Enantioselective Reductive Coupling of 1,3-Enynes to Heterocyclic Aromatic Aldehydes and Ketones via Rhodium-Catalyzed Asymmetric Hydrogenation:  Mechanistic Insight into the Role of Brønsted Acid Additives

2006 ◽  
Vol 128 (51) ◽  
pp. 16448-16449 ◽  
Author(s):  
Venukrishnan Komanduri ◽  
Michael J. Krische
Keyword(s):  
Asymmetric Hydrogenation ◽  
Aromatic Aldehydes ◽  
Reductive Coupling ◽  
Bronsted Acid ◽  
Brønsted Acid ◽  
Mechanistic Insight ◽  
Brönsted Acid ◽  
Aldehydes And Ketones ◽  
Insight Into

Computational insight into the mechanism of the Pd(0)–Brønsted acid cooperatively catalysed head-to-tail dimerization of terminal alkynes

RSC Advances ◽  
2015 ◽  
Vol 5 (103) ◽  
pp. 84636-84642 ◽  
Author(s):  
Hao Zhang ◽  
Xiaoguang Bao
Keyword(s):  
Terminal Alkynes ◽  
Bronsted Acid ◽  
Brønsted Acid ◽  
Mechanistic Insight ◽  
Brönsted Acid ◽  
Insight Into

The Pd(0)–Brønsted acid cooperatively catalysed head-to-tail dimerization of terminal alkynes was computationally studied to gain a mechanistic insight.

scholarly journals Covalent or Non-Covalent? A Mechanistic Insight into the Enantioselective Brønsted Acid Catalyzed Dearomatization of Indoles with Allenamides

ChemCatChem ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 2442-2449 ◽  
Author(s):  
Pietro Giacinto ◽  
Andrea Bottoni ◽  
Andrea Garelli ◽  
Gian Pietro Miscione ◽  
Marco Bandini
Keyword(s):  
Bronsted Acid ◽  
Brønsted Acid ◽  
Mechanistic Insight ◽  
Brönsted Acid ◽  
Acid Catalyzed ◽  
Insight Into

scholarly journals On the Role of Protonic Acid Sites in Cu Loaded FAU31 Zeolite as a Catalyst for the Catalytic Transformation of Furfural to Furan

Molecules ◽  
2021 ◽  
Vol 26 (7) ◽  
pp. 2015
Author(s):  
Łukasz Kuterasiński ◽  
Małgorzata Smoliło-Utrata ◽  
Joanna Kaim ◽  
Wojciech Rojek ◽  
Jerzy Podobiński ◽  
...  
Keyword(s):  
Active Sites ◽  
Acid Sites ◽  
Bronsted Acid ◽  
Brønsted Acid ◽  
Brønsted Acid Sites ◽  
Protonic Acid ◽  
Brönsted Acid ◽  
Brönsted Acid Sites ◽  
Bronsted Acid Sites

The aim of the present paper is to study the speciation and the role of different active site types (copper species and Brønsted acid sites) in the direct synthesis of furan from furfural catalyzed by copper-exchanged FAU31 zeolite. Four series of samples were prepared by using different conditions of post-synthesis treatment, which exhibit none, one or two types of active sites. The catalysts were characterized by XRD, low-temperature sorption of nitrogen, SEM, H2-TPR, NMR and by means of IR spectroscopy with ammonia and CO sorption as probe molecules to assess the types of active sites. All catalyst underwent catalytic tests. The performed experiments allowed to propose the relation between the kind of active centers (Cu or Brønsted acid sites) and the type of detected products (2-metylfuran and furan) obtained in the studied reaction. It was found that the production of 2-methylfuran (in trace amounts) is determined by the presence of the redox-type centers, while the protonic acid sites are mainly responsible for the furan production and catalytic activity in the whole temperature range. All studied catalysts revealed very high susceptibility to coking due to polymerization of furfural.

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

Facile synthesis of chiral indolines through asymmetric hydrogenation of in situ generated indoles

2018 ◽  
Vol 5 (19) ◽  
pp. 2805-2809 ◽  
Author(s):  
Chang-Bin Yu ◽  
Jie Wang ◽  
Yong-Gui Zhou
Keyword(s):  
Asymmetric Hydrogenation ◽  
Hydrogenation Process ◽  
Bronsted Acid ◽  
Brønsted Acid ◽  
Facile Synthesis ◽  
One Pot ◽  
Brönsted Acid ◽  
Palladium Catalyzed ◽  
Intramolecular Condensation

A concise synthesis of chiral indolines has been developed through intramolecular condensation, deprotection and palladium-catalyzed asymmetric hydrogenation in a one-pot process with up to 96% ee. A strong Brønsted acid played an important role in both the formation of indoles and asymmetric hydrogenation process.

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