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Silicone‐Supported Cinchona Alkaloid Derivatives as Insoluble Organocatalysts in the Enantioselective Dimerization of Ketenes
Author(s) -
Cancogni Damiano,
Mandoli Alessandro,
Jumde Ravindra P.,
Pini Dario
Publication year - 2012
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201101320
Subject(s) - cinchona , chemistry , enantioselective synthesis , silicone , yield (engineering) , organic chemistry , catalysis , organocatalysis , silylation , alkaloid , silyl ether , cinchona alkaloids , combinatorial chemistry , materials science , metallurgy
A straightforward procedure is presented for the covalentimmobilization 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.