Polymer-Supported Enantioselective Bifunctional Catalysts for Nitro-Michael Addition of Ketones and Aldehydes
作者:Lital Tuchman-Shukron、Scott J. Miller、Moshe Portnoy
DOI:10.1002/chem.201102474
日期:2012.2.20
L‐amino acid as a spacer and a urea‐forming moiety in a polymer‐supported bifunctional urea–primary amine catalyst, based on (1R, 2R)‐(+)‐1,2‐diphenylethylenediamine, significantly improves the catalyst’s activity and stereoselectivity in the asymmetric addition of ketones and aldehydes to nitroolefins. Yields and enantioselectivities, unprecedented for immobilized catalysts, were obtained with such challenging
Highly enantioselective Michael addition of acetone to nitroolefins catalyzed by chiral bifunctional primary amine-thiourea catalysts with acetic acid
作者:Qing Gu、Xing-Tao Guo、Xin-Yan Wu
DOI:10.1016/j.tet.2009.04.087
日期:2009.7
Highlyenantioselective Michael reaction of acetone with a variety of nitroolefins catalyzed by N-[(1R,2R)-2-aminocyclohexyl]-N′-(2,3,4,6-tetra-O-acetyl-β-d-glucopyranosyl)-thiourea (1b) together with acetic acid is described. The Michael addition products were obtained in high yields (76–94%) and up to 96% ee.
N -[(1 R,2 R)-2-氨基环己基] -N '-(2,3,4,6-四-O-乙酰基-β- d催化的丙酮与多种硝基烯烃的高度对映选择性迈克尔反应描述了-吡喃葡萄糖基)-硫脲(1b)与乙酸。迈克尔加成产物的收率很高(76-94%),ee最高可达96%。
Highly Efficient Amine Organocatalysts Based on Bispidine for the Asymmetric Michael Addition of Ketones to Nitroolefins
作者:Zhigang Yang、Jie Liu、Xiaohua Liu、Zhen Wang、Xiaoming Feng、Zhishan Su、Changwei Hu
DOI:10.1002/adsc.200800341
日期:2008.9.5
highly diastereoselective and enantioselective Michael addition of cyclohexanone, acetone and other ketones to nitroolefins was developed by the use of an amine organocatalyst based on bispidine. Additionally, a theoretical study of transition structures revealed that this bispidine-based primary-secondary amine catalyst could serve through an enamine intermediate and H-bond interaction, which was
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).