1,4-Cyclohexadienes allow a direct comparison of epoxidation and C-H oxidation within the same molecule and give evidence for radical pathways during the Jacobsen epoxidation.
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http://dx.doi.org/10.1039/b415723k | DOI Listing |
Environ Sci Technol
August 2024
Department of Biological Sciences, University of Bergen, Bergen N-5020, Norway.
The widespread use of bisphenol A (BPA) in polycarbonate plastics and epoxy resins has made it a prevalent environmental pollutant in aquatic ecosystems. BPA poses a significant threat to marine and freshwater wildlife due to its documented endocrine-disrupting effects on various species. Manufacturers are increasingly turning to other bisphenol compounds as supposedly safer alternatives.
View Article and Find Full Text PDFJ Org Chem
April 2024
Key Laboratory of Drug-Targeting and Drug Delivery System of the Education Ministry and Sichuan Province, Sichuan Engineering Laboratory for Plant-Sourced Drug and Sichuan Research Center for Drug Precision Industrial Technology, West China School of Pharmacy, Sichuan University, Chengdu 610041, P. R. China.
A streamlined and efficient approach to the key epoxide intermediate for the asymmetric synthesis of triazole antifungal agents is presented. This synthesis highlights a P(NMe)-mediated nonylidic olefination of α-keto ester, ensuring the exclusive formation of the requisite ()-alkene, followed by a highly enantioselective Jacobsen epoxidation to establish the two vicinal stereocenters in a single step. The versatility of this strategy is exemplified through the efficient synthesis of efinaconazole and ravuconazole.
View Article and Find Full Text PDFJ Am Chem Soc
December 2023
Aix Marseille Univ, CNRS, Centrale Marseille, iSm2, AMUTech, Marseille 13397, France.
Accessing each enantiomer of a chiral molecule starting from a racemic mixture remains a daunting challenge in chemistry. Indeed, until now, only a few solutions exist to separate enantiomers of an equimolar mixture of a chiral precursor. In this study, we establish a new strategy to prepare simultaneously and physically separate both enantioenriched enantiomers of a molecule starting from a racemic substrate.
View Article and Find Full Text PDFOrg Biomol Chem
August 2023
Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, Maharashtra, India.
A concise asymmetric total synthesis of diosniponols A and B has been achieved based on an enantioselective Jacobsen kinetic resolution of racemic epoxide and the important 2,3-dihydro-4-pyran-4-one moiety being installed by the metal-free δ-hydroxyalkynone rearrangement catalyzed by -TsOH. A diastereoselective catalytic hydrogenation set the required all- stereochemistry leading to diosniponol A, which then, under the Mitsunobu inversion conditions, provided diosniponol B. The structure and absolute stereochemistry of the natural products were further confirmed.
View Article and Find Full Text PDFPlanta Med
June 2023
Núcleo de Pesquisa em Produtos Naturais e Sintéticos (NPPNS), Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brazil.
Licarin A, a dihydrobenzofuranic neolignan presents in several medicinal plants and seeds of nutmeg, exhibits strong activity against protozoans responsible for Chagas disease and leishmaniasis. From biomimetic reactions by metalloporphyrin and Jacobsen catalysts, seven products were determined: four isomeric products yielded by epoxidation from licarin A, besides a new product yielded by a vicinal diol, a benzylic aldehyde, and an unsaturated aldehyde in the structure of the licarin A. The incubation with rat and human liver microsomes partially reproduced the biomimetic reactions by the production of the same epoxidized product of 343 [M + H].
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