Highly enantio- and diastereoselective Michael addition of cyclohexanone to nitroolefins catalyzed by a chiral glucose-based bifunctional secondary amine-thiourea catalyst
A novel bifunctional thiourea bearing a saccharide-scaffold and a secondary amino group was synthesized, and was proven to be an effective organocatalyst for the asymmetric Michael reaction of cyclohexanone to both aryl and alkyl nitroolefins. The corresponding adducts were obtained with excellent diastereo- (up to >99/1 dr) and enantioselectivities (up to 97% ee).
An Ionic Liquid Containing L-Proline Moiety as Highly Efficient and Recyclable Chiral Organocatalyst for Michael Addition
作者:Jiang Li、Xia Bing Li、Sha Sha Ma、Juan Liu、Ben Hao Li、Bao Lin Li
DOI:10.1002/bkcs.10848
日期:2016.8
A novel chiral ionic liquid containing proline moiety was synthesized. It can be used as a highlyefficient and recyclable chiral organocatalyst for Michaeladdition of cyclohexanone with (E)‐β‐nitroalkenes in methanol at room temperature. The Michaeladdition affords the corresponding products in satisfactory yields of isolated products (78–98%) with high diastereoselectivities and excellent enantioselectivities
Highly enantioselective Michael addition reactions in water catalyzed by an insoluble MPS-supported 4-sulfonamidyl prolinol tert-butyldiphenylsilyl ether
作者:Yongming Chuan、Guihua Chen、Yungui Peng
DOI:10.1016/j.tetlet.2009.04.011
日期:2009.6
The development of a highly efficient, insoluble, and non-swelling MPS-supported organocatalyst for the direct asymmetric Michael reaction of ketones and aldehydes to nitrostyrenes at room temperature in water is described. Excellent yields (up to 100%) and high stereoselectivities (up to 94% dr and 93% ee) were achieved with 10 mol % of the catalyst. The resin-bound catalyst was simply separated and
An efficient asymmetricMichaeladdition of cyclic ketones to β-nitrostyrenes using secondary diamine as an organocatalyst derived from l-proline and (R)-α-methylbenzyl amine has been described. This pyrrolidine based catalyst 1 was found to be very effective to synthesize various γ-nitrocarbonyl compounds in good yield (up to 81%) with excellent stereoselectivity (up to >99:1 dr and >99% ee).
Organocatalyzed asymmetric Michael addition by an efficient bifunctional carbohydrate–thiourea hybrid with mechanistic DFT analysis
作者:Chandra S. Azad、Imran A. Khan、Anudeep K. Narula
DOI:10.1039/c6ob02158a
日期:——
core scaffold were synthesized and examined as catalysts for the asymmetricMichael addition reaction of aryl/alkyl trans-β-nitrostyrenes over cyclohexanone and other Michael donors having active methylene. Excellent enantioselectivities (<95%), diastereoselectivities (<99%), and yields (<99%) were attained undersolvent free conditions using 10 mol% of 1d0. The obtained results were explained through