Adducts from the radical addition of xanthates to ethyl vinyl sulfide readily undergo elimination of the xanthate group upon thermolysis to give vinylic and/or allylic sulfides, depending on the structure. In the case of α-xanthyl ketones, the adducts are converted into α-keto vinyl carbinols by rearrangement of the sulfoxides derived from the vinylic and allylic sulfides.