Enantioselective Vinylogous Reactions of 3-Alkylidene Oxindoles

Synthesis ◽  
2018 ◽  
Vol 50 (13) ◽  
pp. 2463-2472 ◽  
Author(s):  
Renato Dalpozzo ◽  
Raffaella Mancuso
Keyword(s):  
Natural Products ◽  
Asymmetric Synthesis ◽  
Bioactive Compounds ◽  
Carbonyl Compounds ◽  
Important Class ◽  
Chiral Molecules ◽  
Research Groups ◽  
Mannich Reactions ◽  
The Creation ◽  
Synthetic Derivatives

Oxindoles represent an important class of bioactive compounds and synthetic derivatives found in many natural products. Most of these compounds are chiral molecules and the challenge of their asymmetric synthesis has fascinated many research groups. In particular, the creation of chiral centers out of the oxindole ring by vinylogous addition to 3-alkylidene-substituted oxindoles (3-alkylidene-1,3-dihydro-2H-indol-2-ones) has emerged in recent years. This review aims to give an overview of this topic.1 Introduction2 Aldol and Mannich Reactions3 Addition to Unsaturated Carbonyl Compounds4 Addition to Nitroalkenes5 Miscellaneous6 Conclusion

scholarly journals Step economy in the Stereoselective Synthesis of Functionalized Oxindoles via Organocatalytic Domino/One-pot Reactions

2021 ◽  
Vol 25 ◽  
Author(s):  
Martina Bortolami ◽  
Francesca Leonelli ◽  
Marta Feroci ◽  
Fabrizio Vetica
Keyword(s):  
Natural Products ◽  
Asymmetric Synthesis ◽  
Bioactive Compounds ◽  
Stereoselective Synthesis ◽  
Environmentally Friendly ◽  
Important Class ◽  
One Pot ◽  
Asymmetric Organocatalysis ◽  
Toxic Approach

: Oxindoles are an important class of heterocyclic scaffolds widely present in natural products and bioactive compounds. For this reason, a plethora of methodologies for the stereoselective synthesis of enantioenriched oxindoles has been studied over the years. Among all the reported synthetic strategies, organocatalysis has proven to be a powerful tool for the asymmetric synthesis of this class of compounds being a step- and atom-economical, environmentally friendly, and non-toxic approach. This review will outline the application of asymmetric organocatalysis in the synthesis of chiral oxindole-based structures, relying on domino/one-pot reaction sequences in a step-economical fashion.

A Mini-Review: Achievements in the Thiolysis of Epoxides

2020 ◽  
Vol 17 (4) ◽  
pp. 352-362 ◽  
Author(s):  
Zhihua Chen ◽  
Saeed Mohammadi Nasr ◽  
Mosstafa Kazemi ◽  
Masoud Mohammadi
Keyword(s):  
Natural Products ◽  
Bioactive Compounds ◽  
Ring Opening ◽  
Solvent Free ◽  
Organosulfur Compounds ◽  
Important Class ◽  
Research Groups ◽  
Diverse Range ◽  
Solvent Free Conditions ◽  
Ring Opening Reactions

The β-hydroxy sulfides are an important class of organosulfur compounds that have a key role in the synthesis of bioactive compounds containing biological and natural products. The thiolysis of epoxides is the most common and best route for the synthesis of β-hydroxy sulfides. During the last decade, the applications of a diverse range of catalysts and promoter agents in green and organic mediums as well as under solvent-free conditions for the regioselective ring-opening reactions of epoxides with thiols in order to synthesize β-hydroxy sulfides have been studied by various research groups. This review is focused on the important achievements reported in the literature for the thiolysis of epoxides.

Glucose - and Allose-Derived Chiral Auxiliaries

2019 ◽  
Vol 800 ◽  
pp. 36-41
Author(s):  
Evija Rolava ◽  
Jevgeņija Lugiņina ◽  
Māris Turks
Keyword(s):  
Asymmetric Synthesis ◽  
Bioactive Compounds ◽  
Heterocyclic Compounds ◽  
Biologically Active ◽  
Important Class ◽  
Chiral Auxiliaries ◽  
Asymmetric Alkylation ◽  
Pharmaceutical Agents

Oxazolidinones are an important class of heterocyclic compounds that are used as chiral auxiliaries in asymmetric synthesis and as biologically active pharmaceutical agents. Moreover, carbohydrates are ideal scaffolds to generate libraries of bioactive compounds due the presence of defined configuration. We report here asymmetric alkylation studies on N-derivatized glucose-and allose-based spirooxazolidinones which do act as chiral auxiliaries.

Asymmetric Organocatalytic Syntheses of Bioactive Compounds

2021 ◽  
Vol 18 ◽  
Author(s):  
Estibaliz Sansinenea ◽  
Aurelio Ortiz
Keyword(s):  
Natural Products ◽  
Asymmetric Synthesis ◽  
Bioactive Compounds ◽  
Cascade Reactions ◽  
Biologically Active ◽  
Active Compounds ◽  
Total Syntheses ◽  
Main Structure ◽  
New Methodologies ◽  
High Stereoselectivity

Background: The total syntheses of complex natural products have evolved to include new methodologies to save time, simplifying the form to achieve these natural compounds. Objective: In this review, we have described the asymmetric synthesis of different natural products and biologically active compounds of the last ten years until the current day. Results: An asymmetric organocatalytic reaction is the key to generate stereoselectively the main structure with the required stereochemistry. Conclusion: Even more remarkable, the organocatalytic cascade reactions, which are carried out with high stereoselectivity, as well as a possible approximation of the organocatalysts activation with substrates are also described.

Internal Chelation within Functionalized Organoindium Reagents: Prospects for Regio- and Stereocontrol in the Allylation, Propargylation and Allenylation of Carbonyl Compounds

Synthesis ◽  
2020 ◽  
Vol 52 (08) ◽  
pp. 1147-1180
Author(s):  
Bartosz K. Zambroń
Keyword(s):  
Natural Products ◽  
Asymmetric Synthesis ◽  
Functional Groups ◽  
Carbonyl Compounds ◽  
Specific Nature ◽  
Organometallic Reagents ◽  
Unique Manner

The low basicity, selective nucleophilicity, and mildness of organoindium compounds allow for the incorporation of many important yet sensitive functional groups into their structure, including examples capable of intramolecularly chelating the indium center within these reagents. The specific nature of such chelated organoindiums causes the reactions involving them to proceed in a unique manner, often with regio- and stereoselectivity inaccessible with simple organometallic reagents. This review covers the rare examples of regio- and stereoselective allylation, propargylation, and allenylation of carbonyl compounds with chelated organoindiums, including brief descriptions of the applications of the resulting adducts in the asymmetric synthesis of natural products and synthetic targets of biological and medicinal interest.1 Introduction2 Internal Chelation Control in the Allylation Processes2.1 Allylindiums with a Chelating Center at the γ-Position2.2 Allylindiums with a chelating Center at the δ-Position2.3 Allylindiums with a Chelating Center at ε- and ζ-Positions2.4 Allylindiums with a Chelating Center at γ′- and δ′-Positions3 Internal Chelation Control in Propargylation and Allenylation Processes­3.1 Additions of Chelated Allenylindiums3.2 Additions of Chelated Propargylindiums4 Conclusion

Asymmetric Synthesis of α‐Difluorinated β‐Amino Sulfones via Detrifluoroacetylative Mannich Reactions

2021 ◽  
Author(s):  
Ziyi Li ◽  
Nana Wang ◽  
Haibo Mei ◽  
Hiroyuki Konno ◽  
Vadim A. Soloshonok ◽  
...  
Keyword(s):  
Asymmetric Synthesis ◽  
Mannich Reactions

scholarly journals Anabaenopeptins: What We Know So Far

Toxins ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 522
Author(s):  
Patrick Romano Monteiro ◽  
Samuel Cavalcante do Amaral ◽  
Andrei Santos Siqueira ◽  
Luciana Pereira Xavier ◽  
Agenor Valadares Santos
Keyword(s):  
Secondary Metabolites ◽  
Bioactive Compounds ◽  
Inhibitory Activity ◽  
Important Class ◽  
Biotechnological Applications ◽  
Peptide Synthetases ◽  
Ecological Roles ◽  
Cyclic Hexapeptides ◽  
Key Features

Cyanobacteria are microorganisms with photosynthetic mechanisms capable of colonizing several distinct environments worldwide. They can produce a vast spectrum of bioactive compounds with different properties, resulting in an improved adaptative capacity. Their richness in secondary metabolites is related to their unique and diverse metabolic apparatus, such as Non-Ribosomal Peptide Synthetases (NRPSs). One important class of peptides produced by the non-ribosomal pathway is anabaenopeptins. These cyclic hexapeptides demonstrated inhibitory activity towards phosphatases and proteases, which could be related to their toxicity and adaptiveness against zooplankters and crustaceans. Thus, this review aims to identify key features related to anabaenopeptins, including the diversity of their structure, occurrence, the biosynthetic steps for their production, ecological roles, and biotechnological applications.

Enantioselective Radical Functionalization of Imines and Iminium Intermediates via Visible Light Photoredox Catalysis

Synthesis ◽  
2020 ◽  
Author(s):  
Jia-Jia Zhao ◽  
Hong-Hao Zhang ◽  
Shouyun Yu
Keyword(s):  
Visible Light ◽  
Asymmetric Synthesis ◽  
Carbonyl Compounds ◽  
Asymmetric Reduction ◽  
Chemical Transformations ◽  
Photoredox Catalysis ◽  
Radical Coupling ◽  
Mild Conditions ◽  
Iminium Ions ◽  
Radical Functionalization

Visible light photoredox catalysis has recently emerged as a powerful tool for the development of new and valuable chemical transformations under mild conditions. Visible-light promoted enantioselective radical transformations of imines and iminium intermediates provide new opportunities for the asymmetric synthesis of amines and asymmetric β-functionalization of unsaturated carbonyl compounds. In this review, the advance in the catalytic asymmetric radical functionalization of imines, as well as iminium intermediates, are summarized. 1 Introduction 2 The enantioselective radical functionalization of imines 2.1 Asymmetric reduction 2.2 Asymmetric cyclization 2.3 Asymmetric addition 2.4 Asymmetric radical coupling 3 The enantioselective radical functionalization of iminium ions 3.1 Asymmetric radical alkylation 3.2 Asymmetric radical acylation 4 Conclusion

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