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
4-Fluoro and 4-Hydroxy Pyrrolidine-thioxotetrahydropyrimidinones: Organocatalysts for Green Asymmetric Transformations in Brine
作者:Nikolaos Kaplaneris、Giorgos Koutoulogenis、Marianna Raftopoulou、Christoforos G. Kokotos
DOI:10.1021/acs.joc.5b00283
日期:2015.6.5
The synthesis of both trans- and cis-diastereomers of pyrrolidinine-thioxotetrahydropyrimidinone bearing either a fluorine or a hydroxyl group was accomplished. The new compounds were tested for their catalytic properties in a variety of asymmetric organic transformations and compared with the first generation catalyst. It was found that the new catalysts could efficiently catalyze the reactions in
4-Trifluoromethanesulfonamidyl prolinol tert-butyldiphenylsilyl ether as a highly efficient bifunctional organocatalyst for Michael addition of ketones and aldehydes to nitroolefins
作者:Chao Wang、Chun Yu、Changlu Liu、Yungui Peng
DOI:10.1016/j.tetlet.2009.02.211
日期:2009.5
4-Trifluoromethanesulfonamidyl prolinol tert-butyldiphenylsilyl ether bifunctionalorganocatalyst 3a is a highly efficient catalyst for the asymmetric Michaeladdition reactions of ketones and aldehydes to nitrostyrenes, leading to syn-selective adducts with excellent yields (>99%), high diastereoselectivities (up to 99:1 dr) and excellent enantioselectivities (up to 99% ee). Control experiments suggested that the
l-Prolinal Dithioacetal: A Highly Effective Organocatalyst for the Direct Nitro-Michael Addition to Selected Cyclic and Aromatic Ketones
作者:Piotr Pomarański、Zbigniew Czarnocki
DOI:10.1055/s-0037-1611531
日期:2019.9
trans-β-nitrostyrenes. Also, the first asymmetric syntheses of selected 2-methyl-4-nitro-1,3-diphenylbutan-1-one derivatives by application of the obtained organocatalyst is presented. The synthesis of novel l-prolinal dithioacetal and its application as an organocatalyst for the direct Michael addition of cyclic ketones and acetophenone derivatives to trans-β-nitrostyrene and related compounds is described
Based on the electrostatic adsorption between acidic resins and organocatalysts, a series of resin-supported chiral organocatalysts were designed and synthesized. They were evaluated for the asymmetric Michael addition of cyclohexanone with nitrostyrene, in which, catalyst 3 (Fig. 1) exhibited the best catalytic performance. This reaction proceeded under catalyst 3 smoothly at room temperature without