Synthesis of Tryptamines through a Novel Brønsted Acid Mediated Tandem Reaction Initiated by α-Iminol Rearrangement of Transient 2-Substituted 2-Hydroxycyclobutylimines

Synthesis ◽  
2020 ◽  
Author(s):  
Angelo Frongia ◽  
Lorenzo Serusi ◽  
Federico Cuccu ◽  
Francesco Secci ◽  
David J. Aitken
Keyword(s):  
Condensation Reaction ◽  
Ring Expansion ◽  
Ring Closure ◽  
Tandem Reaction ◽  
Bronsted Acid ◽  
Brønsted Acid ◽  
Brönsted Acid ◽  
Rearrangement Process

AbstractA novel Brønsted acid promoted condensation reaction between a primary aniline and 2-hydroxycyclobutanone provides access to diverse tryptamine derivatives in moderate to good yields. The proposed mechanism involves an α-iminol rearrangement, ring expansion, ring closure, and a depart-and-return rearrangement process.

Novel access to azaphosphiridine complexes and first applications using Brønsted acid-induced ring expansion reactions

2010 ◽  
Vol 39 (14) ◽  
pp. 3472 ◽  
Author(s):  
Stefan Fankel ◽  
Holger Helten ◽  
Gerd von Frantzius ◽  
Gregor Schnakenburg ◽  
Jörg Daniels ◽  
...  
Keyword(s):  
Ring Expansion ◽  
Bronsted Acid ◽  
Brønsted Acid ◽  
Brönsted Acid

Simple assembly of polysubstituted pyrazoles and isoxazoles via ring closure–ring opening domino reaction of 3-acyl-4,5-dihydrofurans with hydrazines and hydroxylamine

2016 ◽  
Vol 14 (10) ◽  
pp. 2905-2915 ◽  
Author(s):  
Alexey O. Chagarovskiy ◽  
Ekaterina M. Budynina ◽  
Olga A. Ivanova ◽  
Victor B. Rybakov ◽  
Igor V. Trushkov ◽  
...  
Keyword(s):  
Ring Opening ◽  
Ring Closure ◽  
Domino Reaction ◽  
Bronsted Acid ◽  
Brønsted Acid ◽  
Brönsted Acid ◽  
Simple Assembly

A general approach to 2-(pyrazolyl-/isoxazolyl-)ethanols based on the Brønsted acid-initiated reaction of 3-acyl-4,5-dihydrofurans with hydrazines or hydroxylamine was developed.

Brønsted Acid Catalyzed Cyclization of Inert N-Substituted Pyrroles to Benzo[f]pyrrolo[1,2-a][1,4]diazepines

Synlett ◽  
2021 ◽  
Author(s):  
Jinlong Zhang ◽  
Gaoxi Jiang ◽  
Zeng Gao ◽  
Jinlong Qian ◽  
Huameng Yang
Keyword(s):  
Ring Closure ◽  
Acid Catalysts ◽  
Bronsted Acid ◽  
Brønsted Acid ◽  
Mild Conditions ◽  
Intermolecular Cyclization ◽  
Chiral Phosphoric Acid ◽  
Brönsted Acid ◽  
Acid Catalyzed ◽  
High Yields

AbstractTwo approaches involving intramolecular and intermolecular cyclization, respectively, have been developed for the direct and practical construction of a series of important benzo[f]pyrrolo[1,2-a][1,4]azepines by using Brønsted acid catalysts. Upon catalysis by TsOH, the intramolecular dehydroxylation/ring closure of 3-hydroxy-2-[2-(1H-pyrrol-1-yl)benzyl]isoindolin-1-ones provided various racemic benzo[f]pyrrolo[1,2-a][1,4]azepines in high yields. Furthermore, enantioenriched benzo[f]pyrrolo[1,2-a][1,4]azepines were also obtained by chiral phosphoric acid catalyzed intermolecular addition of [2-(1H-pyrrol-1-yl)phenyl]methanamines to 2-formylbenzoates under mild conditions.

A Brønsted acid catalyzed tandem reaction for the diastereoselective synthesis of cyclobuta-fused tetrahydroquinoline carboxylic esters

2021 ◽  
Author(s):  
Valentina Marras ◽  
Pierluigi Caboni ◽  
Francesco Secci ◽  
Régis Guillot ◽  
David J. Aitken ◽  
...  
Keyword(s):  
Michael Addition ◽  
Tandem Reaction ◽  
Bronsted Acid ◽  
Brønsted Acid ◽  
Diastereoselective Synthesis ◽  
Cyclization Process ◽  
Brönsted Acid ◽  
Acid Catalyzed ◽  
Carboxylic Esters

We have established a Brønsted acid catalyzed diastereoselective synthesis of diversely substituted cyclobuta-fused tetrahydroquinoline carboxylic esters through a new tandem aza-Michael addition-aza-Friedel–Crafts cyclization process.

Brønsted acid mediated intramolecular cyclopropane ring expansion/[4 + 2]-cycloaddition

2019 ◽  
Vol 17 (47) ◽  
pp. 10004-10008 ◽  
Author(s):  
Jian Li ◽  
Shangrong Zhu ◽  
Qiuneng Xu ◽  
Li Liu ◽  
Shenghu Yan
Keyword(s):  
Ring Opening ◽  
Cyclopropane Ring ◽  
Ring Expansion ◽  
Cascade Reaction ◽  
Bronsted Acid ◽  
Brønsted Acid ◽  
Brönsted Acid ◽  
Cyclopropyl Ketone

A cascade reaction of 3-hydroxy-2-phenylisoindolin-1-one and cyclopropyl ketone has been developed via BrØnsted acid-promoted ring-opening/intramolecular cross-cycloaddition/[4 + 2]-cycloaddition process.

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