Brønsted acid-catalyzed, enantioselective synthesis of 1,4-dihydroquinoline-3-carboxylates via in situ generated ortho-quinone methide imines

2017 ◽  
Vol 15 (17) ◽  
pp. 3706-3716 ◽  
Author(s):  
Tomáš Hodík ◽  
Christoph Schneider
Keyword(s):  
Phosphoric Acid ◽  
Acid Catalysis ◽  
Nitrogen Heterocycles ◽  
Enantioselective Synthesis ◽  
Quinone Methide ◽  
Keto Esters ◽  
Brönsted Acid ◽  
Acid Catalyzed ◽  
Straightforward Approach

A straightforward approach toward the synthesis of a broad range of 1,4-dihydroquinoline-3-carboxylates is described. Under phosphoric acid catalysis in situ-generated ortho-quinone methide imines reacted with β-keto esters to form the nitrogen heterocycles with good chemical yields and enantioselectivities.

Practical catalytic enantioselective synthesis of 2,3-dihydroquin-azolinones by chiral brønsted acid catalysis

2021 ◽  
Author(s):  
Yongbiao Guo ◽  
Zhenhua Gao ◽  
Junchen Li ◽  
Xiaojing Bi ◽  
Enxue Shi ◽  
...  
Keyword(s):  
Phosphoric Acid ◽  
Acid Catalysis ◽  
Enantioselective Synthesis ◽  
Bronsted Acid ◽  
Brønsted Acid ◽  
Brönsted Acid ◽  
Chiral Bronsted Acid ◽  
Bronsted Acid Catalysis

An efficient, practical and scalable protocol to prepare chiral 2,3-dihydroquinazolinones was developed under catalysis of spirocyclic SPINOL-phosphoric acid.

A chiral Brønsted acid-catalyzed highly enantioselective Mannich-type reaction of α-diazo esters with in situ generated N-acyl ketimines

2018 ◽  
Vol 54 (28) ◽  
pp. 3516-3519 ◽  
Author(s):  
Rajshekhar A. Unhale ◽  
Milon M. Sadhu ◽  
Sumit K. Ray ◽  
Rayhan G. Biswas ◽  
Vinod K. Singh
Keyword(s):  
Phosphoric Acid ◽  
Reaction Conditions ◽  
Type Reaction ◽  
Chiral Phosphoric Acid ◽  
Brönsted Acid ◽  
Diazo Esters ◽  
Reaction Proceeds ◽  
Acid Catalyzed ◽  
Chiral Bronsted Acid

A chiral phosphoric acid-catalyzed asymmetric Mannich-type reaction of α-diazo esters with in situ generated N-acyl ketimines, derived from 3-aryl-3-hydroxyisoindolinones has been demonstrated. The reaction proceeds smoothly under mild reaction conditions.

scholarly journals Chiral Brønsted acid-catalyzed enantioselective Friedel–Crafts reaction of 2-methoxyfuran with aliphatic ketimines generated in situ

2016 ◽  
Vol 7 (2) ◽  
pp. 1057-1062 ◽  
Author(s):  
Azusa Kondoh ◽  
Yusuke Ota ◽  
Takazumi Komuro ◽  
Fuyuki Egawa ◽  
Kyohei Kanomata ◽  
...  
Keyword(s):  
Phosphoric Acid ◽  
Acid Catalyst ◽  
Bronsted Acid ◽  
Brønsted Acid ◽  
Chiral Phosphoric Acid ◽  
Brönsted Acid ◽  
Acid Catalyzed ◽  
Chiral Bronsted Acid

An enantioselective Friedel–Crafts reaction with aliphatic ketimines generated in situ from hemiaminal ethers afforded products with high enantioselectivity under the influence of a chiral phosphoric acid catalyst.

scholarly journals A combined continuous microflow photochemistry and asymmetric organocatalysis approach for the enantioselective synthesis of tetrahydroquinolines

2013 ◽  
Vol 9 ◽  
pp. 2457-2462 ◽  
Author(s):  
Erli Sugiono ◽  
Magnus Rueping
Keyword(s):  
Phosphoric Acid ◽  
Continuous Flow ◽  
Acid Catalysis ◽  
Catalytic Amount ◽  
Cascade Reaction ◽  
Enantioselective Synthesis ◽  
Transfer Hydrogenation ◽  
Subsequent Reduction ◽  
Brönsted Acid ◽  
Asymmetric Organocatalysis

A continuous-flow asymmetric organocatalytic photocyclization–transfer hydrogenation cascade reaction has been developed. The new protocol allows the synthesis of tetrahydroquinolines from readily available 2-aminochalcones using a combination of photochemistry and asymmetric Brønsted acid catalysis. The photocylization and subsequent reduction was performed with catalytic amount of chiral BINOL derived phosphoric acid diester and Hantzsch dihydropyridine as hydrogen source providing the desired products in good yields and with excellent enantioselectivities.

scholarly journals Chiral Brønsted acid-catalyzed Friedel–Crafts alkylation of electron-rich arenes with in situ-generated ortho-quinone methides: highly enantioselective synthesis of diarylindolylmethanes and triarylmethanes

2015 ◽  
Vol 51 (8) ◽  
pp. 1461-1464 ◽  
Author(s):  
Satyajit Saha ◽  
Santosh Kumar Alamsetti ◽  
Christoph Schneider
Keyword(s):  
Enantioselective Synthesis ◽  
Bronsted Acid ◽  
Brønsted Acid ◽  
Quinone Methides ◽  
Reaction Conditions ◽  
Brönsted Acid ◽  
Acid Catalyzed ◽  
Chiral Bronsted Acid ◽  
Hydrogen Bonded

Hydrogen-bonded, in situ-generated ortho-quinone methides undergo highly enantioselective Friedel–Crafts reactions with indoles and naphthols under mild reaction conditions.

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