Visible-light-promoted radical cyclisation of unactivated alkenes in benzimidazoles: synthesis of difluoromethyl- and aryldifluoromethyl-substituted polycyclic imidazoles

• Yujun Pang,
• Jinglan Yan,
• Nawaf Al-Maharik,
• Qian Zhang,
• Zeguo Fang and
• Dong Li

Beilstein J. Org. Chem. 2025, 21, 234–241, doi:10.3762/bjoc.21.15

• reaction (Table 1). Employing PIDA as the promoter, THF as the solvent, and 72 W white LED as the light source, the desired product 3a formed in 85% isolated yield at room temperature (Table 1, entry 1). We found that the hypervalent iodine reagent was of significant importance for the present

Reactivity of hypervalent iodine(III) reagents bearing a benzylamine with sulfenate salts

• Beatriz Dedeiras,
• Catarina S. Caldeira,
• José C. Cunha,
• Clara S. B. Gomes and
• M. Manuel B. Marques

Beilstein J. Org. Chem. 2024, 20, 3281–3289, doi:10.3762/bjoc.20.272

• conducted at room temperature for 20 hours, which resulted in a reduction of the yield for 5aa to 9% (Table 1, entry 5). This result might be due to the reactivity of this hypervalent iodine reagent. Indeed, we have previously observed that the transfer of the benzylamine moiety to carbon-based nucleophiles

Structure and thermal stability of phosphorus-iodonium ylids

• Andrew Greener,
• Stephen P. Argent,
• Coby J. Clarke and
• Miriam L. O’Duill

Beilstein J. Org. Chem. 2024, 20, 2931–2939, doi:10.3762/bjoc.20.245

• and potential decomposition pathways will enable the future design and development of new reagents. Keywords: hypervalent iodine; reagent development; structural analysis; thermal stability; thermogravimetric analysis; Introduction Hypervalent iodine(III) reagents have experienced a renaissance in

Hydrogen-bond activation enables aziridination of unactivated olefins with simple iminoiodinanes

• Phong Thai,
• Lauv Patel,
• Diyasha Manna and
• David C. Powers

Beilstein J. Org. Chem. 2024, 20, 2305–2312, doi:10.3762/bjoc.20.197

• , signaling the binding of HFIP to 2c enhanced the electron transfer kinetics between the hypervalent iodine reagent and the electrode [45]. Further additions of HFIP further increased the current response and shifted the peak potential, with 10 µL and 15 µL of HFIP showing responses with Epr at −1.55 V and

Solvent-dependent chemoselective synthesis of different isoquinolinones mediated by the hypervalent iodine(III) reagent PISA

• Ze-Nan Hu,
• Yan-Hui Wang,
• Jia-Bing Wu,
• Ze Chen,
• Dou Hong and
• Chi Zhang

Beilstein J. Org. Chem. 2024, 20, 1914–1921, doi:10.3762/bjoc.20.167

• isoquinolinone derivatives. The method provides highly chemoselective access to 3- or 4-substituted isoquinolinone derivatives by reacting o-alkenylbenzamide derivatives with PISA in either acetonitrile or wet hexafluoro-2-isopropanol. Keywords: annulation; C–H amination; hypervalent iodine reagent; iodine(III

• option for the preparation of isoquinolinone derivatives. In 2020, two reports have been published on the conversion of alkyne-tethered N-alkoxybenzamides to isoquinolinones by intramolecular oxidative annulation, either electrochemically or using the hypervalent iodine reagent phenyliodine(III

• zwitterionic water-soluble hypervalent iodine reagent (phenyliodonio)sulfamate (PISA). In water, PISA is strongly acidic, and the pH value can reach 2.05 in a saturated aqueous solution. With PISA, various indoles have been synthesized via C–H amination of 2-alkenylanilines involving an aryl migration

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

• research group [71] reported the synthesis of spirocarbocyclic compounds 106 from arylalkynes 105 using a hypervalent iodine reagent generated in situ by the oxidation of bis(iodoarene) 25 in the presence of mCPBA as an terminal oxidant (Scheme 38). Wang and co-workers [110] developed a hypervalent iodine

• substrates and polymer-supported hypervalent iodine reagent was used in one step. In this report, p-substituted phenolic compound 131 was cyclized to spirocyclic compound 133 in 50% yield containing a seven membered ring system. The cyclization reaction was carried out using polymer-supported PIFA reagent

β-Hydroxy sulfides and their syntheses

• Mokgethwa B. Marakalala,
• Edwin M. Mmutlane and
• Henok H. Kinfe

Beilstein J. Org. Chem. 2018, 14, 1668–1692, doi:10.3762/bjoc.14.143

• -catalyzed 1,2-acetoxysulfenylation of Baylis–Hillman products at 50 °C under an oxygen atmosphere as shown in Scheme 35 [70]. The β-ketomethylene 94 substrate was generated in situ from the oxidation of Baylis–Hillman product 93 using a hypervalent iodine reagent (iodoxybenzoic acid, IBX) in an ionic liquid

Glycosylation reactions mediated by hypervalent iodine: application to the synthesis of nucleosides and carbohydrates

• Yuichi Yoshimura,
• Hideaki Wakamatsu,
• Yoshihiro Natori,
• Yukako Saito and
• Noriaki Minakawa

Beilstein J. Org. Chem. 2018, 14, 1595–1618, doi:10.3762/bjoc.14.137

• thietane nucleosides [47]. The substrate of the coupling reaction was prepared as shown in Scheme 6 starting from benzyloxyacetaldehyde (50). When a hypervalent iodine reagent was used for glycosylation with a diastereomeric mixture of sulfide 53, the reaction stereoselectively gave the ring-expanded

• nucleoside 54 in 30% yield, but did not give the desired thietane nucleoside at all (Scheme 6). Considered that the ring-expansion occurred in the absence of the hypervalent iodine reagent, the Nishizono and co-workers speculated that the reaction mechanism was as shown in Scheme 7. First, the Lewis acid

• , similar deformylation by action of hypervalent iodine has also been demonstrated: the β-fragmentation reaction of an anomeric alkoxy radical of carbohydrates was mediated by a hypervalent iodine reagent [73]. The reaction results in the formation of carbohydrates with a reduction of one carbon. From the

Atom-economical group-transfer reactions with hypervalent iodine compounds

• Andreas Boelke,
• Peter Finkbeiner and
• Boris J. Nachtsheim

Beilstein J. Org. Chem. 2018, 14, 1263–1280, doi:10.3762/bjoc.14.108

• usage of 1.5 to 2.0 equivalents of the hypervalent iodine reagent 20b lowers the conclusive atom efficiencies. In another closely related procedure, Das and co-workers employed PIDA derivatives 20b for an aromatization–arylation cascade of exocyclic β-enaminones 27 [46]. Under basic reaction conditions

• -catalysed reaction with diazo compounds 42 (Scheme 22) [56]. This strategy is not only atom economic regarding the applied hypervalent iodine reagent but also with regard to the chosen substrate. The metal carbene species generated from the diazo compounds displays nucleophilic as well as electrophilic

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

• discovery of the first hypervalent iodine reagent (HIR) [1] and hypervalent iodine chemistry has started to flourish as one of the important and leading areas in organic synthesis. In recent years many excellent reviews have detailed the bonding, reactivity, synthesis, and uses of hypervalent iodine

• new kind of binaphthyl-based chiral I(III) prereagent 19 with the 8 and 8′ positions of the naphthalene substituents being occupied by iodide. Here they have observed that this chiral hypervalent iodine reagent 19 in the presence of co-oxidant m-CBPA is very useful for the dearomatizing

• with moderate enantioselectivity (Scheme 4). Although modest ees were obtained, this chiral oxazoline-based compound demonstrated encouraging potential as a new class of chiral hypervalent iodine reagent. Fujita et al. synthesized non C2-symmetric chiral iodoarene reagents 9a derived from lactic acid

Rhodium-catalyzed C–H functionalization of heteroarenes using indoleBX hypervalent iodine reagents

• Erwann Grenet,
• Ashis Das,
• Paola Caramenti and
• Jérôme Waser

Beilstein J. Org. Chem. 2018, 14, 1208–1214, doi:10.3762/bjoc.14.102

• unique reactivity of the benziodoxolone hypervalent iodine reagent. The scope and limitations of the reaction were then studied (Scheme 2). The diversification of the directing group was examined first. The unsubstituted pyridine group led to the formation of product 7a in 86% yield. The electron-rich 5

• hypervalent iodine reagent was then investigated with three selected compounds only. A bromo substituent on the benzene ring was well tolerated (7q). The coupling could be also performed with N–H unprotected indoleBX reagents to afford products 7r and 7s in 84% and 77% yield, respectively. We also applied

• corresponding hypervalent iodine reagent (0.20 mmol, 1.00 equiv) were solubilized in dry MeOH (2.0 mL, 0.1 M) under N2 atmosphere. The mixture was stirred at 80 °C for 12 h. The mixture was then diluted with DCM (5 mL) and quenched with a saturated aqueous solution of NaHCO3 (5 mL). The two layers were

Rapid transformation of sulfinate salts into sulfonates promoted by a hypervalent iodine(III) reagent

• Elsa Deruer,
• Vincent Hamel,
• Samuel Blais and
• Sylvain Canesi

Beilstein J. Org. Chem. 2018, 14, 1203–1207, doi:10.3762/bjoc.14.101

• the alcohol. In this paper, we demonstrate that sulfonates may be produced from alcohols in the presence of sufinates through a reaction mediated by a hypervalent iodine reagent. Under these conditions, the byproduct is a weak acid such as acetic acid rather than hydrochloric acid. Results and

• -iodosuccinimide (NIS) were also tested; it appeared that this process was much more efficient in the presence of iodane sources (Table 1). DIB was chosen as the hypervalent iodine reagent of choice since it is more compatible with alcohols than IBX or DMP. The reaction proceeded in modest to good yields depending

Selective carboxylation of reactive benzylic C–H bonds by a hypervalent iodine(III)/inorganic bromide oxidation system

• Toshifumi Dohi,
• Shohei Ueda,
• Kosuke Iwasaki,
• Yusuke Tsunoda,
• Koji Morimoto and
• Yasuyuki Kita

Beilstein J. Org. Chem. 2018, 14, 1087–1094, doi:10.3762/bjoc.14.94

• hypervalent iodine reagent were reported, both of which include the formation of benzyl radicals during the key initial reaction step. Togo and co-workers developed a reaction system consisting of stoichiometric amounts of PIDA with catalytic amounts of molecular iodine and p-toluenesulfonamide for the

• initiated by the decomposition of PIFA to form the trifluoroacetoxy radical under visible light irradiation [50]. Our approach for the generation of radical species for the benzylic carboxylation using a hypervalent iodine reagent relies on the unique reactivity of the hypervalent iodine(III)–bromine bond

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

• transmetallation with an appropriate metalloid substrate. This concept is counter to previous mechanisms in which the electrophilic hypervalent iodine reagent is attacked by unsaturated C–C bonds [18][19][20][21][22]. To show evidence for this transmetallation event, benzyl metalloid groups were used under the

• hypervalent iodine-guided electrophilic substitution (HIGES) reaction were performed by varying the hypervalent iodine starting material, the activator, the solvent, and the temperature at which the activated hypervalent iodine reagent formed (Table 1). Varying the temperature at 25 °C, 0 °C, and −50 °C did

• directions seek to elucidate the mechanism of the HIGES reaction and to develop the methodology into a reaction capable of synthesizing a variety of diphenylmethane structures. Experimental General procedure: The hypervalent iodine reagent (1.0 equiv) was added to the appropriate solvent. The reaction was

Chlorination of phenylallene derivatives with 1-chloro-1,2-benziodoxol-3-one: synthesis of vicinal-dichlorides and chlorodienes

• Zhensheng Zhao and
• Graham K. Murphy

Beilstein J. Org. Chem. 2018, 14, 796–802, doi:10.3762/bjoc.14.67

• efficient new process for the chlorination of substituted phenylallene derivatives using the hypervalent iodine reagent 1-chloro-1,2-benziodoxol-3-one (1b). The reactions disclosed here represent the first report of a regioselective chlorination of phenylallenes, in which the 2,3-allene olefin undergoes

Diels–Alder cycloadditions of N-arylpyrroles via aryne intermediates using diaryliodonium salts

• Huangguan Chen,
• Jianwei Han and
• Limin Wang

Beilstein J. Org. Chem. 2018, 14, 354–363, doi:10.3762/bjoc.14.23

• coupling for pyrroles using a hypervalent iodine reagent and a stabilizer for pyrrolyliodonium intermediates (Scheme 1c) [9]. The reactions readily provided a variety of desired coupling products in good yields. In general, the mechanism of these arylations was postulated by generating aryl radicals with

CF₃SO₂X (X = Na, Cl) as reagents for trifluoromethylation, trifluoromethylsulfenyl-, -sulfinyl- and -sulfonylation and chlorination. Part 2: Use of CF₃SO₂Cl

• Hélène Chachignon,
• Hélène Guyon and
• Dominique Cahard

Beilstein J. Org. Chem. 2017, 13, 2800–2818, doi:10.3762/bjoc.13.273

• -cyanotrifluoromethylations [22] of alkenes under photoredox catalysis. These reactions proceeded through a formyl or a cyano group migration triggered by the addition of the trifluoromethyl radical onto the alkene moiety. Both methodologies were developed using Togni’s hypervalent iodine reagent as the CF3 source, but it

• introduction of the CF3 moiety on enol acetates (Scheme 29) [37]. Anecdotally, CF3SO2Cl was evaluated for the trifluoromethylation of allylsilanes, but, disappointingly, gave lower yields than Togni’s hypervalent iodine reagent [38]. More recently, Balaraman and co-workers studied extensively the reaction of β

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

• reactions with K2S2O8, I2O5 or a hypervalent iodine reagent, and (iii) photochemical activation. Most of the works concerned cascade intramolecular reactions in which a C–C bond is formed after the initial trifluoromethylation. Therefore, Lipshutz and co-workers reported a copper-catalysed intramolecular

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

• tryptophan derivatives with appropriate aldehydes. A hypervalent iodine reagent, iodobenzene diacetate was used in stoichiometric quantities to facilitate both oxidative decarboxylation/dehydrogenation of 108–110 to afford the desired natural products 111–113 (Scheme 42). Conclusion Substantial amount of

Gold-catalyzed direct alkynylation of tryptophan in peptides using TIPS-EBX

• Gergely L. Tolnai,
• Jonathan P. Brand and
• Jerome Waser

Beilstein J. Org. Chem. 2016, 12, 745–749, doi:10.3762/bjoc.12.74

• is highly attractive, but the use of a carbon linker is usually required. Herein, we report the gold-catalyzed direct alkynylation of tryptophan in peptides using the hypervalent iodine reagent TIPS-EBX (1-[(triisopropylsilyl)ethynyl]-1,2-benziodoxol-3(1H)-one). The reaction proceeded in 50–78% yield

• the Sonogashira reaction, which requires modified non-natural amino acids [32][33]. In 2013, our group reported the alkynylation of thiols using the hypervalent iodine reagent TIPS-EBX (1a, 1-[(triisopropylsilyl)ethynyl]-1,2-benziodoxol-3(1H)-one) (Scheme 1A) [34]. The reaction was almost

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

• such oxidative reaction conditions. For example, triphenylphosphine is easily oxidized to triphenylphosphine oxide by a hypervalent iodine reagent that has been used as an oxidant for gold-catalyzed C–H arylation [69]. Appropriate ligands that are tolerant to the oxidative conditions would offer

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

• -aryl migration step. This was mediated by a hypervalent iodine reagent, PhI(OAc)2 (13), conducted in trimethyl orthoformate (14, TMOF) and methanol (Scheme 2). The direct saponification of the resulting rearranged methyl ester with an excess of base thus completed the telescoped flow synthesis of

Recent advances in transition metal-catalyzed Csp²-monofluoro-, difluoro-, perfluoromethylation and trifluoromethylthiolation

• Grégory Landelle,
• Armen Panossian,
• Sergiy Pazenok,
• Jean-Pierre Vors and
• Frédéric R. Leroux

Beilstein J. Org. Chem. 2013, 9, 2476–2536, doi:10.3762/bjoc.9.287

• -releasing groups at the 5-position, and considering the regioselective 3-functionalization of N-methylindole, the authors proposed the following catalytic cycle: 1) electrophilic palladation of indole, 2) oxidation of the resulting Pd(II) species by the combination of the hypervalent iodine reagent and

• trifluoromethylation; indeed, all of them used the same electrophilic CF3 source, namely Togni’s benziodoxolone reagent. M. Sodeoka and coworkers reported on the trifluoromethylation of indoles with Togni’s hypervalent iodine reagent in the presence of catalytic copper(II) acetate [82]. No additives were necessary

• towards a variety of functional groups (Table 23) [93]. Q. Shen reported on the copper-catalyzed trifluoromethylation of aryl- and alkenylboronic acids employing Togni's hypervalent iodine reagent. The reaction proceeds in good to excellent yields affording a wide range of trifluoromethylated products

Zinc–gold cooperative catalysis for the direct alkynylation of benzofurans

• Yifan Li and
• Jérôme Waser

Beilstein J. Org. Chem. 2013, 9, 1763–1767, doi:10.3762/bjoc.9.204

• auration and reductive elimination [33]. The role of the zinc Lewis acid is not completely clear at this stage, but it may act by complexing the carboxylate group of the hypervalent iodine reagent, enhancing its electrophilic reactivity [19][34]. In fact, a complete shift of the 1H NMR signals of TIPS-EBX

• acid, together with the use of the hypervalent iodine reagent TIPS-EBX (8). Preliminary results obtained with 8-methoxypsoralen (2) demonstrated that the reaction could also be applied to more complex furocoumarin natural products. Experimental General procedure for the alkynylation of benzofurans

• Yifan Li Jerome Waser Laboratory of Catalysis and Organic Synthesis, Ecole Polytechnique Fédérale de Lausanne, EPFL SB ISIC LCSO, BCH4306, 1015 Lausanne, Switzerland 10.3762/bjoc.9.204 Abstract The direct alkynylation of benzofurans was achieved for the first time using the hypervalent iodine

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

• the Dess–Martin periodinane (DMP), a hypervalent iodine reagent popular amongst synthetic chemists. In the solid state, the highly crystalline compound forms an intricate coordination polymer held together by intermolecular halogen and hydrogen bonds. Keywords: crystal structure; Dess–Martin