Synthesis and Reactivity of Ruthenium Phosphite Indenylidene Complexes
The synthesis of the four olefin metathesis precatalysts Caz-1a-d, featuring the NHC ligand N,N'-bis(2,4,6-trimethylphenyl)imidazolin-2-ylidene (SIMes) and four different phosphites (P((OPr)-Pr-i)(3), P(OPh)(3), P(OEt)(3), and P(OMe)(3)), is reported. The complexes are readily synthesized from...
| 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:10256/8658 |
| Acceso en línea: | http://hdl.handle.net/10256/8658 |
| Access Level: | acceso embargado |
| Palabra clave: | Ruteni -- Compostos -- Síntesi Ruthenium compounds -- Synthesis Catalitzadors Catalysts Metàtesi (Química) Metathesis (Chemistry) |
| Sumario: | The synthesis of the four olefin metathesis precatalysts Caz-1a-d, featuring the NHC ligand N,N'-bis(2,4,6-trimethylphenyl)imidazolin-2-ylidene (SIMes) and four different phosphites (P((OPr)-Pr-i)(3), P(OPh)(3), P(OEt)(3), and P(OMe)(3)), is reported. The complexes are readily synthesized from commercially available [RuCl2(3-phenylinden-1-ylidene)-(pyridine)(SIMes)] (Ind-III) in yields of up to 88%. These complexes adopt an unusual cis configuration between the phosphite and the NHC ligands. NMR experiments and computational studies confirm that the cis complexes are thermodynamically favored in comparison to their trans counterparts. In addition, the isomerization from trans to cis occurs via a mononuclear and non-dissociative mechanism. Among the four precatalysts, cis-Caz-1a, featuring a P((OPr)-Pr-i)(3) ligand, displays the highest activity in ring-closing metathesis and cross-metathesis transformations. Experiments at low catalyst loadings demonstrated the potential of this catalyst, allowing better conversions than with commonly used commercially available precatalysts |
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