SYNTHESIS OF CONJUGATED DIENES FROM PROPENE OR OTHER ALKENES BY THE ENE-TYPE REACTION OF THIONIUM IONS

The known ene-type addition of thionium ions to alkenes has now been applied to the synthesis of homoallylic sulfides, from thionium ions RHC = S+Ar (R = alkyl, Ar = 4-chlorophenyl) and propene or other unactivated alkenes. Oxidation and thermal dehydrosulfenylation then lead to conjugated dienes. Because the reaction conditions are compatible with many functional groups, this method is simple and useful.