An Efficient and Practical Method for the Enantioselective Synthesis of Tertiary Trifluoromethyl Carbinols

An efficient sulfinamide/olefin based chiral ligand, MetSulfolefin, has been developed for the enantioselective rhodium-catalysed addition of aryl-boronic acids to trifluoromethyl ketones. This shelf-stable ligand is insensitive to air, oxygen and moisture, and it is obtained in only two high yielding steps from cheap commercially available (R)-tert-butanesulfinamide. The new ligand tolerates the use of hindered boronic acids and leads to the formation of a series of chiral trifluoromethyl-substituted tertiary carbinols in high yields and excellent enantioselectivities (up to >99% ee). (Figure presented.).