Experimental and Computational Study of the ( Z)-Selective Formation of Trisubstituted Olefins and Benzo-Fused Oxacycles from the Ruthenium-Catalyzed Dehydrative C-H Coupling of Phenols with Ketones
| Autor: | Ho Ryu, Hanbin Lee, Manoj V. Mane, Mu-Hyun Baik, Chae S. Yi, Debashis Sahu |
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| Rok vydání: | 2018 |
| Předmět: |
Models
Molecular chemistry.chemical_element Alkenes 010402 general chemistry 01 natural sciences Biochemistry Medicinal chemistry Catalysis Ruthenium Article chemistry.chemical_compound Colloid and Surface Chemistry Phenols Phenol Computer Simulation Olefin fiber Molecular Structure 010405 organic chemistry Cationic polymerization General Chemistry Ketones 0104 chemical sciences Coupling (electronics) chemistry |
| Zdroj: | Journal of the American Chemical Society. 140(32) |
| ISSN: | 1520-5126 |
| Popis: | The cationic Ru–H complex was found to be an effective catalyst for the dehydrative C–H coupling of phenols with ketones to form the trisubstituted olefin products. The coupling of phenol with linear ketones led to highly stereoselective formation of the (Z)-olefin products. The dehydrative coupling of phenol with enones and diones efficiently formed the benzopyrene and related oxacyclic derivatives. The reaction of 3,5-dimethoxyphenol with cyclohexanone-2,2,6,6-d(4) showed a significant H/D exchange to both vinyl and α-CH(2) positions on the olefin product (72–75% D). A significant carbon isotope effect was observed on the ortho-arene carbon of the olefin product. The free energies of intermediate species for the entire catalytic cycle were successfully computed by using the DFT method. The DFT study revealed that the E/Z stereoselectivity is a result of the energy difference in the insertion step of ortho-metalated phenol to an enol form of the ketone substrate (ΔΔE = 9.6 kcal/mol). The coupling method provides a direct catalytic C–H olefination method for ketones to form trisubstituted olefins without employing any reactive reagents or forming any wasteful byproducts. |
| Databáze: | OpenAIRE |
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