The Development of Double Axially Chiral Phosphoric Acids and Their Catalytic Transfer Hydrogenation of Quinolines

Abstract

Building a better scaffold: Low loadings (0.2–1 mol %) of new double axially chiral phosphoric acid catalysts 1 based on bis-binol scaffold were used for asymmetric transfer hydrogenation. 2-Aryl- and 2-alkyl-substituted quinolines gave tetrahydroquinolines in excellent yields and with up to 98 % ee and 2,3-disubstituted tetrahydroquinolines were prepared in high diastereo- and enantioselectivities (up to >20:1 and 92 % ee).