N-Sulfanylimides as the Sulfur Source for Alkyl Allenyl Sulfoxides via [2,3]-Sigmatropic Rearrangement

Sulfenyl chlorides are a reliable starting material to access allenyl sulfoxides with aryl or haloalkyl groups by way of sulfenate ester formation followed by [2,3]-sigmatropic rearrangement. Application of the chemistry of alkanesulfenyl chlorides is much less common due to competing fates along the reaction pathway. In this paper, N-sulfanylsuccimides (thiosuccinimides) are shown to be a viable replacement for sulfenyl chlorides. A number of allenyl alkyl sulfoxides are prepared in fair to good yields (21-73 %, 21 examples). In addition, some butyn-1,4-diols can be selectively monofunctionalized to form allenyl sulfoxides (26-71 %) with a hydroxyalkyl group geminal to the sulfur. Butynediols also permit synthetic access to dienes via successive sulfenate ester formation and [2,3]-sigmatropic rearrangement reactions. N-2-Trimethylsilylethylthosucinimides were among the highest yielding of the thioimides.