Reaction of enolates derived from esters and ketones to an easily prepared alkylidene [1, 3] dithiane-1, 3-dioxide afforded the respective adducts with good yields and selectivities generally exceeding 85: 15. The base used for enolate addition played no significant role for the reaction outcome, and addition of a silyl enole ether gave similar results. The thus formed oxygenated S, S-acetals were transformed into the corresponding 1, 4-dicarbonyls ...