We herein report an unprecedented strategy for the asymmetric α-chlorination of β-keto esters with hypervalent iodine-based Cl-transfer reagents using simple Cinchona alkaloid catalysts. Our investigations support an α-chlorination mechanism where the Cinchona species serves as a nucleophilic catalyst by reacting with the chlorinating agent to generate a chiral electrophilic Cl-transfer reagent in situ. Using at least 20 mol-% of the alkaloid catalyst allows for good yields and enantioselectivities for a variety of different β-keto esters under operationally simple conditions.
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http://dx.doi.org/10.1002/ejoc.202001217 | DOI Listing |
Sci Rep
December 2024
Department of Pharmacognosy, College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Korea.
Despite significant advancements with combination anti-retroviral agents, eradicating human immunodeficiency virus (HIV) remains a challenge due to adverse effects, adherence issues, and emerging viral resistance to existing therapies. This underscores the urgent need for safer, more effective drugs to combat resistant strains and advance acquired immunodeficiency syndrome (AIDS) therapeutics. Eight triterpene esters (1-8) were identified from Uncaria rhynchophylla hooks.
View Article and Find Full Text PDFNat Commun
December 2024
School of Physical Science and Technology, ShanghaiTech University, Shanghai, 201210, China.
The strain-release-driven reactions of bicyclo[1.1.0]butanes (BCBs) have received significant attention from chemists.
View Article and Find Full Text PDFNat Commun
December 2024
Key Laboratory of Phytochemistry and Natural Medicines, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China.
The functionalized polycycle with densely contiguous tertiary stereocenters is a formidable challenge in synthesizing the parvistemoline family of Stemona alkaloids. We herein report their catalytic, asymmetric total syntheses in 13-14 steps from commercially available 2-(methoxycarbonyl)-pyrrole, featuring the development and deployment of an Ir/Pd-synergistically-catalyzed allylation of α-non-substituted keto esters with secondary aryl-substituted alcohols, stereodivergently accessible to four stereoisomers. Using chiral Pd-enolate and Ir π-allyl complex under neutral conditions, no epimerization occurs.
View Article and Find Full Text PDFNat Commun
December 2024
State Key Laboratory of Heavy Oil Processing, China University of Petroleum (East China), Qingdao, China.
Catalytic upcycling of polyethylene terephthalate (PET) into high-value oxygenated products is a fascinating process, yet it remains challenging. Here, we present a one-step tandem strategy to realize the thermal catalytic oxidation upcycling of PET to terephthalic acid (TPA) and high-value glycolic acid (GA) instead of ethylene glycol (EG). By using the Au/NiO with rich oxygen vacancies as catalyst, we successfully accelerate the hydrolysis of PET, accompanied by obtaining 99% TPA yield and 87.
View Article and Find Full Text PDFJ Biomol Struct Dyn
February 2025
Department of Chemistry, School of Advanced Sciences, Vellore Institute of Technology, Vellore, India.
is one of the opportunistic pathogens that may cause serious health problems and can produce several virulence factors, which are responsible for various infections, particularly in immunocompromised patients. They are responsible for producing infections on indwelling medical devices by attaching on to them and forming a biofilm. Antibiofilm, antivirulence, and gene expression studies of biofilm treated with esters of flavonols were evaluated.
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