A straightforward procedure is presented for the covalent immobilization of ester and silyl ether derivatives of the Cinchona alkaloid 10,11-dihydroquinidine within insoluble cross-linked silicone elastomeric films. These materials were effective heterogeneous organocatalysts in the asymmetric dimerization of ketenes, which provided chiral Weinreb β-ketoamides in 28–83 yield and 79–99 ee in the course of several recycles. A productivity/enantioselectivity protocol is also proposed to better assess the relative merits of soluble and supported asymmetric catalytic systems towards process intensification.
|Autori:||Cancogni D; Mandoli A; Jumde R; Pini D|
|Titolo:||Silicone-Supported Cinchona Alkaloid Derivatives as Insoluble Organocatalysts in the Enantioselective Dimerization of Ketenes|
|Anno del prodotto:||2012|
|Digital Object Identifier (DOI):||10.1002/ejoc.201101320|
|Appare nelle tipologie:||1.1 Articolo in rivista|