New chiral ferrocenyl P,S-ligands for highly diastereo- and enantioselective Ag(I)-catalyzed asymmetric [3+2] cycloaddition of azomethine ylides
作者:Mei-Ling Han、Dao-Yong Wang、Pei-Wei Zeng、Zhuo Zheng、Xiang-Ping Hu
DOI:10.1016/j.tetasy.2012.02.017
日期:2012.2
A new family of chiral ferrocenyl P,S-ligands incorporating an indole ring at the alpha-ferrocenylmethyl position has been prepared via a Friedel-Crafts alkylation reaction of (R-c,S-Fc)-PPFA with a variety of 2-indole thioethers. These newly developed ferrocenyl P,S-ligands proved to be efficient in the AgOAc-catalyzed asymmetric [3+2] cycloaddition of azomethine ylides with various dipolarophiles, giving cycloadducts with high diastereoselectivities and enantioselectivities (up to 99% ee). (C) 2012 Elsevier Ltd. All rights reserved.
Chiral ferrocenyl P,S-ligands for highly efficient copper-catalyzed asymmetric [3+2] cycloaddition of azomethine ylides
作者:Fu-Zhong Han、Sai-Bo Yu、Cheng Zhang、Xiang-Ping Hu
DOI:10.1016/j.tet.2015.01.003
日期:2016.5
on benzimidazole and imidazole backbones have been prepared from Ugi's amine through a three-step transformation. These ligands were successfully employed in the Cu-catalyzed asymmetric [3+2] cycloaddition of azomethineylides with various electron-deficient olefins, giving the corresponding cycloadducts in high endo-selectivities and excellent enantioselectivities (up to 99% ee).