Pyridine-Directed Asymmetric Hydrogenation of 1,1-Diarylalkenes.

Highly enantioselective pyridine-directed rhodium-catalyzed asymmetric hydrogenation of challenging 1,1-diarylalkenes is achieved by using [Rh(NBD)DuanPhos]BF4 as a precatalyst. Various types of 2-pyridine substituted 1,1-diarylalkenes could be hydrogenated with good to excellent enantioselectivities, which provide an efficient route to the synthesis of pharmaceutically and biologically active compounds containing a 2-pyridyl ethane unit.