Cooperative Reductive Elimination: The Missing Piece in the Oxidative Coupling Mechanistic Puzzle
<p> The reaction between benzoic acid and methylphenylacetylene to form an isocoumarin is catalyzed by Cp*Rh(OAc)<sub>2</sub> in the presence of Cu(OAc)<sub>2</sub>(H<sub>2</sub>O) as an oxidant and a leading example of oxidative-coupling reactions. Its mech...
| Autores: | , |
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| Tipo de recurso: | artículo |
| Fecha de publicación: | 2016 |
| País: | España |
| Institución: | Varias* (Consorci de Biblioteques Universitáries de Catalunya, Centre de Serveis Científics i Acadèmics de Catalunya) |
| Repositorio: | Recercat. Dipósit de la Recerca de Catalunya |
| OAI Identifier: | oai:recercat.cat:2072/305766 |
| Acceso en línea: | http://hdl.handle.net/2072/305766 https://doi.org/10.1002/anie.201510540 |
| Access Level: | acceso abierto |
| Palabra clave: | Oxidative coupling Density functional calculations Reductive elimination C-C coupling Reaction mechanisms |
| Sumario: | <p> The reaction between benzoic acid and methylphenylacetylene to form an isocoumarin is catalyzed by Cp*Rh(OAc)<sub>2</sub> in the presence of Cu(OAc)<sub>2</sub>(H<sub>2</sub>O) as an oxidant and a leading example of oxidative-coupling reactions. Its mechanism was elucidated by DFT calculations with the B97D functional. The conventional mechanism, with separate reductive-elimination and reoxidation steps, was found to yield a naphthalene derivative as the major product by CO<sub>2</sub> extrusion, contradicting experimental observations. The experimental result was reproduced by an alternative mechanism with a lower barrier: In this case, the copper acetate oxidant plays a key role in the reductive-elimination step, which takes place through a transition state containing both rhodium and copper centers. This cooperative reductive-elimination step would not be accessible with a generic oxidant, which, again, is in agreement with available experimental data.</p> |
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