Radical Addition of Thiols to Oxa(aza)bicyclic Alkenes in Water

Abstract An air‐promoted radical addition reaction of various thiols to oxa(aza)bicyclic alkenes is reported, leading to the corresponding exo adducts in good to excellent yields (up to 99%) in water without the use of any metal catalyst, photoredox catalyst or radical initiator reagent under mild conditions. The reaction has a wide scopeof oxa(aza)bicyclic alkenes and thiols, which provides an easy and clean way for the direct preparation of thioethers. A proposed mechanism of an exo free radical attacking the double bond of an oxa(aza)bicyclic alkene was investigated by DFT calculations of stepwise reaction pathways and control experiments.