Oxidative dehydrogenation of C–C and C–N bonds: A convenient approach to access diverse (dihydro)heteroaromatic compounds

• Santanu Hati,
• Ulrike Holzgrabe and
• Subhabrata Sen

Beilstein J. Org. Chem. 2017, 13, 1670–1692, doi:10.3762/bjoc.13.162

• generate U which undergoes further reductive elimination to afford 90 (Scheme 33). A ferric chloride (FeCl3)-catalyzed tert-butyl hydroperoxide (TBHP)-mediated synthesis of 2-arylquinazolin-4(1H)-one 92 was reported by Zhao et al. o-Aminobenzamides are reacted with diverse alcohols with 2 mol % of ferric

• chloride in the presence of tert-butyl hydroperoxide (5.5 M in decane, 1.5 mmol) to furnish the final compounds within 7 hours (Scheme 34). This optimized protocol displayed robust functional group tolerance and was further utilised to synthesise aromatic 2-arylquinazoline with excellent yield [93

Synthesis of oligonucleotides on a soluble support

• Harri Lönnberg

Beilstein J. Org. Chem. 2017, 13, 1368–1387, doi:10.3762/bjoc.13.134

• hydroperoxide in MeCN [52]. On using 2.5 equiv of the phosphoramidite block and 10 equiv of tetrazole as an activator in MeCN, 98–99% coupling yields were obtained. Support-bound octamer, DMTr-d(5´-TAGCGCTA-3´)-PEG could be obtained in 93% yield and a 20-mer in 85% yield. These yields are surprisingly high

• average coupling yield was 96%. The mixture was concentrated and subjected to gel permeation chromatography in MeOH to remove the low molecular weight compounds. The pooled fractions containing the support-bound oligonucleotides were concentrated and oxidized with tert-butyl hydroperoxide. The excess of

• precipitative PEG support was applied, tetraethylthiuram disulfide (TETD; 0.5 mol L−1 in MeCN; 10-fold excess) was used as the sulfurization reagent [66] instead of tert-butyl hydroperoxide used for the oxidation in the synthesis of unmodified ODNs [51]. On using 2.5 equiv of phosphoramidites for coupling, a

α-Acetoxyarone synthesis via iodine-catalyzed and tert-butyl hydroperoxide-mediateded self-intermolecular oxidative coupling of aryl ketones

• Liquan Tan,
• Cui Chen and
• Weibing Liu

Beilstein J. Org. Chem. 2017, 13, 1079–1084, doi:10.3762/bjoc.13.107

• self-intermolecular oxidative coupling of aryl ketones using I2−tert-butyl hydroperoxide (TBHP). Under the optimum conditions, various aryl ketones gave the corresponding products in moderate to excellent yields. A series of control experiments were performed; the results suggest the involvement of

• ketones from aryl ketones using I2 and tert-butyl hydroperoxide (TBHP) [16][17][18] (Scheme 1). Several oxidative cross-coupling methods have been developed for the synthesis of α-acetoxy ketones from ketone derivatives and carboxylic acids [10], benzylic alcohols [19], toluene derivatives [20][21] and

• ). However, decreasing the amount of Na2CO3 from 1.0 equiv to 0.1 equiv significantly decreased the product yield. The effects of other peroxides, i.e., di-tert-butyl peroxide (DTBP), benzoyl peroxide, dicumyl peroxide (DCP), cumene hydroperoxide (CHP), potassium hydrogen persulfate, and 3

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

• at other positions. In 2015, Sun and co-workers developed a Pd(OAc)2 catalyzed ortho-hydroxylation of 2-arylpyridines using tert-butyl hydroperoxide (TBHP) as oxidant [62]. The reaction was carried out at 115 °C in 1,2-dichloroethane (DCE), affording the corresponding phenols in moderate to good

Synthesis of 1-indanones with a broad range of biological activity

• Marika Turek,
• Dorota Szczęsna,
• Marek Koprowski and
• Piotr Bałczewski

Beilstein J. Org. Chem. 2017, 13, 451–494, doi:10.3762/bjoc.13.48

Copper-catalyzed asymmetric sp³ C–H arylation of tetrahydroisoquinoline mediated by a visible light photoredox catalyst

• Pierre Querard,
• Inna Perepichka,
• Eli Zysman-Colman and
• Chao-Jun Li

Beilstein J. Org. Chem. 2016, 12, 2636–2643, doi:10.3762/bjoc.12.260

• developed the first direct sp3 C–H arylation of THIQ with arylboronic acids using a copper catalyst (Scheme 1) [30]. Oxygen gas and tert-butyl hydroperoxide (TBHP) were used as external oxidants, which gave moderate to good isolated yields (up to 75%). In addition, we demonstrated the first enantioselective

Experimental and theoretical investigations into the stability of cyclic aminals

• Edgar Sawatzky,
• Antonios Drakopoulos,
• Martin Rölz,
• Christoph Sotriffer,
• Bernd Engels and
• Michael Decker

Beilstein J. Org. Chem. 2016, 12, 2280–2292, doi:10.3762/bjoc.12.221

• with KMnO4 or a mixture of potassium iodide and tert-butyl hydroperoxide (TBHP) give access to quinazolinones and have been reported for the synthesis of the naturally occurring alkaloids deoxyvasicinone, mackinazolinone or rutaecarpine [22][28] (Scheme 2). Besides total oxidation of the aminal core

TBHP-mediated highly efficient dehydrogenative cross-oxidative coupling of methylarenes with acetanilides

• Cui Chen,
• Weibing Liu and
• Peng Zhou

Beilstein J. Org. Chem. 2016, 12, 2250–2255, doi:10.3762/bjoc.12.217

• ). Results and Discussion We began by studying the reaction of toluene (1a) and acetanilide (2a) as model substrates to identify the optimal conditions (Table 1). In the presence of I2 (0.1 equiv) and tert-butyl hydroperoxide (TBHP, 2.0 equiv), the study commenced to optimize the reaction time (Table 1

• -butylperoxy benzoate (TBPB) and cumene hydroperoxide (CHP) proved wholly ineffective for this conversion and no product was observed (Table 1, entries 4–9). Next, the effect of other iodine sources on the reaction was monitored. Pleasingly, ICl and NIS afforded the desired product 3aa successfully, but led to

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

• hetero-Diels–Alder reaction by vanadium in the presence of the oxidant CHP (cumyl hydroperoxide). Regioselectivity of solution-phase nitroso hetero-Diels–Alder reaction with acyl and aryl nitroso dienophiles. Favored regioisomeric outcome for the solution and solid-phase reactions, giving hetero-Diels

Unusual reactions of diazocarbonyl compounds with α,β-unsaturated δ-amino esters: Rh(II)-catalyzed Wolff rearrangement and oxidative cleavage of N–H-insertion products

• Valerij A. Nikolaev,
• Jury J. Medvedev,
• Olesia S. Galkina,
• Ksenia V. Azarova and
• Christoph Schneider

Beilstein J. Org. Chem. 2016, 12, 1904–1910, doi:10.3762/bjoc.12.180

• hydroperoxide G, which then converts into 1,2-dioxetane H [30]. Subsequent cleavage of σ-С–С and О–О bonds in the structure of dioxetane H gives rise to the formation of amides 4 or 7 and the appropriate рara-substituted benzoic acid, which was isolated in several cases from reaction mixtures. A leading role in

A flow reactor setup for photochemistry of biphasic gas/liquid reactions

• Josef Schachtner,
• Patrick Bayer and
• Axel Jacobi von Wangelin

Beilstein J. Org. Chem. 2016, 12, 1798–1811, doi:10.3762/bjoc.12.170

• . Following an optimized Schenck ene reaction procedure, N-methyl-1,2,3,6-tetrahydrophthalimide (1a) was reacted with molecular oxygen in the presence of methylene blue as sensitizer (Scheme 6). The resultant hydroperoxide motif (2a) constitutes a valuable carbocyclic building block. For reasons of

• derivative 1b [78][79][80][81] was quantitatively converted to hydroperoxide 2b which displayed perfect trans-diastereocontrol. After 48 h in batch mode, 3.37 kWh were consumed per mmol starting material, which in flow mode would suffice for continuous conversion of 36 mmol substrate over 12 h at 0.5 mL min

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

• rearrangements and related processes play an important role in the chemistry of oxidation processes. Thus, the key reagent in the Sharpless epoxidation of allylic alcohols [48] and in the manufacture of propylene oxide via the Prilezhaev reaction [49][50][51] is tert-butyl hydroperoxide. In industry, phenol and

• acetone are mainly produced by the Hock process, which is based on the rearrangement of cumene hydroperoxide. In 2003, phenol was produced to more than 95% by this oxidation process [52][53][54]. Another important application of organic peroxides is the synthesis of lactones from cyclic ketones via the

• oxygen produces the hydroperoxide cholesterol-5α-OOH, which undergoes a Hock oxidation to form atheronal A. The latter possesses proatherogenic effects and triggers the development of cardiovascular diseases [66][67][68][69][70][71]. The development of the chemistry of organic peroxides is closely

Cupreines and cupreidines: an established class of bifunctional cinchona organocatalysts

• Laura A. Bryant,
• Rossana Fanelli and
• Alexander J. A. Cobb

Beilstein J. Org. Chem. 2016, 12, 429–443, doi:10.3762/bjoc.12.46

• ) in the α-hydroxylation of indenones (where n = 1 in 77) using cumyl hydroperoxide (Scheme 19) [58]. Interestingly, the 3,4-dihydronaphthalen-1(2H)-one derivative (where n = 2 in 77) did not afford any detectable product. Transamination A range of α-amino acid derivatives have been accessed by Shi and

Asymmetric α-amination of β-keto esters using a guanidine–bisurea bifunctional organocatalyst

• Minami Odagi,
• Yoshiharu Yamamoto and
• Kazuo Nagasawa

Beilstein J. Org. Chem. 2016, 12, 198–203, doi:10.3762/bjoc.12.22

• asymmetric reactions [19][20]. Recently, we disclosed an α-hydroxylation of tetralone-derived β-keto esters 2 using guanidine–bisurea bifunctional organocatalyst 1a in the presence of cumene hydroperoxide (CHP) as an oxidant (Figure 1a) [21]. This reaction provides the corresponding α-hydroxylation products

Synthesis and nucleophilic aromatic substitution of 3-fluoro-5-nitro-1-(pentafluorosulfanyl)benzene

• Javier Ajenjo,
• Martin Greenhall,
• Camillo Zarantonello and
• Petr Beier

Beilstein J. Org. Chem. 2016, 12, 192–197, doi:10.3762/bjoc.12.21

• nucleophiles the reactions proceeded in good yields except for diethyl chloromethylphosphonate. A very short reaction time was needed in the reaction with bromoform to avoid decomposition of the tribromomethyl anion to dibromocarbene (Table 2, entry 4). Direct hydroxylation with cumene hydroperoxide required

Recent advances in copper-catalyzed C–H bond amidation

• Jie-Ping Wan and
• Yanfeng Jing

Beilstein J. Org. Chem. 2015, 11, 2209–2222, doi:10.3762/bjoc.11.240

• ] reported the copper-catalyzed, tert-butyl hydroperoxide (TBHP)-assisted C–H amidation of tertiary amines 1. By heating at 80 °C, the C–H bond in dimethylaniline underwent direct amidation to provide products 3 in the presence of amides 2. On the other hand, the dephenylation transformation via C–C bond

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

• , Langelandsgade 140, DK 8000 Aarhus, Denmark 10.3762/bjoc.11.234 Abstract Stable heterocyclic hydroperoxide can be easily prepared as a product of fast oxidation of a 1,2,3,4-tetrahydropyridine by 3O2 if the solution is exposed to sunlight. The driving force for the photoinduced electron transfer is calculated

• from electrochemical and spectroscopic data. The outcome of the reaction depends on the light intensity and the concentration of O2. In the solid state the heterocyclic hydroperoxide is stable; in solution it is involved in further reactions. Keywords: heterocyclic hydroperoxide; oxaziridine

• mmol) [17][18] in chloroform (25 mL). Crystals suitable for X-ray analysis were obtained after evaporation of the chloroform by a stream of dioxygen; elemental analysis, 1H, 13C NMR spectra and X-ray analysis confirmed the structure of hydroperoxide 2 (Figure 2) as the only product of the reaction

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

• of a regioselective O-silylation of the secondary hydroperoxide with the tert-butyldiphenylsilyl chloride (TBDPSiCl), but with our surprise most of the starting material was consumed, and after column chromatography separation only the O-silylated derivative of peroxylippidulcine A, 12, and a small

Aerobic addition of secondary phosphine oxides to vinyl sulfides: a shortcut to 1-hydroxy-2-(organosulfanyl)ethyl(diorganyl)phosphine oxides

• Svetlana F. Malysheva,
• Alexander V. Artem’ev,
• Nina K. Gusarova,
• Nataliya A. Belogorlova,
• Alexander I. Albanov,
• C. W. Liu and
• Boris A. Trofimov

Beilstein J. Org. Chem. 2015, 11, 1985–1990, doi:10.3762/bjoc.11.214

• radical center) leads to the formation of R2P(O)-stabilized radical C. The latter recombines with a hydroperoxide radical to afford the metastable hydroperoxide D, thermal decomposition of which give rise to the final product 3. Although quantum chemical computations [MP2/6-311++G(d,p)//B3LYP/6-311++G(d,p

Copper-catalyzed aerobic radical C–C bond cleavage of N–H ketimines

• Ya Lin Tnay,
• Gim Yean Ang and
• Shunsuke Chiba

Beilstein J. Org. Chem. 2015, 11, 1933–1943, doi:10.3762/bjoc.11.209

• subsequent E1-type elimination of a proton provides biaryl alkene 4a (Scheme 5b). The presence of alkoxy radical D in the reaction process could be further supported by the reaction of biaryl hydroperoxide 6, which could be converted into the alkoxy radical D under copper-catalyzed aerobic reaction

• conditions [58]. Indeed treatment of hydroperoxide 6 under the standard reaction conditions afforded 3a in 24% yield along with biaryl alcohol 7 in 25% yield (Scheme 5c). While formation of biaryl alkene 4a could not be avoided at this moment, it is still appealing to probe the potential utility of the

• . Copper-catalyzed aerobic C–C bond cleavage reactions of N–H ketimines. Proposed reaction mechanisms for the formation of 3a, 4a and 5a, and the reaction of hydroperoxide 6. Formation of bromoketone 6e. Electrophilic cyanation of Grignard reagents with pivalonitrile (1f). Electrophilic cyanation with

Antioxidant potential of curcumin-related compounds studied by chemiluminescence kinetics, chain-breaking efficiencies, scavenging activity (ORAC) and DFT calculations

• Adriana K. Slavova-Kazakova,
• Silvia E. Angelova,
• Timur L. Veprintsev,
• Petko Denev,
• Davide Fabbri,
• Maria Antonietta Dettori,
• Maria Kratchanova,
• Vladimir V. Naumov,
• Aleksei V. Trofimov,
• Rostislav F. Vasil’ev,
• Giovanna Delogu and
• Vessela D. Kancheva

Beilstein J. Org. Chem. 2015, 11, 1398–1411, doi:10.3762/bjoc.11.151

• ) and reactivity (IDd/IDm = 1.0) for the couple dimer 9/monomer 5. The unsaturated side chain is favorable for the resonance stabilization of phenoxyl radical. However, the –COOH group at the end of the side chain is able to accelerate the lipid oxidation through hydroperoxide decomposition into free

• radicals [24][25][26][27]. Dimer 9, having two –COOH groups, displays a two-fold higher growing of the hydroperoxide decomposition rate. As a result, no higher antioxidant potential for dimer 9 compared to that of monomer 5 was observed. Couples dimer 6/monomer 2 and dimer 9/monomer 5 are structurally

• all four dimers tested, and this is in a good agreement with the theoretical BDE values, which are rather close. In contrast to the initiated oxidation, during lipid autoxidation (model 2) the rate of initiation increased with time as a result of accelerated hydroperoxide decomposition and of

The synthesis of active pharmaceutical ingredients (APIs) using continuous flow chemistry

• Marcus Baumann and
• Ian R. Baxendale

Beilstein J. Org. Chem. 2015, 11, 1194–1219, doi:10.3762/bjoc.11.134

• singlet oxygen mediated ene-reaction, a Hock cleavage of the resulting hydroperoxide 58 followed by oxidation with triplet oxygen and a final peracetalisation (Scheme 9). Based on previous work by the Seeberger group and others [63][64][65] a simple flow photoreactor set-up comprising of a layer of FEP

New palladium–oxazoline complexes: Synthesis and evaluation of the optical properties and the catalytic power during the oxidation of textile dyes

• Rym Hassani,
• Mahjoub Jabli,
• Yakdhane Kacem,
• Jérôme Marrot,
• Damien Prim and
• Béchir Ben Hassine

Beilstein J. Org. Chem. 2015, 11, 1175–1186, doi:10.3762/bjoc.11.132

• evidence of the kinetic studies and the literature data, we propose the mechanistic pathway depicted in Scheme 4. The first step involves the complexation of the azo dye to palladium(II) hydroperoxide 13, followed by a peroxymetalation of the azo moiety. This then affords the pseudocyclic five membered

Synthesis of dinucleoside acylphosphonites by phosphonodiamidite chemistry and investigation of phosphorus epimerization

• William H. Hersh

Beilstein J. Org. Chem. 2015, 11, 184–191, doi:10.3762/bjoc.11.19

• by elemental sulfur [43]. As shown in Scheme 3, oxidation of 12 and 13 with anhydrous tert-butyl hydroperoxide gave the acylphosphonates 14 and 15. These products were immediately hydrolyzed by addition of approximately 2 equiv of aqueous triethylammonium bicarbonate (TEAB) to give the H-phosphonate

Cross-dehydrogenative coupling for the intermolecular C–O bond formation

• Igor B. Krylov,
• Vera A. Vil’ and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2015, 11, 92–146, doi:10.3762/bjoc.11.13

• works, the oxidative coupling of alcohols, aldehydes, or formamides with 1,3-dicarbonyl compounds or phenols was accomplished in the presence of tert-butyl hydroperoxide and copper salts (Table 5). In most cases, the range of phenols applicable to the coupling is limited to 2-acylphenols. However, 2

• , Mn) was achieved. tert-Butyl hydroperoxide acts both as the oxidizing agent and the O-component in the coupling. The best results were obtained in the reaction catalyzed by Cu(ClO4)2·6H2O. It was hypothesized that copper serves for the formation of the reactive complex with 1,3-dicarbonyl compounds