Serial cyclic endoperoxides

The presence of a double bond two carbons away from the peroxyl radical enables attack of the peroxyl radical on this double bond to form an endoperoxide and a carbon-centered radical [11-13]. The 1,2-dioxolanyl radical generated by 5-exo cycliza-tion is a key intermediate in the formation of secondary products such as serial cyclic endoperoxides, isoprostanes, and diepoxides. 

The 1,2-dioxolanyl radical can react with a second molecnle of oxygen. If an additional double bond is present in the appropriate position, the resulting peroxyl radical can once again react with this double bond giving rise to serial cyclic endoperoxides [14-16],... 

---