Enantioselective Synthesis of Polycyclic γ-Lactams with Multiple Chiral Carbon Centers via Ni(0)-Catalyzed Asymmetric Carbonylative Cycloadditions without Stirring
作者:Keita Ashida、Yoichi Hoshimoto、Norimitsu Tohnai、David E. Scott、Masato Ohashi、Hanae Imaizumi、Yuichiro Tsuchiya、Sensuke Ogoshi
DOI:10.1021/jacs.9b12493
日期:2020.1.22
GR-24, a racemic variant of which is a potential seedgermination stimulator and plant-growth regulator. A key of the procedure presented here is a nickel(0)/chiral phosphoramidite-catalyzed asymmetric [2+2+1] carbonylative cycloaddition between readily accessible ene-imines and carbon monoxide, which proceeded enantioselectively to furnish up to 90% ee (>99% ee after recrystallization). The results
Two successive asymmetric reductive aminations (ARAs) have been merged into one reaction system to generate enantiopure C2-symmetric secondary amines. The iridium-phosphoramidite complex successfully manages the dual ARAs by using two distinctly different types of amine sources: an inorganic ammonium salt and an organic primary amine.