Radical addition of ethers to alkenes under dioxygen catalyzed by N-hydroxyphthalimide (NHPI)/Co(OAc)2

The reaction of various ethers with alkenes bearing an electron-withdrawing substituent in the presence of N-hydroxyphthalimide combined with Co(OAc)2 under dioxygen produced the corresponding adducts in which oxygen is incorporated to alkenes in good yields. Oxcetane, furan and pyrane smoothly added to ethyl fumarate even at room temperature to give coupling products in high yields. An acyclic ether like dibutyl ether also added to fumarate under mild conditions to give a hydroxylated adduct in satisfactory selectivity.