Sterically Congested 2,6‐Disubstituted Anilines from Direct C−N Bond Formation at an Iodine(III) Center

Lucchetti, Nicola; Scalone, Michelangelo; Fantasia, Serena; Muñiz, Kilian

doi:10.1002/anie.201606599

Cited by 40 publications

(22 citation statements)

References 62 publications

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“…This type of intermediate is expected in LC reactions but can rarely be detected. The groups of Quideau and Muñiz have reported such compounds using an ortho -nitro substituted phenol and tetrafluorophthalimide as nucleophiles, respectively [38–39]. Those compounds were isolable at room temperature and could be converted to the arylated products upon heating.…”

Section: Resultsmentioning

confidence: 99%

Metal-free formal synthesis of phenoxazine

Kervefors¹,

Becker²,

Dey³

et al. 2018

Beilstein J. Org. Chem.

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A transition metal-free formal synthesis of phenoxazine is presented. The key step of the sequence is a high-yielding O-arylation of a phenol with an unsymmetrical diaryliodonium salt to provide an ortho-disubstituted diaryl ether. This species was cyclized to acetylphenoxazine in moderate yield. The overall yield in the three-step sequence is 72% based on recovered diaryl ether. An interesting, unusually stable iodine(III) intermediate in the O-arylation was observed by NMR and could be converted to the product upon longer reaction time.

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Section: Resultsmentioning

confidence: 99%

Metal-free formal synthesis of phenoxazine

Kervefors¹,

Becker²,

Dey³

et al. 2018

Beilstein J. Org. Chem.

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“…Although bis(phenylsulfonyl)imide can aminate arenes under photochemical conditions, 44 attempts towards reductive C-N bond formation at iodine(III) did not provide the corresponding aniline derivatives. 45 This context was studied for the bistosylimido diphenyl iodonium salt 69, which can be obtained through standard arylation at the acetoxy precursor 2 (Scheme 18). It did not show any C-N bond formation even at elevated temperatures.…”

Section: Scheme 13 Propargylic Amines From Iodine(iii)-mediated Aminmentioning

confidence: 99%

“…This observation set the basis for the development of a selective amination of sterically congested aryliodonium salts to 2,6-disubstituted anilines. 45 Enantioselective diamination of alkenes. The intermolecular diamination of alkenes by means of iodine(III) reagents has recently become the most successful approach in the field, particularly with respect to the elusive number of enantioselective transformations.…”

Section: Scheme 13 Propargylic Amines From Iodine(iii)-mediated Aminmentioning

confidence: 99%

Promoting Intermolecular C–N Bond Formation under the Auspices of Iodine(III)

Muñiz

2018

Acc. Chem. Res.

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106

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The quest for the development of new protocols that provide general conditions for oxidative carbon-nitrogen bond formation has grown over recent years. Within this context, due to feasibility and benignity considerations in biochemical sciences, reactions that rely on main group oxidants as the only promoters have received particular interest. We have recently found that simple protonolysis events enable the incorporation of nitrogenated groups of the bissulfonimide family into the coordination sphere of common iodine(III) complexes such as diacetoxy iodobenzene. The products of the type ArI(OAc)(NTs) represent rare examples of iodine(III) compounds displaying reactive iodine-nitrogen single bonds. Further protonolysis furnishes the corresponding iodine(III) compounds ArI(NTs) containing two defined iodine-nitrogen single bonds for unprecedented dual transfer of both nitrogenated groups. It is of great synthetic importance that these new compounds contain iodine-nitrogen entities, which upon dissociation in solution lead to electrophilic iodine centers and nucleophilic nitrogen groups. This has enabled the development of a body of conceptually new amination reactions, which do not rely on conventional electrophilic nitrogen reagents but rather employ iodine(III) as an electrophilic activator and bissulfonimides as the source of subsequent nucleophilic amination. Additional diversification arises from the ambident nature of bissulfonimines enabling oxygenation pathways. The exciting chemistry covered in this Account comprises structural features of the reagents (including X-ray analysis), scope and limitation in synthetic amination of different hydrocarbons (including sp-, sp-, and sp-hybridized centers as in acetylenes, alkenes, enols, butadienes, allenes, arenes, and alkylketones), and physical-organic and theoretical analysis of the underlying reaction mechanisms. The oxidative transformations with all their rich diversifications originate from the versatile redox chemistry of the iodine(III) and iodine(I) pair, which shares several aspects of transition metal high oxidation state chemistry. For the present aryliodine(III) reagents, steric and electronic fine-tuning is possible through accurate engineering of the arene substituent. In addition to the general reactivity of the I-N bond, chiral aryliodine(III) reagents with defined stereochemical information in the aryl backbone are conceptually compatible with this approach. Thus, the development of enantioselective amination reactions with up to 99% ee was also successful. Several of the active enantioselective reagents have been isolated and structurally characterized. Following this approach for the important class of chiral vicinal diamines, an unprecedented direct diamination of alkenes could be conducted in an enantioselective catalytic manner under full intermolecular reaction control. This latter reaction is based on the precise engineering of a chiral aryliodine(III) catalyst in combination with bismesylimide as nitrogen source. It is the consequence o...

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“…Metal-free methods by classic S N Ar are also attractive, but only possible on very electron-deficient arene substrates [ 5 ]. Diaryliodonium salts are useful reagents for metal-free aryl transfer [ 6 – 10 ] and Muñiz and co-workers have recently reported an elegant study on sterically controlled C–N coupling of 2,6-disubstituted aryl(phenyl)iodonium salts and imides [ 11 ]. We have been investigating the generality of electronically controlled aryl transfer from aryl(trimethoxyphenyl)iodonium salts [ 12 – 14 ] and describe here the development of a C–N coupling of a phthalimide anion with non-sterically biased aryl groups.…”

Section: Introductionmentioning

confidence: 99%

Imide arylation with aryl(TMP)iodonium tosylates

Basu¹,

Sandtorv²,

Stuart³

2018

Beilstein J. Org. Chem.

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Herein, we describe the synthesis of N-aryl phthalimides by metal-free coupling of potassium phthalimide with unsymmetrical aryl(TMP)iodonium tosylate salts. The aryl transfer from the iodonium moiety occurs under electronic control with the electron-rich trimethoxyphenyl group acting as a competent dummy ligand. The yields of N-aryl phthalimides are moderate to high and the coupling reaction is compatible with electron-deficient and sterically encumbered aryl groups.

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Sterically Congested 2,6‐Disubstituted Anilines from Direct C−N Bond Formation at an Iodine(III) Center

Cited by 40 publications

References 62 publications

Metal-free formal synthesis of phenoxazine

Metal-free formal synthesis of phenoxazine

Promoting Intermolecular C–N Bond Formation under the Auspices of Iodine(III)

Imide arylation with aryl(TMP)iodonium tosylates

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