Metal-free O–H/C–H difunctionalization of phenols by o-hydroxyarylsulfonium salts in water

Chen, Dengfeng; Feng, Qingyuan; Yang, Yunqin; Cai, Xu‐Min; Wang, Fei; Huang, Shenlin

doi:10.1039/c6sc04504a

Cited by 55 publications

(28 citation statements)

References 60 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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“…With phenolic substrates, the reaction leads to the concomitant formation of new C–S and C–O bonds, as was reported by Huang et al in 2017 (Scheme 28a). 83 Initially, the interrupted Pummerer reaction leads to the formation of the corresponding sulfonium salts 139 . By heating the reaction in water in the presence of micellar macromolecules, an intramolecular transfer of the R 1 substituent from sulfur to oxygen is triggered, likely occurring via a Smiles-like rearrangement.…”

Section: Sulfoxidesmentioning

confidence: 99%

Bond-Forming and -Breaking Reactions at Sulfur(IV): Sulfoxides, Sulfonium Salts, Sulfur Ylides, and Sulfinate Salts

et al. 2019

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Organosulfur compounds have long played a vital role in organic chemistry and in the development of novel chemical structures and architectures. Prominent among these organosulfur compounds are those involving a sulfur(IV) center, which have been the subject of countless investigations over more than a hundred years. In addition to a long list of textbook sulfur-based reactions, there has been a sustained interest in the chemistry of organosulfur(IV) compounds in recent years. Of particular interest within organosulfur chemistry is the ease with which the synthetic chemist can effect a wide range of transformations through either bond formation or bond cleavage at sulfur. This review aims to cover the developments of the past decade in the chemistry of organic sulfur(IV) molecules and provide insight into both the wide range of reactions which critically rely on this versatile element and the diverse scaffolds that can thereby be synthesized.

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“…We were delighted to find that the desired oxidation reaction was feasible in organic solvent/water or pure water, albeit in low yields ( Table 1, entries 3 to 5). As our continuing efforts exploring sustainable synthetic methodology in water, [10] we further evaluated this oxidation in aqueous micellar medium. To our delight, in the presence of TPGS-750-M, a "benign-by-design" amphiphile developed by Lipshutz, [11] acetophenone could indeed be obtained in a higher yield in water at 30 8C ( Given the superb activity of TPGS-750-M in micellar catalysis, [12,13] we were curious to explore if the structurally similar amphiphiles derived from dehydroabietinol would be suitable alternatives.…”

Section: Resultsmentioning

confidence: 99%