Manganese-Catalyzed Asymmetric Hydrogenation of Quinolines Enabled by pi–pi Interaction
The first example of non-noble metal-catalyzed asymmetric hydrogenation of aromatic N-heterocycles is reported. A new chiral pincer manganese catalyst showed outstanding catalytic activity in the asymmetric hydrogenation of a wide range of quinolines, affording high yields and excellent enantioselectivities (up to 97% ee). A turnover number of 3840 was reached at a low catalyst loading (S/C=4000), which was competitive with the activity of most effective noble metal catalysts for this reaction. The precise regulation of the enantioselectivity were ensured by a p–p interaction.