title: Pd-Catalyzed Aerobic Oxidative Biaryl Coupling: Non-Redox Cocatalysis by Cu(OTf)2and Discovery of Fe(OTf)3as a Highly Effective Cocatalyst.
abstract: Copper salts find widespread use in Pd-catalyzed oxidation reactions, and they are typically used as oxidants or redox-active cocatalysts. Here, we probe the origin of a dramatic acceleration effect of Cu(OTf)2in the C-H/C-H aerobic oxidative coupling of o-xylene. NMR spectroscopic analysis of the PdIIcatalyst in the presence of Cu(OTf)2, together with other experimental and DFT computational studies of the catalytic reaction, show that Cu(OTf)2activates the PdIIcatalyst for C-H activation via a non-redox pathway and has negligible impact on catalyst reoxidation. These observations led to the testing of other metal triflate salts as cocatalysts, the results of which show that Fe(OTf)3is even more effective than Cu(OTf)2.
authors.affiliation: Department of Chemistry, University of Wisconsin-Madison , 1101 University Avenue, Madison, Wisconsin 53706, United States.
authors.forename: Dian
authors.initials: D
authors.lastname: Wang
authors.affiliation: Department of Chemistry, University of Wisconsin-Madison , 1101 University Avenue, Madison, Wisconsin 53706, United States.
authors.forename: Shannon S
authors.identifier: 0000-0002-9000-7665
authors.initials: SS
authors.lastname: Stahl
mesh_terms: D002384:Catalysis; D003300:Copper / Q000737:chemistry*; D005290:Ferric Compounds / Q000737:chemistry*; D008698:Mesylates / Q000737:chemistry*; D015394:Molecular Structure; D010084:Oxidation-Reduction; D010165:Palladium / Q000737:chemistry*; D014992:Xylenes / Q000138:chemical synthesis* / Q000737:chemistry
chemical_list: D005290:Ferric Compounds; D008698:Mesylates; D014992:Xylenes; D010165:Palladium; D003300:Copper; C012077:trifluoromethanesulfonic acid