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-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
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
The carbamate esters as organocatalysts in asymmetric Michael addition reactions in aqueous media: when pyrrolidine backbone surpasses 1,2-diaminocyclohexane
作者:Anirban Mondal、Kartick C. Bhowmick
DOI:10.24820/ark.5550190.p010.692
日期:——
isobutyl ester has been synthesized. The newly developed pyrrolidine ring containing carbamate ester surpassed 1,2diaminocyclohexane derived carbamate ester in asymmetric Michael addition reactions in aqueousmedia providing Michael products with yields (up to 97%), syn diastereoselectivities (up to 97%) and enantioselectivities (up to 94%).
An efficient and novel organocatalyst has been developed for the asymmetric desymmetrization of meso- and prochiral ketones by directMichaeladdition to nitroolefins. This strategy can afford the desymmetrization products with excellent diastereo- (up to >99:1) and enantioselectivity (up to 96%) in great yields (up to 95%).