Abstract
Epoxidation of olefins was successfully achieved using molecular oxygen in the presence of an aldehyde and a catalytic amount of CuCl2 at room temperature. Hexanal was found to be a particularly good reducing agent for the CuCl2-catalyzed epoxidation. A good correlation was observed between the reactivity and the calculated ionization potential for some of the aldehydes tested. The present system was applied to epoxidation of a range of olefins in high to excellent yields.