Metal-free visible-light-promoted C(sp 3 )-H functionalization of aliphatic cyclic ethers using trace O 2 .

Presented is a light-promoted C-C bond forming reaction yielding sulfone and phosphate derivatives at room temperature in the absence of metals or photoredox catalyst. This transformation proceeds in neat conditions through an auto-oxidation mechanism which is maintained through the leaching of trace amounts of O 2 as sole green oxidant.