Epoxidation is one of the most fundamental and important reactions in organic synthesis.1 Various methods have been de- veloped and exploited, and the search for new environmentally friendly methods using molecular oxygen (O2) as the sole oxi- dant has attracted much interest. However, there have been few reports concerning the epoxidation of alkenes using 1atm of O2 without the use of reducing reagents.2 Montmorillonites (monts) of smectite clays are ...