A novel and recyclable catalyst, a C3-symmetrical cinchonine-squaramide, has been developed for the asymmetric Michaeladdition of 1,3-dicarbonylcompounds to nitroalkenes. When using only 1 mol% of catalyst 1a for the reaction, high reaction yields with excellent enantioselectivities and diastereoselectivities (up to 96% yield,>99% ee,>99:1 dr) were achieved, in which the results for cyclic keto esters
Ferrocene Analogues of Hydrogen-Bond-Donor Catalysts: An Investigative Study on Asymmetric Michael Addition of 1,3-Dicarbonyl Compounds to Nitroalkenes
作者:Rajiv Trivedi、Kadiyala Rao、M. Kantam
DOI:10.1055/s-0034-1379491
日期:——
moieties. A stepwise sequential route was used to assemble the various components of these ferrocene derivatives. The resulting bifunctional catalysts were used successfully in asymmetric Michael additions of 1,3-dicarbonylcompounds to β-nitrostyrenes. The corresponding products were obtained in high yields and in good to excellent enantioselectivities and diastereoselectivities under mild conditions by
Asymmetric Michael addition reactions catalyzed by calix[4]thiourea cyclohexanediamine derivatives
作者:Zheng-Yi Li、Hong-Xiao Tong、Yuan Chen、Hong-Kui Su、Tangxin Xiao、Xiao-Qiang Sun、Leyong Wang
DOI:10.3762/bjoc.14.164
日期:——
rim-functionalized calix[4]thiourea cyclohexanediamine derivatives have been designed, synthesized and used as catalysts for enantioselective Michael addition reactions between nitroolefins and acetylacetone. The optimal catalyst 2 with a mono-thiourea group exhibited good performance in the presence of water/toluene (v/v = 1:2). Under the optimal reaction conditions, high yields of up to 99% and moderate
Enantio- and Diastereoselective Asymmetric Addition of 1,3-Dicarbonyl Compounds to Nitroalkenes in a Doubly Stereocontrolled Manner Catalyzed by Bifunctional Rosin-Derived Amine Thiourea Catalysts
作者:Xianxing Jiang、Yifu Zhang、Xing Liu、Gen Zhang、Luhao Lai、Lipeng Wu、Jiannan Zhang、Rui Wang
DOI:10.1021/jo9009276
日期:2009.8.7
rosin-derived amine thiourea catalysts were designed and synthesized. The doubly stereocontrolled asymmetric addition of a variety of 1,3-dicarbonyl compounds to nitroalkenes was investigated. These rosin-derived chiral thioureas have been shown to serve as effective catalysts for this double-sterecontrolled organocatalytic process by the investigation of the efficacy of the thiourea catalysts in comparison with