Cycloalkanones are easily converted into aryl-substituted cyclic alkenes by the addition of an arylGrignard reagent followed by dehydration. These alkenes are good substrates for asymmetricepoxidation. We have found that the addition of allylic and benzylic Grignard reagents can occurpreferentially at the benzylic position of the derived epoxides to give the quaternary stereogeniccenter. This approach led to a short synthesis of the nanomolar serotonin re-uptake inhibitor (−)-mesembrine.