The metal-free C8-H functionalization of quinoline N-oxides with ynamides is unveiled for the first time by the intramolecular Friedel-Crafts-type reaction of quinolyl enolonium intermediates generated from Brønsted acid-catalyzed addition of quinoline N-oxides to ynamides. Various quinoline N-oxides and terminal ynamides prove to be suitable substrates for this method. A one-pot protocol was then developed for the metal-free direct C8-H functionalization of quinolines.
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http://dx.doi.org/10.1039/d1cc02138a | DOI Listing |
J Org Chem
December 2024
Natural Products and Green Chemistry Division, Central Salt and Marine Chemicals Research Institute (CSIR), G. B. Marg, Bhavnagar 364002, Gujarat, India.
A simple cobalt-catalyzed, picolinamide-directed C8-H sulfoxamination of 1-naphthalamides with NH-sulfoximines has been developed. This cross-dehydrogenative C-H/N-H coupling reaction offers a facile route to N-arylated sulfoximines, exhibiting high yields, a broad substrate scope, and excellent functional group tolerance and scalability.
View Article and Find Full Text PDFNat Commun
March 2024
Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai, 200240, People's Republic of China.
Chemically modified nucleosi(ti)des and functional oligonucleotides (ONs, including therapeutic oligonucleotides, aptamer, nuclease, etc.) have been identified playing an essential role in the areas of medicinal chemistry, chemical biology, biotechnology, and nanotechnology. Introduction of functional groups into the nucleobases of ONs mostly relies on the laborious de novo chemical synthesis.
View Article and Find Full Text PDFJ Org Chem
December 2023
Department of Chemistry, University of North Bengal, Darjeeling734013,India.
An operationally simple and efficient protocol for copper(II)-mediated, picolinamido-directed C8-H sulfonamidation of 1-naphthylamine derivatives with various sulfonamides has been developed. Remarkably, this cross-dehydrogenative C-H/H-N coupling reaction exhibits a broad substrate scope with excellent functional group tolerance, is scalable, and enables an expeditious route to a library of unsymmetrical -arylated sulfonamides in good to excellent yields with exclusive site selectivity.
View Article and Find Full Text PDFPhys Chem Chem Phys
August 2023
BioISI - Instituto de Biossistemas e Ciências Integrativas, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal.
Pd(II) catalysts, particularly the acetate salt in acetic acid, tended to favor regioselective C-H activation of quinoline N-oxides (QOs) at the C2 position. However, Pd(II)Cl was shown to catalyze their C-H activation at C8 and, in the presence of water, C8-H activation was accompanied by the formation of 2-quinolinones. The aim of the DFT study described in this work was to shed light on the complete mechanism of these competing catalytic reactions, when PdCl reacts with QO and benzaldehyde in dichloroethane.
View Article and Find Full Text PDFOrg Lett
November 2022
State Key Laboratory of Chemo/Biosensing and Chemometrics, Advanced Catalytic Engineering Research Center of the Ministry of Education, College of Chemistry and Chemical Engineering, Hunan University, Changsha, 410082, P. R. China.
An efficient difunctionalization at C5/C8 of imidazo[1,2]pyrazines has been developed using disulfides and Grignard reagents under cheap cobalt catalysis. This one-pot, two-step, three-component transformation is performed under mild conditions; various Grignard reagents (aryl and alkyl) and disulfides are tolerated. Mechanistic studies and control experiments demonstrate this reaction proceeded via an anionic intermediate.
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