Dienophilic behavior of (S)-2-p-tolylsulfinyl butenolide☆

Abstract The study of the reactions of (S)-2-p-tolylsulfinyl butenolide ( 2 ) with cyclic and acyclic dienes is reported. The reactivity and stereoselectivity of this dienophile is compared with those of (S)-2- p -tolylsulfinyl cyclopentenone ( 3 ) in order to obtain information about the stereochemical models so far proposed.