Synthesis of New Chiral Aryl Diphosphite Ligands Derived from Pyranoside Backbone of Monosacharides and Their Application in Copper-Catalyzed Asymmetric Conjugate Addition of Diethylzinc to Cyclic Enones
作者:Lailai Wang、Yue-Ming Li、Chiu-wing Yip、Liqin Qiu、Zhongyuan Zhou、Albert S. C. Chan
DOI:10.1002/adsc.200404053
日期:2004.7
New chiral aryl diphosphite ligands based on the pyranoside backbones of glucose and galactose were prepared. These ligands were tested in the Cu-catalyzed asymmetricconjugateaddition of diethylzinc to cyclic enones with up to 88% ee. The stereoselectivity was found to be dependent on the ring size of the substrate as well as the ligand and copper source. The enantioselectivity depends on the absolute