. Chem. 2017, 13, 1596–1660, doi:10.3762/bjoc.13.159

Mechanochemical synthesis of graphene oxide-supported transition metal catalysts for the oxidation of isoeugenol to vanillin

• Ana Franco,
• Sudipta De,
• Alina M. Balu,
• Araceli Garcia and
• Rafael Luque

Beilstein J. Org. Chem. 2017, 13, 1439–1445, doi:10.3762/bjoc.13.141

• this work, new transition metal-based catalysts were proposed to investigate their efficiency in vanillin production. Reduced graphene oxide supported Fe and Co catalysts showed high conversion of isoeugenol under mild reaction conditions using H2O2 as oxidizing agent. Fe catalysts were more selective

• as compared to Co catalysts, providing a 63% vanillin selectivity at 61% conversion in 2 h. The mechanochemical process was demonstrated as an effective approach to prepare supported metal catalysts that exhibited high activity for the production of vanillin from isoeugenol. Keywords: H2O2

• employed [14][19][20][21]. However, the selectivity of vanillin still remains an important issue. In this work, we report the mechanochemical design of transition-metal-based catalysts supported on reduced graphene oxide support for the oxidation of isoeugenol into vanillin using H2O2 as oxidant. The

Total synthesis of elansolids B1 and B2

• Liang-Liang Wang and
• Andreas Kirschning

Beilstein J. Org. Chem. 2017, 13, 1280–1287, doi:10.3762/bjoc.13.124

• alcohol described above (124.0 mg, 0.21 mmol, 1.0 equiv) in THF (0.75 mL) was added a solution of TBAF (c = 1.0 M in THF, 0.84 mL, 4.0 equiv) and the mixture was stirred for 15 min. Methanol (2.23 mL), KHCO3 (41.85 mg, 0.42 mmol, 2.0 equiv) and H2O2 (35% in H2O, 0.36 mL, 4.18 mmol, 20 equiv) were

Transition-metal-free one-pot synthesis of alkynyl selenides from terminal alkynes under aerobic and sustainable conditions

• Adrián A. Heredia and
• Alicia B. Peñéñory

Beilstein J. Org. Chem. 2017, 13, 910–918, doi:10.3762/bjoc.13.92

• confirmed the presence of H2O2 [43] resulting from the superoxide radical anion (O2·−) generated during reaction under oxygen atmosphere. It is also possible that the superoxide radical anion oxidizes the alkyl selenide anion (11) to the corresponding alkyl selenide radical and the formed O22− affords H2O2

• air atmosphere, the presence of oxygen promotes the oxidation of anion 11 to 8 [45], continuing the cycle until complete consumption of 11. Due to the aerobic conditions and the presence of oxidative species such as O2·−, O22− or H2O2, the oxidative retro-alkylation is favored [46][47][48][49

Isoxazole derivatives as new nitric oxide elicitors in plants

• Anca Oancea,
• Emilian Georgescu,
• Florentina Georgescu,
• Alina Nicolescu,
• Elena Iulia Oprita,
• Catalina Tudora,
• Lucian Vladulescu,
• Marius-Constantin Vladulescu,
• Florin Oancea and
• Calin Deleanu

Beilstein J. Org. Chem. 2017, 13, 659–664, doi:10.3762/bjoc.13.65

• reactive oxygen species (ROS) production in plant tissues. Usually, NO and ROS, such as O2−, OH· and H2O2, together are required to induce the activation of various defense-related enzymes in plants [55]. Plant cells contain oxygen radical detoxifying enzymes and nonenzymatic antioxidants which have an

Transition-metal-catalyzed synthesis of phenols and aryl thiols

• Yajun Liu,
• Shasha Liu and
• Yan Xiao

Beilstein J. Org. Chem. 2017, 13, 589–611, doi:10.3762/bjoc.13.58

• they used a stoichiometric amount of reactive iron complex [Fe(II)(BPMEN)(CH3CN)2](ClO4)2 to achieve ortho-hydroxylation of benzoic acid in the presence of H2O2, affording salicylic acid in low yields [52]. In the past decade, the selectivity and yield of C–H hydroxylation of arenes were highly

• °C (Scheme 31). In 2015, Itoh and co-workers employed PdCl2 as catalyst and the hydroxylation of arylpyridines was carried out in 4-methyl-2-pentanone at 100 °C in the presence of H2O2 (Scheme 32) [61]. In terms of reactivity, substituent at the para-position of the phenyl ring is more favored than

• (Scheme 51). 1.2.4 Vanadium mediated C–H hydroxylation of arenes: In 2012, Mizuno employed divanadium-substituted phosphotungstate, and accomplished the direct hydroxylation of structurally simple arenes to phenols in the presence of H2O2 [84]. The reaction occurred at 60 °C in CH3CN/t-BuOH (1:1) and

Studies directed toward the exploitation of vicinal diols in the synthesis of (+)-nebivolol intermediates

• Runjun Devi and
• Sajal Kumar Das

Beilstein J. Org. Chem. 2017, 13, 571–578, doi:10.3762/bjoc.13.56

• of the allyl group in 16 with 9-BBN and the oxidation of the resulting organoborane with NaOH and H2O2 furnished alcohol 17 in 96% yield. A one-pot PCC oxidation–Wittig olefination (with Ph3P=CHCO2Et) of 17 provided (E)-α,β-unsaturated ester 18 in 85% yield over 2 steps. Compound 18 was then

Adsorption of RNA on mineral surfaces and mineral precipitates

• Elisa Biondi,
• Yoshihiro Furukawa,
• Jun Kawai and
• Steven A. Benner

Beilstein J. Org. Chem. 2017, 13, 393–404, doi:10.3762/bjoc.13.42

• washed with (in this order) tap water, ddH2O, 30% H2O2, ddH2O, EtOH 99%. Minerals were then air-dried for about 30 min in a sterile environment. For each mineral, droplets (2 μL) containing ≈100 fmol of radiolabeled RNA were spotted on the surface and let adsorb for 45 min at room temperature. Macro

• extensively washed with tap water, ddH2O, 30% H2O2, ddH2O, and then EtOH (99%) to remove all organic species. The specimens were then air-dried under cover for about 30 min. Droplets (2 μL) containing ≈100 fmol of radiolabeled RNA were spotted on the surface of each crystal. The material was allowed to adsorb

Total synthesis of a Streptococcus pneumoniae serotype 12F CPS repeating unit hexasaccharide

• Peter H. Seeberger,
• Claney L. Pereira and
• Subramanian Govindan

Beilstein J. Org. Chem. 2017, 13, 164–173, doi:10.3762/bjoc.13.19

• a mixture of AcOH/H2O/t-BuOH prior to ester hydrolysis using LiOH/H2O2 enabled the hexasaccharide 1 to be obtained in 37% yield (Scheme 9). Conclusion The first total synthesis of the S. pneumoniae serotype 12F capsular polysaccharide repeating unit hexasaccharide 1 was achieved by means of a linear

• (0.5 M in MeOH) in MeOH, ii. NaOH (4 M, 2 M, 1 M, 0.5 M, 0.1 M) solution in THF, iii. H2O2, LiOH, THF, H2O; successful sequence (d) Pd/C, AcOH, H2O, t-BuOH (e) H2O2, LiOH, THF, H2O, 37% over two steps. Supporting Information Supporting Information File 44: Experimental details and full

Stabilization of nanosized titanium dioxide by cyclodextrin polymers and its photocatalytic effect on the degradation of wastewater pollutants

• Tamás Zoltán Agócs,
• István Puskás,
• Erzsébet Varga,
• Mónika Molnár and
• Éva Fenyvesi

Beilstein J. Org. Chem. 2016, 12, 2873–2882, doi:10.3762/bjoc.12.286

• environments, can set up a photo-Fenton system with H2O2 produced in situ generating OH radicals of high oxidizing capacity [42][43]. Nitrate could also produce OH radicals when absorbing UV light, but the low concentration of nitrate in tap water can insignificantly contribute to enhancing photodegradation

A new protocol for the synthesis of 4,7,12,15-tetrachloro[2.2]paracyclophane

• Donghui Pan,
• Yanbin Wang and
• Guomin Xiao

Beilstein J. Org. Chem. 2016, 12, 2443–2449, doi:10.3762/bjoc.12.237

• precursor of parylene D, from 2,5-dichloro-p-xylene. In the first bromination step, with H2O2–HBr as a bromide source, this procedure becomes organic-waste-free and organic-solvent-free and can appropriately replace the existing bromination methods. The Winberg elimination–dimerization step, using aqueous

• sodium hydroxide solution instead of silver oxide for anion exchange, results in a significant improvement in product yield. Furthermore, four substituted [2.2]paracyclophanes were also prepared in this convenient way. Keywords: bromination; dimerization; H2O2–HBr system; paracyclophane; polymerization

• drawbacks such as low atom efficiency and the requirement of reagent residue elimination [14]. In contrast to traditional brominating reagents, the H2O2–HBr system, which generates active bromine in situ, is a convenient and green brominating agent [15]. Furthermore, the use of the H2O2–HBr couple improves

Silica-supported sulfonic acids as recyclable catalyst for esterification of levulinic acid with stoichiometric amounts of alcohols

• Raimondo Maggi,
• N. Raveendran Shiju,
• Veronica Santacroce,
• Giovanni Maestri,
• Franca Bigi and
• Gadi Rothenberg

Beilstein J. Org. Chem. 2016, 12, 2173–2180, doi:10.3762/bjoc.12.207

• toluene (120 mL) and the resulting supported propylmercaptane has been oxidized to propanesulfonic acid by treatment with 30% aq H2O2 (100 mL; 1 mol) for 24 h under stirring at rt, adding a few drops of concentrated sulfuric acid after 12 h. Acidity has been measured via the titration method [35] (0.51

Stereo- and regioselectivity of the hetero-Diels–Alder reaction of nitroso derivatives with conjugated dienes

• Lucie Brulíková,
• Aidan Harrison,
• Marvin J. Miller and
• Jan Hlaváč

Beilstein J. Org. Chem. 2016, 12, 1949–1980, doi:10.3762/bjoc.12.184

• TiO2 nanoparticle assemblies using H2O2 [51]. Geminal chloronitroso compounds are synthesized or in situ generated from their corresponding oximes by chlorination. As halogen source elemental chlorine [52][53][54], nitrosyl chloride [55], alkyl hypochlorites [56], N-chlorourea [57], tert-butyl

Rearrangements of organic peroxides and related processes

• Ivan A. Yaremenko,
• Vera A. Vil’,
• Dmitry V. Demchuk and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2016, 12, 1647–1748, doi:10.3762/bjoc.12.162

• > perbenzoic acid > peracetic acid >> H2O2 > t-BuOOH [196]. The migratory ability of substituents in the Criegee intermediate decreases in the following series: tertiary alkyl > cyclohexyl > secondary alkyl > benzyl > phenyl > primary alkyl > cyclopentyl, cyclopropyl > methyl. In some cases, stereoelectronical

• hydrogen peroxide. Oxidizing systems containing hydrogen peroxide as the oxidizing agent allow the usual and asymmetric oxidation of the substrate to the target product with high conversion and yield. In recent years, the inexpensive, commercially available, and environmentally friendly H2O2 was utilized

• theoretically studied mechanism of the oxidation reaction promoted by H2O2 and the Lewis acid BF3 [217][219]. In the first step, the hydrogen peroxide–boron trifluoride complex 8 reacts with ketone 9 to form adduct 10. The latter intermediate rearranges through transition state 11 into the tetrahedral

Automated glycan assembly of a S. pneumoniae serotype 3 CPS antigen

• Markus W. Weishaupt,
• Stefan Matthies,
• Mattan Hurevich,
• Claney L. Pereira,
• Heung Sik Hahm and
• Peter H. Seeberger

Beilstein J. Org. Chem. 2016, 12, 1440–1446, doi:10.3762/bjoc.12.139

• trisaccharide 5. Reagents and conditions: a) LiOH, H2O2, THF, −5 °C to rt; b) NaOH, MeOH, 0 °C to rt; c) Pd(OH)2/C, MeOH/H2O/AcOH (50:25:1 v/v/v), 71% over 3 steps. Supporting Information Supporting Information File 184: Experimental details as well as full characterization of all new compounds

Nucleic acids through condensation of nucleosides and phosphorous acid in the presence of sulfur

• Tuomas Lönnberg

Beilstein J. Org. Chem. 2016, 12, 670–673, doi:10.3762/bjoc.12.67

• polymerization. Proposed oxidants for prebiotic phosphite chemistry include H2O2 and Fe(III). The present paper describes the polymerization of thymidine and triethylammonium phosphite, with elemental sulfur acting as the oxidant. Up to pentameric oligonucleotides with internucleosidic phosphorothioate linkages

Aluminacyclopentanes in the synthesis of 3-substituted phospholanes and α,ω-bisphospholanes

• Vladimir A. D’yakonov,
• Alevtina L. Makhamatkhanova,
• Rina A. Agliullina,
• Leisan K. Dilmukhametova,
• Tat’yana V. Tyumkina and
• Usein M. Dzhemilev

Beilstein J. Org. Chem. 2016, 12, 406–412, doi:10.3762/bjoc.12.43

• additional asymmetric centre С(1′) in the substituent, and the total yield of these compounds is 90–93%. Phospholanes 2а–h readily react with H2O2 in chloroform, owing to the presence of a lone electron pair at phosphorus to give phospholane 1-oxides 3а–h in quantitative yields. The reaction of 2а–h with S8

• (10d), 1,4-bis(1-methylphospholan-3-yl)butane (10e), and 1,6-bis(1-phenylphospholan-3-yl)hexane (10с) in 85 % yields. Similarly to phospholanes 2a–h, the resulting bisphospholanes 10a–c readily react with H2O2 in chloroform or with elemental sulfur to furnish the corresponding bisphospholane 1,1

Diastereoselective synthesis of new O-alkylated and C-branched inositols and their corresponding fluoro analogues

• Charlotte Collet,
• Françoise Chrétien,
• Yves Chapleur and
• Sandrine Lamandé-Langle

Beilstein J. Org. Chem. 2016, 12, 353–361, doi:10.3762/bjoc.12.39

• bromide under classical conditions in the presence of NaH at reflux [44] to afford myo-9 and scyllo-9 in good yield of 80% and 82%, respectively. The hydroxylated arm was obtained by hydroboration using BH3 on the unsaturated compounds myo-9 and scyllo-9 followed by an oxidation with H2O2/NaOH allowing

• , after hydroboration using BH3 in THF at 0 °C followed by conventional oxidation using H2O2/NaOH, in 70–80% yield. Subsequent catalytic hydrogenation under pressure with Pd(OH)2 as the catalyst [45] allowed to obtaining quantitatively the fully hydroxylated inositols myo-3, scyllo-3, myo-4 and scyllo-4

• , iPrOH, rt, 2 h, 58 and 30%; b) allyl bromide, NaH, 70 °C, 2 h, 80–82%; c) BH3, THF, rt, 6 h then H2O2, NaOH, rt, 12 h, 75–78%; d) Pd(OH)2, MeOH/CH2Cl2/H2O 10:10:1 (v/v/v), 45 psi, 18 h, quantitative. Synthesis of O-alkylated fluorinated inositol derivatives 2. Synthesis of C-alkenylated inositol

Synthesis and reactivity of aliphatic sulfur pentafluorides from substituted (pentafluorosulfanyl)benzenes

• Norbert Vida,
• Jiří Václavík and
• Petr Beier

Beilstein J. Org. Chem. 2016, 12, 110–116, doi:10.3762/bjoc.12.12

• maleic acid derivative 4 in the product mixture. Control experiments in which 8 or 3 were reacted with H2O2/H2SO4 did not provide 4. This suggests that 4 may be formed by a second hydroxylation of 6 to 9. The second electrophilic aromatic hydroxylation is a favorable process because 6 is a more activated

• 12. To test this hypothesis, both 10 and 11 were subjected to oxidation by H2O2/H2SO4 mixture. Indeed, the yield of 3 decreased considerably while the yield of 4 increased somewhat but still remains low (Scheme 3). The presumed intermediate 2-(pentafluorosulfanyl)-1,4-benzoquinone (12) in the pathway

• substituents ortho to the SF5 group are relatively uncommon [21]. Reduction with sodium dithionite [20] provided aminophenol 14 in good overall yield and oxidation with MnO2 [22] gave benzoquinone 12 also in a good yield. Further oxidation with H2O2/H2SO4 resulted in a mixture of four SF5-containing products

Photoinduced 1,2,3,4-tetrahydropyridine ring conversions

• Baiba Turovska,
• Henning Lund,
• Viesturs Lūsis,
• Anna Lielpētere,
• Edvards Liepiņš,
• Sergejs Beljakovs,
• Inguna Goba and
• Jānis Stradiņš

Beilstein J. Org. Chem. 2015, 11, 2166–2170, doi:10.3762/bjoc.11.234

• contains the mixture of 3, 4 and 5. The same product mixture was obtained if the solution of 1 is treated with concentrated H2O2 or Fenton reagent. The reaction starts even if the irradiation wavelengths only partially cover the absorption band of 1. It explains also the observed fact that during the

Stereoselective synthesis of hernandulcin, peroxylippidulcine A, lippidulcines A, B and C and taste evaluation

• Marco G. Rigamonti and
• Francesco G. Gatti

Beilstein J. Org. Chem. 2015, 11, 2117–2124, doi:10.3762/bjoc.11.228

• quantitative yield (Scheme 3). However, any attempt of isolating each isomer of peroxylippidulcine by column chromatography technique failed. In addition, the singlet dark oxidation (H2O2 with a catalytic amount of Na2MoO4 at 55 °C) was tested, but without success [33]. Then, we tried to separate 2a–c by means

Selected synthetic strategies to cyclophanes

• Sambasivarao Kotha,
• Mukesh E. Shirbhate and
• Gopalkrushna T. Waghule

Beilstein J. Org. Chem. 2015, 11, 1274–1331, doi:10.3762/bjoc.11.142

One-pot odourless synthesis of thioesters via in situ generation of thiobenzoic acids using benzoic anhydrides and thiourea

• Mohammad Abbasi and
• Reza Khalifeh

Beilstein J. Org. Chem. 2015, 11, 1265–1273, doi:10.3762/bjoc.11.141

• containing Et3N and a thick brick-red liquid was formed. Next, H2O (1 mL) and H2O2 (1.2 mmol) were added to the reaction mixture and the resulting solution was stirred for 1 h at room temperature. Extractive work-up with EtOAc followed by silica gel column chromatography afforded benzoyl disulfide in 91