The reactivity of propellane C−C bonds towards cerium(IV) ammonium nitrate (CAN) was studied utilizing photochemical initiation in acetonitrile. Synthetic as well as computational (B3LYP/6-311+G** and MP2/6-31G*) data strongly suggest that the activation of the C−C bonds in cyclopropane and cyclobutane derivatives involves NO3 radical attack on the hydrocarbon ring and does not proceed through single