Three ruthenium complexes bearing backbone-monosubstituted CAACs were prepared and displayed dramatic improvement in catalytic efficiency not only in RCM reaction but also in the ethenolysis of methyl oleate, compared to those bearing backbone-disubstituted CAACs.
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http://dx.doi.org/10.1039/c3cc45823g | DOI Listing |
Org Biomol Chem
December 2024
Department of Organic Chemistry, University of Madras, Guindy Campus, Tamilnadu, Chennai 600025, India.
A simple and efficient Ru(II)-catalyzed olefination of 3-(arylbenzylidene)indolin-2-ones with alkenes is described. This is an atom and step-economical strategy with a wide substrate scope, good functional group tolerance, and suitability for gram scale synthesis. A plausible mechanism is also proposed for this synthetic transformation involving the formation of a 5-membered ruthenacycle and insertion of the alkene followed by β-hydride elimination to deliver the desired product.
View Article and Find Full Text PDFJ Org Chem
April 2024
School of Traditional Chinese Medicine, Southern Medical University, Guangzhou 510515, China.
The first ruthenium-catalyzed carboamination of olefins with α-carbonyl sulfoxonium ylides is reported. The utilization of an inexpensive ruthenium catalyst enables the concise synthesis of pharmaceutically important isoindolin-1-ones, which possess both a stereogenic center and β-carbonyl side chain. This method is mild, efficient, and scalable and allows for the coupling of a wide range of aryl-, heteroaryl-, alkenyl-, and alkyl-substituted sulfoxonium ylides.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
March 2024
Max-Planck-Institut für Kohlenforschung, 45470, Mülheim/Ruhr, Germany.
Guangnanmycin A is a recently discovered congener of the well-known antitumor drug lead leinamycin; its macrolactam ring, however, is even more strained than that of the parent compound. The first synthetic foray towards this challenging target is reported, which relies on molybdenum-catalyzed macrocyclization by ring closing alkyne metathesis (RCAM) followed by ruthenium-catalyzed redox isomerization of the propargyl alcohol thus formed; the resulting enone enabled the introduction of the yet missing exo-methylene group by a modified Peterson olefination. The signature disulfide moiety of guangnanmycin A was installed by strain-driven thia-Michael addition followed by conversion of the thioether thus formed into an unsymmetric disulfide with the aid of (methylthio)dimethylsulfonium tetrafluoroborate and MeSSMe.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
February 2024
School of Chemistry, Key Laboratory of Bioinorganic and Synthetic Chemistry of Ministry of Education, Guangdong Key Laboratory of Chiral Molecule and Drug Discovery, Sun Yat-Sen University, 510006, Guangzhou, P. R. China.
A versatile and readily available chiral amide directing group has been developed for the ruthenium(II)-catalyzed asymmetric C-H activation. Asymmetric C-H activation of the related chiral benzamides with various olefins, aldehydes and propargylic alcohols has been accomplished with high stereoselectivities, affording a series of chiral products including 3,4-dihydroisocoumarins (up to 96 % ee), isocoumarins (up to 92 % ee), phthalides (up to 99 % ee), chiral bicyclo[2.2.
View Article and Find Full Text PDFJ Org Chem
November 2023
Catalysis and Energy Laboratory, Department of Chemistry, Pondicherry University (A Central University), Puducherry, Puducherry 605014, India.
The C-C bond formation reactions are important in organic synthesis. Heck reaction is known to arylate the terminal carbon of olefins; however, direct alkylation of the terminal carbon of olefin is limited. Herein, we report a novel ruthenium-catalyzed selective cross-coupling reaction of styrene and α-diazoesters to form a new C-C bond over cyclopropanation via the C-H insertion process for the first time.
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