Asymmetric Induction of the Iodolactonization Reaction of α-Sulfurated γ-Unsaturated Amides

The 1,3-asymmetric iodolactonization reaction of enantiopure α-sulfurated γ-unsaturated amides has been investigated. With sulfinyl and sulfonyl groups, a poorly stereoselective reaction was observed, whereas with a sulfanyl moiety, the diastereoselectivity can be high as 96:4. The role of the oxygen atom on the sulfur moiety is discussed.