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

• achievements reported in this area. Keywords: atom-economy; couplings; hypervalent iodine; oxidation; tandem reactions; Introduction Synthetic applications of the hypervalent iodine chemistry have grown exponentially in the last four decades as highlighted by several books and comprehensive reviews dedicated

• than its O-tautomer 88, the rearrangement step seems to be much faster. The use of the radical scavenger TEMPO had no effect on the reaction outcome suggesting that the initial hypothesis is correct. By screening additives, it was shown that the hypervalent iodine could be quickly generated in situ by

• application of modern transition-metal-catalyzed methods. Simple hypervalent iodine reagents can now be considered as valuable building blocks in the synthesis of both polyfunctionalized compounds and complex polycyclic skeletons. We believe that the application of this strategy could be a source of

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

• -dimethyl-1,2-benziodoxole (1’, Figure 2), are effective and efficient hypervalent iodine reagents for trifluoromethylation reactions of a variety of substrates [22][23]. These reagents have found wide applications in the area of organofluorine chemistry, synthetic method development as well as medicinal

• [52][53][54][55] have been developed for accessing this exclusive class of heterocycles. In our previous works, we have realized the application of hypervalent iodine reagents for the construction of the 2H-azirine skeleton starting from enamines 2 via intramolecular oxidative cyclization (Scheme 1

• -obtained trifluoromethylated enamines could undergo a hypervalent iodine-mediated intramolecular azirination to give the corresponding trifluoromethylated 2H-azirines [56][57]. To test this conversion, the readily available enamine 5a was used as a model substrate. The treatment of 5a with Togni reagent 1

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

• Andreas Boelke Peter Finkbeiner Boris J. Nachtsheim Institute for Organic and Analytical Chemistry, University of Bremen, 28359 Bremen, Germany 10.3762/bjoc.14.108 Abstract Hypervalent iodine compounds, in particular aryl-λ3-iodanes, have been used extensively as electrophilic group-transfer

• atom efficiency. Keywords: atom economy; benziodoxolones; homogeneous catalysis; hypervalent iodine; iodonium salts; Introduction Atom economy (AE) is an important parameter which helps to evaluate the overall efficiency of a chemical reaction or a chemical process [1][2]. It is defined as the

• -economical transformations using hypervalent iodine reagents (iodanes) as electrophilic group-transfer reagents. Iodanes, in particular iodonium salts, are well-balanced reagents in terms of stability, reactivity and synthetic and/or commercial availability and therefore it is not surprising to see these

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

• Soumen Ghosh Suman Pradhan Indranil Chatterjee Department of Chemistry, Indian Institute of Technology Ropar, Nangal Road, Rupnagar, Punjab 140001, India 10.3762/bjoc.14.107 Abstract The recent years have witnessed a remarkable growth in the area of chiral hypervalent iodine chemistry. These

• last 25 years. This review highlights the contribution of different chiral hypervalent iodine reagents in diverse asymmetric conversions. Keywords: alkene functionalization; asymmetric synthesis; hypervalent iodine; organocatalysis; oxidation; Introduction It is more than one century ago since the

• 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

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

• heteroarenes was realized using the benziodoxolone hypervalent iodine reagents indoleBXs. Functionalization of the C–H bond in bipyridinones and quinoline N-oxides catalyzed by a rhodium complex allowed to incorporate indole rings into aza-heteroaromatic compounds. These new transformations displayed complete

• regioselectivity for the C-6 position of bipyridinones and the C-8 position of quinoline N-oxides and tolerated a broad range of functionalities, such as halogens, ethers, or trifluoromethyl groups. Keywords: C–H activation; hypervalent iodine; indoleBX; indoles; pyridinones; rhodium catalysis; Introduction

• nitrogen and a transition metal catalyst (reaction 1, Scheme 1A) [11][12][13][14][15][16][17][18][19]. In particular, Li and co-workers have used ethynylbenziodoxolone (EBX) hypervalent iodine reagents to achieve a regiodivergent alkynylation of the pyridinone core employing either a gold(I) or a rhodium

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

• aromatic systems or cyclic ethers through a ring opening pathway. Keywords: hypervalent iodine; oxidation; sulfinates; sulfonation; sulfonium; Introduction Over the past few decades, hypervalent iodine reagents [1][2][3][4] have emerged as versatile and environmentally benign substitutes for heavy metal

• 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

One hundred years of benzotropone chemistry

• Arif Dastan,
• Haydar Kilic and
• Nurullah Saracoglu

Beilstein J. Org. Chem. 2018, 14, 1120–1180, doi:10.3762/bjoc.14.98

• repeated the synthesis of 12 through a molecular bromination–dehydrobromination sequence starting with 162 [137]. Hypervalent iodine(V)-based reagents such as IBX (or 2-iodoxybenzoic acid) and Dess–Martin periodinane (DMP) are commonly used in organic synthesis as oxidizing agent to form both unsaturated

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

• . Hypervalent iodine reagents have drawn researchers’ considerable attentions due to their versatile reactivity, low toxicity, ready availability, environmental friendliness, and regenerability [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27]. Our group has dedicated to the peptide synthesis

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

• trisubstituted double bond occurred with excellent selectivity and moderate to good yields. Keywords: halogenation; hypervalent iodine; monoterpenes; Introduction In nature, mostly in marine environments, halogenated compounds are produced by means of various enzymes that rely on widely available halides as

• 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

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

• , reports aimed at realizing efficient and selective metal-free C(sp3)–H transformations are rather limited; however, investigations by several research groups are still ongoing [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30]. Hypervalent iodine reagents are now widely accepted as a safe

• oxidations was recognized for displaying the new reactivities of hypervalent iodine reagents toward C(sp3)–H bonds [38][39]. By exploiting the radical behavior of trivalent iodine reagents discovered previously [40][41], the activation of trivalent iodine reagents, e.g., phenyliodine(III) diacetate (PIDA

• 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

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

• . Keywords: acetoxylation; carboxylic acids; decarboxylation; hypervalent iodine; iodine; Introduction The decarboxylative functionalization of carboxylic acids and the derivatives thereof is an important transformation in organic synthesis. In recent years, increasing efforts have been devoted to the

• 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

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

• Cyrus Mowdawalla Faiz Ahmed Tian Li Kiet Pham Loma Dave Grace Kim I. F. Dempsey Hyatt Department of Chemistry and Biochemistry, Adelphi University, 1 South Ave., Garden City, NY, 11530, USA 10.3762/bjoc.14.91 Abstract The reactivity of benzyl hypervalent iodine intermediates was explored in

• congruence with the reductive iodonio-Claisen rearrangement (RICR) to show that there may be an underlying mechanism which expands the reasoning behind the previously known C–C bond-forming reaction. By rationalizing the hypervalent iodine’s metal-like properties it was concluded that a transmetallation

• mechanism could be occurring with metalloid groups such as silicon and boron. Hypervalent iodine reagents such as Zefirov’s reagent, cyclic iodonium reagents, iodosobenzene/BF3, and PhI(OAc)2/BF3 or triflate-based activators were tested. A desirable facet of the reported reaction is that iodine(I) is

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

• Innovation Foundation (DGMIF), 80 Cheombok-ro, Dong-gu, Daegu, Republic of Korea 10.3762/bjoc.14.89 Abstract Hypervalent iodine-mediated olefin functionalization provides a rapid gateway towards accessing both various heterocyclic cores and functional groups. In this regard, we have developed a Ritter-type

• . Keywords: amido-amidation; hypervalent iodine; isoxazoline; metal-free; oxyamidation; pyrazoline; Introduction Isoxazoline and pyrazoline-containing heterocycles are abundant in natural products and biologically active molecules [1][2][3][4][5]. Thus, these scaffolds are also important from the standpoint

• , diverse halonium sources have been utilized for the synthesis of isoxazolines via halocyclization. Furthermore, transition metal-, visible light, and hypervalent iodine-mediated oxidative cyclization protocols provide isoxazoline backbones bearing diverse substituents such as –SR, -CF3, -OH and halogens

Fluorocyclisation via I(I)/I(III) catalysis: a concise route to fluorinated oxazolines

• Felix Scheidt,
• Christian Thiehoff,
• Gülay Yilmaz,
• Stephanie Meyer,
• Constantin G. Daniliuc,
• Gerald Kehr and
• Ryan Gilmour

Beilstein J. Org. Chem. 2018, 14, 1021–1027, doi:10.3762/bjoc.14.88

• ; cyclisation; fluorination; gauche effect; hypervalent iodine; oxazolines; Introduction Marine and terrestrial natural product bioprospecting has established a broad spectrum of structurally complex, bioactive metabolites containing the venerable 2-oxazoline unit [1][2]. This diversity is exemplified by the

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

• ; biheterocycles; hypervalent iodine; iodine; oxidatively assisted esterification; Introduction In recent years, the interest in heterocyclic organohypervalent iodine compounds has experienced an unprecedented growth [1][2][3][4][5][6]. A variety of new hypervalent iodine heterocycles have been prepared, and

• 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

Cross-coupling of dissimilar ketone enolates via enolonium species to afford non-symmetrical 1,4-diketones

• Keshaba N. Parida,
• Gulab K. Pathe,
• Shimon Maksymenko and
• Alex M. Szpilman

Beilstein J. Org. Chem. 2018, 14, 992–997, doi:10.3762/bjoc.14.84

• of enolates may be used to form the 1,4-diketone products in 38 to 74% yield. Due to the use of two TMS enol ethers as precursors, an optimization of the cross-coupling should include investigating the order of addition. Keywords: 1,4-diketones; enolates; enolonium species; hypervalent iodine

• -coupling by using cerium(IV) as a one-electron oxidant [11]. Importantly for the discussion of the present work, Wirth’s strategy relied on a hypervalent iodine [13][14][15] mediated oxidative cross-coupling. Although these processes add a further step to the process, carrying out the cross-coupling in an

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

• derivative at room temperature is a result of the rapid generation of the pentavalent species from the trivalent species during the reaction. 5-Methoxy-2-iodobenzamide would be an efficient and environmentally benign catalyst for the oxidation of alcohols, especially benzylic alcohols. Keywords: hypervalent

• fundamental and frequently used transformation in organic synthesis. Heavy metal-based oxidants such as chromium(VI), lead(IV), and mercury(II) have been extensively used for this purpose for a long time. However, these oxidants are highly toxic and produce hazardous waste. Recently, hypervalent iodine

• iodobenzene and 4-iodobenzenesulfonic acid (12) as catalysts [58][59]. As part of our study on the development of multifunctionalized organocatalysts based on hypervalent iodine chemistry [60][61][62][63][64][65][66], we found that N-isopropyl-2-iodobenzamide (13), when utilized as a catalyst with Oxone® at

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

• Diaryliodonium salts, which are also known as diaryl-λ3-iodanes, are widely considered to be an important and practically useful class of hypervalent iodine compounds [1][2][3][4]. Diaryliodonium salts have found broad synthetic application as electrophilic arylating reagents in reactions with various

• 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

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

• regioselective reaction of aryl- and α-substituted phenylallenes with the hypervalent iodine (HVI) reagent 1-chloro-1,2-benziodoxol-3-one. The reaction typically results in vicinal dichlorides, except with proton-containing α-alkyl substituents, which instead give chlorinated dienes as the major product

• . Experimental evidence suggests that a radical mechanism is involved. Keywords: allene; chlorination; hypervalent iodine; synthetic methods; vinyl chloride; Introduction Organochlorine compounds are vital as polymer precursors [1], as pharmaceuticals [2][3] and agrochemicals [4][5][6] and as functional

• vicinal-dichlorination of phenylallenes; however, no such chlorination reaction has yet been achieved [29][30][31][32][33][34]. Recent reports of reactions between hypervalent iodine reagents and phenylallenes have highlighted the possible product outcomes achievable through ionic and radical reaction

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

• )-isomer. Keywords: 1,2-difunctionalization of alkenes; enantioselective synthesis; hypervalent iodine; oxidation; Findings Hypervalent aryl-λ3-iodanes have been widely used for metal-free oxidation with high selectivity in organic synthesis [1][2][3]. The reactivity of an aryl-λ3-iodane is controlled by

Synthesis of fluoro-functionalized diaryl-λ³-iodonium salts and their cytotoxicity against human lymphoma U937 cells

• Prajwalita Das,
• Etsuko Tokunaga,
• Hidehiko Akiyama,
• Hiroki Doi,
• Norimichi Saito and
• Norio Shibata

Beilstein J. Org. Chem. 2018, 14, 364–372, doi:10.3762/bjoc.14.24

• )phenyl)iodonium exhibited the greatest potency in vitro against U937 cells. Evaluation of the cytotoxicity of selected phenylaryl-λ3-iodonium salts against AGLCL (a normal human B cell line) was also examined. Keywords: biological activity; diaryliodonium salt; fluorine; hypervalent iodine; lymphoma

• compounds in the pharmaceutical history indicates that some of these reagents have a heterocyclic skeleton which makes them suitable as drug candidates [29][30][31][32]. Among these compounds, our group is interested in investigating the biological activity of hypervalent iodine-type reagents [33

• ]. Hypervalent iodine compounds have been receiving a lot of attention lately due to their varied applications in organic synthesis [33][34][35][36][37][38][39][40]. A wide range of bioactive compounds make use of diaryliodonium reagents as a part of their synthesis [41][42][43]. On the other hand, there are

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

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 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

• , 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

• 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

• persulfate by hypervalent iodine oxidants such as iodobenzene diacetate (PIDA, Scheme 28) [49], or iodobenzene bis(trifluoroacetate) (PIFA) [50]. Fu and co-workers proposed the reaction mechanism depicted in Scheme 28. PIDA reacted with CF3SO2Na under heating conditions to produce two radicals: CF3• along