Improved Synthesis of Pyrroles and Indoles via Lewis Acid Catalyzed Mukaiyama—Michael-Type Addition/Heterocyclization of Enolsilyl Derivatives on 1,2-Diaza-1,3-butadienes. Role of the Catalyst in the Reaction Mechanism.

ChemInform ◽  
2007 ◽  
Vol 38 (33) ◽  
Author(s):  
Orazio A. Attanasi ◽  
Gianfranco Favi ◽  
Faolino Filippone ◽  
Samuele Lillini ◽  
Fabio Mantellini ◽  
...  
Keyword(s):  
Reaction Mechanism ◽  
Lewis Acid ◽  
Michael Type Addition ◽  
Acid Catalyzed

Critical role of Bronsted acid in Lewis-acid-catalyzed synthesis of Amadori and Heyns compounds of β-amino acids

2021 ◽  
pp. 1-11
Author(s):  
Debasree Chanda ◽  
Gangothri M. Venkataswamy ◽  
Lagamawwa V. Hipparagi ◽  
Nanishankar V. Harohally
Keyword(s):  
Amino Acids ◽  
Lewis Acid ◽  
Critical Role ◽  
Bronsted Acid ◽  
Brønsted Acid ◽  
Brönsted Acid ◽  
Acid Catalyzed

Mechanistic Studies on Lewis Acid Catalyzed Biginelli Reactions in Ionic Liquids: Evidence for the Reactive Intermediates and the Role of the Reagents

2012 ◽  
Vol 77 (22) ◽  
pp. 10184-10193 ◽  
Author(s):  
Luciana M. Ramos ◽  
Adrian Y. Ponce de Leon y Tobio ◽  
Marcelo R. dos Santos ◽  
Heibbe C. B. de Oliveira ◽  
Alexandre F. Gomes ◽  
...  
Keyword(s):  
Ionic Liquids ◽  
Lewis Acid ◽  
Reactive Intermediates ◽  
Mechanistic Studies ◽  
Acid Catalyzed ◽  
Biginelli Reactions

Lewis Acid Catalyzed Reactions of Chiral Imidazolidinones and Oxazolidinones: Insights on the Role of the Catalyst

2011 ◽  
Vol 76 (17) ◽  
pp. 6997-7004 ◽  
Author(s):  
Filipe J. S. Duarte ◽  
Snezhana M. Bakalova ◽  
Eurico J. Cabrita ◽  
A. Gil Santos
Keyword(s):  
Lewis Acid ◽  
Acid Catalyzed ◽  
Catalyzed Reactions

scholarly journals On the Thermodynamic Control of Ring Opening of 4-Substituted 1,3,3-Tris-Carbethoxycyclobutene and the Role of the C-3 Substituent in Masking the Kinetic Torquoselectivity. An alternate reaction pathway

2021 ◽  
Author(s):  
Veejendra Yadav ◽  
Dasari L V K Prasad ◽  
Arpita Yadav ◽  
Maddali L N Rao
Keyword(s):  
Lewis Acid ◽  
Ring Opening ◽  
Reaction Pathway ◽  
Chloride Ion ◽  
Thermodynamic Control ◽  
Heterolytic Cleavage ◽  
Acid Catalyzed ◽  
Halogen Acid

<p>The predominant transformations of 4-methyl- and 4-phenyl-1,3,3-<i>tris</i>-carbethoxycyclobutenes to s-<i>trans</i>-<i>trans</i>-1,1,3-<i>tris</i>-carbethoxy-4-methyl- and 4-phenyl-1,3-butadienes, respectively, proceed through pathways entailing heterolytic cleavage of the s<sub>C3C4</sub> bond rather than the usual four-electron conrotatory ring opening following the rules of torquoselectivity. The adventitious or in situ generated halogen acid from CDCl<sub>3</sub> catalyzes the reaction of 4-methyl-1,3,3-<i>tris</i>-carbethoxycyclobutene by protonation of one of the two ester groups on C3 and, thereby, weakening the s<sub>C3C4</sub> bond to allow its heterolytic S<sub>N</sub>2 cleavage by the chloride ion. This is followed by <i>cisoid</i><b>→</b><i>transoid</i> isomerization and loss of the elements of the halogen acid to form the products. In the Lewis acid-catalyzed reaction of 4-phenyl-1,3,3-<i>tris</i>-carbethoxycyclobutene in CH<sub>2</sub>Cl<sub>2</sub>, coordination of the Lewis acid with one of two ester groups on C3 is followed by heterolytic cleavage of the s<sub>C3C4</sub> bond. The resultant species subsequently undergoes <i>cisoid</i><b>→</b><i>transoid</i> isomerization before losing the Lewis acid to form the products.<br></p>

The Role of Salts and Brønsted Acids in Lewis Acid-Catalyzed Aqueous-Phase Glucose Dehydration to 5-Hydroxymethylfurfural

ChemCatChem ◽  
2014 ◽  
Vol 7 (3) ◽  
pp. 501-507 ◽  
Author(s):  
Pauli Wrigstedt ◽  
Juha Keskiväli ◽  
Markku Leskelä ◽  
Timo Repo
Keyword(s):  
Aqueous Phase ◽  
Lewis Acid ◽  
Bronsted Acids ◽  
Acid Catalyzed

AlCl3-Catalyzed Intramolecular Hydroarylation of Arenes with Alkynes

Synlett ◽  
2017 ◽  
Vol 28 (16) ◽  
pp. 2159-2162 ◽  
Author(s):  
Guangxin Gu ◽  
Hao Guo ◽  
Yang Li ◽  
Yu Wang ◽  
Dawen Xu ◽  
...  
Keyword(s):  
Reaction Mechanism ◽  
Lewis Acid ◽  
Substitution Reaction ◽  
Functional Group ◽  
Catalytic Amount ◽  
Main Group ◽  
Electrophilic Aromatic Substitution ◽  
Aromatic Substitution ◽  
Main Group Metal ◽  
Acid Catalyzed

Herein, we wish to report the main-group metal Lewis acid catalyzed intramolecular hydroarylation of arenes with alkynes. This cyclization proceeds efficiently in the presence of a catalytic amount of AlCl3, affording phenanthrenes in moderate to excellent yields. The catalyst is cheap and nontoxic. The functional-group tolerance is high. A plausible electrophilic aromatic substitution reaction mechanism is proposed for this transformation.

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