(3R)-3-farnesyl-6-hydroxy-2,3,5-trimethyl-4-oxocyclohexa-1,5-diene-1-carboxylate + 2-oxoglutarate + O2 = (3R)-[(10S)-11-epoxyfarnesyl]-2,3,5-trimethyl-6-oxido-4-oxocyclohexa-1,5-diene-1-carboxylate + succinate + CO2
(3r)-3-farnesyl-6-hydroxy-2,3,5-trimethyl-4-oxocyclohexa-1,5-diene-1-carboxylate + 2-oxoglutarate + o2 = (3r)-[(10s)-11-epoxyfarnesyl]-2,3,5-trimethyl-6-oxido-4-oxocyclohexa-1,5-diene-1-carboxylate + succinate + co2