Novel thiourea-amine bifunctional catalysts for asymmetric conjugate addition of ketones/aldehydes to nitroalkenes: rational structural combination for high catalytic efficiency
A series of thiourea-amine bifunctionalcatalysts have been developed by a rational combination of prolines with cinchona alkaloids, which are connected by a thiourea motif. The catalyst 3a, prepared from L-proline and cinchonidine, was found to be a highly efficient catalyst for the conjugateaddition of ketones/aldehydes to a wide range of nitroalkenes (up to 98/2 dr and 96% ee). The privileged cinchonidine
Lipase/Acetamide-Catalyzed Carbon-Carbon Bond Formations: A Mechanistic View
作者:Xiao-Yang Chen、Guo-Jun Chen、Jun-Liang Wang、Qi Wu、Xian-Fu Lin
DOI:10.1002/adsc.201201080
日期:2013.3.25
A lipase B from Candida antarctica (CALB)/acetamide‐catalyzed Michael addition of less‐activated ketones and aromatic nitroolefins has been developed, which is particularly interesting because neither CALB nor acetamide can independently catalyze the reaction to any appreciable extent. This co‐catalyst system was applicable to the Michael additions of cyclic and acyclic ketones to a series of aromatic
trifunctional catalyst was successfully prepared by bonding (1R,2R)-(+)-1,2-DPEN to sulfonic acidresin. The catalyst was characterized by elemental analysis, thermogravimetric (TG) analysis and infrared (IR) spectroscopy. The results indicated the coexistence of sulfonic, sulfonamido and primary amino groups on the surface of the resin. Based on the IR spectroscopy of the catalyst treated with a solution
l-Proline derived triamine as a highly stereoselective organocatalyst for asymmetric Michael addition of cyclohexanone to nitroolefins
作者:Haibin Chen、Yu Wang、Siyu Wei、Jian Sun
DOI:10.1016/j.tetasy.2007.05.035
日期:2007.6
triamine 4 has been developed as a highly efficient and stereoselective organocatalyst for the asymmetric Michaeladdition of cyclohexanone to nitroolefins. In the presence of (CF3SO2)2NH, 4 catalyzed the reaction of cyclohexanone to a variety of nitroolefins with high yields (up to 99%) and excellent diastereoselectivities (up to 99:1 dr) and enantioselectivities (up to 98% ee).
脯氨酸衍生的三胺4已被开发为一种高效且立体选择性的有机催化剂,用于环己酮向硝基烯烃的不对称迈克尔加成反应。在(CF 3 SO 2)2 NH存在下,4催化环己酮与各种硝基烯烃的反应,产率高(高达99%),非对映选择性(高达99:1 dr)和对映选择性(高达98)。 %ee)。
Asymmetric Michael Addition Induced by the Anion of an Imidazolium Salt
作者:Vincent Gauchot、Julien Gravel、Andreea R. Schmitzer
DOI:10.1002/ejoc.201201068
日期:2012.11
We describe the application of a chiral catalytic imidazoliumsalt derived from trans-L-hydroxyproline, the anion being the catalytic entity, as a catalyst for the asymmetricMichaeladdition. We report the first example of a catalytic Michaeladdition using this type of catalyst, leading to excellent yields (up to 99 %) and good selectivities (up to 99:1 dr, up to 82 % ee).