Efficient Enantioselective Syntheses of Chiral Natural Products Facilitated by Ligand Design

2019 ◽  
Vol 20 (1) ◽  
pp. 23-40 ◽  
Author(s):  
He Yang ◽  
Wenjun Tang
Keyword(s):  
Natural Products ◽  
Ligand Design ◽  
Enantioselective Syntheses

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.

scholarly journals N-(1-Phenylethyl)aziridine-2-carboxylate esters in the synthesis of biologically relevant compounds

2019 ◽  
Vol 15 ◽  
pp. 1722-1757
Author(s):  
Iwona E Głowacka ◽  
Aleksandra Trocha ◽  
Andrzej E Wróblewski ◽  
Dorota G Piotrowska
Keyword(s):  
Amino Acids ◽  
Natural Products ◽  
Natural Compounds ◽  
Review Article ◽  
Chiral Auxiliary ◽  
Biologically Relevant ◽  
Alternative Approaches ◽  
Approved Drugs ◽  
Enantioselective Syntheses ◽  
New Procedures

Since Garner’s aldehyde has several drawbacks, first of all is prone to racemization, alternative three-carbon chirons would be of great value in enantioselective syntheses of natural compounds and/or drugs. This review article summarizes applications of N-(1-phenylethyl)aziridine-2-carboxylates, -carbaldehydes and -methanols in syntheses of approved drugs and potential medications as well as of natural products mostly alkaloids but also sphingoids and ceramides and their 1- and 3-deoxy analogues and several hydroxy amino acids and their precursors. Designed strategies provided new procedures to several drugs and alternative approaches to natural products and proved efficiency of a 2-substituted N-(1-phenylethyl)aziridine framework as chiron bearing a chiral auxiliary.

Enantioselective syntheses of indanes: from organocatalysis to C–H functionalization

2016 ◽  
Vol 45 (5) ◽  
pp. 1368-1386 ◽  
Author(s):  
Cyril Borie ◽  
Lutz Ackermann ◽  
Malek Nechab
Keyword(s):  
Natural Products ◽  
Recent Progress ◽  
Enantioselective Catalysis ◽  
Enantioselective Syntheses ◽  
Major Progress

The indanyl core is ubiquitous in a large variety of drugs and natural products. Remarkable recent progress has been accomplished in the step-economical assembly of functionalization of chiral indanes by means of enantioselective catalysis, with major progress being achieved in organocatalysis and C–H activation chemistry.

Enantioselective syntheses of bioactive epoxyquinone natural products (+)-harveynone and (−)-asperpentyn

2012 ◽  
Vol 53 (32) ◽  
pp. 4093-4095 ◽  
Author(s):  
Goverdhan Mehta ◽  
Subhrangsu Roy ◽  
Subhas Chandra Pan
Keyword(s):  
Natural Products ◽  
Enantioselective Syntheses

scholarly journals Unexpected Racemization in the Course of the Acetalization of (+)-(S)-5-Methyl-Wieland–Miescher Ketone with 1,2-Ethanediol and TsOH under Classical Experimental Conditions

2019 ◽  
Vol 20 (24) ◽  
pp. 6147
Author(s):  
Francesca Leonelli ◽  
Irene Piergentili ◽  
Giulio Lucarelli ◽  
Luisa Maria Migneco ◽  
Rinaldo Marini Bettolo
Keyword(s):  
Natural Products ◽  
Experimental Conditions ◽  
Enantiomerically Pure ◽  
Bioactive Natural Products ◽  
Classical Procedure ◽  
Enantioselective Syntheses

(+)-(S) and (−)-(R)-5-methyl-Wieland-Miescher ketone (+)-1 and (−)-1, are important synthons in the diastereo and enantioselective syntheses of biological and/or pharmacological interesting compounds. A key step in these syntheses is the chemoselective C(1)O acetalization to (+)-5 and (−)-5, respectively. Various procedures for this transformation have been described in the literature. Among them, the classical procedure based on the use of 1,2-ethanediol and TsOH in refluxing benzene in the presence of a Dean-Stark apparatus. Within our work on bioactive natural products, it occurred to us to observe the partial racemization of (+)-5 in the course of the acetalization of (+)-1 by means of the latter methodology. Aiming to investigate this drawback, which, to our best knowledge, has no precedents in the literature, we acetalized with 1,2-ethanediol and TsOH in refluxing benzene and in the presence of a Dean–Stark apparatus under various experimental conditions, enantiomerically pure (+)-1. It was found that the extent of racemization depends on the TsOH/(+)-1 and 1,2-ethanediol/(+)-1 ratios. Mechanism hypotheses for this partial and unexpected racemization are provided.

Enantioselective Syntheses of Yohimbine Alkaloids: Proving Grounds for New Catalytic Transformations

Synthesis ◽  
2021 ◽  
Author(s):  
Karl A. Scheidt ◽  
Eric R Miller
Keyword(s):  
Natural Products ◽  
Chemical Synthesis ◽  
Total Synthesis ◽  
State Of The Art ◽  
The State ◽  
Catalytic Transformations ◽  
Bond Forming ◽  
The Past ◽  
Catalytic Asymmetric ◽  
Enantioselective Syntheses

The total synthesis of bioactive alkaloids is an enduring challenge and an indication of the state of the art of chemical synthesis. With the explosion of catalytic asymmetric methods over the past three decades, these compelling targets have been fertile proving grounds for enantioselective bond forming transformations. We summarize these activities herein both to highlight the power and versatility of these methods and to instill future inspiration for new syntheses of these privileged natural products.

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