Effective and recyclable dendritic catalysts for the direct asymmetric Michael addition of aldehydes to nitrostyrenes
作者:Yawen Li、Xin-Yuan Liu、Gang Zhao
DOI:10.1016/j.tetasy.2006.07.004
日期:2006.8
Direct catalytic enantio- and diastereoselective Michael addition reaction of aldehydes to nitrostyrenes is described using a series of recyclable chiral 2-trimethylsilanyloxy-methyl-pyrrolidine-based dendritic catalysts. Good yields (up to 82%), and high diastereoselectivities (up to syn/anti = 95/5) and enantioselectivities (up to 99% ee) have been obtained.
使用一系列可循环使用的手性2-三甲基甲硅烷基氧基-甲基-吡咯烷基树枝状催化剂描述了醛与硝基苯乙烯的直接催化对映和非对映选择性迈克尔加成反应。获得了良好的收率(高达82%),高的非对映选择性(高达syn / anti = 95/5)和对映选择性(高达99%ee)。
The Use ofN-Alkyl-2,2′-bipyrrolidine Derivatives as Organocatalysts for the Asymmetric Michael Addition of Ketones and Aldehydes to Nitroolefins
The direct Michaeladdition of aldehydes and ketones to nitroolefins, catalyzed by N-i-Pr-2,2′-bipyrrolidine, is described. The desired 1,4-adducts are obtained in excellent yields with enantioselectivities up to 95% ee and dr up to 95 : 5 of the syn aldehydeaddition product. An unexpected inversion of diastereoselectivity was observed for the addition of α-hydroxy ketones to β-arylnitroolefins with
New N-alkyl-3,3'-bimorpholine derivatives (iPBM) were revealed to be efficient organocatalysts for the asymmetric direct Michael addition of aldehydes to nitroolefins and a vinyl sulfone. In these transformations using iPBM, 1,4-adducts were afforded in high yields, with good to high levels of diastereo- and enantioselectivity. The stereochemical outcome of the reaction could be explained by an acyclic
Two chiral ammonium ionicliquids 1a and 1b have been newly synthesized from commercially available (+)-cis-2-benzamidocyclohexanecarboxylic acid. These CILs have been demonstrated to be efficient organocatalysts for asymmetric Michaeladdition of aldehydes to nitroolefins with excellent yields (up to 99%), high enantioselectivities (up to 90%) and modest to high diastereoselectivities (syn/anti ratio
Diamine-Catalyzed Asymmetric Michael Additions of Aldehydes and Ketones to Nitrostyrene
作者:Alexandre Alexakis、Olivier Andrey
DOI:10.1021/ol026543q
日期:2002.10.1
[reaction: see text] The direct Michaeladdition of aldehydes and ketones to nitrostyrene, catalyzed by N-i-Pr-2,2'-bipyrrolidine, is described. The desired 1,4-adducts are obtained in excellent yield with enantioselectivities up to 85% ee and dr up to 95:5 of the syn product.