Efficient imidation of C(sp3)–H bonds adjacent to oxygen atoms of aryl ethers under metal-free conditions

A highly regio- and diastereo-selective Brønsted acid-catalyzed tandem hydrothiolation/Friedel-Crafts reaction of linear 1,3-dienes has been developed for the first time, which provides a metal-free, atom-economic and concise way of constructing...

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Black phosphorus as a metal-free, visible-light-active heterogeneous photoredox catalyst for the direct C–H arylation of heteroarenes

Chemical Communications ◽

10.1039/d0cc01874k ◽

2020 ◽

Vol 56 (44) ◽

pp. 5901-5904 ◽

Cited By ~ 2

Author(s):

Erbay Kalay ◽

Hüseyin Küçükkeçeci ◽

Haydar Kilic ◽

Önder Metin

Keyword(s):

Visible Light ◽

Black Phosphorus ◽

Diazonium Salts ◽

Metal Free ◽

Visible Light Active ◽

First Time

We report for the first time the employment of black phosphorus (BP) as a metal free, visible-light-active and reusable heterogeneous photoredox catalyst for the direct C–H arylation of heteroarenes (furan and thiophene) with aryl diazonium salts.

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THE CHEMICAL STABILITY OF THE S-METHYL XANTHATES OF SOME SIMPLE ALCOHOLS

Canadian Journal of Chemistry ◽

10.1139/v56-167 ◽

1956 ◽

Vol 34 (9) ◽

pp. 1302-1314 ◽

Cited By ~ 6

Author(s):

D. L. Vincent ◽

C. B. Purves

Keyword(s):

Hydrogen Peroxide ◽

Methyl Ester ◽

Methyl Iodide ◽

Chemical Stability ◽

Periodic Acid ◽

High Yield ◽

Methylating Agents ◽

First Time ◽

Oxygen Atoms

n-Octadecyl S-methyl xanthate, m.p. 38–39°, and n-hexadecyl S-methyl xanthate, m.p. 28–28.5°, were prepared for the first time, and were used to study the behavior of the S-methyl xanthate group toward reagents commonly used in research on carbohydrates. Although stable to some conditions of acetylation, hydrolysis, and methanolysis, the S-methyl xanthate group was destroyed by all methylating agents tried, with the exception of nitrosomethylurethane. The latter reagent converted a sodium xanthate salt in high yield to the S-methyl ester. Octadecyl and hexadecyl S-methyl xanthates when oxidized with hydrogen peroxide yielded crystalline substances of composition C20H40O4S2 and C18H36O4S2, respectively, whose structures were not determined. These substances each contained three additional oxygen atoms. Various attempts to estimate the S-methyl xanthate group by oxidation with bromine or periodic acid, or by reduction to methyl iodide, were unsuccessful.

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A metal-free biaryl coupling reaction activated by a sulfonium salt

Organic Chemistry Frontiers ◽

10.1039/c8qo00798e ◽

2018 ◽

Vol 5 (22) ◽

pp. 3219-3225 ◽

Cited By ~ 6

Author(s):

Kazuhiro Higuchi ◽

Takuhiro Tago ◽

Yusuke Kokubo ◽

Motoki Ito ◽

Masanori Tayu ◽

...

Keyword(s):

Coupling Reaction ◽

Sulfonium Salt ◽

One Pot ◽

Metal Free ◽

Trifluoromethanesulfonic Anhydride ◽

Biaryl Coupling ◽

Aryl Ethers

A metal-free biaryl coupling reaction of phenol or aryl ethers mediated by a sulfonium salt formed from diphenyl sulfoxide and trifluoromethanesulfonic anhydride has been developed. The method is a rapid, one-pot reaction, leaving no traces of the sulfonium moiety in the product.

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FABRICATED METAL-FREE CARBON NITRIDE CHARACTERIZATIONS FOR FLUORESCENCE CHEMICAL SENSOR OF NITRATE IONS

Jurnal Teknologi ◽

10.11113/jt.v76.5812 ◽

2015 ◽

Vol 76 (13) ◽

Cited By ~ 2

Author(s):

Nor Shuhada Alim ◽

Hendrik O. Lintang ◽

Leny Yuliati

Keyword(s):

Carbon Nitride ◽

Diffuse Reflectance ◽

Chemical Sensor ◽

Thermal Polymerization ◽

Fluorescence Sensor ◽

Free Carbon ◽

Metal Free ◽

Nitrate Ions ◽

Relative Standard ◽

First Time

In this study, a metal-free carbon nitride (CN) was investigated for the first time as a potential fluorescence sensor for detection of nitrate ions (NO3-). The CN was prepared through thermal polymerization of urea precursor at 823 K and characterized by diffuse reflectance ultraviolet-visible (DR UV-Vis), Fourier transform infrared (FTIR), and fluorescence spectroscopies. The DR UV-Vis spectrum confirmed that CN could absorb light up to 450 nm. On the other hand, the FTIR spectrum revealed the presence of graphitic CN single and double bond characters in the 800-1700 cm-1 region. From the fluorescence spectroscopy, three excitation peaks at 278, 310 and 369 nm were observed due to the presence of N=C, C=O and N-C groups, respectively. The fluorescence sensor capability of the CN was then investigated using concentrations of NO3- in the range of 300-1800 mM. It was confirmed that the intensities of the emission sites were quenched linearly with the concentrations of the NO3-. The CN showed good reproducibility with relative standard deviation (RSD) values were 1.5-7.2%. These results suggested that CN can act as the fluorescence sensor for NO3-.

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Transition-Metal-Free, Intermolecular Azidoheteroarylation of Alkenes: Efficient Access to β-Azidoalkylated Quinoxalinones and Preliminary Antifungal Evaluation Against Magnaporthe grisea

Synthesis ◽

10.1055/s-0040-1707514 ◽

2020 ◽

Vol 52 (16) ◽

pp. 2395-2409

Author(s):

Weiwei Qin ◽

Zhaodong Li ◽

Yiming Du ◽

Yue Chen ◽

Yun-Lin Liu

Keyword(s):

Transition Metal ◽

Magnaporthe Grisea ◽

Single Step ◽

Domino Reaction ◽

Efficient Synthesis ◽

Metal Free ◽

Efficient Access ◽

First Time ◽

Antibacterial Evaluation ◽

Addition Pathway

An efficient, PhI(OAc)2-mediated, radical azidoheteroarylation of alkenes under transition-metal-free conditions is reported by employing TMSN3 and quinoxalin-2(1H)-ones as coupling partners. This domino reaction allows an eﬃcient synthesis of valuable orangoazides containing quinoxalin-2(1H)-one derivatives and could be extended to phosphinyl-alkylated quinoxalin-2(1H)-one in a single step in moderate to excellent yields under mild conditions, as demonstrated by the preliminary antibacterial evaluation against Magnaporthe grisea for the first time. Mechanistic studies revealed that this transformation undergoes a cascade addition pathway controlled by a polar radical.

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Catalytic Conversion of Carbon Dioxide through C-N Bond Formation

Molecules ◽

10.3390/molecules24010182 ◽

2019 ◽

Vol 24 (1) ◽

pp. 182 ◽

Cited By ~ 14

Author(s):

Jing-Yuan Li ◽

Qing-Wen Song ◽

Kan Zhang ◽

Ping Liu

Keyword(s):

Carbon Dioxide ◽

Catalytic Mechanism ◽

Bond Formation ◽

Catalytic Efficiency ◽

Chemical Fixation ◽

Catalytic Systems ◽

Formation Reaction ◽

Metal Free ◽

The Past ◽

Regulatory Strategies

From the viewpoint of green chemistry and sustainable development, it is of great significance to synthesize chemicals from CO2 as C1 source through C-N bond formation. During the past several decade years, many studies on C-N bond formation reaction were involved, and many efforts have been made on the theory. Nevertheless, several great challenges such as thermodynamic limitation, low catalytic efficiency and selectivity, and high pressure etc. are still suffered. Herein, recent advances are highlighted on the development of catalytic methods for chemical fixation of CO2 to various chemicals through C-N bond formation. Meanwhile, the catalytic systems (metal and metal-free catalysis), strategies and catalytic mechanism are summarized and discussed in detail. Besides, this review also covers some novel synthetic strategies to urethanes based on amines and CO2. Finally, the regulatory strategies on functionalization of CO2 for N-methylation/N-formylation of amines with phenylsilane and heterogeneous catalysis N-methylation of amines with CO2 and H2 are emphasized.

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Metal-Free Addition of Boronic Acids to Silylnitronates

Synlett ◽

10.1055/s-0039-1690845 ◽

2020 ◽

Vol 31 (09) ◽

pp. 856-860

Author(s):

Laurent El Kaïm ◽

Mansour Dolé Kerim ◽

Pakoupati Boyode ◽

Julian Garrec

Keyword(s):

Reaction Mechanism ◽

Double Bond ◽

Boronic Acids ◽

Dft Study ◽

Metal Free ◽

Nitro Derivatives ◽

Oxime Derivatives ◽

Nitrogen Double Bond ◽

First Time ◽

Aryl Transfer

We report for the first time a metal-free addition of boronic acids to silylnitronates to afford oxime derivatives through aryl transfer on the carbon nitrogen double bond. A reaction mechanism has been proposed in relation with a DFT study on the key aryl transfer. This arylation process is effective for cycloalkenyl nitro derivatives leading to oximes that may be oxidatively converted into 3-arylisoxazole derivatives.

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A cascade process for the synthesis of ortho-formyl allyl aryl ethers and 2H-chromen-2-ol derivatives from arynes via trapping of o-quinone methide with an activated alkene

Organic & Biomolecular Chemistry ◽

10.1039/c8ob02507j ◽

2019 ◽

Vol 17 (2) ◽

pp. 333-346 ◽

Cited By ~ 7

Author(s):

Abhilash Sharma ◽

Pranjal Gogoi

Keyword(s):

Transition Metal ◽

Direct Synthesis ◽

Quinone Methide ◽

Cascade Process ◽

Metal Free ◽

Synthetic Strategy ◽

Aryl Ethers ◽

Three Component Coupling

A transition-metal free synthetic strategy for the direct synthesis of ortho-formyl substituted allyl aryl ethers and 2H-chromen-2-ol derivatives via a cascade three-component coupling of arynes, activated alkene and N,N-dimethylformamide.

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