Development of Chiral (<i>S</i>)-Prolinol-Derived Ligands for Palladium-Catalyzed Asymmetric Allylic Alkylation: Effect of a Siloxymethyl Group on the Pyrrolidine Backbone
A series of novel chiral aminophosphine ligands are designed and readily prepared from (S)-prolinol. The reactivity and selectivity in the palladium-catalyzedasymmetricallylicalkylation of 1,3-diphenyl-2-propenyl acetate with a dimethyl malonate−BSA−LiOAc system using these chiral ligands are evaluated, and the structural elucidation of ligands and palladium complex is also conducted. Moreover,
Palladium-catalyzedasymmetricallylicalkylation of 1,3-diphenyl-2-propenyl acetate (4) with a dimethyl malonate-BSA-LiOAc system has been successfully carried out in the presence of a new chiral prolinol-derived aminophosphine ligand (3e) in good yield with good enantioselectivity (up to 96% ee).