Design of Efficient Ketone Catalysts for Epoxidation by Using the Field Effect

By using the field effect (through-space charge-dipole or dipole−dipole interactions), efficient ketone catalysts 7 and 10 were developed for in situ epoxidation of olefins with Oxone. With either ketone 7 (10−20 mol %) or 10 (5−10 mol %) as catalyst, epoxidation of various olefins (2 mmol scale) at room temperature with 1.5 equiv of Oxone was complete in a short period of time with excellent isolated yields of epoxides (80−97%) and good ketone recovery (∼80%). Furthermore, the in situ epoxidation of olefins can be performed on a large scale (20−100 mmol) directly with 5 mol % of commercially available tetrahydrothiopyran-4-one, which is oxidized by Oxone to ketone 10 during the epoxidation reactions.