Direct Synthesis of Sulfinylated Benzofulvenes via BF·EtO-Promoted Cascade Reactions of Arylsulfinic Acids with 1,3-Enynes.

A novel and efficient method for the selective synthesis of sulfinylated benzofulvenes has been developed through the BF·EtO-promoted electrophilic addition/cyclization of 1,3-enynes. This metal-free cascade reaction employs readily accessible arylsulfinic acids as sulfinyl cation sources at room temperature and provides a wide range of functionalized benzofulvenes in good to excellent yields under mild conditions.