A straightforward procedure is presented for the covalentimmobilization of ester and silyl ether derivatives of theCinchona 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. A series of hydroquinidine derivatives embedded into elastomeric silicone films was prepared and used as insoluble organocatalysts in the asymmetric dimerization of ketenes. A protocol was introduced to compare the productivity/ enantioselectivity of the supported catalysts with those of their analogous soluble counterparts.
Silicone-supported Cinchona alkaloid derivatives as insoluble organocatalysts in the enantioselective dimerization of ketenes / D. Cancogni, A. Mandoli, R.P. Jumde, D. Pini. - In: EUROPEAN JOURNAL OF ORGANIC CHEMISTRY. - ISSN 1434-193X. - 2012:7(2012 Jan 25), pp. 1336-1345.
|Titolo:||Silicone-supported Cinchona alkaloid derivatives as insoluble organocatalysts in the enantioselective dimerization of ketenes|
|Parole Chiave:||Alkaloids; Asymmetric catalysis; Ketene dimerization; Organocatalysis; Silicones; Supported catalysts; Organic Chemistry; Physical and Theoretical Chemistry|
|Settore Scientifico Disciplinare:||Settore CHIM/06 - Chimica Organica|
|Data di pubblicazione:||25-gen-2012|
|Digital Object Identifier (DOI):||http://dx.doi.org/10.1002/ejoc.201101320|
|Appare nelle tipologie:||01 - Articolo su periodico|