Chiral amides are important structure in many natural products and pharmaceuticals, yet their efficient synthesis from simple amide feedstock remains challenge due to its weak Lewis basicity. Herein, we describe our study of the enantioselective synthesis of chiral amides by N-alkylation of primary amides taking advantage of an achiral rhodium and chiral squaramide co-catalyzed carbene N-H insertion reaction. This method features mild condition, rapid reaction rate (in all cases 1 min) and a wide substrate scope with high yield and excellent enantioselectivity. Further product transformations show the synthetic potential of this reaction. Mechanistic studies reveal that the non-covalent interactions between the catalyst and reaction intermediate play a critical role in enantiocontrol.
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http://dx.doi.org/10.1038/s41467-024-48266-5 | DOI Listing |
J Am Chem Soc
January 2025
Key Laboratory of Chemical Biology of Fujian Province, iChEM, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, Fujian 361005, China.
Regiodivergent asymmetric synthesis represents a transformative strategy for the efficient generation of structurally diverse chiral products from a single set of starting materials, significantly enriching their enantiomeric composition. However, the design of radical-mediated regiodivergent and enantioselective reactions that can accommodate a wide range of functional groups and substrates has posed significant challenges. The obstacles primarily lie in switching the regioselectivity and achieving high enantiodiscrimination, especially when dealing with high-energy intermediates.
View Article and Find Full Text PDFChiral amines and amino alcohols form an important category of molecules employed in the designing of new drugs and catalyst. Herein, we present a helically-twisted stereodynamic dialdehyde probe 1 for the determining of absolute configuration, and enantiomeric excess of chiral amine and amino alcohols. Probe 1 is based on the pyridine-2,6-dicarboxamide (PDC) core and undergoes rapid interconversion between the P- and M- conformers.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Department of Chemistry and the Hong Kong Branch of Chinese National Engineering Research Centre for Tissue Restoration & Reconstruction, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR 999077, China.
Catalytic enantioselective substitution of the readily available racemic α-halo carbonyl compounds by nitrogen nucleophiles represents one of the most convenient and direct approaches to access enantioenriched α-amino carbonyl compounds. Distinct from the two available strategies involving radicals and enolate ions, herein we have developed a new protocol featuring an electronically opposite way to weaken/cleave the carbon-halogen bond. A suitable chiral anion-based catalyst enables effective asymmetric control over the key positively charged intermediates.
View Article and Find Full Text PDFJ Sep Sci
December 2024
College of Chemistry and Chemical Engineering, Yunnan Normal University, Kunming, China.
Chiral macrocycles have emerged as attractive media for chromatographic enantioseparation due to their excellent host-guest recognition properties. In this study, a new chiral stationary phase (CSP) based on 1,1'-binaphthyl chiral polyimine macrocycle (CPM) was reported. The CPM was synthesized by one-step aldehyde-amine condensation of (S)-2,2'-dihydroxy-[1,1'-binaphthalene]-3,3'-dicarboxaldehyde with 1,2-phenylenediamine and bonded on thiolated silica via the thiol-ene click reaction to afford the CSP.
View Article and Find Full Text PDFChirality
December 2024
Department of Engineering "Enzo Ferrari", (DIEF), Univ. of Modena, Modena, Italy.
In this work, we exploit the electronic features of tetrathiafulvalene (TTF) as a backbone in synthesizing chiral derivatives. The aim is to make use of TTF's well-known and unique redox and semiconducting properties in the fields of enantio-selective recognition and chiral charge transfer (CT) complex preparation, with the ultimate objective of obtaining devices with various potential applications, ranging from plasmonics to quantum computing. In particular, both cyclohexane-bis (TTF-amide)-based enantiomers 1-(S,S) and 1-(R,R), stable under an oxidation regime, have been selected, and under these conditions, the electrochemical enantiospecific response of the four possible systems, coming from the combination with L- and D-tartaric acid, respectively, was tested.
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