The facile formation of the B and C ring of rac-desoxyequilenin and of a chrysenone derivative in just one preparative step is demonstrated, applying a gold-catalyzed domino process, which involves a benzopyrylium cation as the key intermediate and an intramolecular [3 + 2] cycloaddition as the key step.
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http://dx.doi.org/10.1021/jo060606r | DOI Listing |
Chem Commun (Camb)
August 2024
Natural Products and Medicinal Chemistry Division, CSIR-Indian Institute of Integrative Medicine, Canal Road, Jammu-180001, India.
A one-pot domino protocol employing gold(I) catalysis has been developed for the cascade trifluoromethyl-amination/sulfoximination of quinones. Togni I serves as the trifluoromethyl installing precursor, while amine or sulfoximine serves as the aminating source. Preliminary investigations suggest a mutual activation of Togni I and the amine precursor, facilitating the facile difunctionalization of quinones with excellent regioselectivity.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
August 2023
Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto, 606-8501, Japan.
Angew Chem Int Ed Engl
August 2022
State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Tianshui Road 222, Lanzhou, 730000, Gansu, P. R. China.
It is reported herein that by exploiting the commonly shared bicyclic decahydroquinoline motif, a gold-catalyzed enamide-alkyne cycloisomerization reaction is developed to access tricyclic cores in a simple way. These tricyclic cores further serve as an advanced platform for the divergent enantioselective collective total syntheses of five Lycopodium alkaloids, belonging to three different structural types, in a concise and protecting-group-free fashion. The key transformations in the second phase include: 1) a transannular reductive Heck cyclization for installation of the azepane ring in fawcettidine, fawcettimine, and lycoposerramine Q; 2) a domino Mukaiyama hydration/Grob fragmentation process for construction of the ten-membered lactam system in phlegmariurine B; 3) a Fukuyama one-pot protocol for the construction of the 2-pyridone motif in lycoposerramine R.
View Article and Find Full Text PDFChem Rec
December 2021
Côte d'Azur University, Institut de Chimie de Nice, UMR 7272 CNRS, Valrose Park, Faculty of Sciences, 06108, Nice Cedex 2, France.
The field of gold catalysis has been in constant expansion during the last twenty years. Based on the precept of π-activation of unsaturated simple substrates, several new rearrangements have been discovered, implying aryl, alkyne, alkene or keto derivatives as key partners. In this personal account, the main contributions in the field of gold catalysis from our group will be highlighted, emphasizing the recent reports, starting from 1,6- and 1,5-enynes and then moving to keto-ynes derivatives.
View Article and Find Full Text PDFJ Org Chem
December 2021
Côte d'Azur University, Institut de Chimie de Nice, Valrose Park, 06108 Nice Cedex 2, France.
A novel and mild synthetic route for the preparation of functionalized polycyclic indole skeletons via a gold-mediated cycloisomerization/alkoxylation of 1,6-aldehyde-yne has been developed. This atom-economical catalytic process that associates IPrAu(MeCN)BF and an alcohol demonstrated remarkable selectivity in accessing functionalized 3,4-dihydro-1-[1,4]oxazino[4,3-]indole derivatives of high synthetic utility (21 examples, yields of ≤96%) and could be optimized under asymmetric conditions with an enantiomeric excess of ≤86%.
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