Direct detection of key intermediates in rhodium(I)-catalyzed [2+2+2] cycloadditions of alkynes by ESI-MS
The mechanism of the Rh-catalysed [2+2+2] cycloaddition reaction of diynes with monoynes has been examined using ESI-MS and ESI-CID-MS analysis. The catalytic system used consisted of the combination of a cationic rhodium(I) complex with bisphosphine ligands, which generates highly active complexes...
| Autores: | , , , , |
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| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2012 |
| 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:10256/11342 |
| Acceso en línea: | http://hdl.handle.net/10256/11342 |
| Access Level: | acceso embargado |
| Palabra clave: | Reaccions d'addició Addition reactions Catalitzadors de rodi Rhodium catalyst Espectrometria de masses Mass spectrometry Rodi Rhodium Funcional de densitat, Teoria del Density functionals Ciclització (Química) Ring formation (Chemistry) |
| Sumario: | The mechanism of the Rh-catalysed [2+2+2] cycloaddition reaction of diynes with monoynes has been examined using ESI-MS and ESI-CID-MS analysis. The catalytic system used consisted of the combination of a cationic rhodium(I) complex with bisphosphine ligands, which generates highly active complexes that can be detected by ESI(+) experiments. ESI-MS on-line monitoring has allowed the detection for the first time of all of the intermediates in the catalytic cycle, supporting the mechanistic proposal based mainly on theoretical calculations. For all ESI-MS experiments, the structural assignments of ions are supported by tandem mass spectrometry analyses. Computer model studies based on density functional theory (DFT) support the structural proposal made for the monoyne insertion intermediate. The collective studies provide new insight into the reactivity of cationic rhodacyclopentadienes, which should facilitate the design of related rhodium-catalysed C-C couplings. Detecting intermediates: The mechanism of the Rh I-catalyzed [2+2+2] cycloaddition reaction was examined using ESI-MS (see scheme). All of the intermediates in the catalytic cycle were detected by ESI-MS for the first time and characterized by ESI-MS/MS. DFT was used to support the structural proposal made for the monoyne insertion intermediate |
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