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.

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.

scholarly journals Organocatalytic Synthesis of α,α–Diaryl Substituted α–Amino Acid Derivatives by an Interrupted Three-Component Ugi Reaction

2019 ◽  
Vol 92 (2) ◽  
pp. 203-209 ◽  
Author(s):  
Danijel Glavač ◽  
Ivanka Jerić ◽  
Matija Gredičak
Keyword(s):  
Reaction Mechanism ◽  
Amino Acid ◽  
Ugi Reaction ◽  
Amino Acid Derivatives ◽  
Acid Catalysts ◽  
Bronsted Acid ◽  
Brønsted Acid ◽  
Brönsted Acid ◽  
Bronsted Acid Catalysts

An organocatalytic interrupted three-component Ugi reaction for the synthesis of α,α–diaryl α–amino acid derivatives is described. The transformation proceeds with a range of isocyanides and 3-aryl isoindolinone alcohols using Brønsted acid catalysts to afford products in good to excellent yields. Based on the obtained results, a reaction mechanism is proposed and discussed.

scholarly journals Brønsted Acid-Catalyzed Epimerization-Free Preparation of Dual-Protected Amino Acid Derivatives

ACS Omega ◽  
2017 ◽  
Vol 2 (6) ◽  
pp. 2967-2976 ◽  
Author(s):  
Pedro P. de Castro ◽  
Isabela M. R. Rimulo ◽  
Angelina M. de Almeida ◽  
Renata Diniz ◽  
Giovanni W. Amarante
Keyword(s):  
Amino Acid ◽  
Amino Acid Derivatives ◽  
Bronsted Acid ◽  
Brønsted Acid ◽  
Protected Amino Acid ◽  
Brönsted Acid ◽  
Acid Catalyzed

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.

Efficient Synthesis of Chromenes from Vinyl o-Quinone Methides via a Brønsted Acid Catalyzed Electrocyclization Process

Synthesis ◽  
2018 ◽  
Vol 50 (12) ◽  
pp. 2416-2422 ◽  
Author(s):  
Man-Su Tu ◽  
Guang-Jian Mei ◽  
Feng Shi ◽  
Si-Jia Liu ◽  
Xiao-Li Jiang ◽  
...  
Keyword(s):  
Efficient Method ◽  
Research Area ◽  
Environmentally Benign ◽  
Bronsted Acid ◽  
Brønsted Acid ◽  
Efficient Synthesis ◽  
Quinone Methides ◽  
Efficient Approach ◽  
Brönsted Acid ◽  
Acid Catalyzed

An efficient approach for the synthesis of chromene derivatives from vinyl o-quinone methides was established via a Brønsted acid catalyzed electrocyclization. By using this methodology, a series of structurally diversified chromenes was synthesized in a highly atom-economic and environmentally benign manner with generally good to excellent yields (up to 98% yield). This reaction will not only provide an efficient method for the construction of chromene scaffolds, but also enrich the research area of o-quinone methides.

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.

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