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).
Enantiodivergent Brucine Diol-Catalyzed 1,3-Dipolar Cycloaddition of Azomethine Ylides with α,β-Unsaturated Ketones
作者:Jian-Yuan Li、Hun Young Kim、Kyungsoo Oh
DOI:10.1002/adsc.201500958
日期:2016.3.17
Enantiodivergent catalyst systems were developed using metals with different ionic radii and a multifunctional brucine diol (BD) ligand. The catalytic use of purported 1:1 Cu‐BD complexes in the 1,3‐dipolar cycloaddition of azomethine ylides with chalcones resulted in the selective formation of endo‐pyrrolidines in 87–96% ees with an absolute stereochemical outcome of (2R,3S,4R,5S). In contrast, an
New Chiral Ferrocenyl P,S-Ligands for Highly Diastereo-/Enantioselective Catalytic [3 + 2] Cycloaddition of Azomethine Ylides with Cyclic and Acyclic Enones
developed and successfully applied in a highly endo-selective catalytic asymmetric cycloaddition of azomethine ylides with various enones, including cyclic and acyclic α-enones. For cyclic α-enones, a [Cu(CH3CN)4]ClO4/(Rc,SFc)-2f complex catalyzed the cycloaddition to give the sole endo-cycloadducts in perfect enantioselectivities (normally 99% ee), while an AgOAc/(Rc,SFc)-2f catalytic system exhibited good
Zn(ii)-catalyzed asymmetric [3 + 2] cycloaddition of acyclic enones with azomethine ylides
作者:Sundaravel Vivek Kumar、Jeremiah Olusegun、Patrick J. Guiry
DOI:10.1039/d4ob00854e
日期:——
The Zn(II)/UCD-Imphanol-catalyzed highly endo-selective [3 + 2] asymmetriccycloaddition of acyclic enones and azomethineylides has been developed. Moderate to high yields (up to 94%) with excellent endo/exo selectivities (99 : 1) and enantioselectivities up to 96.5 : 3.5 er were obtained.
开发了 Zn( II )/UCD-Imphanol 催化的无环烯酮和偶氮甲碱叶立德的高度内选择性 [3 + 2] 不对称环加成反应。获得了中等到高产率(高达 94%),具有出色的内切/外切选择性(99:1)和高达 96.5:3.5 er 的对映选择性。