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.

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.

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.

Enantioselective transfer hydrogenation, a key step for the synthesis of 3-aminotetrahydroquinolines

2016 ◽  
Vol 40 (11) ◽  
pp. 9034-9037 ◽  
Author(s):  
Alexandre Aillerie ◽  
Vincent Lemau de Talencé ◽  
Clément Dumont ◽  
Sylvain Pellegrini ◽  
Frédéric Capet ◽  
...  
Keyword(s):  
Phosphoric Acid ◽  
Catalytic Amount ◽  
Transfer Hydrogenation ◽  
Mild Conditions ◽  
Chiral Phosphoric Acid

An enantioselective transfer hydrogenation has been successfully achieved to furnish 3-aminotetrahydroquinolines. The reaction was conducted in the presence of Hantzsch dihydropyridine and a catalytic amount of chiral phosphoric acid under mild conditions.

scholarly journals Ternary complexes of chiral disulfonimides in transfer-hydrogenation of imines: the relevance of late intermediates in ion pair catalysis

2021 ◽  
Author(s):  
Matej Žabka ◽  
Ruth M. Gschwind
Keyword(s):  
Acid Catalysis ◽  
Computational Study ◽  
Ion Pairing ◽  
Ion Pair ◽  
Ternary Complexes ◽  
Transfer Hydrogenation ◽  
Bronsted Acid ◽  
Brønsted Acid ◽  
Brönsted Acid ◽  
Bronsted Acid Catalysis

In ion pairing catalysis, the structures of advanced intermediates are often not accessible. Here, we present a combined experimental and computational study of ternary complexes in Brønsted acid catalysis, which show unexpected H-bond switching.

scholarly journals Brønsted acid catalysis – the effect of 3,3′-substituents on the structural space and the stabilization of imine/phosphoric acid complexes

2019 ◽  
Vol 10 (20) ◽  
pp. 5226-5234 ◽  
Author(s):  
Maxime Melikian ◽  
Johannes Gramüller ◽  
Johnny Hioe ◽  
Julian Greindl ◽  
Ruth M. Gschwind
Keyword(s):  
Phosphoric Acid ◽  
Acid Catalysis ◽  
Theoretical Studies ◽  
Bronsted Acid ◽  
Brønsted Acid ◽  
Structural Space ◽  
Brönsted Acid ◽  
Bronsted Acid Catalysis

Advanced NMR and theoretical studies reveal detailed insights into monomeric and dimeric structures plus deviating experimental and theoretical E/Z-populations.

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