Concentration Effect in the Asymmetric Michael Addition of Ace- tone to β- Nitrostyrenes Catalyzed by Primary Amine Thioureas
Bifunctional primary amine thiourea (PAT) organocatalysts show remarkable improvement in enantioselectivity and catalytic activity (turnover frequency) in the asymmetric Michael addition of acetone to β-nitrostyrenes upon dilution. Mechanistic investigations indicate that this behavior corresponds t...
| Autores: | , , , |
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| Formato: | artículo |
| Estado: | Versión aceptada para publicación |
| Fecha de publicación: | 2016 |
| País: | España |
| Recursos: | 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:2072/355622 |
| Acesso em linha: | http://hdl.handle.net/2072/355622 https://doi.org/10.1055/s-0036-1589408 |
| Access Level: | acceso abierto |
| Palavra-chave: | 54 |
| Resumo: | Bifunctional primary amine thiourea (PAT) organocatalysts show remarkable improvement in enantioselectivity and catalytic activity (turnover frequency) in the asymmetric Michael addition of acetone to β-nitrostyrenes upon dilution. Mechanistic investigations indicate that this behavior corresponds to the inhibition of off-cycle catalyst deactivation at low concentration, rather than to the operation of aggregation phenomena at high concentration. Reaction at low concentration (≤0.2 M in β-nitrostyrene) leads to the minimization of catalyst deactivation and, thus, to the optimization of yield and ee of the Michael addition products. |
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