Improved Synthetic Method for 5-[(Phenylthio)methyl]oxazoline Derivatives: Electrophilic Cyclization of Allylic Amide Using a Brønsted Acid and Tetrabutylammonium Chloride under Mild Conditions

Synlett ◽  
2020 ◽  
Vol 31 (08) ◽  
pp. 813-817
Author(s):  
Yoshihiro Nagao ◽  
Kou Hiroya
Keyword(s):  
Electrophilic Cyclization ◽  
Bronsted Acid ◽  
Brønsted Acid ◽  
Powerful Method ◽  
Reaction Conditions ◽  
Mild Conditions ◽  
Brönsted Acid ◽  
Reaction Proceeds ◽  
Tetrabutylammonium Chloride ◽  
Oxazoline Derivatives

The synthesis of oxazolines using electrophilic cyclization of allylic amide is a simple and powerful method. However, cyclization involving arylsulfenylation requires harsh reaction conditions. We found that the reaction proceeds under mild heating conditions with the combination of a Brønsted acid and tetrabutylammonium chloride. This method enabled the synthesis of 5-[(arylsulfenyl)methyl]oxazoline derivatives under mild conditions and demonstrated high tolerance for various functional groups.

Auto-oxidation promoted sp3 C–H arylation of glycine derivatives

2018 ◽  
Vol 16 (27) ◽  
pp. 4985-4989 ◽  
Author(s):  
Yuanyuan Wei ◽  
Jie Wang ◽  
Yajun Wang ◽  
Xiaoqiang Yao ◽  
Caixia Yang ◽  
...  
Keyword(s):  
Amino Acid ◽  
Environmentally Benign ◽  
Amino Acid Derivatives ◽  
Bronsted Acid ◽  
Brønsted Acid ◽  
Reaction Conditions ◽  
Brönsted Acid ◽  
Reaction Proceeds ◽  
Glycine Derivatives

An auto-oxidation promoted sp3 C–H arylation reaction between N-aryl glycine derivatives and electron-rich arenes, leading to the formation of N-aryl α-aryl α-amino acid derivatives, is described. This atom-economical and environmentally benign reaction proceeds smoothly under mild reaction conditions and requires only Brønsted acid and oxygen (balloon). A plausible radical involved mechanism is proposed.

scholarly journals New opportunities in the stereoselective dearomatization of indoles

2016 ◽  
Vol 88 (3) ◽  
pp. 207-214 ◽  
Author(s):  
Elisabetta Manoni ◽  
Assunta De Nisi ◽  
Marco Bandini
Keyword(s):  
Acid Catalysis ◽  
Bronsted Acid ◽  
Brønsted Acid ◽  
Reaction Conditions ◽  
Brönsted Acid ◽  
High Yields ◽  
First Time ◽  
Tailored Design ◽  
Bronsted Acid Catalysis

AbstractThe regio- and stereoselective dearomatization of indoles is realized for the first time by combining readily available indolyl precursors and electron-rich allenes, namely allenamides and aryloxyallenes. Inter- as well as intramolecular condensations were realized under gold and Brønsted acid catalysis providing a range of densely functionalized indoline and indolenine cores in high yields and excellent stereochemical outcome. Chemodivergent reaction profiles (Micheal-type addition vs. [2+2]-cycloaddition) were realized by a tailored design of both reaction conditions and functionalization of the reaction partners.

Brønsted acid-catalyzed 1,2-fluorine migration with fluoroepoxides

2015 ◽  
Vol 44 (45) ◽  
pp. 19636-19641 ◽  
Author(s):  
Tao Luo ◽  
Rui Zhang ◽  
Xiao Shen ◽  
Wei Zhang ◽  
Chuanfa Ni ◽  
...  
Keyword(s):  
Fluorine Atom ◽  
Acid Catalysis ◽  
Bronsted Acid ◽  
Brønsted Acid ◽  
Atom Economy ◽  
Mild Conditions ◽  
Brönsted Acid ◽  
Acid Catalyzed ◽  
Bronsted Acid Catalysis

An efficient 1,2-fluorine migration reaction was realized under Brønsted acid catalysis in the absence of an external fluorinating source. The high fluorine atom economy and very mild conditions make this reaction a promising protocol for the construction of the C–F bond.

Organic Photoredox Catalytic α-C(sp3)–H Phosphorylation of Saturated Aza-Heterocycles

2021 ◽  
Author(s):  
Ming-Jun Yi ◽  
Teng-Fei Xiao ◽  
Wen-Hui Li ◽  
Yi-Fan Zhang ◽  
Pen-Ji Yan ◽  
...  
Keyword(s):  
Acid Catalysis ◽  
Bronsted Acid ◽  
Brønsted Acid ◽  
Metal Free ◽  
Mild Conditions ◽  
Brönsted Acid ◽  
Bronsted Acid Catalysis

A metal-free C(sp3)–H phosphorylation of saturated aza-heterocycles via the merger of organic photoredox and Brønsted acid catalysis was established under mild conditions. This protocol provided a straightforward and economic access...

An uncommon use of irradiated flavins: Brønsted acid catalysis

2020 ◽  
Vol 56 (42) ◽  
pp. 5661-5664
Author(s):  
Yukihiro Arakawa ◽  
Tomohiro Mihara ◽  
Hiroki Fujii ◽  
Keiji Minagawa ◽  
Yasushi Imada
Keyword(s):  
Visible Light ◽  
Visible Light Irradiation ◽  
Acid Catalysis ◽  
Light Irradiation ◽  
Bronsted Acid ◽  
Brønsted Acid ◽  
Mild Conditions ◽  
Brönsted Acid ◽  
Bronsted Acid Catalysis

Visible light irradiation to flavins in the presence of thiols and O2 provides Brønsted acidic species that can be used as efficient catalysts for thioacetalizations and for Mannich-type reactions under non-irradiation and mild conditions.

Synthesis of 1-Alkyl-3-(2-oxo-2-aryl/alkyl-ethyl)indolin-2-ones through Gold/Brønsted Acid Relay Actions: Observation of Selective C=C Bond Cleavage of Enaminones

Synthesis ◽  
2017 ◽  
Vol 49 (16) ◽  
pp. 3609-3618 ◽  
Author(s):  
Yanzhong Li ◽  
Yulei Zhao ◽  
Yang Yuan ◽  
Lingkai Kong ◽  
Fangfang Zhang
Keyword(s):  
Reaction Mechanism ◽  
Bond Cleavage ◽  
Bronsted Acid ◽  
Brønsted Acid ◽  
Reaction Conditions ◽  
One Pot ◽  
Esi Ms ◽  
Ms Analysis ◽  
Brönsted Acid

A novel gold(I)/Brønsted acid sequential catalyzed/promoted procedure to synthesize 1-alkyl-3-(2-oxo-2-aryl/alkyl-ethyl)indolin-2-ones under mild reaction conditions is developed. This methodology is realized by relay actions of gold and a Brønsted acid in a one-pot multistep manner. The gold(I)-catalyzed chemoselective C(sp2)-H functionalization of enaminones and Brønsted acid promoted cleavage of the C=C bond are integrated effectively. Based on the results of control experiments and ESI-MS analysis, a possible reaction mechanism is proposed.

Aminoxylation of Thioalkynes through Radical-Polar Crossover

Synlett ◽  
2019 ◽  
Vol 31 (06) ◽  
pp. 592-594
Author(s):  
Giovanni Di Mauro ◽  
Martina Drescher ◽  
Sara Tkaczyk ◽  
Nuno Maulide
Keyword(s):  
Bronsted Acid ◽  
Brønsted Acid ◽  
Reaction Conditions ◽  
One Pot ◽  
Brönsted Acid ◽  
Direct Formation

A one-pot procedure for the aminoxylation of thioalkynes for the direct formation of α-functionalized thioesters under mild reaction conditions is reported. A ketenethionium ion is the key intermediate, which is generated in situ by Brønsted acid mediated protonation and undergoes a radical-polar crossover.

Efficient hydroarylation and hydroalkenylation of vinylarenes by Brønsted acid catalysis

RSC Advances ◽  
2016 ◽  
Vol 6 (80) ◽  
pp. 76780-76784 ◽  
Author(s):  
Muwen Liu ◽  
Jinlong Zhang ◽  
Hui Zhou ◽  
Huameng Yang ◽  
Chungu Xia ◽  
...  
Keyword(s):  
Acid Catalysis ◽  
Bronsted Acid ◽  
Brønsted Acid ◽  
Reaction Conditions ◽  
Brönsted Acid ◽  
High Yields ◽  
Bronsted Acid Catalysis

Brønsted acid Tf2NH-catalyzed hydroarylation and hydroalkenylation of 4 vinylarenes under mild reaction conditions is herein shown to provide access to 1,1-diarylalkane scaffolds and trans-1,3-diaryl-1-butenes in high yields and with excellent regioselectivity.

scholarly journals Re2O7-catalyzed reaction of hemiacetals and aldehydes with O-, S-, and C-nucleophiles

2013 ◽  
Vol 9 ◽  
pp. 1526-1532 ◽  
Author(s):  
Wantanee Sittiwong ◽  
Michael W Richardson ◽  
Charles E Schiaffo ◽  
Thomas J Fisher ◽  
Patrick H Dussault
Keyword(s):  
Bronsted Acid ◽  
Brønsted Acid ◽  
Silyl Ethers ◽  
Mild Conditions ◽  
Brönsted Acid ◽  
Nitrogen Nucleophiles

Re(VII) oxides catalyze the acetalization, monoperoxyacetalization, monothioacetalization and allylation of hemiacetals. The reactions, which take place under mild conditions and at low catalyst loadings, can be conducted using hemiacetals, the corresponding O-silyl ethers, and, in some cases, the acetal dimers. Aldehydes react under similar conditions to furnish good yields of dithioacetals. Reactions of hemiacetals with nitrogen nucleophiles are unsuccessful. 1,2-Dioxolan-3-ols (peroxyhemiacetals) undergo Re(VII)-promoted etherification but not allylation. Hydroperoxyacetals (1-alkoxyhydroperoxides) undergo selective exchange of the alkoxide group in the presence of either Re2O7 or a Brønsted acid.

Bronsted acid catalysed chemo- and ortho-selective aminomethylation of phenol

2021 ◽  
Author(s):  
Zhiqiong Tang ◽  
Dongdong Li ◽  
Yidi Yue ◽  
Dan Peng ◽  
Lu Liu
Keyword(s):  
Bronsted Acid ◽  
Brønsted Acid ◽  
Available N ◽  
Mild Conditions ◽  
Selective Functionalization ◽  
Brönsted Acid

We have developed a Bronsted acid catalysed highly ortho-selective functionalization of free phenols with readily available N,O-acetals under mild conditions, furnishing various corresponding aminomethylated phenol products in moderate to excellent...

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