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

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

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.

Synthesis and evaluation of 7-hydroxyindan-1-one-derived chiral auxiliaries

2005 ◽  
Vol 83 (5) ◽  
pp. 413-419 ◽  
Author(s):  
Arun A Narine ◽  
Peter D Wilson
Keyword(s):  
Asymmetric Synthesis ◽  
Alder Reaction ◽  
Diels Alder ◽  
Chiral Auxiliaries ◽  
Diels Alder Reaction ◽  
High Degree

A series of novel chiral acetals were prepared from 7-hydroxyindan-1-one and a variety of substituted chiral nonracemic C2-symmetric 1,2-ethanediols (R = Me, Ph, CH2OMe, CH2OBn, CH2O(1-Np), and i-Pr). These acetals were evaluated as chiral auxiliaries for use in asymmetric synthesis. A high degree of stereochemical induction was observed in the diethylaluminum chloride-promoted Diels–Alder reaction of an acrylate derivative (R = i-Pr) with cyclopentadiene (91:9 dr). This demonstrated that these acetals could serve as effective chiral directors in asymmetric substrate-directed reactions.Key words: 7-hydroxyindan-1-one, chiral nonracemic C2-symmetric 1,2-diols, acetals, chiral auxiliaries, Diels–Alder reaction.

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.

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

Syntheses and Applications of Singh’s Catalyst

Synthesis ◽  
2020 ◽  
Vol 52 (23) ◽  
pp. 3577-3582
Author(s):  
Rama Kanwar Khangarot ◽  
Manisha Khandelwal ◽  
Sumit Kumar Ray
Keyword(s):  
Asymmetric Synthesis ◽  
Short Review ◽  
Aldol Reactions ◽  
Organic Media

Singh’s catalyst has emerged as one of the most promising and valuable catalysts in the field of asymmetric synthesis. Since its discovery, it has proven to be one of the best organocatalysts for asymmetric direct aldol reactions, and is equally efficient in aqueous and organic media. In this Short Review, we summarize reactions utilizing Singh’s catalyst under various conditions.1 Introduction2 Synthesis of Singh’s Catalyst3 Applications in Asymmetric Synthesis4 Conclusion

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