On the role of promoters in hydrogenations on metals; α,β-unsaturated aldehydes and ketones

1997 ◽  
Vol 149 (1) ◽  
pp. 27-48 ◽  
Author(s):  
V. Ponec
Keyword(s):  
Unsaturated Aldehydes ◽  
Aldehydes And Ketones

scholarly journals Theoretical Insight into the Reversal of Chemoselectivity in Diels-Alder Reactions of α,β-Unsaturated Aldehydes and Ketones Catalyzed by Brønsted and Lewis Acids

Organics ◽  
2021 ◽  
Vol 2 (1) ◽  
pp. 38-49
Author(s):  
Lakhdar Benhamed ◽  
Sidi Mohamed Mekelleche ◽  
Wafaa Benchouk
Keyword(s):  
Lewis Acids ◽  
Major Product ◽  
Diels Alder ◽  
Unsaturated Ketone ◽  
Unsaturated Aldehydes ◽  
Aldehydes And Ketones ◽  
Theoretical Insight ◽  
Insight Into ◽  
Good Agreement

Experimentally, a reversal of chemoselectivity has been observed in catalyzed Diels–Alder reactions of α,β-unsaturated aldehydes (e.g., (2E)-but-2-enal) and ketones (e.g., 2-hexen-4-one) with cyclopentadiene. Indeed, using the triflimidic Brønsted acid Tf2NH as catalyst, the reaction gave a Diels–Alder adduct derived from α,β-unsaturated ketone as a major product. On the other hand, the use of tris(pentafluorophenyl)borane B(C6F5)3 bulky Lewis acid as catalyst gave mainly the cycloadduct of α,β-unsaturated aldehyde as a major product. Our aim in the present work is to put in evidence the role of the catalyst in the reversal of the chemoselectivity of the catalyzed Diels–Alder reactions of (2E)-but-2-enal and 2-Hexen-4-one with cyclopentadiene. The calculations were performed at the ωB97XD/6-311G(d,p) level of theory and the solvent effects of dichloromethane were taken into account using the PCM solvation model. The obtained results are in good agreement with experimental outcomes.

scholarly journals Thermoregulated phase-separable rhodium nanoparticle catalyst for selective hydrogenation of α,β-unsaturated aldehydes and ketones

RSC Advances ◽  
2017 ◽  
Vol 7 (79) ◽  
pp. 50343-50346 ◽  
Author(s):  
Xiuru Xue ◽  
Mingming Niu ◽  
Yicheng Xu ◽  
Yanhua Wang
Keyword(s):  
Selective Hydrogenation ◽  
Unsaturated Aldehydes ◽  
Highly Efficient ◽  
Aldehydes And Ketones ◽  
Rhodium Nanoparticle ◽  
Nanoparticle Catalyst

Highly efficient and recyclable thermoregulated phase-separable Rhnano catalysts applied for the selective hydrogenation of α,β-unsaturated aldehydes and ketones are presented.

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