scholarly journals Vinylogous Hydrazone Strategy for the Organocatalytic Alkylation of Heteroaromatic Derivatives

2021 ◽  
Author(s):  
Beata Łukasik ◽  
Justyna Kowalska ◽  
Sebastian Frankowski ◽  
Lukasz Albrecht
Keyword(s):  
Heteroaromatic System ◽  
Unsaturated Aldehydes

A new umpolung approach for the asymmetric FriedelCrafts-type alkylation of electron-poor heteroaromatic systems has been developed. It is based on the vinylogous reactivity of hydrazones derived from heteroaromatic aldehydes. Donating effect of the hydrazone moiety can be efficiently transferred over the heteroaromatic system activating it towards asymmetric FriedelCrafts reaction with α,β-unsaturated aldehydes realized under aminocatalytic conditions. Excellent enantioselectivities have been obtained owing to the application of MacMillan imidazolidinone catalyst. Unmasking of hydrazone moiety has been also realized resulting in the development of a unique strategy for the asymmetric functionalization of electron-poor heteroaromatic systems.

scholarly journals Vinylogous Hydrazone Strategy for the Organocatalytic Alkylation of Heteroaromatic Derivatives

2021 ◽  
Author(s):  
Beata Łukasik ◽  
Justyna Kowalska ◽  
Sebastian Frankowski ◽  
Lukasz Albrecht
Keyword(s):  
Heteroaromatic System ◽  
Unsaturated Aldehydes

A new umpolung approach for the asymmetric FriedelCrafts-type alkylation of electron-poor heteroaromatic systems has been developed. It is based on the vinylogous reactivity of hydrazones derived from heteroaromatic aldehydes. Donating effect of the hydrazone moiety can be efficiently transferred over the heteroaromatic system activating it towards asymmetric FriedelCrafts reaction with α,β-unsaturated aldehydes realized under aminocatalytic conditions. Excellent enantioselectivities have been obtained owing to the application of MacMillan imidazolidinone catalyst. Unmasking of hydrazone moiety has been also realized resulting in the development of a unique strategy for the asymmetric functionalization of electron-poor heteroaromatic systems.

THE TOXICITY AND DETOXIFICATION OF α, β-UNSATURATED ALDEHYDES

1999 ◽  
Vol 14 (supplement) ◽  
pp. 74-75
Author(s):  
Akira HIRATSUKA ◽  
Kenichiro HIROSE ◽  
Hiroaki NAKANO ◽  
Tadashi WATABE
Keyword(s):  
Unsaturated Aldehydes

Asymmetric Peroxidation of α,β-Unsaturated Aldehydes under Diarylprolinol Ether Catalysis

2017 ◽  
Vol 21 (19) ◽  
Author(s):  
K. O'Reilly ◽  
M. K. Gupta ◽  
H. Gandhi ◽  
V. P. Kumar ◽  
T. P. O'Sullivan
Keyword(s):  
Unsaturated Aldehydes

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.

Assembly of Fluorinated Chromanones via Enantioselective Tandem Reaction

2021 ◽  
Author(s):  
Mengxue Lu ◽  
Zongli Xiong ◽  
Yuqiao Zhou ◽  
Xin Wang ◽  
Xiaoyi Li ◽  
...  
Keyword(s):  
Enantioselective Synthesis ◽  
Tandem Reaction ◽  
Unsaturated Aldehydes ◽  
Stereogenic Centers ◽  
First Time

The enantioselective synthesis of fluorinated tricyclic chromanones with multiple vicinal stereogenic centers has been realized for the first time, through the tandem reaction between 2-fluorinated 1-(2-hydroxyaryl)-1,3-diketones and α,β-unsaturated aldehydes. In...

ChemInform Abstract: Syntheses and Structures of Indolo(6,7-g)indoles, a New Heteroaromatic System.

ChemInform ◽  
1990 ◽  
Vol 21 (8) ◽  
Author(s):  
Y. NAGAWA ◽  
M. GOTO ◽  
K. HONDA ◽  
H. NAKANISHI
Keyword(s):  
Heteroaromatic System

ChemInform Abstract: CYCLOADDITIONS OF DIAZOESTERS TO α,β-UNSATURATED ALDEHYDES

1979 ◽  
Vol 10 (10) ◽  
Author(s):  
A. F. NOELS ◽  
J. N. BRAHAM ◽  
A. J. HUBERT ◽  
PH. TEYSSIE
Keyword(s):  
Unsaturated Aldehydes

Platinum and cobalt intermetallic nanoparticles confined within MIL-101(Cr) for enhanced selective hydrogenation of the carbonyl bond in α,β-unsaturated aldehydes: synergistic effects of electronically modified Pt sites and Lewis acid sites

2021 ◽  
Author(s):  
Muhammad Zahid ◽  
Jiang Li ◽  
Ahmed Ismail ◽  
Francisco Zaera ◽  
Yujun Zhu
Keyword(s):  
Synergistic Effect ◽  
Reduction Method ◽  
Synergistic Effects ◽  
Acid Sites ◽  
Lewis Acid Sites ◽  
Unsaturated Aldehydes ◽  
Uniform Dispersion ◽  
Carbonyl Bond ◽  
Method Show ◽  
Intermetallic Nanoparticles

PtCo/MIL-101(Cr) with high uniform dispersion Pt–Co IMNs synthesized by a polyol reduction method show higher activity for selective catalytic hydrogenation of α,β-unsaturated aldehydes due to the synergistic effect of PtCo and MIL-101(Cr) support.

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