Hypervalent iodine-guided electrophilic substitution: para-selective substitution across aryl iodonium compounds with benzyl groups

• Cyrus Mowdawalla,
• Faiz Ahmed,
• Tian Li,
• Kiet Pham,
• Loma Dave,
• Grace Kim and
• I. F. Dempsey Hyatt

Beilstein J. Org. Chem. 2018, 14, 1039–1045, doi:10.3762/bjoc.14.91

• metal-like properties of iodine(III) were particularly significant in the development of the reaction reported in this communication [15][16]. A commonality in the RICR is that the proposed mechanisms involve an unstable allyl or propargyl hypervalent iodine intermediate. To the best of our knowledge

Hypervalent iodine-mediated Ritter-type amidation of terminal alkenes: The synthesis of isoxazoline and pyrazoline cores

• Sang Won Park,
• Soong-Hyun Kim,
• Jaeyoung Song,
• Ga Young Park,
• Darong Kim,
• Tae-Gyu Nam and
• Ki Bum Hong

Beilstein J. Org. Chem. 2018, 14, 1028–1033, doi:10.3762/bjoc.14.89

• , this hypervalent iodine-mediated Ritter-type oxyamidation of 1a proved less efficient in the presence of solvent combinations with acetonitrile, despite acetonitrile being used in vast excess (see Supporting Information File 1, Table S1). Herein, we entail the first example of a hypervalent iodine(III

• Scheme 4. First, an activation of hypervalent iodine(III) by the Lewis acid generates the active iodine(III) species A in situ. The resulting iodine(III) then, in turn, forms the electrophilic iodonium intermediate B with the terminal alkene of the allyl ketone oxime or allyl ketone tosylhydrazone. The

• subsequent 5-exo-type cyclization by nucleophilic attack on the iodonium then leads to the isoxazoline or pyrazoline cores (C) bearing the hypervalent iodine(III) group. Following iodine activation by the Lewis acid, the iodonium ion D undergoes nucleophilic substitution with excess acetonitrile to form

Preparation, structure, and reactivity of bicyclic benziodazole: a new hypervalent iodine heterocycle

• Akira Yoshimura,
• Michael T. Shea,
• Cody L. Makitalo,
• Melissa E. Jarvi,
• Gregory T. Rohde,
• Akio Saito,
• Mekhman S. Yusubov and
• Viktor V. Zhdankin

Beilstein J. Org. Chem. 2018, 14, 1016–1020, doi:10.3762/bjoc.14.87

• numerous reactions employing these compounds as reagents for organic synthesis have been reported. The benziodoxole-based five-membered iodine heterocycles represent a particularly important class of hypervalent iodine(III) reagents. Substituted benziodoxoles 1 (Scheme 1a) are commonly employed as

• and peptides [23][24][25]. Numerous examples of five-membered hypervalent iodine(III) heterocycles containing other than oxygen heteroatoms, such as sulfur [26], boron [27][28], phosphorous [29], or nitrogen [30][31][32], have been synthesized and characterized by X-ray crystallography. In particular

• , several nitrogen containing heterocyclic iodine(III) compounds 5, benziodazoles, have been reported by Gougoutas [31], Balthazor [32], and our group [33][34][35] (Scheme 1c). X-ray structural studies of these benziodazoles confirmed the presence of covalent bonding between iodine and nitrogen atoms in the

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

• based on the use of inexpensive, commercially available oxidants is an important and challenging goal. A vast majority of existing procedures involve the interaction of electrophilic hypervalent iodine(III) species with suitable arenes through ligand exchange processes [16][17][18][19][20]. The reactive

• hypervalent iodine(III) species can be used as stable reagents or can be generated in situ [21][22][23][24][25]. In particular, Olofsson and co-workers reported procedures based on the in situ generation of reactive λ3-iodane species directly from arenes, which was a significant achievement in this field [26

• the generation of iodine(III) species in the oxidation of phenols [43]. In the present work, we report the development of a reliable and convenient procedure for the preparation of diaryliodonium bromides using Oxone in the presence of sulfuric acid. Results and Discussion After having investigated

Enantioselective dioxytosylation of styrenes using lactate-based chiral hypervalent iodine(III)

• Morifumi Fujita,
• Koki Miura and
• Takashi Sugimura

Beilstein J. Org. Chem. 2018, 14, 659–663, doi:10.3762/bjoc.14.53

• Morifumi Fujita Koki Miura Takashi Sugimura Graduate School of Material Science, University of Hyogo, Kohto, Kamigori, Hyogo 678-1297, Japan 10.3762/bjoc.14.53 Abstract A series of optically active hypervalent iodine(III) reagents prepared from the corresponding (R)-2-(2-iodophenoxy)propanoate

• derivative was employed for the asymmetric dioxytosylation of styrene and its derivatives. The electrophilic addition of the hypervalent iodine(III) compound toward styrene proceeded with high enantioface selectivity to give 1-aryl-1,2-di(tosyloxy)ethane with an enantiomeric excess of 70–96% of the (S

Oxidative cycloaddition of hydroxamic acids with dienes or guaiacols mediated by iodine(III) reagents

• Hisato Shimizu,
• Akira Yoshimura,
• Keiichi Noguchi,
• Victor N. Nemykin,
• Viktor V. Zhdankin and
• Akio Saito

Beilstein J. Org. Chem. 2018, 14, 531–536, doi:10.3762/bjoc.14.39

• moderate to high yields. The present method could be applied to the HDA reactions of acylnitroso species with o-benzoquinones generated by the oxidative dearomatization of guaiacols. Keywords: acylnitroso; benzoquinone; cycloaddition; dearomatization; iodine(III); Introduction The hetero-Diels–Alder (HDA

• research on the syntheses of heterocycles by iodine(III)-mediated/catalyzed oxidative cycloaddition reactions [17][18][19], we have found that iodine(III) reagents are effective in the oxidation of N–O bonds of oximes in the cycloaddition reaction of in situ formed nitrile oxides [20][21]. Although Adam

• and Bottke’s group have demonstrated that (diacetoxyiodo)benzene (DIB) and iodosylbenzene are applicable to the ene reactions of acylnitroso species derived from hydroxamic acids [22], the iodine(III)-mediated oxidative cycloaddition reaction of hydroxamic acids with dienes is still unknown. Herein

Progress in copper-catalyzed trifluoromethylation

• Guan-bao Li,
• Chao Zhang,
• Chun Song and
• Yu-dao Ma

Beilstein J. Org. Chem. 2018, 14, 155–181, doi:10.3762/bjoc.14.11

• -membered-ring transition state. Note that the presence of an olefin moiety in the product promised further conversion to other types of CF3-containing molecules. Later, the group of Wang [50] employed cheap copper chloride as the catalyst and a hypervalent iodine(III) reagent 1j as both the oxidant and the

CF₃SO₂X (X = Na, Cl) as reagents for trifluoromethylation, trifluoromethylsulfenyl-, -sulfinyl- and -sulfonylation. Part 1: Use of CF₃SO₂Na

• Hélène Guyon,
• Hélène Chachignon and
• Dominique Cahard

Beilstein J. Org. Chem. 2017, 13, 2764–2799, doi:10.3762/bjoc.13.272

• , CF3H, as an ideal source of trifluoromethide offered new horizons for atom-economical, low-cost trifluoromethylation reactions. With regard to electrophilic CF3 donors, S-(trifluoromethyl)sulfonium salts developed by Yagupolskii and Umemoto and hypervalent iodine(III)-CF3 reagents developed by Togni

Syntheses, structures, and stabilities of aliphatic and aromatic fluorous iodine(I) and iodine(III) compounds: the role of iodine Lewis basicity

• Tathagata Mukherjee,
• Soumik Biswas,
• Andreas Ehnbom,
• Subrata K. Ghosh,
• Ibrahim El-Zoghbi,
• Nattamai Bhuvanesh,
• Hassan S. Bazzi and
• John A. Gladysz

Beilstein J. Org. Chem. 2017, 13, 2486–2501, doi:10.3762/bjoc.13.246

• , acetone; 58–69%). Subsequent reactions with NaOCl/HCl give iodine(III) dichlorides RfnCH2ICl2 (n = 11, 13; 33–81%), which slowly evolve Cl2. The ethereal fluorous alcohols CF3CF2CF2O(CF(CF3)CF2O)xCF(CF3)CH2OH (x = 2–5) are similarly converted to triflates and then to iodides, but efforts to generate the

• to alkenes [7][8]. In previous papers, we have reported convenient preparations of a variety of fluorous alkyl iodides [13][14][15], aryl iodides [16][17], and hypervalent iodine(III) derivatives [16][17][18][19]. The latter have included aliphatic iodine(III) bis(trifluoroacetates) [18][19] and

• dichlorides [17], and aromatic iodine(III) bis(acetates) [16] and dichlorides [17]. The bis(carboxylates) have been employed as recyclable reagents for oxidations of organic substrates [16][18][19], and some of the dichlorides are depicted in Scheme 1. Others have described additional fluorous iodine(III

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

• bond synthesis under ball-milling conditions. Cross dehydrogenative coupling reactions between benzaldehydes and benzylamines were performed in presence of phenyliodine diacetate (PIDA) using the acid salt NaHSO4 [81]. The highly exergonic reaction (contact explosive) of acidic iodine(III) and basic

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

• -phenylpentanoic acid (3, Scheme 1a–c) [14]. These three cyclizations exemplify three different proposed reaction pathways, i.e., iodine(III) activation of alkenes, alkynes and ketones. These cyclizations can be rendered enantioselective by the generation of non-racemic chiral iodine(III) species from chiral

• by an in situ generated iodine(III) species followed by intramolecular attack by the amide (Scheme 3). Subsequent addition of water leads to the loss of the iodoarene and tautomerization of the resulting enol generates the ketone 6. With these results in hand, we envisaged an alternative approach to

• , 6p is formed under the reaction conditions but the oxazoline ring is readily hydrolysed due to the influence of the electron-withdrawing nitro group on the aromatic ring. The mechanism of this cyclization is proposed to proceed through the formation of iodine(III)-enolate 9 followed by intramolecular

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

• for their synthesis have been developed. Among them are reactions between lithium or sodium acetylides and electrophilic selenium reactants [23]. The use of hypervalent iodine(III) species [24] or alkynyl bromides with RSeLi [25] as nucleophilic selenium species or the reaction of alkynyl bromides

Pyridylidene ligand facilitates gold-catalyzed oxidative C–H arylation of heterocycles

• Kazuhiro Hata,
• Hideto Ito,
• Yasutomo Segawa and
• Kenichiro Itami

Beilstein J. Org. Chem. 2015, 11, 2737–2746, doi:10.3762/bjoc.11.295

• was also detected. Furthermore, a significant amount of methyl 2-iodobenzoate (5) was generated through the esterification of a co-product (2-iodobenzoic acid) with methanol. We also tested other iodine(III) reagents such as PhI(OAc)2, PhI(OCOCF3)2 and PhI(OH)(OTs), but they all resulted in lower

• mechanism of the gold-catalyzed C–H arylation of heteroarenes with arylsilanes as shown in Scheme 1. A gold(I) complex A is first oxidized to gold(III) species B by the iodine(III) reagent E derived from IBA by the exchange of a hydroxy group with an existing acid such as CSA, HCl and MeOH. We independently

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

• of amides 87 [82], and the acyloxylation of compounds containing the S-methyl-S-pyridylsulfoximine moiety 88 [83] were accomplished to prepare coupling products 90–95 (Scheme 19). In some cases, the latter reaction proceeds efficiently even at room temperature. Iodine(III) compounds 89

• of iodine(III) oxidants (50–130 °C, Scheme 19 and Scheme 20). Under similar conditions methyl groups of N-(quinolin-8-yl)amides were acetoxylated using the Cu(OAc)2 catalyst (50 mol %) and AgOAc (3 equiv) as acetoxylating agent. The acetoxylation of alkyl groups of O-acetyl oximes 102 taking place in

• , for example, molecular iodine, the Bu4NI/t-BuOOH system, organic iodine(III or V) compounds, bromides combined with oxidants, hypochlorite, and so on, acted as oxidants. The oxidative coupling of primary alcohols 130 with methanol or trifluoroethanol and the oxidative coupling of aldehydes 132 with

New developments in gold-catalyzed manipulation of inactivated alkenes

• Michel Chiarucci and
• Marco Bandini

Beilstein J. Org. Chem. 2013, 9, 2586–2614, doi:10.3762/bjoc.9.294

• aryltrimethylsilanes. b) Oxyarylation of alkenes catalyzed by gold in presence of iodine-(III) compound IBA as an external oxidant. Oxy- and amino-arylation of alkenes by [Au(I)]/[Au(III)] photoredox catalysis. Comparison of the catalytic activity of TfOH and PPh3AuOTf in the addition of phenols to alkenes

Regioselective 1,4-trifluoromethylation of α,β-unsaturated ketones via a S-(trifluoromethyl)diphenylsulfonium salts/copper system

• Satoshi Okusu,
• Yutaka Sugita,
• Etsuko Tokunaga and
• Norio Shibata

Beilstein J. Org. Chem. 2013, 9, 2189–2193, doi:10.3762/bjoc.9.257

• % yield (Table 1, entry 10). Using 4.0 equiv of Umemoto’s reagent 3b instead of 3a gave the product 2a in 27% yield (Table 1, entry 12). S-(Trifluoromethyl)benzothiophenium salt 3c [24], trifluoromethylsulfoxinium salt 3d [25], and hypervalent iodine(III) CF3 reagent 3e [26] did not proceed or provided

Hypervalent iodine/TEMPO-mediated oxidation in flow systems: a fast and efficient protocol for alcohol oxidation

• Nida Ambreen,
• Ravi Kumar and
• Thomas Wirth

Beilstein J. Org. Chem. 2013, 9, 1437–1442, doi:10.3762/bjoc.9.162

• Nida Ambreen Ravi Kumar Thomas Wirth Cardiff University, School of Chemistry, Park Place, Cardiff CF10 3AT, UK 10.3762/bjoc.9.162 Abstract Hypervalent iodine(III)/TEMPO-mediated oxidation of various aliphatic, aromatic and allylic alcohols to their corresponding carbonyl compounds was

• -oxyl) as a catalyst in the oxidation of alcohols has gained much attention in recent years [10][11][12]. The redox cycle involves beside TEMPO also the corresponding hydroxylamine and the oxoammonium cation, which oxidizes the alcohol and is converted to TEMPO–H [13]. Hypervalent iodine(III) reagents

Study on the total synthesis of velbanamine: Chemoselective dioxygenation of alkenes with PIFA via a stop-and-flow strategy

• Huili Liu,
• Kuan Zheng,
• Xiang Lu,
• Xiaoxia Wang and
• Ran Hong

Beilstein J. Org. Chem. 2013, 9, 983–990, doi:10.3762/bjoc.9.113

• , mediated by metals such as Os, Mn, Pd, Ru, Fe, and Ag [26][27][28][29][30][31][32][33][34][35][36][37]. On the other hand, the metal-free hypervalent iodine(III)-mediated reactions have recently enjoyed a renaissance attracting extensive investigations [38][39]. It is particularly interesting in the case

The crystal structure of the Dess–Martin periodinane

• Albert Schröckeneder,
• Desiree Stichnoth,
• Peter Mayer and
• Dirk Trauner

Beilstein J. Org. Chem. 2012, 8, 1523–1527, doi:10.3762/bjoc.8.172

• . However, the standard protocol for the preparation of 1 requires filtration and washing of the filter cake with ether. The combined filtrates thus consist of a solution of residual 1 and various byproducts, including iodine(III) intermediates, in a mixed solution of ether and acetic anhydride. We reasoned

Organic synthesis using (diacetoxyiodo)benzene (DIB): Unexpected and novel oxidation of 3-oxo-butanamides to 2,2-dihalo-N-phenylacetamides

• Wei-Bing Liu,
• Cui Chen,
• Qing Zhang and
• Zhi-Bo Zhu

Beilstein J. Org. Chem. 2012, 8, 344–348, doi:10.3762/bjoc.8.38

• ; 3-oxo-N-phenylbutanamides; Introduction Hypervalent iodine(III) reagents [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] have received much attention, as reflected by the plethora of publications and reviews [19][20][21][22][23]. This is due to their low toxicity, ready availability

Hypervalent iodine(III)-induced methylene acetoxylation of 3-oxo-N-substituted butanamides

• Wei-Bing Liu,
• Cui Chen,
• Qing Zhang and
• Zhi-Bo Zhu

Beilstein J. Org. Chem. 2011, 7, 1436–1440, doi:10.3762/bjoc.7.167

• ][29][30]. The availability of iodine(III) and iodine(V) compounds and the development of new reagents, along with their low toxicity, ready availability, easy handling, clean transformation and reactivity, their selectivity under a variety of conditions, and their tolerance to different functional

• groups make these compounds valuable tools in organic synthesis [31][32][33][34][35][36]. Our interest in the chemistry of polyvalent iodine(III) reagents [37][38][39] prompted us to exploit the reactivity of (diacetoxyiodo)benzene (DIB). We report herein the use of DIB, as a nucleophile and oxidant, to

• electrons of the carbamoyl nitrogen [39][40][41] or carbonyl oxygen [42][43][44][45] on the iodine(III) of DIB, forming intermediates 3 and 5, respectively. Alternatively, DIB attacks the C–C double bond of the enol derived from 1a and forms intermediate 6 [46][47]. The subsequent N–I, O–I and C–I bond

A practical microreactor for electrochemistry in flow

• Kevin Watts,
• William Gattrell and
• Thomas Wirth

Beilstein J. Org. Chem. 2011, 7, 1108–1114, doi:10.3762/bjoc.7.127

• syntheses as mild, non-toxic and highly selective reagents. Iodine(III) reagents with two carbon ligands are known as iodonium salts. These salts are attractive alternatives to oxidants and catalysts based on heavy metals, as they have similar properties to those of heavy metal complexes and can, therefore

Aromatic and heterocyclic perfluoroalkyl sulfides. Methods of preparation

• Vladimir N. Boiko

Beilstein J. Org. Chem. 2010, 6, 880–921, doi:10.3762/bjoc.6.88

Shelf-stable electrophilic trifluoromethylating reagents: A brief historical perspective

• Norio Shibata,
• Andrej Matsnev and
• Dominique Cahard

Beilstein J. Org. Chem. 2010, 6, No. 65, doi:10.3762/bjoc.6.65

• family of hypervalent iodine(III)-CF3 reagents as mild electrophilic trifluoromethylating agents suitable for reactions with carbon- and heteroatom-centered nucleophiles. These reagents further demonstrated generality in trifluoromethylation of a wide range of nucleophiles including the

• , enamines, and thiolate anions with these reagents, albeit in low to moderate yields [28]. Neutral hypervalent iodine(III)–CF3 reagent Initial attempts by Yagupolskii and Umemoto to synthesize iodonium salts with a trifluoromethyl group were unsuccessful. Whilst iodonium salts including p

Benzyne arylation of oxathiane glycosyl donors

• Martin A. Fascione and
• W. Bruce Turnbull

Beilstein J. Org. Chem. 2010, 6, No. 19, doi:10.3762/bjoc.6.19

• with external alcohols would be easier to achieve if the phenyl sulfonium ion was formed with a less reactive counter ion. However, oxidation of 1-ABT in the presence of ketal 14 with NIS [33], or hypervalent iodine (III) with either bis(acetoxy)iodobenzene [PhI(OAc)2] [34] or bis(trifluoroacetoxy