The first examples of the synthesis of 1, 3-dienyl sulfoxides by Heck reactions are described. Both racemic and enantiomerically pure exocyclic 1-p-tolylsulfinyl-1, 3-dienes 1 are readily prepared by the intramolecular Heck reaction of their corresponding vinyl iodides in the presence of Pd (OAc) 2 as catalyst and Ag2CO3 as base.