Rhodium-Catalyzed Asymmetric Hydrogenation and Transfer Hydrogenation of α-Nitro Ketones.

A catalytic protocol for the enantioselective hydrogenation and transfer hydrogenation of α-nitro ketones was developed, providing a wide range of β-nitro-α-phenylethanols with high yields and excellent enantioselectivities (up to 98% yield and up to >99.9% ee). Compatibility with a wide range of solvents and bases demonstrates the robustness of this reaction. The synthetic potential of the protocol was demonstrated by the high TON experiment as well as the application in the synthesis of key intermediates of mirabegron (S/C = 10,000, 95% yield, 99% ee).