A Sulfenylation Reaction: Direct Synthesis of 3-Arylsulfinylindoles from Arylsulfinic Acids and Indoles in Water

A novel and efficient electrophilic sulfenylation of indoles with arylsulfinic acids is realized. The reaction utilizes readily available starting materials in water under catalyst- and additive-free conditions, providing an alternative and attractive approach to 3-arylsulfinylindoles with high yields. Preliminary mechanistic investigation suggested that the reaction is through an electrophilic substitution process.