Reactivity of a Hypervalent Iodine Trifluoromethylating Reagent toward THF: Ring Opening and Formation of Trifluoromethyl Ethers

Fantasia, Serena; Welch, Jan M.; Togni, Antonio

doi:10.1021/jo9025429

Cited by 74 publications

(41 citation statements)

References 42 publications

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“…Therefore, it is reasonable to assume that the ratedetermining step of the reaction involves the protonated form of reagent 1 and CD 3 CN. This is in line with our previous observations concerning the trifluoromethylation of THF [15] and toluenesulfonic acid. [11] On the basis of these rate studies and our previous experience with these systems, we propose the mechanism shown in Scheme 3.…”

supporting

confidence: 93%

“…Thus, as an example, the structure of compound 4 in solution was determined by multinuclear NMR methods. Figure 2 shows sections of the corresponding 19 F, 15 The structure of the two constitutional isomers 8 and 9 were determined in solution by analogous NMR methods and confirmed by X-ray analysis. Corresponding ORTEP representations and selected geometrical parameters are shown in Figure 3.…”

mentioning

confidence: 89%

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A Ritter‐Type Reaction: Direct Electrophilic Trifluoromethylation at Nitrogen Atoms Using Hypervalent Iodine Reagents

et al. 2010

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The unique features the trifluoromethyl group imparts to pharmaceuticals, crop-protection agents, and functional materials emphasize the necessity to design and develop new reagents and methods for the direct trifluoromethylation of a wide range of organic substrates. Electrophilic trifluoromethylation, that is, the reaction of a suitable reagent capable of formally transferring an intact CF 3 + unit, has been shown to be one of these methods.[1] However, despite the availability of several such effective reagents, the electrophilic trifluoromethylation of hard nucleophiles, for example, oxygen-or nitrogen-centered ones, remains challenging. In particular, the formation of a N À CF 3 bond by such a reaction is still extremely rare. In fact, the NCF 3 unit is usually constructed by the interconversion of suitable functional groups. Thus, fluorination of N-formylamines, [2] thiuram sulfides, [3] isocyanates, [4] and trichloromethylamines, [5] the reaction of secondary amines with CBr 2 F 2 and tetrakis(dimethylamino)ethylene, [6] and the electrochemical fluorination of alkylamines [7] constitute the still relatively modest set of methods. Of these, the most frequently used approach is the oxidative desulfurization-fluorination of dithiocarbamates first described for the generation of NCF 3 groups by Hiyama and Kuroboshi.[8]The single, still very recent report of a direct trifluoromethylation at nitrogen is due to Umemoto and co-workers.[9] They describe the direct N-trifluoromethylation of amines, anilines, and pyridines under very mild conditions achieved with in situ generated and thermally unstable O-(trifluoromethyl)dibenzofuranium salts (corresponding reactions of alcohols and phenols are also known). However, this type of reagent suffers from several shortcomings. The active CF 3 source is obtained by photochemical decomposition of diazonium salts at very low temperature, and the synthesis requires several steps including the construction of a CF 3 O-aryl moiety. It is therefore likely that this methodology will not replace the corresponding functional-group interconversions in the near future.We have shown that a new generation of readily accessible trifluoromethylation reagents based on hypervalent iodine, such as compounds 1 and 2 (Scheme 1), display the desired reactivity towards a number of C-, S-, P-, and O-centered nucleophiles. Despite their purported soft nature, reagents 1 and 2 do trifluoromethylate alcohols and sulfonic acids upon activation with Lewis [10] and Brønsted acids, [11] respectively, thus significantly expanding their application range.During a recent investigation of the direct electrophilic trifluoromethylation of heteroarenes [12] using reagent 1 and catalytic amounts of bis(trifluoromethanesulfonyl)imide (HNTf 2 ) in acetonitrile, we surprisingly found that benzotriazole (3) is converted to the corresponding N-substituted N-trifluoroimidoyl derivative 4, as shown in Scheme 2. The generation of compound 4 corresponds to a novel Rittertype [13] reaction during which a new NÀCF 3 bond...

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A Ritter‐Type Reaction: Direct Electrophilic Trifluoromethylation at Nitrogen Atoms Using Hypervalent Iodine Reagents

et al. 2010

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“…In contrast, phenols experiment trifluoromethylation predominantly at the aromatic positions [82]. The latter trifluoromethylation reagent also promoted ringopening of tetrahydrofuran to form oligomeric trifluoromethyl ethers [83].…”

Section: Trifluoromethylation Of Sp 3 Nitrogen Oxygen and Sulfurmentioning

confidence: 99%

Recent advances in the trifluoromethylation methodology and new CF3-containing drugs

Zhu

Wang

et al. 2014

Journal of Fluorine Chemistry

410

209

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“…[22] The trifluoromethylation of other hydroxylated compounds were also investigated. [22] The trifluoromethylation of other hydroxylated compounds were also investigated.…”

Section: Electrophilic Trifluoromethylation Of Alcohols or Hydroxylatmentioning

confidence: 99%

Synthetic Approaches to Trifluoromethoxy‐Substituted Compounds

2016

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Because of the unique properties of the trifluoromethoxy group, molecules bearing this moiety will find applications in various fields, particularly in the life sciences. However, despite the great interest in this functional group, only a small number of trifluoromethoxylated molecules are currently synthetically accessible. Over the last few years, several innovative and promising strategies for the synthesis of trifluoromethoxylated compounds have been described. This Minireview discusses these existing methods with a particular focus on more recent advances.

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Reactivity of a Hypervalent Iodine Trifluoromethylating Reagent toward THF: Ring Opening and Formation of Trifluoromethyl Ethers

Cited by 74 publications

References 42 publications

A Ritter‐Type Reaction: Direct Electrophilic Trifluoromethylation at Nitrogen Atoms Using Hypervalent Iodine Reagents

A Ritter‐Type Reaction: Direct Electrophilic Trifluoromethylation at Nitrogen Atoms Using Hypervalent Iodine Reagents

Recent advances in the trifluoromethylation methodology and new CF3-containing drugs

Synthetic Approaches to Trifluoromethoxy‐Substituted Compounds

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