[7]Helicenebisquinones can be made easily and in quantity by reacting the silyl enol ethers of a 9,10-dialkoxy-, or better a 9,10-disiloxy-, 3,6-diacetylphenanthrene, with p-benzoquinone. If an ethyl enol ether is used in place of the silyl enol ether, the transformation proceeds in much lower yield. The [7]helicenes are efficiently resolved into their enantiomers, and absolute configurations are assigned.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1021/jo981380y | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Visible light-mediated formal alkylation and [4+1]-cycloaddition strategies of silyl enol ethers with aryldiazoacetates.
Chem Commun (Camb)
December 2024
Universidade Estadual de Campinas, Instituto de Química, CEP 13083-862, Campinas, SP, Brazil.
A reaction sequence of visible light-mediated cyclopropanation/acid-promoted ring-opening is described for the formal alkylation of silyl enol ethers with aryldiazoacetates. Under the same conditions, the Danishefsky's diene can react with aryldiazoacetates to afford [4+1]-cycloaddition adducts. Key mechanistic aspects are proposed based on experimental evidence and DFT calculations.
View Article and Find Full Text PDFVisible-light-driven net-1,2-hydrogen atom transfer of amidyl radicals to access β-amido ketone derivatives.
Chem Sci
January 2025
Key Laboratory of Medicinal Chemistry for Natural Resource, Ministry of Education, Yunnan Key Laboratory of Research and Development for Natural Products, School of Pharmacy, Yunnan University Kunming 650500 P. R. China
Hydrogen atom transfer (HAT) processes provide an important strategy for selective C-H functionalization. Compared with the popularity of 1,5-HAT processes, however, net-1,2-HAT reactions have been reported less frequently. Herein, we report a unique visible-light-mediated net-1,2-HAT of amidyl radicals for the synthesis of β-amido ketone derivatives.
View Article and Find Full Text PDFIridium-Catalyzed Enantioselective Vinylogous and Bisvinylogous Allenylic Substitution.
JACS Au
November 2024
Department of Organic Chemistry, Indian Institute of Science, Bangalore560012, India.
Compared to the widely explored enol silanes, the applicability of their extended variants especially as bisvinylogous nucleophiles in enantioselective catalysis has been sparse. Herein, we describe the first enantioselective vinylogous and bisvinylogous allenylic substitution using silyl dienol and trienol ethers, respectively, as a nucleophile. With racemic allenylic alcohols as the electrophile, these enantioconvergent reactions are cooperatively catalyzed by an Ir(I)/(phosphoramidite,olefin) complex and Lewis acidic La(OTf) and display remarkable regio- and diastereoselectivity in most cases.
View Article and Find Full Text PDFRhodium-catalyzed synthesis of Si-stereogenic alkoxysilanes and silyl enol ethers hydrosilylation of carbonyl compounds.
Chem Commun (Camb)
November 2024
Shenzhen Grubbs Institute and Department of Chemistry, Guangdong Provincial Key Laboratory of Catalysis, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China.
A highly efficient rhodium-catalyzed asymmetric hydrosilylation of aldehydes, ketones, and α,β-unsaturated ketones with dihydrosilanes is developed, that allows the rapid assembly of a variety of Si-stereogenic alkoxysilanes and silyl enol ethers in good yields and enantioselectivities under mild conditions. The applicability of this methodology was demonstrated by a series of stereospecific transformations to construct diverse Si-stereogenic derivatives.
View Article and Find Full Text PDFAccess to Carbonyl Azides via Iodine(III)-Mediated Cross-Coupling.
Org Lett
November 2024
School of Chemistry and Materials Science, Jiangsu Key Laboratory of Green Synthesis for Functional Materials, Jiangsu Normal University, Xuzhou, Jiangsu 221116, China.
Herein, we present a prominent metal-free C-N cross-coupling platform that enables access to carbamoyl- and ketoazides from isocyanides or silyl enol ethers and trimethylsilyl azide (TMSN) with an aid of iodine(III) promoter. This offers a rapid route to a diverse set of synthetically valuable azide decorated fragments with excellent substrate scope and good to excellent yields. The disclosed platform exemplifies the use of TMSN for incorporation of the azide fragment without the loss of N.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!