The SuperQuat (4-substituted 5,5-dimethyloxazolidine-2-one) family of chiral auxiliaries was first developed by us in the 1990s to address the shortcomings of the Evans (4-substituted oxazolidin-2-one) family of chiral auxiliaries. The incorporation of geminal dimethyl substitution at C(5) has two effects: (i) it induces a conformational bias on an adjacent, otherwise conformationally labile C(4)-substituent so that it projects towards the N-acyl fragment, thus offering superior diastereofacial selectivity in a range of transformations; and (ii) it hinders nucleophilic attack at the endocyclic carbonyl group, facilitating recovery and recyclability of the auxiliary, with enhanced cleavage properties. This review summarises the development and some of the most common uses of the SuperQuat family of chiral auxiliaries, particularly in the synthesis of natural products or other targets having bioloigcal interest. Where possible, comparisons with the performances of the corresponding Evans auxiliaries are presented.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1039/c8ob02819b | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Asymmetric gem-Hydroboration and gem-Hydrogenation of Ynamides: A New Gateway to Chiral Fischer Carbene Complexes and their Catalytic Transformations.
Angew Chem Int Ed Engl
January 2025
Max-Planck-Institut fur Kohlenforschung, Organometallic Chemistry, Kaiser-Wilhelm-Platz 1, 45470, Mülheim/Ruhr, GERMANY.
Ynamides, when reacted with H2 or HBpin in the presence of [Cp*RuCl]4, convert into chiral-at-metal Fischer carbenes by regioselective gem-hydrogenation or gem-hydroboration of the polarized triple bond, respectively. gem-Hydroboration concomitantly affords a carbogenic borylated stereocenter adjacent to the ruthenium carbene unit, the configuration of which can be controlled using an Evans auxiliary. These are the first examples of asymmetric gem-addition reactions to alkynes known in the literature; representative pianostool ruthenium carbene complexes formed by this unconventional route were characterized by crystallographic and spectroscopic means.
View Article and Find Full Text PDFA modular approach to catalytic stereoselective synthesis of chiral 1,2-diols and 1,3-diols.
Nat Commun
January 2025
The Institute for Advanced Studies and Hongyi Honor College, Wuhan University, Wuhan, China.
Optically pure 1,2-diols and 1,3-diols are the most privileged structural motifs, widely present in natural products, pharmaceuticals and chiral auxiliaries or ligands. However, their synthesis relies on the use of toxic or expensive metal catalysts or suffer from low regioselectivity. Catalytic asymmetric synthesis of optically pure 1,n-diols from bulk chemicals in a highly stereoselective and atom-economical manner remains a formidable challenge.
View Article and Find Full Text PDFDiscovery of Staircase Chirality through the Design of Unnatural Amino Acid Derivatives.
Research (Wash D C)
December 2024
School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, China.
Chirality has garnered significant attention in the scientific community since its discovery by Louis Pasteur over a century ago. It has been showing a profound impact on chemical, biomedical, and materials sciences. Significant progress has been made in controlling molecular chirality, as evidenced by the several Nobel Prizes in chemistry awarded in this area, particularly for advancements in the asymmetric catalytic synthesis of molecules with central and axial chirality.
View Article and Find Full Text PDFSurface Decoration of Cellulose With Trifluoromethylphenyl Substituted Thiourea: A Robust Hydrogen-Bonding Catalyst in Conjunction With L-Proline for the Asymmetric Direct Mannich Reaction.
Biopolymers
January 2025
Department of Chemistry, Faculty of Engineering and Science, Bursa Technical University, Bursa, Turkey.
Cellulose is one of the most abundant biopolymers in nature. Despite being the subject of research in various fields, it is not as famous as chitosan in catalyst design. Herein, a novel thiourea-functionalized cellulose (CTU-6) was synthesized as a robust hydrogen bonding catalyst with the degree of substitution (DS) of 0.
View Article and Find Full Text PDFEnantiospecific Synthesis of Planar Chiral Rhodium and Iridium Cyclopentadienyl Complexes: Enabling Streamlined and Computer-Guided Access to Highly Selective Catalysts for Asymmetric C-H Functionalizations.
J Am Chem Soc
December 2024
Laboratory of Asymmetric Catalysis and Synthesis, Institute of Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne 1015, Switzerland.
Chiral cyclopentadienyl (Cp) metal complexes are frequently used in asymmetric catalysis by virtue of their high reactivity and selectivity. Planar-chiral-only rhodium and iridium cyclopentadienyl complexes are particularly promising due to unrestricted chemical space for Cp ligand design while retaining structural simplicity. However, they are currently still niche because of a lack of efficient synthetic strategies that avoid lengthy chiral auxiliary routes or chiral preparatory HPLC resolution of the complexes.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!