Helical peptide foldamer catalyzed Michael addition reactions of nitroalkane or dialkyl malonate to α,β-unsaturated ketones are reported along with the mechanistic considerations of the enantio-induction. A wide variety of α,β-unsaturated ketones, including β-aryl, β-alkyl enones, and cyclic enones, were found to be catalyzed by the helical peptide to give Michael adducts with high enantioselectivities
Based on different chiral diamine skeletons, a series of bifunctional primary amine-thiophosphoramides were synthesized and screened as the catalysts for the asymmetric Michael addition of acetone to both aromatic and aliphatic nitroolefins. Under the catalysis of a thiophosphoramide derived from 1,2-diphenylethane-1,2-diamine, the corresponding adducts were obtained in high yields (up to >99%) with
A series of bifunctional primary amine-thiophosphoramides were synthesized, which proven to be effective organocatalysts for the asymmetric Michael reaction of acetone to both aryl and alkyl nitro olefins in the presence of phenol as a protic additive. The corresponding adducts were obtained in excellent chemical yields (up to >99 %) with excellent enantioselectivities (up to 97 % ee).
Enantioselective Organocatalytic Michael Addition of Aliphatic Ketones to Nitrodienes
作者:Tianxiong He、Xin-Yan Wu
DOI:10.1080/00397911.2010.529227
日期:2012.3.1
Abstract A highly enantioselectiveMichaeladdition of aliphatic ketones to nitrodienes has been achieved that is catalyzed by readily available chiral thioureas derived from (1R,2R)-diphenylethane-1,2-diamine. Treatment of ketones with nitrodienes in the presence of 10 mol% thiourea 1a and 10 mol% benzoic acid in toluene provided the desired Michael adducts with excellent enantioselectivities (up to 99%
Highly Enantioselective Michael Addition of Aromatic Ketones to Nitrodienes and the Application to the Synthesis of Chiral γ-Aminobutyric Acid
作者:Xin-Yan Wu、Xing-Tao Guo、Feng Sha
DOI:10.1055/s-0036-1588604
日期:——
oic acid. A highly enantioselective Michaeladdition of aromatic ketones to α,β,γ,δ-unsaturated nitro compounds is described. In the presence of a chiral primary amine-thiourea based on dehydroabietic amine, γ-nitro ketones were obtained in excellent enantioselectivities (up to 95% ee) with up to 95% yield. In addition, this methodology has been successfully applied in the asymmetric synthesis of chiral