Is there a radical intermediate in the (salen)Mn-catalyzed epoxidation of alkenes?

Article abstract of DOI:10.1002/anie.199717231

For the direct epoxidation of alkenes radical intermediates play no role. Instead investigations with the radical traps 1a-c indicate that manganaoxetane intermediates are present. Radicals can form from the latter, particularly in the case of sterically crowded oxetanes, by homolytic cleavage of the Mn-C bond.