In our search for new antimalarial agents inspired by natural products, we describe herein the synthesis, the evaluation of in vitro antiplasmodial activity, and the SARstudies for a series of endoperoxide antimalarials based on the plakortin scaffold. These simplified analogues are characterized by: (i) a 3,6-dihydro-1,2-dioxin ring or a 1,2-dioxane ring disubstituted at C-4 and C-5; (ii) a pentyl