Enantioselective Copper-Catalyzed Trifluoromethylation of Benzylic Radicals via Ring Opening of Cyclopropanols

Summary The asymmetric trifluoromethylation of aryl-substituted cyclopropanols via a radical ring-opening pathway is reported herein, which provides an easy and straightforward access to structurally diverse β-CF3 ketones in good yields and excellent enantioselectivities under very mild conditions. Critical to the success of the copper-catalyzed radical relay is that a benzylic radical intermediate can be enantioselectively trapped by reactive (L∗)CuIICF3. In addition, a novel quinolinyl-containing bisoxazoline ligand plays a significant role in the asymmetric trifluoromethylation.