Metal-free mechanochemical oxidations in Ertalyte^® jars

• Andrea Porcheddu,
• Francesco Delogu,
• Lidia De Luca,
• Claudia Fattuoni and
• Evelina Colacino

Beilstein J. Org. Chem. 2019, 15, 1786–1794, doi:10.3762/bjoc.15.172

• compounds under very mild conditions [6][7]. Initially used in a stoichiometric amount [8], over the last 20 years it has been exploited successfully in catalytic quantities in combination with other oxidants [9]. A diverse range of co-oxidant agents (N-chlorosuccinimide, NaOCl, Oxone®, PhIO, PhICl2, PhI

• process [55]. Also, Oxone® and NH2CONH2·H2O2 appeared to fail in the oxidation of 3-phenyl-1-propanol (1a) to the corresponding aldehyde. Subsequently, we turned our attention to sodium hypochlorite (NaOCl), an inexpensive and widely used oxidizing reagent also applied as a disinfectant and household

N-(1-Phenylethyl)aziridine-2-carboxylate esters in the synthesis of biologically relevant compounds

• Iwona E. Głowacka,
• Aleksandra Trocha,
• Andrzej E. Wróblewski and
• Dorota G. Piotrowska

Beilstein J. Org. Chem. 2019, 15, 1722–1757, doi:10.3762/bjoc.15.168

• bulkiness of the tert-butyldimethylsilyloxy group in 205 three different approaches to stereoselective dihydroxylations of the C=C bond were elaborated. Thus, treatment with Oxone® gave the anti-epoxide 206 which was regioselectively opened in a boron

Recent advances on the transition-metal-catalyzed synthesis of imidazopyridines: an updated coverage

• Gagandeep Kour Reen,
• Ashok Kumar and
• Pratibha Sharma

Beilstein J. Org. Chem. 2019, 15, 1612–1704, doi:10.3762/bjoc.15.165

Mechanistic studies of an L-proline-catalyzed pyridazine formation involving a Diels–Alder reaction with inverse electron demand

• Anne Schnell,
• J. Alexander Willms,
• S. Nozinovic and
• Marianne Engeser

Beilstein J. Org. Chem. 2019, 15, 30–43, doi:10.3762/bjoc.15.3

• ; found, 326.0165; EIMS m/z (%): 326.0 (3%) [M]+•, 247.1 (4%) [M − Br]+, 116.0 (100%) [M − C7H5BrN3]+, 103.0 (36%), 76.0 (7%). TBCA preparation The synthesis of tribromoisocyanuric acid was conducted according to the procedure of de Almeida et al. [57]. A solution of OXONE® (14.29 g, 46.49 mmol, 3 equiv

DABCO- and DBU-promoted one-pot reaction of N-sulfonyl ketimines with Morita–Baylis–Hillman carbonates: a sequential approach to (2-hydroxyaryl)nicotinate derivatives

• Soumitra Guin,
• Raman Gupta,
• Debashis Majee and
• Sampak Samanta

Beilstein J. Org. Chem. 2018, 14, 2771–2778, doi:10.3762/bjoc.14.254

• as the requirement of high temperatures or use of strong oxidants (H2O2, oxone, K2S2O8, TBHP, PIDA, NHPI etc.) that are not much compatible with functionality, precluding late-stage functionalization. Moreover, the scope of substitution on the pyridine ring is limited which in turn hampers the

The mechanochemical synthesis of quinazolin-4(3H)-ones by controlling the reactivity of IBX

• Md Toufique Alam,
• Saikat Maiti and
• Prasenjit Mal

Beilstein J. Org. Chem. 2018, 14, 2396–2403, doi:10.3762/bjoc.14.216

• ]. During the reaction with the stronger oxidant PIDA, the basicity of the amine was regulated using an externally added acid salt, NaHSO4 (Figure 2a). In Figure 2b, a comparison in the reactivities of arylamines in the presence of non-iodine-based oxidant oxone [32] and IBX (iodine-based oxidant) is shown

• . Anilines readily reacted with oxone leading to the formation of the azo derivatives [32], while their treatment with IBX led to explosive decomposition. The reactions of 2-aminobenzamide with arylaldehydes in the presence of IBX afforded quinazolin-4(3H)-ones at maximum contact of the reactants, i.e

•  1, entries 3 and 4). The reaction also took place, albeit affording the product in lower yield, with in situ-generated IBX [33], i.e., by using an IBA (2-iodobenzoic acid)–oxone combination (Table 1, entry 5). Interestingly, when silica gel [34] was used as additive during the handling of liquid

Hypervalent iodine compounds for anti-Markovnikov-type iodo-oxyimidation of vinylarenes

• Igor B. Krylov,
• Stanislav A. Paveliev,
• Mikhail A. Syroeshkin,
• Alexander A. Korlyukov,
• Pavel V. Dorovatovskii,
• Yan V. Zubavichus,
• Gennady I. Nikishin and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2018, 14, 2146–2155, doi:10.3762/bjoc.14.188

• reaction time were varied (Table 1). In general, the iodo-oxyimidation reaction is characterized by the following: The product 3aa is formed regardless what kind of hypervalent iodine compound is used (Table 1, entries 1-14) and Oxone (Table 1, entries 15 and 16) as the oxidant. The best yield of 3aa (90

• system [74], (NH4)2S2O8, and DDQ were ineffective in the studied process (Table 1, entries 17–22). A satisfactory yield of 3aa (44%) was achieved using Oxone as the oxidant (Table 1, entry 15). The addition of a catalytic amount of 2-iodobenzoic acid, which forms hypervalent iodine compounds in the

• presence of Oxone [75], did not lead to an increased yield of 3aa (Table 1, entry 16). Dichloromethane proved to be the best solvent for the reaction, as carrying out the reaction in other solvents led to a decrease in the yield of 3aa (Table 1, entries 5–7). Increasing the amount of PhI(OAc)2 from 0.6

Preparation and X-ray structure of 2-iodoxybenzenesulfonic acid (IBS) – a powerful hypervalent iodine(V) oxidant

• Irina A. Mironova,
• Pavel S. Postnikov,
• Rosa Y. Yusubova,
• Akira Yoshimura,
• Thomas Wirth,
• Viktor V. Zhdankin,
• Victor N. Nemykin and
• Mekhman S. Yusubov

Beilstein J. Org. Chem. 2018, 14, 1854–1858, doi:10.3762/bjoc.14.159

• -iodobenzenesulfonate with Oxone or sodium periodate in water is reported. The single crystal X-ray diffraction analysis reveals a complex polymeric structure consisting of three units of IBS as potassium salt and one unit of 2-iodoxybenzenesulfonic acid linked together by relatively strong I=O···I intermolecular

• to the respective carbonyl compounds with Oxone® (2KHSO5·KHSO4·K2SO4) in nitromethane, acetonitrile, or ethyl acetate [13]. Recent research has revealed the extreme activity of IBS as a catalyst in numerous other oxidations, such as: the oxidation of benzylic and alkane C–H bonds [14], the oxidation

• different approaches: direct oxidation of 2-iodobenzenesulfonic acid (2) by Oxone or hydrolysis of methyl 2-iodoxybenzenesulfate (3, Scheme 1) [18]. The hydrolysis of sulfonic ester 3 forms IBS as a mixture with methanol which is quickly oxidized by IBS in situ producing the corresponding iodine(III

Synthesis of spirocyclic scaffolds using hypervalent iodine reagents

• Fateh V. Singh,
• Priyanka B. Kole,
• Saeesh R. Mangaonkar and
• Samata E. Shetgaonkar

Beilstein J. Org. Chem. 2018, 14, 1778–1805, doi:10.3762/bjoc.14.152

• iodine species or by generation of a similar active catalytic species in situ by the oxidation of iodoarene using a terminal oxidant. More commonly, m-chloroperbenzoic acid (mCPBA) and oxone are used as oxidant to generate the hypervalent iodine species in situ via oxidation of iodoarenes. In 2014, Singh

Hypervalent organoiodine compounds: from reagents to valuable building blocks in synthesis

• Gwendal Grelier,
• Benjamin Darses and
• Philippe Dauban

Beilstein J. Org. Chem. 2018, 14, 1508–1528, doi:10.3762/bjoc.14.128

• using Oxone as a terminal oxidant, thereby allowing for extending the scope of the reaction in terms of iodoarenes. Tandem oxidation–catalytic couplings A large range of oxidation reactions can be performed with [bis(acyloxy)iodo]arenes best represented by the commercially available reagents PhI(OAc)2

A survey of chiral hypervalent iodine reagents in asymmetric synthesis

• Soumen Ghosh,
• Suman Pradhan and
• Indranil Chatterjee

Beilstein J. Org. Chem. 2018, 14, 1244–1262, doi:10.3762/bjoc.14.107

• acid derivatives) with potassium bromate or Oxone (2KHSO5/KHSO4/K2SO4) efficiently delivered the I(V) reagents 4 (Scheme 2c) [28][29]. Although good product yields were obtained for the oxidation of sulfides, the ees were very low. New classes of chiral hypervalent iodine reagents were obtained by the

Iodine(III)-mediated halogenations of acyclic monoterpenoids

• Laure Peilleron,
• Tatyana D. Grayfer,
• Joëlle Dubois,
• Robert H. Dodd and
• Kevin Cariou

Beilstein J. Org. Chem. 2018, 14, 1103–1111, doi:10.3762/bjoc.14.96

• more user-friendly protocols that rely on Oxone® [20], DIB [24], or PIFA [25] since the iodide source is an iodide salt and not molecular iodine. Chlorination In the case of chlorination, we have yet to observe adducts arising from the vicinal difunctionalization of the double bond and, in accordance

2-Iodo-N-isopropyl-5-methoxybenzamide as a highly reactive and environmentally benign catalyst for alcohol oxidation

• Takayuki Yakura,
• Tomoya Fujiwara,
• Akihiro Yamada and
• Hisanori Nambu

Beilstein J. Org. Chem. 2018, 14, 971–978, doi:10.3762/bjoc.14.82

• to benzophenone in the presence of Oxone® (2KHSO5·KHSO4·K2SO4) as a co-oxidant at room temperature. A study on the substituent effect of the benzene ring of N-isopropyl-2-iodobenzamide on the oxidation revealed that its reactivity increased in the following order of substitution: 5-NO2 < 5-CO2Me, 3

• iodine; iodobenzamide; organic catalysis; oxidation; oxone; Introduction The development of an efficient and environmentally benign organic synthesis is required for minimizing material use, energy consumption, and environmental pollution in the production of both bulk and fine chemicals. Oxidation is a

• developed as catalysts for the oxidation of alcohols in the presence of Oxone® (2KHSO5·KHSO4·K2SO4) as a co-oxidant. In these reported systems, high temperatures (40–70 °C) are often required to generate potentially explosive pentavalent iodine compounds in situ except for the reactions involving

One-pot synthesis of diaryliodonium salts from arenes and aryl iodides with Oxone–sulfuric acid

• Natalia Soldatova,
• Pavel Postnikov,
• Olga Kukurina,
• Viktor V. Zhdankin,
• Akira Yoshimura,
• Thomas Wirth and
• Mekhman S. Yusubov

Beilstein J. Org. Chem. 2018, 14, 849–855, doi:10.3762/bjoc.14.70

• , Park Place, Main Building, Cardiff CF10 3AT, UK 10.3762/bjoc.14.70 Abstract A facile synthesis of diaryliodonium salts utilizing Oxone as versatile and cheap oxidant has been developed. This method shows wide applicability and can be used for the preparation of iodonium salts containing electron

• -donating or electron-withdrawing groups in good yields. In addition, this procedure can be applied to the preparation of symmetric iodonium salts directly from arenes via a one-pot iodination–oxidation sequence. Keywords: diaryliodonium salts; iodine; iodonium; oxidation; Oxone; Introduction

• highly desirable goal. Previously, we have published the utilization of Oxone® (2KHSO5·KHSO4·K2SO4) as a readily available and effective oxidant for the preparation of various hypervalent iodine compounds [36][37][38][39][40][41][42]. Oxone is used as an efficient oxidant for the direct conversion of

One-pot preparation of 4-aryl-3-bromocoumarins from 4-aryl-2-propynoic acids with diaryliodonium salts, TBAB, and Na₂S₂O₈

• Teppei Sasaki,
• Katsuhiko Moriyama and
• Hideo Togo

Beilstein J. Org. Chem. 2018, 14, 345–353, doi:10.3762/bjoc.14.22

• 2.0 equivalents or TBAB was increased to 2.5 equivalents under the same conditions, the yields of 3-bromo-4-phenylcoumarin (3Aa) were decreased to 51 and 69%, respectively (Table 2, entries 10 and 11). Moreover, when Na2S2O8 was changed to K2S2O8, (NH4)2S2O8, and Oxone® (2KHSO5·KHSO4·K2SO4), the

Mechanochemical synthesis of small organic molecules

• Tapas Kumar Achar,
• Anima Bose and
• Prasenjit Mal

Beilstein J. Org. Chem. 2017, 13, 1907–1931, doi:10.3762/bjoc.13.186

• and co-workers reported bromination of phenol derivatives, chalcones, 1,3-dicarbonyl compounds using NaBr as bromine source and oxone as oxidant under ball-milling conditions [96]. Within 1 h they could isolate more than 90% of mono or poly-brominated products of phenol and 1,3-dicarbonyl compounds

• agent oxone (Scheme 24) [97]. Carbon–carbon double (C=C) and triple (C≡C) bonds-containing compounds are also reported to undergo dihalogenation reactions under mechanochemical conditions. In 2014, Mal and co-workers reported a mild aryl halogenation reaction using respective N-halosuccinimide (NXS

• ). However, NCS-cericammonium nitrate (CAN) successfully yielded mono-chlorinated products [88]. Consecutively, the same group reported metal-free oxidative iodination of electron rich aromatic rings with molecular iodine and oxone (Scheme 25) [98]. This method proved to be highly chemoselective and no

Iodoarene-catalyzed cyclizations of N-propargylamides and β-amidoketones: synthesis of 2-oxazolines

• Somaia Kamouka and
• Wesley J. Moran

Beilstein J. Org. Chem. 2017, 13, 1823–1827, doi:10.3762/bjoc.13.177

• -iodoanisole provided a diminished yield of 6a (Table 1, entry 2) [12]. The iodoarene was found to be essential for the conversion of the starting material, as its absence led to complete return of 4a (Table 1, entry 3). Using Oxone as oxidant led to essentially no conversion of 4a (Table 1, entry 4). Changing

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

• ≈0.6 equivalents of oxone as an appropriate oxidant in wet dimethylformamide, at room temperature for the reaction of o-phenylenediamine 31 with appropriate aldehydes to afford 2-substituted benzimidazoles 32 in excellent yield [42]. The reaction conditions are amenable to a wide range of substrates

• excellent yield. The only limitation observed in this procedure is the use of aldehydes that contain functionalities which are susceptible to oxidation in the presence of oxone, failed to generate the desired products (Scheme 8a). An interesting application of oxone in the synthesis of 2-substituted

• benzimidazoles 33a, involved a one-pot condensation–ring distortion–oxidative dehydrogenation of o-aminobenzylamines 33 and appropriate aldehydes [43]. The reaction conditions included 0.6 equiv of oxone at room temperature with DMF as the solvent. Various aliphatic, aromatic and heteroaromatic aldehydes are

Urea–hydrogen peroxide prompted the selective and controlled oxidation of thioglycosides into sulfoxides and sulfones

• Adesh Kumar Singh,
• Varsha Tiwari,
• Kunj Bihari Mishra,
• Surabhi Gupta and
• Jeyakumar Kandasamy

Beilstein J. Org. Chem. 2017, 13, 1139–1144, doi:10.3762/bjoc.13.113

• within 1.5 h. However, corresponding sulfone was obtained in a moderated yield due to instability which undergoes partial amount of decomposition. In general, olefins functional groups are known to undergo epoxidation or dihydroxylation with different oxidizing agents (e.g. m-CPBA, t-BuOOH, oxone, etc

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

• (OAc)2-catalyzed ortho-hydroxylation of the synthesized diarylpyridines [59]. Their protocol employed oxone as oxidant, allowing the conversion to complete within 2 hours in PEG-3400/t-BuOH at 80–90 °C (Scheme 30). By employing their protocol, ortho-hydroxyarenes were predominately formed. This method

• developed by the Kamal and Nagesh group [65]. In their reaction system, oxone was used as oxidant, Cs2CO3 as base and DMF as solvent (Scheme 36). The reaction occurred at 120 °C and afforded the corresponding phenols in moderate yields. The catalytic system could also be used for alkoxylation of 2

• according to the proposed reaction mechanism. In 2015, Jiao and co-workers employed an oxime methyl ester as directing group and achieved the hydroxylation of arenes [67]. The reaction used Pd(OAc)2 as catalyst, PPh3 or DEAD as ligand and oxone as oxidant, affording the corresponding phenols in gratifying

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

• for 24 h (Scheme 12) [230]. Oxone is a convenient reagent for the transformation of α,β-unsaturated ketones 43 of determined stereochemistry into vinyl acetates 44 via the Baeyer–Villiger reaction in dry DMF for 7–39 h (Scheme 13) [231]. Oxidation with H2O2–heteroorganic catalyst systems: The activity

Towards potential nanoparticle contrast agents: Synthesis of new functionalized PEG bisphosphonates

• Souad Kachbi-Khelfallah,
• Maelle Monteil,
• Margery Cortes-Clerget,
• Evelyne Migianu-Griffoni,
• Jean-Luc Pirat,
• Olivier Gager,
• Julia Deschamp and
• Marc Lecouvey

Beilstein J. Org. Chem. 2016, 12, 1366–1371, doi:10.3762/bjoc.12.130

• one step has been performed. Thus, tested oxidants were the Jones reagent [22], potassium permanganate [23], with catalytic o-iodoxybenzoic acid (IBX) in oxone [24] and catalytic 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) with bis(acetoxy)iodobenzene (BAIB) [25]. The first two conditions led to a

• PEG chain cleavage and the recovery of benzoic acid from alcohol 2. Besides, the mixture IBX/oxone gave the expected product inseparable of IBX byproducts. Only oxidation using TEMPO and BAIB furnished the pure corresponding carboxylic acid. Nevertheless, the low obtained yields encouraged us to test

Base metal-catalyzed benzylic oxidation of (aryl)(heteroaryl)methanes with molecular oxygen

• Hans Sterckx,
• Johan De Houwer,
• Carl Mensch,
• Wouter Herrebout,
• Kourosch Abbaspour Tehrani and
• Bert U. W. Maes

Beilstein J. Org. Chem. 2016, 12, 144–153, doi:10.3762/bjoc.12.16

• conditions. Oxidations of this kind using Oxone® [10][11], NaOCl [12] or especially peroxides [13][14][15][16][17][18][19] as the terminal oxidant are quite numerous. However, transformations using molecular oxygen are rare. Ishii showed that organocatalysts such as N-hydroxyphthalimide (NHPI) in combination

Friedel–Crafts-type reaction of pyrene with diethyl 1-(isothiocyanato)alkylphosphonates. Efficient synthesis of highly fluorescent diethyl 1-(pyrene-1-carboxamido)alkylphosphonates and 1-(pyrene-1-carboxamido)methylphosphonic acid

• Anna Wrona-Piotrowicz,
• Janusz Zakrzewski,
• Anna Gajda,
• Tadeusz Gajda,
• Anna Makal,
• Arnaud Brosseau and
• Rémi Métivier

Beilstein J. Org. Chem. 2015, 11, 2451–2458, doi:10.3762/bjoc.11.266

• Oxone®. 1-(Pyrene-1-carboxamido)methylphosphonic acid was obtained in a 87% yield by treating the corresponding diethyl phosphonate with Me3Si-Br in methanol. All of the synthesized amidophosphonates were emissive in solution and in the solid state. The presence of a phosphonato group brought about an

• desulfurization of thioamides to amides via reaction with Oxone®. Now we want to apply this approach to the synthesis of N-thioacyl- and acyl derivatives of 1-aminoalkylphosphonates from arenes and 1-(isothiocyanato)alkylphosphonates. 1-Aminoalkylphosphonates and their derivatives are compounds of biological

• reaction conditions. The structures of 2a–d were confirmed by spectroscopic and elemental analysis data and (for 3a) by a single-crystal X-ray diffraction study (vide infra). Thioamidophoshonates 2a–d readily reacted with Oxone® in acetonitrile–water at room temperature to afford the corresponding

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

• oxidative dehydrogenation. Then we tested another procedure, in which the co-oxidant O2 was replaced with Oxone [29], but even in this case the conversion (6% by GC) was worse than that achieved using bubbling O2. Further attempts of optimizing the oxidative dehydrogenative step of the Stahl protocol were