As far as SWiM remembers, O
3 is active on olefins as isosafrol, where it oxidizes the propenyl pi-bond and converts the propenylbenzene analogue to its benzaldehyde derivative (i.e. isosafrole -> piperonal).
Stability of the methylenedioxybridge: be sure to keep it away from Lewis bases as AlX
3 (X=Cl, Br, I) and all those other stuff that can be used for the O-demethylation of methoxybenzene derivatives (such as vanillin, isoeugenol etc). Don't have the exact references and patents handy, but SWiM remembers they are used for the synthesis of 3,4-dimethoxybenzaldehyde and 3,4-dimethoxyphenylpropene from piperonal and (iso)safrole respectively.
Doped(TM) since 19.... euhm... a long time