4,4'-Disubstituted BINAPs for highly enantioselective Ru-catalyzed asymmetric hydrogenation of ketones.
A family of tunable precatalysts Ru(4,4'-BINAP)(chiral diamine)Cl2 was synthesized and used for highly enantioselective hydrogenation of aromatic ketones. This result differs from previous chiral diphosphines that rely on the bis(xylyl)phosphino groups to control enantioselectivity. An X-ray structural study reveals that the bulky substituents on the 4,4'-positions of BINAP can effectively create a suitable chiral pocket in the transition state and thus provide a new mechanism for the enantiocontrol in such a remarkable asymmetric catalytic process.
Department of Chemistry, CB#3290, University of North Carolina, Chapel Hill, North Carolina 27599, USA.
Aiguo
A
Hu
Helen L
HL
Ngo
Wenbin
W
Lin