UV Light-Driven Asymmetric Vinylogous Aldol Reaction of Isatins with 2-Alkylbenzophenones and Enantioselective Synthesis of 3-Hydroxyoxindoles

2022 ◽  
Author(s):  
Shixuan Cao ◽  
Jiatian Li ◽  
Taisan Yan ◽  
Jie Han ◽  
Zhengjie He
Keyword(s):  
Natural Products ◽  
Ultraviolet Light ◽  
Uv Light ◽  
Aldol Reaction ◽  
Enantioselective Synthesis

Chiral 3-hydroxyoxindoles are biologically important molecular motifs which frequently present in natural products and artificial compounds. Herein, we report an ultraviolet light-driven asymmetric vinylogous aldol reaction between versatile isatins and...

Enantioselective Syntheses of Flavonoid Diels-Alder Natural Products: A Review

2018 ◽  
Vol 15 (2) ◽  
pp. 221-229 ◽  
Author(s):  
Shah Bakhtiar Nasir ◽  
Noorsaadah Abd Rahman ◽  
Chin Fei Chee
Keyword(s):  
Natural Products ◽  
Organic Synthesis ◽  
Lewis Acid ◽  
Alder Reaction ◽  
Diels Alder ◽  
Enantioselective Synthesis ◽  
Chiral Ligand ◽  
Asymmetric Syntheses ◽  
Diels Alder Reaction ◽  
Enantioselective Syntheses

Background: The Diels-Alder reaction has been widely utilised in the syntheses of biologically important natural products over the years and continues to greatly impact modern synthetic methodology. Recent discovery of chiral organocatalysts, auxiliaries and ligands in organic synthesis has paved the way for their application in Diels-Alder chemistry with the goal to improve efficiency as well as stereochemistry. Objective: The review focuses on asymmetric syntheses of flavonoid Diels-Alder natural products that utilize chiral ligand-Lewis acid complexes through various illustrative examples. Conclusion: It is clear from the review that a significant amount of research has been done investigating various types of catalysts and chiral ligand-Lewis acid complexes for the enantioselective synthesis of flavonoid Diels-Alder natural products. The results have demonstrated improved yield and enantioselectivity. Much emphasis has been placed on the synthesis but important mechanistic work aimed at understanding the enantioselectivity has also been discussed.

Formal Total Syntheses of Crocacin A-D

2005 ◽  
Vol 70 (10) ◽  
pp. 1696-1708 ◽  
Author(s):  
Magnus Besev ◽  
Christof Brehm ◽  
Alois Fürstner
Keyword(s):  
Natural Products ◽  
Aldol Reaction ◽  
Cross Coupling ◽  
Coupling Reactions ◽  
Total Syntheses ◽  
Cross Coupling Reactions ◽  
Palladium Catalyzed ◽  
The Common ◽  
Selective Addition

A concise route to the common polyketide fragment5of crocacin A-D (1-4) is presented which has previously been converted into all members of this fungicidal and cytotoxic family of dipeptidic natural products by various means. Our synthesis features asyn-selective titanium aldol reaction controlled by a valinol-derived auxiliary, a zinc-mediated, palladium-catalyzedanti-selective addition of propargyl mesylate10to the chiral aldehyde9, as well as a comparison of palladium-catalyzed Stille and Suzuki cross-coupling reactions for the formation of the diene moiety of the target.

Enantioselective synthesis of pyrro[3,4-c]quinoline pseudo-natural products

2021 ◽  
pp. 153228
Author(s):  
Jie Liu ◽  
Felix Otte ◽  
Carsten Strohmann ◽  
Herbert Waldmann
Keyword(s):  
Natural Products ◽  
Enantioselective Synthesis

scholarly journals Enantioselective synthesis of (−)-chloramphenicol via silver-catalysed asymmetric isocyanoacetate aldol reaction

2016 ◽  
Vol 14 (1) ◽  
pp. 93-96 ◽  
Author(s):  
Allegra Franchino ◽  
Pavol Jakubec ◽  
Darren J. Dixon
Keyword(s):  
Aldol Reaction ◽  
Enantioselective Synthesis ◽  
Asymmetric Aldol ◽  
Asymmetric Aldol Reaction ◽  
Catalytic Asymmetric

A concise synthesis of (−)-chloramphenicol, based on the catalytic asymmetric aldol reaction between 4-nitrobenzaldehyde and benzhydryl isocyanoacetate, is reported.

Evaluation of the Effect of Ultraviolet Light Excitation during Characterization of Silicon Carbide Epitaxial Layers

2018 ◽  
Vol 924 ◽  
pp. 261-264
Author(s):  
Hrishikesh Das ◽  
Swapna Sunkari ◽  
Oener Akdik ◽  
Andrei Konstantinov ◽  
Krister Gumaelius ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Ultraviolet Light ◽  
Defect Detection ◽  
Uv Light ◽  
Surface Treatments ◽  
Uv Laser ◽  
Original State ◽  
Optimal Surface ◽  
Light Excitation

The scanning of Silicon Carbide (SiC) epitaxy wafers for defects by ultraviolet (UV) laser or lamps is widely prevalent. In this work, we document the effects of UV light excitation on the SiC epitaxy material. An increase in background photoluminescence (PL) is observed after repeated scans. The effect of this increase on defect detection is shown. Optimal surface treatments to recover the material back to the original state are demonstrated. Further, some surface treatments are proposed which reduce the effect of the UV light excitation and prevent to a large extent the rise in background PL.

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