A Brønsted Acid Catalyzed Redox Arylation

Peng, Bo; Huang, Xueliang; Xie, Lan‐Gui; Maulide, Nuno

doi:10.1002/anie.201310865

Cited by 165 publications

(52 citation statements)

References 76 publications

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“…Recently, we34353637383940 and others41424344454647484950515253545556 reported the metal-free, sulfoxide directed57 C–H functionalization of a variety of molecular scaffolds, which was enabled by an interrupted Pummerer reaction28. Spurred on by these recent achievements, we considered the use of benzothiophene S -oxides 1 for the synthesis of important C3-functionalized benzothiophenes, as the corresponding sulfonium salts I and II , formed after reaction with the coupling partners, lack aromaticity about the five-membered ring and should therefore undergo facile C–C bond formation via [3,3]-sigmatropic rearrangement58, thus delivering unexplored reactivity not accessible in benzothiophenes.…”

Section: Resultsmentioning

confidence: 99%

Regioselective synthesis of C3 alkylated and arylated benzothiophenes

et al. 2017

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Benzothiophenes are heterocyclic constituents of important molecules relevant to society, including those with the potential to meet modern medical challenges. The construction of molecules would be vastly more efficient if carbon–hydrogen bonds, found in all organic molecules, can be directly converted into carbon–carbon bonds. In the case of elaborating benzothiophenes, functionalization of carbon–hydrogen bonds at carbon-number 3 (C3) is markedly more demanding than at C2 due to issues of regioselectivity (C3 versus C2), and the requirement of high temperatures, precious metals and the installation of superfluous directing groups. Herein, we demonstrate that synthetically unexplored but readily accessible benzothiophene S-oxides serve as novel precursors for C3-functionalized benzothiophenes. Employing an interrupted Pummerer reaction to capture and then deliver phenol and silane coupling partners, we have discovered a directing group-free method that delivers C3-arylated and -alkylated benzothiophenes with complete regioselectivity, under metal-free and mild conditions.

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Section: Resultsmentioning

confidence: 99%

Regioselective synthesis of C3 alkylated and arylated benzothiophenes

et al. 2017

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“…Initially,w ei nvestigated the reaction between the ynamide 10 a and sulfoxide 6a.Reaction conditions for the redox arylation of ynamides,a sp reviously described by our group, [14] afforded a-arylated amide 12 a in a7 1% yield of isolated product but ap oor 73:27 e.r. (Entry 1, Table 1).…”

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confidence: 99%

An Asymmetric Redox Arylation: Chirality Transfer from Sulfur to Carbon through a Sulfonium [3,3]‐Sigmatropic Rearrangement

et al. 2017

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A general, asymmetric redox arylation of ynamides and thioalkynes with chiral sulfoxides is reported. This is the first example of a general 1,4-chirality transfer from sulfur to a carbon stereocenter through a sulfonium [3,3]-sigmatropic rearrangement. This reaction delivers α-arylated thioesters and amides under mild conditions in an atom-economical manner. The products are formed in high yields with enantiomeric ratios up to 99.5:0.5. Quantum chemical calculations suggest a mechanism for the chirality transfer from sulfur to carbon and explain the experimentally observed correlation of the enantioselectivity with both the catalyst and the substrate.

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“…We also managed to alkylate the benzylic position using NaHMDS as a base and MeI as an electrophile to give 6 . Finally, the arylsulfanyl moiety can be easily removed under mild conditions while preserving the triisopropylsilyl group to give 7 …”

Section: Methodsmentioning

confidence: 99%

Vinyl Cation Stabilization by Silicon Enables a Formal Metal‐Free α‐Arylation of Alkyl Ketones

et al. 2019

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The ability of silicon to stabilize vinyl cationic species leads to a redox arylation of alkynes whereby the stringent limitations of reactivity and regioselectivity of alkyl‐substituted alkynes are lifted. This allows the synthesis of a range of α‐silyl‐α′‐arylketones under mild conditions in good to excellent yields and with high functional group tolerance, whereby the silicon moiety in the final products can either be removed for a formal acetone monoarylation transform, or capitalized upon for subsequent electrophilic substitutions at either side of the carbonyl group.

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A Brønsted Acid Catalyzed Redox Arylation

Abstract: A Brønsted acid catalyzed redox arylation of ynamides that employs aryl sulfoxides as the arylating agents is reported. This metal-free transformation proceeds at room temperature and efficiently affords α-arylated oxazolidinones in a redox-neutral, atom-economic fashion.

Cited by 165 publications

References 76 publications

Regioselective synthesis of C3 alkylated and arylated benzothiophenes

Regioselective synthesis of C3 alkylated and arylated benzothiophenes

An Asymmetric Redox Arylation: Chirality Transfer from Sulfur to Carbon through a Sulfonium [3,3]‐Sigmatropic Rearrangement

Vinyl Cation Stabilization by Silicon Enables a Formal Metal‐Free α‐Arylation of Alkyl Ketones

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