A selective, nonchelation-assisted methylation of arenes has been developed. The overall transformation, which combines a C-H functionalization reaction with a nickel-catalyzed cross-coupling, offers rapid access to methylated arenes with high para selectivity. The reaction is amenable to late-stage methylation of small-molecule pharmaceuticals.
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http://dx.doi.org/10.1002/anie.201804628 | DOI Listing |
Org Lett
December 2024
Department of Chemistry, Indian Institute of Technology Guwahati, North Guwahati, Assam 781039, India.
Herein, an organocatalytic asymmetric desymmetrizing [4+2] cycloaddition/base-mediated oxidative aromatization reaction sequence has been developed between spirophthalide 2,5-cyclohexadienones and β-methyl cinnamaldehydes. The reaction proceeds through chiral dienamine intermediate formation, and the densely functionalized spirocyclic isobenzofuranone-embedded chiral arenes were formed in high yields with excellent enantioselectivities. A 2-fold desymmetrization reaction was also performed, and the products were obtained in high enantioselectivities.
View Article and Find Full Text PDFChempluschem
December 2024
Budapest University of Technology and Economics, Department of Chemical and Environmental Process Engineering, Muegyetem rkp. 3., 1111, Budapest, HUNGARY.
The palladium-catalyzed aminocarbonylation is one of the most effective methods for the synthesis of carboxamides having great importance. Replacing fossil-based organic solvents in this routinely used catalytic protocol with biomass-derived media is crucial for developing environmentally safe alternatives and towards sustainability considerations. In this study, the open-chain derivatives of bio-originated substance g-valerolactone i.
View Article and Find Full Text PDFDalton Trans
December 2024
Department of Inorganic Chemistry, Faculty of Science, Charles University, Hlavova 2030, 128 00 Prague, Czech Republic.
C-H bond functionalisation has developed into a powerful synthetic methodology that is applicable to a wide array of substrates, including organometallic compounds. In this study, racemic, planar-chiral 1,2-dihydroferroceno[]isoquinoline and analogous helical compounds with one or two additional -fused benzene rings were synthesised by palladium-catalysed C-H bond activation/cyclisation of -[(bromoaryl)methyl]--(methylsulfonyl)aminoferrocenes. These starting materials are readily accessible from FcNHSOMe (Fc = ferrocenyl) and appropriate vicinal bromo-(bromomethyl)arenes.
View Article and Find Full Text PDFChem Commun (Camb)
December 2024
Department of Medicinal Chemistry, Uppsala University, 751 23 Uppsala, Sweden.
A new functional group transformation allowing the synthesis of methyl-dithioesters from readily available trifluoromethyl arenes defluorinative functionalization has been developed. This microwave-assisted method is operationally simple, rapid, and eliminates the need for pre-functionalization while accommodating a broad range of functional groups. In addition, it does not rely on highly odorous thiol sources, and utilizes the commercially available reagent BFSMe complex as a multifunctional Lewis acid/sulfur source/defluorination and demethylation agent.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
November 2024
Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, D-45470, Mülheim an der Ruhr, Germany.
Here we report the reaction of aryl thianthrenium salts that allows selective functionalization of the meta position of arenes. The combination of a site-selective thianthrenation with a Catellani reaction provides access to 3,5-dimethylated arenes. The developed reaction is complementary to the previously discovered reductive ipso-alkylation of aryl thianthrenium salts and extends the possibilities for late-stage methylation of arenes with a single aryl thianthrenium salt.
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