A novel and efficient method for the highly enantioselective synthesis of chiral 4,5-dihydropyridazin-3-one derivatives has been developed based on the chiral N-heterocyclic carbene-catalyzed oxidative annulation between α,β-unsaturated aldehydes and hydrazones. Meanwhile, the selective synthesis of either 4,5-dihydropyridazin-3-ones or pyridazin-3-one derivatives from the same reactants has been achieved by simply varying catalytic and reaction conditions.
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http://dx.doi.org/10.1021/acs.joc.5b00784 | DOI Listing |
Nat Commun
January 2025
School of Chemistry, Chemical Engineering, and Biotechnology, Nanyang Technological University, Singapore, 637371, Singapore.
Acylation stands as a fundamental process in both biological pathways and synthetic chemical reactions, with acylated saccharides and their derivatives holding diverse applications ranging from bioactive agents to synthetic building blocks. A longstanding objective in organic synthesis has been the site-selective acylation of saccharides without extensive pre-protection of alcohol units. In this study, we demonstrate that by simply altering the chirality of N-heterocyclic carbene (NHC) organic catalysts, the site-selectivity of saccharide acylation reactions can be effectively modulated.
View Article and Find Full Text PDFOrg Lett
December 2024
Department of Chemistry, Indian Institute of Technology Ropar, Rupnagar, Punjab 140001, India.
Developing asymmetric transformations using electroredox and N-heterocyclic carbene (NHC)-catalyzed radical pathways is still desirable and challenging. Herein, we report an iodide-promoted β-carbon activation (LUMO-lowering process) of enals via electroredox carbene catalysis coupled with a hydrogen evolution reaction (HER). This strategy offers an environmentally friendly and sustainable route for rapidly assembling synthetically useful chiral naphthopyran-3-one in good to excellent yield and enantioselectivity using traceless electrons as inexpensive and greener oxidants.
View Article and Find Full Text PDFJ Org Chem
December 2024
Anhui Province Key Laboratory of Value-Added Catalytic Conversion and Reaction Engineering, School of Chemistry and Chemical Engineering, Hefei University of Technology, Hefei 230009, China.
An innovative solution that overcomes the long-standing inherently low efficiency in -heterocyclic carbene-catalyzed aerobic oxidation of aldehydes is reported. This solution included the design and synthesis of a novel polymerized catalyst and the utilization of a flow reactor. The unprecedentedly high efficiency achieved via this protocol makes it synthetically applicable.
View Article and Find Full Text PDFChem Sci
December 2024
Key Laboratory of Advanced Light Conversion Materials and Biophotonics School of Chemistry and Life Resources, Renmin University of China Beijing 100872 China
Cyclopropanes are ubiquitous and key structural motifs in commercially available drugs and bioactive molecules. Herein, we present regio-selective acylation of aryl cyclopropanes with cooperative photoredox and N-heterocyclic carbene catalysis. This approach involves a deconstruction-reconstruction strategy γ-chloro-ketones as intermediates and fulfills the formal C(sp)-H functionalization of cyclopropanes.
View Article and Find Full Text PDFChem Rec
December 2024
School of Pharmacy and Food Engineering, Wuyi University, Jiangmen, 529020, China.
N-heterocyclic carbene (NHC) organocatalysis has been developed as a powerful tool in modern synthetic chemistry. NHC catalytic activation of ynals and alkynoic acid derivatives provided versatile reactions that involve acetylenic Breslow and/or acylazolium as key intermediates, and diverse transformations have been established for access to molecules with unique skeletons in efficient fashions. Herein we summarize the recent achievements in NHC-catalyzed reactions involving acetylenic Breslow and/or acylazolium intermediates.
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