Auxiliary strategy for the general and practical synthesis of diaryliodonium(III) salts with diverse organocarboxylate counterions

• Naoki Miyamoto,
• Daichi Koseki,
• Kohei Sumida,
• Elghareeb E. Elboray,
• Naoko Takenaga,
• Ravi Kumar and
• Toshifumi Dohi

Beilstein J. Org. Chem. 2024, 20, 1020–1028, doi:10.3762/bjoc.20.90

• wide range of substituents on (hetero)aryl iodine(III) compounds, including electron-rich, electron-poor, sterically congested, and acid-labile groups, as well as a broad range of aliphatic and aromatic carboxylic acids for the synthesis of diverse aryl(TMP)iodonium(III) carboxylates in high yields

• trifluoroacetic acid, followed by coupling with 1,3,5-trimethoxybenzene [18] (Scheme 1A). This process demonstrated tolerance for a wide range of electron-rich and electron-deficient (hetero)aryl iodine(III) compounds. Wirth and colleagues reported the flow synthesis of diaryliodonium(III) trifluoroacetates using

• (TFE, Scheme 2B) [21]. Our group previously reported the synthesis of diaryliodonium(III) salts by combining hypervalent iodine(III) reagents with electron-rich arenes in fluoroalcohol solvents, such as TFE or 1,1,1,3,3,3-hexafluoro-2-propanol [21][22]. These solvents stabilize the cationic

Three-component N-alkenylation of azoles with alkynes and iodine(III) electrophile: synthesis of multisubstituted N-vinylazoles

• Jun Kikuchi,
• Roi Nakajima and
• Naohiko Yoshikai

Beilstein J. Org. Chem. 2024, 20, 891–897, doi:10.3762/bjoc.20.79

• Jun Kikuchi Roi Nakajima Naohiko Yoshikai Graduate School of Pharmaceutical Sciences, Tohoku University, 6-3 Aoba, Aramaki, Aoba-ku, Sendai 980-8578, Japan 10.3762/bjoc.20.79 Abstract A stereoselective N-alkenylation of azoles with alkynes and iodine(III) electrophile is reported. The reaction

• reaction of azoles with alkynes and iodine(III) electrophile, benziodoxole triflate (BXT, 1; Scheme 1c). Displaying exclusive trans-selectivity, the reaction tolerates a broad range of azoles, including pyrazole, 1,2,3-triazole, tetrazole, indazole, and benzotriazole, with internal alkynes as coupling

• preparation of hitherto inaccessible types of densely functionalized vinylazoles with tetrasubstituted olefinic moiety. Results and Discussion Our group has demonstrated benziodoxole triflate (BXT) [26] and related compounds as a versatile iodine(III) electrophile for the inter- and intramolecular

Combining the best of both worlds: radical-based divergent total synthesis

• Kyriaki Gennaiou,
• Antonios Kelesidis,
• Maria Kourgiantaki and
• Alexandros L. Zografos

Beilstein J. Org. Chem. 2023, 19, 1–26, doi:10.3762/bjoc.19.1

• reported the flow-controlled divergent synthesis of aporphine and morphinandienone alkaloids based on biomimetic common scaffolds (e.g., 180) using hypervalent iodine(III) reagents. Capitalizing on previously reported mechanistic investigations, they assumed that 180 can rearrange to glaucine (183) through

Redox-active molecules as organocatalysts for selective oxidative transformations – an unperceived organocatalysis field

• Elena R. Lopat’eva,
• Igor B. Krylov,
• Dmitry A. Lapshin and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2022, 18, 1672–1695, doi:10.3762/bjoc.18.179

• the key factor for the high chemoselectivity. Hypervalent iodine catalysis Effective hypervalent iodine(III)-catalyzed processes (for example, oxidative double C=C bond functionalization, oxidative cyclizations, CH-functionalization of carbonyl compounds, etc.) employing mainly peroxoacids or electric

• current as terminal oxidants were developed [139][140][141][142][143][144][145]. The key step in the catalytic cycle involving aryl iodides is the formation of iodine(III) species. Enantioselective oxidative processes mediated by chiral hypervalent iodine compounds were reviewed recently [146]. In the

• configuration of the final product. A fundamentally different mechanism distinguishes the 1,2-diiodo-4,5-dimethoxybenzene catalyst from other aryl iodides. In contrast to the standard mechanism, in which iodine(III) is an active intermediate species, in the case of 1,2-diiodo-4,5-dimethoxybenzene, the iodine

Menadione: a platform and a target to valuable compounds synthesis

• Acácio S. de Souza,
• Ruan Carlos B. Ribeiro,
• Dora C. S. Costa,
• Fernanda P. Pauli,
• David R. Pinho,
• Matheus G. de Moraes,
• Fernando de C. da Silva,
• Luana da S. M. Forezi and
• Vitor F. Ferreira

Beilstein J. Org. Chem. 2022, 18, 381–419, doi:10.3762/bjoc.18.43

• published an alternative and sustainable methodology, using phenyliodine(III) bis(trifluoroacetate) (PIFA) as an oxidizing agent of the demethylation reaction [86]. The hypervalent iodine(III) proved to be a good oxidizing agent in the formation of 10 (92% yield) (Table 3, entry 2). According to the authors

An improved, scalable synthesis of Notum inhibitor LP-922056 using 1-chloro-1,2-benziodoxol-3-one as a superior electrophilic chlorinating agent

• Nicky J. Willis,
• Elliott D. Bayle,
• George Papageorgiou,
• David Steadman,
• Benjamin N. Atkinson,
• William Mahy and
• Paul V. Fish

Beilstein J. Org. Chem. 2019, 15, 2790–2797, doi:10.3762/bjoc.15.271

• et al. described the electrophilic chlorination of arenes and heterocycles by 1-chloro-1,2-benziodoxol-3-one (12) [18][19]. The hypervalent iodine(III) reagent 12 is reported to be a mild and effective reagent for the chlorination of nitrogen containing heterocycles which is easy to prepare and is

Thermal stability of N-heterocycle-stabilized iodanes – a systematic investigation

• Andreas Boelke,
• Yulia A. Vlasenko,
• Mekhman S. Yusubov,
• Boris J. Nachtsheim and
• Pavel S. Postnikov

Beilstein J. Org. Chem. 2019, 15, 2311–2318, doi:10.3762/bjoc.15.223

• )cyclic iodanes. Albeit aryl-λ3-iodanes are viewed as safe and stable under ambient temperatures, systematic thermal degradation studies of hypervalent iodine reagents are still rare. In 1992 Varvoglis and co-workers investigated the thermal degradation of a variety of aryl iodine(III) dicarboxylates into

Recent advances in transition-metal-catalyzed incorporation of fluorine-containing groups

• Xiaowei Li,
• Xiaolin Shi,
• Xiangqian Li and
• Dayong Shi

Beilstein J. Org. Chem. 2019, 15, 2213–2270, doi:10.3762/bjoc.15.218

• ] presented the nucleophilic fluorination of diaryliodonium salts with KF through a Cu(I/III) catalytic cycle mechanism. This procedure preferentially fluorinates the smaller aromatic ligand on iodine(III). Also, the addition of Cu(OTf)2 and 18-crown-6 promoted the fluorination effectively. Finally, excellent

Mechanochemistry of supramolecules

• Anima Bose and
• Prasenjit Mal

Beilstein J. Org. Chem. 2019, 15, 881–900, doi:10.3762/bjoc.15.86

• exothermic reactions between amines and iodine(III) [114]. By this process undirected C(sp3)–H bonds were shown to be functionalized for dehydrogenative imination reactions. Overall, at 1,5-distances (remote) a dehydrogenative and intramolecular C(sp3)–H imination by 4H elimination was readily done via

• the iodine(III) environment. Conclusion Over the last years, substantial progress has been made in the area of mechanochemistry as environmentally benign method in organic synthesis, materials science and supramolecular chemistry. In this review the major focus has been to cover the concept and

• (pyridin-4-yl)ethylene and 4,6-dichlororesorcinol. Halogen-bonded co-crystals via a) I···P, b) I···As, and c) I···Sb bonds [112]. Transformation of contact-explosive primary amines and iodine(III) into a successful chemical reaction for amide synthesis. Undirected C–H functionalization by using the acidic

Selective benzylic C–H monooxygenation mediated by iodine oxides

• Kelsey B. LaMartina,
• Haley K. Kuck,
• Linda S. Oglesbee,
• Asma Al-Odaini and
• Nicholas C. Boaz

Beilstein J. Org. Chem. 2019, 15, 602–609, doi:10.3762/bjoc.15.55

• . Results and Discussion We have recently reported a system of simple combinations of an iodine (III, V, or VII) oxide with a catalytic amount of chloride for the direct oxygenation of methane to its methyl ester [49][50]. Mechanistic studies of this system have indicated that these chloride-iodate

• acid and NHPI oxidation of formed alkyl iodide intermediate to an iodine(III) species was necessary for the conversion to a substituted product [54][55]. While we cannot rule out that oxidation of formed benzylic iodide intermediates occurs in the production of benzylic acetate the production of ester

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

• ]. Aryliodonium imides or iminoiodanes can be prepared by the treatment of electron-deficient amines with iodine(III). However, these compounds explode at higher temperatures [4] and hence are stored under inert atmosphere and low temperature [5]. Polyvalent iodine derivatives are versatile reagents for C–N bond

• of primary amines and hypervalent iodine(III) reagents by controlling the reactivity using an acid salt, NaHSO4, as additive [9]. Results and Discussion The last few decades have witnessed a significant growth in organic synthesis using hypervalent iodines [10][11][12]. Their easy availability, high

Determining the predominant tautomeric structure of iodine-based group-transfer reagents by ¹⁷O NMR spectroscopy

• Nico Santschi,
• Cody Ross Pitts,
• Benson J. Jelier and
• René Verel

Beilstein J. Org. Chem. 2018, 14, 2289–2294, doi:10.3762/bjoc.14.203

• (e.g., 5a versus 5b) these may only provide limited information, as neither nucleus is a primary constituent of the central iodine(III) (a, X–I–O) or iodine(I) (b, O–X) motif of interest. In stark contrast, changes in the oxygen ligand's environment should be readily traceable upon oxidation from

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

• interactions. Furthermore, a new method for the preparation of the reduced form of IBS, 2-iodosylbenzenesulfonic acid, by using periodic acid as an oxidant, has been developed. It has been demonstrated that the oxidation of free 2-iodobenzenesulfonic acid under acidic conditions affords an iodine(III

• 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

• filtration. 1H and 13C NMR spectra of product 4 are identical to the previously reported spectroscopic data for 2-iodosylbenzenesulfonic acid [18][21][22]. In particular, the 1H NMR displayed the characteristic signal of the ortho-proton (relative to iodine(III)) at about 8.0 ppm and 13C NMR exhibited the

Synthesis of new tricyclic 5,6-dihydro-4H-benzo[b][1,2,4]triazolo[1,5-d][1,4]diazepine derivatives by [3⁺ + 2]-cycloaddition/rearrangement reactions

• Lin-bo Luan,
• Zi-jie Song,
• Zhi-ming Li and
• Quan-rui Wang

Beilstein J. Org. Chem. 2018, 14, 1826–1833, doi:10.3762/bjoc.14.155

• the quinolones 6 and phenylhydrazine with a catalytic amount of AcOH in refluxing n-propyl alcohol. Subsequently, the hydrazones 7 were converted into the 4-acetoxy-1-acetyl-4-phenylazo-1,2,3,4-tetrahydroquinolines 8 via the oxidation with hypervalent iodine(III) reagent PhI(OAc)2 (Scheme 2) [45]. The

• -dihydro-4(1H)-quinolone 6a [46]. However, it was odd that the oxidation using the hypervalent iodine(III) reagent PhI(OAc)2 as described for phenylhydrazones 7 failed to produce the expected α-acetoxy-ethoxycarbonyl compound 12. Instead, the hydrazone 11 remained intact and was recovered. Therefore, we

Recent advances in hypervalent iodine(III)-catalyzed functionalization of alkenes

• Xiang Li,
• Pinhong Chen and
• Guosheng Liu

Beilstein J. Org. Chem. 2018, 14, 1813–1825, doi:10.3762/bjoc.14.154

• Xiang Li Pinhong Chen Guosheng Liu State Key Laboratory of Organometallic Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China 10.3762/bjoc.14.154 Abstract Hypervalent iodine(III

• ) reagents have been well-developed and widely utilized in functionalization of alkenes, however, generally either stoichiometric amounts of iodine(III) reagents are required or stoichiometric oxidants such as mCPBA are employed to in situ generate iodine(III) species. In this review, recent developments of

• hypervalent iodine(III)-catalyzed functionalization of alkenes and asymmetric reactions using a chiral iodoarene are summarized. Keywords: asymmetric catalysis; functionalization of alkenes; hypervalent iodine(III); Introduction Hypervalent iodine(III) reagents, also named as λ3-iodanes, have been widely

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

• ][34][35][36][37][38] and electrophilic nature of different iodine(III) reagents has been explored to developed various synthetic transformation including rearrangements [39][40][41][42][43][44][45][46][47][48][49][50][51][52][53][54][55][56][57][58][59][60][61][62]. Hypervalent iodine chemistry has

• reactions. Hypervalent iodine reagents are mainly popular for their oxidative properties but various iodine(III) reagents have been used as electrophiles. Numerous iodine(III) reagents have been successfully used to achieve diverse spirocyclic scaffolds. Phenols 7 or 11 having an internal nucleophile at

• ortho- or para-position can be used as starting material for the synthesis of ortho- and para-spirocyclic compounds in the presence of iodine(III)-based electrophiles (Scheme 1). Phenolic oxygen of compound 7 attacks to the iodine of 8 to form intermediate 9. Furthermore, on nucleophilic attack of the

Metal-free formal synthesis of phenoxazine

• Gabriella Kervefors,
• Antonia Becker,
• Chandan Dey and
• Berit Olofsson

Beilstein J. Org. Chem. 2018, 14, 1491–1497, doi:10.3762/bjoc.14.126

• , unusually stable iodine(III) intermediate in the O-arylation was observed by NMR and could be converted to the product upon longer reaction time. Keywords: arylation; cyclization; diaryl ether; diaryliodonium salt; phenol; Introduction Phenoxazine (1) is a tricyclic compound consisting of an oxazine ring

• underwent an intramolecular N-arylation to provide the cyclized product 2. The overall yield in this three-step sequence is 72% based on recovered diaryl ether. Interestingly, an unusually stable iodine(III) intermediate was formed in the O-arylation. This species survived neutral work-up and could be

Synthesis of trifluoromethylated 2H-azirines through Togni reagent-mediated trifluoromethylation followed by PhIO-mediated azirination

• Jiyun Sun,
• Xiaohua Zhen,
• Huaibin Ge,
• Guangtao Zhang,
• Xuechan An and
• Yunfei Du

Beilstein J. Org. Chem. 2018, 14, 1452–1458, doi:10.3762/bjoc.14.123

• higher temperature was unsuccessful (Table 1, entry 7). Replacing the catalyst CuI with other commonly used copper catalysts including CuCl, CuBr and CuOAc led to a decreased yield in each case (Table 1, entries 8–10). In addition the other commonly employed hypervalent iodine(III) reagents, namely, PIDA

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

• –Hagihara reaction was developed by Dauban and co-workers (Scheme 16) [47]. The first step of this sequence includes an iodine(III)-mediated rhodium-catalysed enantioselective amination of an unactivated C(sp3)–H bond with a chiral sulfonimidamide 31. Afterwards, the iodoarene byproduct of the first step is

• substituted acrylamidines 35 (Scheme 19). The proposed reaction mechanism starts with the activation of DMSO (A) via the iodine(III) species 20b. Iodosoarene C is released under basic conditions, forming the sulfonium intermediate D. This intermediate reacts with the amidine 34 to give the sulfide E, which is

• = Ph). 3. Benziodoxolones Iodine(III) compounds with a benziodoxolone or a benziodoxole structure are privileged reagents for electrophilic group transfer reactions, in particular in electrophilic alkynylations, azidations, cyanations and trifluoromethylations [3][50][51][52][53][54]. Here, 2

Investigations of alkynylbenziodoxole derivatives for radical alkynylations in photoredox catalysis

• Yue Pan,
• Kunfang Jia,
• Yali Chen and
• Yiyun Chen

Beilstein J. Org. Chem. 2018, 14, 1215–1221, doi:10.3762/bjoc.14.103

• radical; alkynylbenziodoxoles; photoredox catalysis; radical alkynylation; Introduction The introduction of the alkynyl group to organic molecules is an important synthetic transformation in organic synthesis [1][2][3][4]. Recently, cyclic iodine(III) reagents (CIR)-substituted alkynes

• (Scheme 4). Tertiary alcohols 6 were reported to be activated by cyclic iodine(III) reagents under photoredox conditions to generate alkoxyl radicals, and subsequently underwent β-fragmentation and alkynylation to yield 7 after eliminating the arylketone [25]. With tertiary alcohol 6a as the alkyl radical

• ’-alkyne 3a gave a slightly lower 63% yield of 9 [21]. β-Ketone alcohols 10 were reported to be activated by cyclic iodine(III) reagents under photoredox conditions to generate alkoxyl radicals, and subsequently underwent β-fragmentation and alkynylation to yield ynone 9 [26]. The unsubstituted BI-alkyne

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

• hypervalent iodine(III) reagent-mediated oxidation of sodium sulfinates has been developed. This transformation involves trapping reactive sulfonium species using alcohols. With additional optimization of the reaction conditions, the method appears extendable to other nucleophiles such as electron-rich

Recyclable hypervalent-iodine-mediated solid-phase peptide synthesis and cyclic peptide synthesis

• Dan Liu,
• Ya-Li Guo,
• Jin Qu and
• Chi Zhang

Beilstein J. Org. Chem. 2018, 14, 1112–1119, doi:10.3762/bjoc.14.97

• Dan Liu Ya-Li Guo Jin Qu Chi Zhang State Key Laboratory of Elemento-Organic Chemistry, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), College of Chemistry, Nankai University, Tianjin 300071, China 10.3762/bjoc.14.97 Abstract The system of the hypervalent iodine(III

• worth noting that FPID can be readily regenerated after the peptide coupling reaction. Keywords: cyclic peptide; FPID; hypervalent iodine(III) reagent; recyclable; solid-phase peptide synthesis (SPPS); Introduction The amide bond is one of the most fundamental functional groups in organic chemistry

• mediated by hypervalent iodine(III) reagents in recent years. In 2012, for the first time, we reported that the hypervalent iodine(III) reagent iodosodilactone (Figure 1) can serve as a condensing reagent to promote esterification, macrolactonization, amidation and peptide coupling reactions in 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

• halofunctionalizations of acyclic monoterpenoids were performed using a combination of a hypervalent iodine(III) reagent and a halide salt. In this manner, the dibromination, the bromo(trifluoro)acetoxylation, the bromohydroxylation, the iodo(trifluoro)acetoxylation or the ene-type chlorination of the distal

• halogenations with increased selectivity. In this regard, hypervalent iodine reagents [6] have emerged as particularly versatile mediators [7][8][9][10]. We have shown that electrophilic halogenations [11][12][13], or pseudohalogenations [14] can be triggered by combining an iodine(III) derivative with a

• suitable halide salt. In particular, the chemoselectivity of the reaction can be finely tuned by adjusting several parameters, such as the nature of the halide as well as of the iodine(III) ligands and the halide counterion [15][16]. In the case of polyprenoids, we mostly devoted our efforts to achieve the

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

• aqueous benzylic oxidations using polymeric iodosobenzene in the presence of inorganic bromide and montmorillonite-K10 [51]. In addition, a radical C–H activation strategy, using nonaqueous hypervalent iodine(III)/inorganic bromide systems that can work in organic solvents, was developed for the novel

• synthesis of lactones via the intramolecular oxidative cyclization of aryl carboxylic acids at the benzyl carbon under transition-metal-free conditions [52]. Based on our previous research and general interest in the unique reactivity of hypervalent iodine(III)–Br bonds [53][54][55][56], we report 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(III)-mediated decarboxylative acetoxylation at tertiary and benzylic carbon centers

• Kensuke Kiyokawa,
• Daichi Okumatsu and
• Satoshi Minakata

Beilstein J. Org. Chem. 2018, 14, 1046–1050, doi:10.3762/bjoc.14.92

• indicated that the reaction proceeds via the formation of an alkyl iodide and the corresponding iodine(III) species as key intermediates. In this context, we concluded that the use of such an oxidation system, combined with the judicious choice of solvent, would enable a decarboxylative C–O bond forming

• formed, and the starting material was recovered. These results strongly support a reaction pathway involving the formation of an alkyl iodide, which is oxidized by PhI(OAc)2 to the corresponding hypervalent iodine(III) species that then undergoes acetoxylation. Based on the experimental results and our