Aerobic Oxidative Sulfenylation of Pyrazolones and Pyrazoles Catalyzed by Metal-Free Flavin–Iodine Catalysis

Tanimoto, Kazumasa; Ohkado, Ryoma; Iida, Hiroki

doi:10.1021/acs.joc.9b02422

Cited by 35 publications

(15 citation statements)

References 76 publications

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“…Similarly, in another attempt riboflavin‐derived alloxazinium salt have been used as a biocatalyst by Tanimoto and co‐workers [197] . They have developed Flavin‐Iodine mediated sulfenylation of pyrazolones ( 113 ) and pyrazoles ( 255 ) using thiophenols ( 9 ) as sulfenylating reagent.…”

Section: Sulfenylationmentioning

confidence: 99%

“…Aryl thiols substituted with electron donating as well as withdrawing substitutents tolerated well and resulted into desired product in good to moderate yield. However, the substituents of indole have little effect on the yield of sulfenylated product (197) (Scheme 66). [176] Chen and co-workers [177] reported a mild, efficient and Cs 2 CO 3 mediated methodology for α-sulfenylation of acetonitrile (200) using thiophenols (9) as sulfenylating reagent.…”

Section: Chemistryselectmentioning

confidence: 99%

“…[196] Similarly, in another attempt riboflavin-derived alloxazinium salt have been used as a biocatalyst by Tanimoto and coworkers. [197] They have developed Flavin-Iodine mediated sulfenylation of pyrazolones (113) and pyrazoles (255) using thiophenols (9) as sulfenylating reagent. The reactivity of various aliphatic, aryl and heteroaryl thiols was investigated under optimized reaction conditions.…”

Section: Biocatalyst Mediated Sulfenylationmentioning

confidence: 99%

See 2 more Smart Citations

Transition Metal‐Free Sulfenylation of C−H Bonds for C−S Bond Formation in Recent Years: Mechanistic Approach and Promising Future

et al. 2021

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Transition metal‐free sulfenylation of C−H bonds for C−S bond formation has recently emerged as sustainable protocols for the functionalisation of various molecules. Researchers have extensively developed such protocols for the construction of biologically relevant sulfur scaffolds. There has been a gradual shift from metal‐catalyzed to metal‐free C−S bond formation methodologies, because the latter offer environmentally benign and inherently safe access to novel synthetic routes in organic chemistry. The present review offers a dynamic discussion on recent advances in transition metal‐free C−S bond formation via C−H bond functionalization using different surrogate sulfenylating reagents. The review has comprehensively been devoted to radical and ionic mechanistic approaches. Some simple and eco‐friendly reagents for sulfenylation viz. tertbutyl hydrogen peroxide (TBHP), hydrogen peroxide (H2O2), iodine/potassium persulphate (I2/K2S2O8), inorganic bases, strong organic acids, iodine, I2/triphenyl phosphine (PPh3), N‐chlorosuccinamide (NCS), N‐bromosuccinamide (NBS), potassium iodate (KIO3), I2/bovine serum albumin (BSA), tetrabutyl ammonium iodide (TBAI)/HBr and graphene oxide along with their mechanistic approach has been detailed in this review. Moreover, modern methods for the C−S bond formation i. e., biocatalyst, electrochemical and visible light induced sulfenylation, and traditional sulfenylation methodologies have also been incorporated.

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Section: Sulfenylationmentioning

confidence: 99%

Section: Chemistryselectmentioning

confidence: 99%

Section: Biocatalyst Mediated Sulfenylationmentioning

confidence: 99%

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Transition Metal‐Free Sulfenylation of C−H Bonds for C−S Bond Formation in Recent Years: Mechanistic Approach and Promising Future

et al. 2021

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“…Iodine has been applied widely as an effective catalyst for the functionalization of cyclic compounds. It shows good catalytic activity in the sulfenylation of indoles 21 and pyrazolones, 22 selenylation of 2H-indazole, 23 C-3 benzylation 24 and consecutive diazenylation/amination 25 of indoles, diazenylation of N-heterocyclic compounds, 26 C-N bond-forming of heterocyclic thiols and thiones, 27 arylation of substituted 1,4-naphthoquinones, 28 and rearrangement of 3-aminoindazoles. 29 Iodine-catalyzed systems have also been a good choice for oxidative transformations.…”

mentioning

confidence: 99%

Oxidative C–H Acyloxylation of Acetone with Carboxylic Acids under Iodine Catalysis

Zhou¹,

Chen²

2020

Synthesis

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“…Thus, numerous approaches based on the nucleophilicity of thiols have been designed over the years, which mostly use air -sensitive noble metal catalysts. [4][5][6][7][8][9] At the opposite, the use of electrophilic sulfur reagents is also a powerful, more eco-friendly…”

mentioning

confidence: 99%

Lewis Acid-Activated 8-Quinolinethiosulfonates: An Efficient Methodology for CS(alkyl) Bond Formation

galardon¹

2020

Preprint

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The importance of sulfur-containing compounds in various fields, ranging from material science1-2 to medicinal chemistry, 3 has called for the development of synthetic strategies to form carbon-sulfur (C-S) bonds. Thus, numerous approaches based on the nucleophilicity of thiols have been designed over the years, which mostly use air-sensitive noble metal catalysts.4- 9 At the opposite, the use of electrophilic sulfur reagents is also a powerful, more eco-friendly approach, in particular for the sulfenylation of C-H bonds into C-S bonds.10-11 In this context, the sulfenylation of indoles (Equation 1) has become a benchmark reaction to develop and test new sulfenyl transfer reagents, because indoles are good nucleophiles and their occurrence in many natural products or biological active compounds makes them attractive synthetic targets.12-14 For instance, metal-catalyzed or metal-free protocols have been proposed, in which disulfides, sulfinic acid and their salts, sulfonyl chlorides, sulfonylhydrazine, or Nthiophtalimides are used as source of electrophilic sulfur.10,15-16 Thiosulfonates (RSO2SR’) are another class of emerging17 reagents, which were also studied for C-S bond formation18-20 and for indole sulfenylation.21 However, despite the large pool of sulfenylation agents listed above, the difficult activation of the chalcogen centre essentially limits these reagents to the formation of C-S(aryl) bonds. On the other hand, the transfer of alkylsulfenyl groups requires harsher activating conditions and is so far still limited<br>

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Aerobic Oxidative Sulfenylation of Pyrazolones and Pyrazoles Catalyzed by Metal-Free Flavin–Iodine Catalysis

Cited by 35 publications

References 76 publications

Transition Metal‐Free Sulfenylation of C−H Bonds for C−S Bond Formation in Recent Years: Mechanistic Approach and Promising Future

Transition Metal‐Free Sulfenylation of C−H Bonds for C−S Bond Formation in Recent Years: Mechanistic Approach and Promising Future

Oxidative C–H Acyloxylation of Acetone with Carboxylic Acids under Iodine Catalysis

Lewis Acid-Activated 8-Quinolinethiosulfonates: An Efficient Methodology for CS(alkyl) Bond Formation

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