Diastereoselective and Enantioselective Epoxidation of Acyclic β-Trifluoromethyl-β,β-Disubstituted Enones by Hydrogen Peroxide with a Pentafluorinated Quinidine-Derived Phase-Transfer Catalyst

An efficient catalytic asymmetric epoxidation of -trifluoromethyl-,-disubstituted unsaturated ketones has been achieved by a pentafluorine-substituted phase-transfer catalyst with hydrogen peroxide (30%). dr) and excellent enantioselectivities (up to 99.7% ee). Low catalyst loading, recycle of catalyst, environmentally benign oxidant and easy transformation of the epoxides into medicinally important trifluoromethylated intermediate make our protocol much more practical.