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
4-Aminothioureaprolinal dithioacetal 4a is a highlyefficientcatalyst for the asymmetric Michaeladdition of ketones and aldehydes to nitroolefins requiring only 3 mol-% catalyst loading. The reactions proceeded smoothly and gave syn selective adducts with excellent yields (up to 98 % yield), diastereoselectivity (up to >99:1 dr), and enantioselectivity (up to 99 % ee) under solvent free conditions
C3-Symmetric Proline-Functionalized Organocatalysts: Enantioselective Michael Addition Reactions
作者:Jarugu Narasimha Moorthy、Satyajit Saha
DOI:10.1002/ejoc.201000569
日期:2010.11
C 3 -Symmetric, tripodal catalyst 4 based on 1,3,5-triethylbenzene, which incorporates the features of a molecular receptor, is shown to catalyze Michaeladditionreactions of carbonyl compounds to β-nitrostyrenes in a high stereoselectivity (up to 99:1 dr and up to 98 % ee).
基于 1,3,5-三乙苯的 C 3 -对称三足催化剂 4 结合了分子受体的特征,显示出以高立体选择性(高达 99: 1 dr 和高达 98 % ee)。
Prolinal dithioacetals: Highly efficient organocatalysts for the direct nitro-Michael additions in both organic and aqueous media
Some novel prolinal dithioacetal derivatives have been synthesized and applied as the organocatalysts for the direct Michaeladdition of ketones and aldehydes to nitroalkenes. High enantioselectivities and diastereoselectivities have been obtained in both organic and aqueous media (dichloromethane, water, or brine).
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)。