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.

scholarly journals Cellulose recycling as a source of raw chirality

2013 ◽  
Vol 85 (8) ◽  
pp. 1683-1692 ◽  
Author(s):  
Valeria Corne ◽  
María Celeste Botta ◽  
Enrique D. V. Giordano ◽  
Germán F. Giri ◽  
David F. Llompart ◽  
...  
Keyword(s):  
Organic Chemistry ◽  
Organic Carbon ◽  
Asymmetric Synthesis ◽  
Building Blocks ◽  
Biologically Active ◽  
Raw Material ◽  
Chiral Auxiliaries ◽  
High Chemical ◽  
Chiral Structure

Modern organic chemistry requires easily obtainable chiral building blocks that show high chemical versatility for their application in the synthesis of enantiopure compounds. Biomass has been demonstrated to be a widely available raw material that represents the only abundant source of renewable organic carbon. Through the pyrolitic conversion of cellulose or cellulose-containing materials it is possible to produce levoglucosenone, a highly functionalized chiral structure. This compound has been innovatively used as a template for the synthesis of key intermediates of biologically active products and for the preparation of chiral auxiliaries, catalysts, and organocatalysts for their application in asymmetric synthesis.

Remarkable Advances in the Asymmetric Synthesis of Biologically Active Natural Compounds from the Advent of Chiral Auxiliaries

2020 ◽  
pp. 1-51
Author(s):  
Gaspar Diaz-Muñoz ◽  
Izabel Luzia Miranda ◽  
Suélen Karine Sartori ◽  
Daniele Cristina de Rezende ◽  
Jefferson Viktor Barros de Paula Baeta ◽  
...  
Keyword(s):  
Asymmetric Synthesis ◽  
Natural Compounds ◽  
Biologically Active ◽  
Chiral Auxiliaries ◽  
Active Natural

Ephedrines as Chiral Auxiliaries in Enantioselective Alkylation Reactions of Acyl Ephedrine Amides and Esters: A Review

2018 ◽  
Vol 15 (1) ◽  
pp. 38-83 ◽  
Author(s):  
Alejandro Cruz ◽  
Itzia I. Padilla-Martínez ◽  
Maria E. Bautista-Ramirez
Keyword(s):  
Asymmetric Synthesis ◽  
Bond Formation ◽  
Alkyl Halides ◽  
Aldol Reactions ◽  
Alkylation Reaction ◽  
Chiral Auxiliaries ◽  
Asymmetric Alkylation ◽  
Chiral Compounds ◽  
High Yields ◽  
Alkylation Reactions

Background: In modern chemistry, the asymmetric synthesis for the preparation of high purity chiral compounds to be used as pharmaceuticals or additives in foods have been of capital importance. Chiral auxiliary reagents are used to control the stereochemistry of the reaction in the generation of new chiral compounds, in this context, Ephedra compounds (ephedrines and pseudoephedrines) and some of their derivatives have been broadly used as chiral ligands in catalysis or chiral inductors in asymmetric synthesis. Objective: This review focuses on recent progress in the use of ephedra compounds and their N-substituted derivatives as chiral auxiliaries in the area of asymmetric synthesis, via the alkylation reaction of the enolates derived from their corresponding N-Acyl or O-Acyl derivatives, in the C-C bond formation. Conclusion: A vast amount of work has been done about the use of ephedra compounds in asymmetric synthesis area, in general, it was found that pseudoephedrines are much more effective than ephedrines and are preferred as chiral auxiliaries in the asymmetric alkylation of the corresponding N-acyl amides or O-Acyl esters. Alkylation with alkyl halides requires the use of more than 4 equivalents of LiCl to accelerate the alkylation rate and to complete the reaction without effecting the diastereoselectivity of the process. In contrast, the use of secondary alkyl halides was found to make the reaction very slow. Furthermore, a lot of work about the alkylation reaction in the opening of epoxides and aziridines, aldolic condensation, Manich reaction, addition of nucleophiles to α,β-unsaturated ephedrine amides and Michael additions have been demonstrated to be effective in the C-C bond formation. The aldol reaction of chiral enolates, proceeds with decreasing yields and enantioselectivities as the steric demand of the α-R of ephedrine amides and the size of carbonyl compound increase. In addition, the use of branched groups on N,N-disubstituted norephedrine esters is highly recommended in the aldol reactions of aromatic and aliphatic aldehydes.In the case of N-Acyl or O-Acyl ephedrines supported on polymers, the reaction proceed with good enantioselectivities but low yields, the enantioselectivities are goods but the yields are low. In general, the removal step of the auxiliary proceeds with low to high yields but without epimerization.

Recent Applications in the Use of Sulfoxides as Chiral Auxiliaries for the Asymmetric Synthesis of Natural and Biologically Active Products

Synthesis ◽  
2020 ◽  
Vol 52 (07) ◽  
pp. 964-978 ◽  
Author(s):  
Xavier Salom-Roig ◽  
Claude Bauder
Keyword(s):  
Asymmetric Synthesis ◽  
Short Review ◽  
Diels Alder ◽  
Biologically Active ◽  
Aldol Reactions ◽  
Chiral Auxiliaries ◽  
Conjugate Additions ◽  
Chiral Sulfoxides ◽  
Diastereoselective Addition ◽  
Nazarov Cyclizations

The contribution of chiral sulfoxides as versatile auxiliaries in the field of organic chemistry has shown a prevalent interest in the asymmetric synthesis of natural products during the last 45 years. In this short review, we report the recent applications of these chiral auxiliaries to the synthesis of natural and biological active products highlighted from 2010 to 2019. We hope to allow the reader to have an overview of the potential of sulfoxide chemistry in the field of enantio­selective synthesis.1 Introduction2 Diastereoselective Additions to Ketones2.1 Reduction of β-Keto Sulfoxides2.2 Reduction of β-Keto Sulfoxides Followed by Bromohydrin Forma tion3 Synthesis of an α-Amino α′-Sulfinyl Ketone Followed by Diastere oselective Reduction of the β-Keto Sulfoxide4 Diastereoselective Addition of Carbanionic Chiral Sulfoxides4.1 Addition to an Aldehyde4.1.1 Aldol Reactions4.1.2 Reformatsky-Type Reactions4.2 Additions to Chiral Sulfinimines5 Diastereoselective Cyclization Reactions Directed by a Chiral Sulf oxide5.1 1,4-Radical Additions5.2 Intramolecular Conjugate Additions5.3 Nazarov Cyclizations5.4 Diels–Alder Reactions6 Atropodiastereoselective Synthesis7 Conclusion

Use of chiral auxiliaries in the asymmetric synthesis of biologically active compounds: A review

Chirality ◽  
2019 ◽  
Vol 31 (10) ◽  
pp. 776-812 ◽  
Author(s):  
Gaspar Diaz‐Muñoz ◽  
Izabel Luzia Miranda ◽  
Suélen Karine Sartori ◽  
Daniele Cristina Rezende ◽  
Marisa Alves Nogueira Diaz
Keyword(s):  
Asymmetric Synthesis ◽  
Biologically Active Compounds ◽  
Biologically Active ◽  
Chiral Auxiliaries ◽  
Active Compounds

Dimroth´s Rearrangement as a Synthetic Strategy Towards New Heterocyclic Compounds

2020 ◽  
Vol 24 (17) ◽  
pp. 1999-2018
Author(s):  
Vitor F. Ferreira ◽  
Thais de B. da Silva ◽  
Fernanda P. Pauli ◽  
Patricia G. Ferreira ◽  
Luana da S. M. Forezi ◽  
...  
Keyword(s):  
Bioactive Compounds ◽  
Heterocyclic Compounds ◽  
Large Scale ◽  
Molecular Diversity ◽  
Biologically Active ◽  
Scale Production ◽  
Dimroth Rearrangement ◽  
Synthetic Strategy ◽  
Large Scale Production ◽  
Synthetic Approaches

Molecular rearrangements are important tools to increase the molecular diversity of new bioactive compounds, especially in the class of heterocycles. This review deals specifically with a very famous and widely applicable rearrangement known as the Dimroth Rearrangement. Although it has originally been observed for 1,2,3-triazoles, its amplitude was greatly expanded to other heterocycles, as well as from laboratory to large scale production of drugs and intermediates. The reactions that were discussed in this review were selected with the aim of demonstrating the windows that may be open by the Dimroth's rearrangement, especially in what regards the development of new synthetic approaches toward biologically active compounds.

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.

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.

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

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