Ozonolysis of (alkenyldioxy) cyclododecyl hydroperoxides in trifluoroethanol gave a separable mixture of the corresponding α-hydroperoxy-and α-hydroxy-substituted spiro- tetraoxacycloalkanes with ring sizes in the range 7–12. Dehydration of the hydroperoxides or oxidation of the hydroxy-compounds afforded the corresponding peroxylactones. The solid-state structure of 1, 2, 6, 7-tetraoxaspiro [7.11] nonadecan-3-one was determined by ...