Hydroperoxide and Endoperoxide Lactones from Photooxygenation of 3-Alkylidenedihydrofuran-2,4-diones
摘要:
3-Alkylidenedihydrofuran-2,4-diones 1 can be photooxygenated with O-2/TBHP to hydroperoxides 3 which slowly decompose to diols 5. Stable endoperoxides 4 are best prepared by photooxygenation of 1 with 2 equiv of O-2 in the presence of CuSO4 and p-TosOH following a nonradical mechanism. They are rapidly reduced by anhydrous FeBr2 to give butenolide 9 indicating a potential antimalarial activity.
Oxidations of 3-alkenyltetronic acids with dimethyldioxirane (DMD) and air: regioselectivity and formation of a spirotricyclic hemiketal endoperoxide lactone