Expeditious and Efficient ortho‐Selective Trifluoromethane‐sulfonylation of Arylhydroxylamines

A metal‐ and oxidant‐free, practical and efficient method for the synthesis of highly versatile and synthetically useful ortho‐trifluoromethanesulfonylated anilines from arylhydroxylamines and trifluoromethanesulfinic chloride was developed. This rapid transformation proceeded smoothly with good yields and excellent ortho‐selectivity in the absence of any metals or ligands. Mechanistically, the reaction comprised a noncanonical O‐trifluoromethanesulfinylation of the arylhydroxylamine, and the subsequent [2,3]‐sigmatropic rearrangement to afford ortho‐trifluoromethanesulfonylated aniline derivatives. The practical application of this reaction was demonstrated by further conversion into a series of functional molecules under different reaction conditions. A rapid, practical, efficient and broad‐spectrum method for the synthesis of highly versatile and synthetically useful ortho‐trifluoromethanesulfonylated anilines from N‐arylhydroxylamines and trifluoromethanesulfinic chloride is described.