A chiral N-heterocyclic carbene-catalyzed benzoin condensation reaction in water has been developed, affording α-hydroxy ketones in good to high yields and high enantioselectivities. Water was proposed as a proton shuttle in the aqueous asymmetric condensation reaction.
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http://dx.doi.org/10.1021/acs.joc.8b00481 | DOI Listing |
Org 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.
View Article and Find Full Text PDFJ Org Chem
November 2024
College of Chemistry and Materials Science, Chemical Biology Key Laboratory of Hebei Province, Key Laboratory of Medicinal Chemistry and Molecular Diagnosis of the Ministry of Education, Hebei University, Baoding 071002, China.
Rapid construction of functionalized aza-anthraquinones has been successfully developed via NHC-catalyzed formal [3 + 3] annulation of 2-aminoquinones with enals. This reaction features several advantages, such as readily available starting materials, mild reaction conditions, and flexible product transformations. The study on the atroposelective version of this strategy was also carried out, and several C-N axial chiral aza-anthraquinones were synthesized in moderate yields with moderate to good enantioselectivities.
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