Pd-Catalyzed Aerobic Oxidative Coupling of Arenes: Evidence for Transmetalation between Two Pd(II)-Aryl Intermediates
| Autor: | Shannon S. Stahl, Dian Wang, Yusuke Izawa |
|---|---|
| Rok vydání: | 2014 |
| Předmět: |
010402 general chemistry
Photochemistry Hydrocarbons Aromatic 01 natural sciences Biochemistry Medicinal chemistry Catalysis Reductive elimination Transmetalation chemistry.chemical_compound Colloid and Surface Chemistry Kinetic isotope effect Trifluoroacetic Acid Bimetallic strip 010405 organic chemistry Communication Aryl General Chemistry Deuterium 0104 chemical sciences 3. Good health Stille reaction Oxygen Kinetics chemistry Indicators and Reagents Oxidative coupling of methane Palladium |
| Zdroj: | Journal of the American Chemical Society |
| ISSN: | 1520-5126 0002-7863 |
| Popis: | Pd-catalyzed aerobic oxidative coupling of arenes provides efficient access to biaryl compounds. The biaryl product forms via C-H activation of two arenes to afford a Pd(II)ArAr' intermediate, which then undergoes C-C reductive elimination. The key Pd(II)ArAr' intermediate could form via a "monometallic" pathway involving sequential C-H activation at a single Pd(II) center, or via a "bimetallic" pathway involving parallel C-H activation at separate Pd(II) centers, followed by a transmetalation step between two Pd(II)-aryl intermediates. Here, we investigate the oxidative coupling of o-xylene catalyzed by a PdX2/2-fluoropyridine catalyst (X = trifluoroacetate, acetate). Kinetic studies, H/D exchange experiments, and kinetic isotope effects provide clear support for a bimetallic/transmetalation mechanism. |
| Databáze: | OpenAIRE |
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